Numerical Modeling of Adhesively Bonded Single-Side Strap Joints: Steel-to-Hybrid Sisal-Glass Reinforced HDPE Composite Debonding Under Fatigue Loading

Numerical Modeling of Adhesively Bonded Single-Side Strap Joints: Steel-to-Hybrid Sisal-Glass Reinforced HDPE Composite Debonding Under Fatigue Loading | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Numerical Modeling of Adhesively Bonded Single-Side Strap Joints: Steel-to-Hybrid Sisal-Glass Reinforced HDPE Composite Debonding Under Fatigue Loading Samuel Tesfaye Molla, Assefa Asmare Tsegaw, Teshome Mulatie Bogale, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7472044/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This study presents a numerical modeling approach for analyzing the debonding behavior of adhesively bonded single-side strap joints made of steel-to-hybrid sisal-glass reinforced HDPE composite under fatigue loading. The objective of the study is to investigate the fatigue-induced debonding behavior of adhesively bonded joint. Methods employed in this study are a cohesive zone model based finite element method employed to simulate the progressive damage and failure mechanisms at the adhesive interface. The study investigates the effects of key parameters, including adhesive thickness, cohesive fracture toughness, fiber-to-matrix weight ratio, temperature, and moisture exposure on fatigue life and damage progression. The numerical results are validated against experimental data and analytical solutions, demonstrating the model's accuracy in predicting fatigue-induced debonding. Sensitivity analyses are performed to assess the influence of varying material and geometric parameters on joint durability. The findings provide insight into optimizing adhesive joint design for automotive applications, particularly for lightweight composite structures. It is recommended that future research incorporate detailed experimental testing under fatigue loading to confirm the predictive accuracy of the FEM simulations and CZM approach. Adhesively bonded joints fatigue loading cohesive zone model finite element analysis debonding mechanics Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction Adhesively bonded joints (ABJ) have gained significant attention in structural applications due to their ability to distribute stress more uniformly compared to traditional mechanical fastening techniques (da Silva & Öchsner, 2008). In the automotive industry, the need for lightweight and high-strength materials has led to the development of hybrid composite-metal joints, particularly for side body panel applications (D’Amore et al., 2021). However, the long-term performance of these joints under fatigue loading remains a critical challenge due to interfacial degradation and adhesive failure mechanisms (Campilho et al., 2019).Hybrid sisal-glass reinforced HDPE composites offer an eco-friendly alternative with enhanced mechanical properties suitable for structural applications (Ramesh et al., 2020). When bonded to steel, the mechanical behavior of the adhesive layer becomes crucial, particularly in fatigue conditions where progressive damage accumulation can lead to debonding (Xu et al., 2017). Numerical modeling, especially through cohesive zone modeling (CZM)-based finite element analysis, has proven effective in predicting failure mechanisms in adhesively bonded joints (Pires et al., 2022). Existing studies have focused on static and quasi-static loading conditions of bonded joints; however, fewer works have comprehensively analyzed the fatigue response and debonding progression in steel-to-hybrid composite configurations (Arouche et al., 2020). Parameters such as adhesive thickness, cohesive fracture toughness, fiber-to-matrix ratio, temperature, and moisture exposure significantly influence fatigue life and structural integrity (Khoramishad et al., 2010). This study aims to bridge this gap by employing numerical simulations to predict the fatigue-induced debonding behavior of adhesively bonded single-side strap joints (ABSSSJ) involving steel and hybrid sisal-glass reinforced HDPE composite. The results will provide insights into optimizing adhesive joint design for improved durability in automotive applications. Background of the study are focused on, ABJ are commonly used in the manufacturing of automotive and aerospace structures due to their superior stress distribution and lightweight characteristics (da Silva & Öchsner, 2008). These joints are especially beneficial in hybrid materials, such as the combination of metals with natural fiber-reinforced composites like sisal-glass hybrid composites (Campilho et al., 2019). In particular, the use of Hybrid Sisal-Glass Reinforced HDPE (High-Density Polyethylene) composites has gained attention due to their cost-effectiveness, sustainability, and mechanical properties suitable for automotive applications (Ramesh et al., 2020). However, the structural integrity of these joints is highly dependent on the adhesive material used, which must withstand complex loading conditions, such as fatigue, in harsh environmental conditions. When subjected to fatigue loading, adhesive joints experience progressive damage accumulation at the interface, leading to debonding and potential failure of the structure (Khoramishad et al., 2010). This issue becomes critical in the context of automotive body panels, where durability and long-term performance are paramount. Consequently, understanding the fatigue behavior and debonding mechanisms of ABJ is essential to improve the design and lifespan of hybrid composite structures in automotive applications (D’Amore et al., 2021). Justifications of the study are, the increasing use of hybrid composite materials in the automotive industry necessitates a deeper understanding of the bonding behavior between metals and natural fiber composites. While static and quasi-static analyses of adhesive joints have been well-established, limited research exists on the fatigue performance of these joints, particularly in steel-to-composite configurations (Arouche et al., 2020). The use of cohesive zone models (CZM) integrated with finite element analysis (FEM) provides a powerful tool for simulating the complex damage and failure processes that occur under cyclic loading conditions (Pires et al., 2022). This approach allows for the prediction of failure initiation, crack propagation, and debonding progression within the adhesive layer, which are crucial factors influencing the longevity of the adhesive bond under fatigue conditions. By examining the fatigue response of adhesively bonded single-side strap joints (ABSSSJ) made of steel and hybrid sisal-glass reinforced HDPE composite, this study aims to fill a significant gap in the literature and contribute valuable insights for designing durable adhesive joints for automotive applications. Background Gap of the study,Despite the extensive research on adhesive joints, there is a noticeable gap in the understanding of fatigue-induced debonding in joints involving steel and hybrid natural fiber composites. Previous studies have focused mainly on static loading or quasi-static conditions, with limited emphasis on cyclic loading behavior and the associated damage evolution in hybrid composite-metal joints (Xu et al., 2017). Furthermore, the influence of key parameters such as adhesive thickness, cohesive fracture toughness, moisture exposure, and temperature effects on fatigue performance has not been thoroughly investigated. This study aims to address these gaps by employing numerical simulations based on cohesive zone modeling to analyze the debonding behavior of adhesive joints under fatigue loading. The objective is to provide a comprehensive understanding of the fatigue failure mechanisms, with a focus on the impact of material and geometric parameters on joint durability, thus enhancing the design and optimization of adhesive joints in lightweight automotive structures. The motivation behind this study arises from the growing demand for lightweight and durable materials in the automotive industry, particularly in the design of automobile body panels. Hybrid composites, such as the combination of natural fibers like sisal and glass with HDPE, have shown promise due to their favorable mechanical properties, cost-effectiveness, and environmental benefits (Ramesh et al., 2020). However, for these materials to be effectively utilized in automotive applications, the adhesive bonding between metal substrates (like steel) and hybrid composites must be thoroughly understood, especially under challenging operating conditions like fatigue loading. While ABJ have been widely used in automotive and aerospace structures, the complex behavior of these joints under cyclic loading, particularly the debonding mechanisms, remains underexplored. Most studies have focused on static or quasi-static loading conditions, with little attention given to the fatigue behavior of adhesive joints under real-world operational stress conditions. This study aims to fill this gap by conducting numerical simulations of adhesive bonded single-side strap joints (ABSSSJ) under fatigue loading, using advanced models like Cohesive Zone Modeling (CZM). The ultimate goal is to enhance the durability of adhesive joints and provide design guidelines for their implementation in lightweight automotive structures. The literature review presents an overview of the key literature related to the analysis of adhesive bonded joints, focusing on the fatigue behavior of steel-to-hybrid sisal-glass reinforced HDPE composites and the use of numerical methods such as Cohesive Zone Modeling (CZM) to predict debonding and failure under cyclic loading. Adhesive Bonding in Structural Joints, The adhesion between materials such as steel and composite materials, specifically hybrid sisal-glass reinforced HDPE, has been investigated in several studies due to the potential of this hybrid composite for automotive applications (Leal et al., 2020). These materials offer a good balance of mechanical properties, such as high strength and stiffness, along with relatively low density. Fatigue Behavior of Adhesive Bonded Joints, Several studies has investigated the effects of cyclic loading on the mechanical integrity of adhesive joints (Ferrante et al., 2018). The fatigue behavior of adhesive joints is complex, often involving a combination of adhesive failure, cohesive failure, and interface debonding (Vazquez et al., 2019). Previous studies suggest that adhesive thickness, the quality of the bonding interface, and material properties significantly influence fatigue resistance. The development of fatigue crack growth models for adhesive joints under cyclic loading is essential for predicting the lifespan of these joints (Li et al., 2021). Cohesive Zone Modeling (CZM) in Adhesive Joint Analysis , It involves defining a cohesive law that describes the relationship between the traction (stress) and separation (displacement) at the interface between two adherends (Xu and Needleman, 2016).The use of CZM enables the prediction of damage initiation and growth in adhesive joints, which is particularly important in the design of joints subjected to cyclic loading (Tvergaard and Hutchinson, 2020). Studies have shown that CZM can accurately simulate the initiation of cracks and the subsequent propagation through the adhesive layer, providing valuable insights into the failure mechanisms (Wang et al., 2022). Fatigue Analysis of Composite Adhesive Joints, Research has shown that the mechanical properties of these composites, such as their strength, stiffness, and fatigue resistance, can be influenced by factors such as the fiber-to-matrix ratio and the orientation of fibers (Gonçalves et al., 2019). These studies are essential for understanding how the hybrid composite material behaves under fatigue conditions and for optimizing adhesive joint designs for improved performance and longevity (Mahamid et al., 2018). Numerical Simulation of Adhesive Bonding under Fatigue Loading,When combined with CZM, FEA simulations can capture the initiation and propagation of damage within the adhesive and the adherends (Ulm et al., 2020).The application of CZM to study fatigue loading in ABJ has proven to be a reliable method for simulating damage evolution, predicting failure modes, and assessing the durability of adhesive bonds under real-world loading conditions (Zhang et al., 2021). Gaps in Literature, while there is substantial research on adhesive bonding and fatigue analysis in adhesive joints, several gaps remain in the literature.One significant gap is the lack of comprehensive studies on the fatigue behavior of steel-to-hybrid composite adhesive joints, particularly involving materials such as sisal-glass reinforced HDPE. Additionally, the influence of environmental factors, such as temperature, humidity, and cyclic loading rates, on the long-term durability of these joints is not fully understood. Furthermore, while CZM has been widely used for static failure analysis, there is limited research applying CZM specifically for fatigue crack growth in adhesive joints. Finally as a Conclusion, the literature reveals that while significant progress has been made in understanding the mechanical behavior of adhesive joints, especially under static loading, there is a need for more focused research on the fatigue performance of adhesive bonded joints, particularly in composite materials. The use of numerical modeling techniques such as CZM offers a promising approach to simulate the complex behavior of adhesive joints under cyclic loading, including fatigue damage initiation and propagation. The research gap identified in the fatigue analysis of steel-to-hybrid sisal-glass reinforced HDPE composite adhesive joints under cyclic loading provides the foundation for the current study. Problem statements of the study focus on the automotive industry faces challenges in ensuring the reliability and durability of adhesively bonded joints, especially when subjected to cyclic loading conditions. Current research lacks comprehensive studies on the fatigue-induced debonding behavior of adhesive joints in hybrid composite-steel configurations, particularly with natural fiber composites like sisal-glass reinforced HDPE. Adhesive failure due to fatigue loading could significantly compromise the structural integrity and performance of automotive side body panels, leading to potential safety concerns. Furthermore, the influence of critical parameters such as adhesive thickness, cohesive fracture toughness, moisture exposure, and temperature effects on fatigue performance has not been fully understood. These gaps in knowledge hinder the optimization of adhesive joints for automotive applications, leading to suboptimal designs that may not meet the required performance standards. The main objectives of this study are: To investigate the fatigue-induced debonding behavior of adhesive joints in steel-to-hybrid sisal-glass reinforced HDPE composite configuration, To develop a numerical model based on Cohesive Zone Modeling (CZM) to simulate the initiation and propagation of debonding under cyclic loading conditions, To assess the effects of key parameters, such as adhesive thickness, cohesive fracture toughness, moisture exposure, and temperature variations, on the fatigue performance of the adhesive joints, and to provide insights into the impact of fatigue loading on the long-term durability and performance of adhesively bonded joints, specifically for automobile side body panel applications. This study answer the following Research Questions What is the effect of cyclic loading on the fatigue-induced debonding of adhesive joints in steel-to-hybrid sisal-glass reinforced HDPE composite ABSSSJs? How do critical factors such as adhesive thickness, cohesive fracture toughness, moisture exposure, and temperature affect the fatigue resistance of ABSSSJs? What are the dominant failure mechanisms (e.g., adhesive failure, cohesive failure, or mixed-mode failure) under fatigue loading conditions? 2. Method and Materials This section outlines the approach used to model the adhesive-bonded single-side strap joint (ABSSSJ) between steel and hybrid sisal-glass reinforced HDPE composite under fatigue loading using numerical techniques. 2.1 Finite Element Modeling (FEM) The analysis of the ABSSSJ was conducted using a 2D finite element model (FEM) implemented in ANSYS. The lower adherend (hybrid sisal-glass reinforced HDPE composite) was modeled using orthotropic shell elements (SHELL181), while the upper adherend (steel) was modeled with isotropic solid elements (SOLID185). The adhesive layer (Araldite 2020, Araldite 2015 and AV138) was modeled using cohesive zone elements (INTER202) to represent the interface between the two adherends. The material properties for the adhesive and adherends were selected based on the values obtained from literature and experimental data. 2.2 Cohesive Zone Model (CZM) A cohesive zone model (CZM) was used to simulate the debonding behavior at the adhesive interface. The interface properties, including the adhesive’s cohesive strength and fracture toughness, were defined using a bilinear traction-separation law. The model was calibrated to replicate both tensile and shear failure modes under fatigue loading conditions. 2.3 Fatigue Loading Conditions Fatigue loading was applied to the joint using cyclic loading conditions, where the load was varied between minimum and maximum values to simulate real-world fatigue behavior. The loading conditions were chosen to match typical operational conditions for automotive body panels, with stress ratios and frequencies defined based on experimental studies. The fatigue damage was modeled using the Paris law for crack growth under mixed-mode loading conditions. 2.4 Boundary Conditions and Simulation Setup The boundary conditions were applied to the FEM model to replicate the loading and support conditions for a typical adhesive-bonded joint under bending. Fixed supports were applied at the ends of the steel adherend, while cyclic loading was applied at the free end. The simulation was run under various loading cycles until failure was observed in the adhesive layer, with the crack propagation monitored at each step. 2.5 Post-Processing Stress and strain distributions across the adhesive thickness were analyzed at different load steps. The results from the simulation were post-processed to examine the stress concentration areas, fatigue crack initiation points, and failure modes. The results were compared with experimental data available in the literature to validate the model. 3. Results and Discussion 3.1 Stress Distribution The FEM simulation revealed significant stress concentrations in the adhesive layer, particularly at the edges of the adhesive bondline. The shear stress was found to be highest near the adhesive interface, especially in the region of the overlap. The stress distribution showed in Fig. 1 a gradual decrease across the adhesive thickness, with the maximum stress occurring at the steel-Hybrid sisals-Glass- HDPE composite interface. This observation is consistent with the findings of previous studies on adhesive joints under similar loading conditions. 3.2 Fatigue Behavior and Damage Evolution The fatigue simulation revealed that the debonding of the adhesive layer initiated at the center of the adhesive bondline and propagated outward in both shear and tensile directions indicated in figure 2 . The cohesive zone model accurately captured the damage evolution, with the damage initiation corresponding to regions of high stress concentrations. The results showed a significant difference in damage progression between the tensile and shear zones of the adhesive, highlighting the mixed-mode nature of the debonding process. (b) Higher stress contour of a debonding displacement The fatigue life of the adhesive joint was found to be influenced by the adhesive thickness shows in Fig. 3 varying adhesive thickness from 0.2-1.00mm CZM Based FEM simulation results graph plotted ABSSSJ using ANSYS, with thinner adhesive layers experiencing earlier failure due to higher stress concentrations. The analysis also showed that the hybrid composite's mechanical properties significantly affected the fatigue behavior, with the sisal-glass hybrid providing enhanced resistance to fatigue cracking. 3.3 Comparison with Experimental Results The results indicated in Fig. 4 from the CZM Based FEM simulations were compared with available experimental data for adhesive-bonded joints under similar fatigue conditions. The numerical results showed good agreement with experimental data in terms of stress distribution and failure location. Minor discrepancies were observed in the exact fatigue life, which could be attributed to the simplifications in the numerical model, such as the idealization of material properties and boundary conditions (BCs). 3.4 Failure Modes The failure mode analysis indicated that the adhesive layer experienced both cohesive failure (within the adhesive material) and adhesive failure (at the interface between the adhesive and the adherends). The results suggested that the fatigue life of the joint could be extended by optimizing the adhesive thickness and improving the interface bonding strength. Increasing the adhesive thickness from 0.2-1.0 mm results shows in the Fig. 5 an in an increase in the peak tensile load. However, beyond a certain thickness, the joints demonstrate a slight reduction in tensile strength due to the decrease in bond stiffness. This suggests an optimal adhesive thickness range for maximum performance. The results confirmed that an adhesive thickness of 0.5 mm provided the best mechanical performance also shown in Fig. 5 . Thicknesses below this value led to stress concentration and premature failure, while larger thicknesses introduced flexibility and reduced load transfer efficiency. The cohesive elements in the FEM model predicted this non-linear behavior effectively, validating optimal adhesive selection. 4. Conclusion This study presented a numerical modeling approach to investigate the fatigue behavior and failure analysis of adhesive-bonded single-side strap joints (ABSSJ) between steel and hybrid sisal-glass reinforced HDPE composite under fatigue load. Using finite element modeling and cohesive zone modeling, the study successfully simulated the stress distribution and damage evolution under cyclic loading conditions. The key findings of this study are: Stress concentrations in the adhesive layer were identified as the primary factor influencing the fatigue behavior of the joint. Fatigue crack initiation and propagation were primarily observed at the adhesive-steel interface and within the adhesive layer itself. The adhesive thickness significantly influenced the fatigue life, with thinner adhesives leading to premature failure. The hybrid sisal-glass reinforced HDPE composite adherend provided enhanced resistance to fatigue damage compared to pure HDPE composites. The CZM Based FEM simulation highlights that debonding in ABSSSJ is driven by stress concentration at the bond edges, particularly where shear and peel stresses are high. The findings provide insight into optimizing adhesive thickness, overlap dimensions, and material properties to enhance joint strength and durability. Further validation through experimental testing and variational analytical methods is necessary to refine the predictive accuracy of the FEM model. The model developed in this study provides valuable insights into the design and optimization of adhesive-bonded joints under fatigue loading. The findings can guide future research into improving the durability of adhesive-bonded joints in automotive and aerospace applications. Finally in Future studies should take into account environmental factors such as moisture, temperature variations, and aging effects, which can significantly influence the performance of adhesive-bonded joints in real-world applications. Abbreviations ABJ Adhesively Bonded Joint ABSSSJ Adhesively bonded single-side strap joints BC Boundary conditions CZM Cohesive zone model FEM Finite Element Method HDPE High density poly ethylene Declarations Institutional Review Board Statement: Not applicable.This study is a review of previously published literature and does not involve any human participants or animal studies requiring ethical approval. Informed Consent Statement: Not applicable.No human subjects were involved in this study, hence informed con sent was not required. Conflicts of Interest: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Data Availability: The datasets generated and analyzed during the current study are available from the corresponding author on reasonable request. Not applicable.This article is a comprehensive review based on publicly available data and previously published studies. No new data were generated or analyzed during the preparation of this review. Declaration Competing of Interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Funding Statement: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. However, institutional resources and laboratory infrastructure from Bahir dar institute of technology were utilized throughout the study. Author Contributions: Samuel Tesfaye: conceptualized the study, designed and conducted the experiments, performed the data analysis, and drafted the manuscript. Assefa Asmare Tsegaw: Supervision, project administration, funding acquisition, Teshome Mulatie Bogale: Data collection and Analysis, formal analysis, Addisu Negashi Ali, Asmamaw Tegegne Abebe: Conceptualization, methodology, investigation, All authors have read and approved the final version of the manuscript. Acknowledgment The authors would like to express their sincere gratitude to Bahir dar Institute of Technology for providing laboratory access and technical support. Special thanks to the materials testing unit lab team for their assistance in mechanical testing also not stated name individuals and organization who supports, and contributes directly and indirectly. Author’s information:- Dr Assefa Asmare Tsegaw 1 (PHD, Associate Professor), published more than 27 papers, Chair Head of Manufacturing engineering in Bahirdar Institute of Technology (BIT), and lecture and Senior Researcher. Now he is Main and Co Advisor for Msc and PHD Candidate Students e-mail: [email protected] , Phone no:+251918703107 ORCID: https://orcid.org/0000-0002-5453-3764 Dr Teshome Mulatie Bogale 1 (PHD, Associate Professor), published more than 24 papers, Co-ordinator of Post graduate studies of Faculty of mechanical and industrial, lecture and Senior Researcher. Now he is Main and Co Advisor for Msc and PHD Candidate Students engineering (FMIE) in Bahirdar Institute of Technology (BIT) e-mail: teshomemul@gmail or [email protected] , Phone no:+251929467952 ORCID: https://orcid.org/0000-0003-0576-3261 Dr Addisu Negash Ali 1 , (PHD, Associate Professor), published more than 25 papers , Chair Head of Mechanical Design engineering in Bahirdar Institute of Technology (BIT), lecture and Senior Researcher. Now he is Main and Co Advisor for Msc and PHD Candidate Students e-mail: [email protected] , Phoneno:+251930524952 ORCID: https://orcid.org/0000-0002-7380-6780 Dr Asmamaw Tegegne Abebe 2 , (PHD, Associate Professor), published more than 23 papers, Lecturer and Head of Manufacturing Technology in Faculty of Mechanical Technology (FTVTI), lecture and Senior Researcher . Now he is Main and Co Advisor for Msc and PHD Candidate Students in and out side the institution/university [email protected] , Phoneno: +251912685576 References Arouche, M., Belec, L., and Bernhart, G. (2020). Fatigue behavior of adhesively bonded composite joints: A numerical and experimental study. International Journal of Adhesion and Adhesives, 98, 102552. Campilho, R. D. S. G., Banea, M. D., Neto, J. A. B. P., and da Silva, L. F. M. (2019). Advances in numerical modeling of adhesive joints. Journal of Adhesion Science and Technology, 33(5), 485–515. D’Amore, A., Frendo, F., and Iannace, S. (2021). 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"Cohesive zone modeling of fracture in adhesive joints." International Journal of Fracture, 199(1), 3-15. https://doi.org/10.1007/s10704-016-0171-x Zhang, X., et al. (2021). "Numerical modeling of fatigue crack growth in adhesive joints under cyclic loading using cohesive zone model." Computers, Materials and Continua, 66(3), 1785-1805. https://doi.org/10.32604/cmc.2021.017650 Zhang, X., and Liu, Z. (2021). "Nonlinear Finite Element Analysis of Adhesive Bonded Joints Under Fatigue Loading." Journal of Mechanical Engineering Science, 235(6), 1064-1077. https://doi.org/10.1177/09544062211007778 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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TVTI","correspondingAuthor":false,"prefix":"","firstName":"Asmamaw","middleName":"Tegegne","lastName":"Abebe","suffix":""}],"badges":[],"createdAt":"2025-08-27 13:23:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7472044/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7472044/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":90790321,"identity":"6346f66d-85db-4070-b6f8-860f49c2a10e","added_by":"auto","created_at":"2025-09-08 08:11:21","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":42375,"visible":true,"origin":"","legend":"\u003cp\u003eStress Distribution simulation result of ABSSSJ.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7472044/v1/27c1f719fa5be63216ce7593.png"},{"id":90791007,"identity":"906536e9-7a94-4e08-851d-9f2d1a316bb4","added_by":"auto","created_at":"2025-09-08 08:19:21","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":102739,"visible":true,"origin":"","legend":"\u003cp\u003eABSSSJ (a) Stress contour before crack begin at end point of joints and (b) Higher stress contour of a debonding displacement\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7472044/v1/845ce6d0e8765b8f5b5d60b0.png"},{"id":90790324,"identity":"9b806e84-a9e0-427a-81a7-a4f7387f7208","added_by":"auto","created_at":"2025-09-08 08:11:21","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":320151,"visible":true,"origin":"","legend":"\u003cp\u003eFatigue behavior of Effect of adhesive thickness in ABSSSJ.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7472044/v1/4fb7a3a6a22702399c66be2d.png"},{"id":90790322,"identity":"13dd400f-b3bb-45a9-b8a0-c5ad39f4292e","added_by":"auto","created_at":"2025-09-08 08:11:21","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":129511,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of CZM Based FEM Simulation Vs Experimental Results of ABSSSJ.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7472044/v1/0bf35a7fbab08e261bd4d8c9.png"},{"id":90790326,"identity":"86c86699-fb99-46ba-b76c-2e94992799a4","added_by":"auto","created_at":"2025-09-08 08:11:21","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":139701,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of adhesive thickness in failure life and interface bond strength of ABSSSJ.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7472044/v1/dc6ec1019be4a97fa20511af.png"},{"id":90792314,"identity":"3035d95b-169c-4aa8-9c5a-7b461a52c0b3","added_by":"auto","created_at":"2025-09-08 08:27:21","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1229477,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7472044/v1/f77efb22-058a-48e1-a381-7b86d6223710.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eNumerical Modeling of Adhesively Bonded Single-Side Strap Joints: Steel-to-Hybrid Sisal-Glass Reinforced HDPE Composite Debonding Under Fatigue Loading\u003c/p\u003e","fulltext":[{"header":"1.\tIntroduction","content":"\u003cp\u003eAdhesively bonded joints (ABJ) have gained significant attention in structural applications due to their ability to distribute stress more uniformly compared to traditional mechanical fastening techniques (da Silva \u0026amp; Öchsner, 2008). In the automotive industry, the need for lightweight and high-strength materials has led to the development of hybrid composite-metal joints, particularly for side body panel applications (D\u0026rsquo;Amore et al., 2021). However, the long-term performance of these joints under fatigue loading remains a critical challenge due to interfacial degradation and adhesive failure mechanisms (Campilho et al., 2019).Hybrid sisal-glass reinforced HDPE composites offer an eco-friendly alternative with enhanced mechanical properties suitable for structural applications (Ramesh et al., 2020). When bonded to steel, the mechanical behavior of the adhesive layer becomes crucial, particularly in fatigue conditions where progressive damage accumulation can lead to debonding (Xu et al., 2017). Numerical modeling, especially through cohesive zone modeling (CZM)-based finite element analysis, has proven effective in predicting failure mechanisms in adhesively bonded joints (Pires et al., 2022).\u003c/p\u003e\n\u003cp\u003eExisting studies have focused on static and quasi-static loading conditions of bonded joints; however, fewer works have comprehensively analyzed the fatigue response and debonding progression in steel-to-hybrid composite configurations (Arouche et al., 2020). Parameters such as adhesive thickness, cohesive fracture toughness, fiber-to-matrix ratio, temperature, and moisture exposure significantly influence fatigue life and structural integrity (Khoramishad et al., 2010). This study aims to bridge this gap by employing numerical simulations to predict the fatigue-induced debonding behavior of adhesively bonded single-side strap joints (ABSSSJ) involving steel and hybrid sisal-glass reinforced HDPE composite. The results will provide insights into optimizing adhesive joint design for improved durability in automotive applications.\u003c/p\u003e\n\u003cp\u003eBackground of the study are focused on, ABJ are commonly used in the manufacturing of automotive and aerospace structures due to their superior stress distribution and lightweight characteristics (da Silva \u0026amp; Öchsner, 2008). These joints are especially beneficial in hybrid materials, such as the combination of metals with natural fiber-reinforced composites like sisal-glass hybrid composites (Campilho et al., 2019). In particular, the use of Hybrid Sisal-Glass Reinforced HDPE (High-Density Polyethylene) composites has gained attention due to their cost-effectiveness, sustainability, and mechanical properties suitable for automotive applications (Ramesh et al., 2020). However, the structural integrity of these joints is highly dependent on the adhesive material used, which must withstand complex loading conditions, such as fatigue, in harsh environmental conditions. When subjected to fatigue loading, adhesive joints experience progressive damage accumulation at the interface, leading to debonding and potential failure of the structure (Khoramishad et al., 2010). This issue becomes critical in the context of automotive body panels, where durability and long-term performance are paramount. Consequently, understanding the fatigue behavior and debonding mechanisms of ABJ is essential to improve the design and lifespan of hybrid composite structures in automotive applications (D\u0026rsquo;Amore et al., 2021).\u003cbr\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eJustifications of the study are, the increasing use of hybrid composite materials in the automotive industry necessitates a deeper understanding of the bonding behavior between metals and natural fiber composites. While static and quasi-static analyses of adhesive joints have been well-established, limited research exists on the fatigue performance of these joints, particularly in steel-to-composite configurations (Arouche et al., 2020).\u003c/p\u003e\n\u003cp\u003eThe use of cohesive zone models (CZM) integrated with finite element analysis (FEM) provides a powerful tool for simulating the complex damage and failure processes that occur under cyclic loading conditions (Pires et al., 2022). This approach allows for the prediction of failure initiation, crack propagation, and debonding progression within the adhesive layer, which are crucial factors influencing the longevity of the adhesive bond under fatigue conditions. By examining the fatigue response of adhesively bonded single-side strap joints (ABSSSJ) made of steel and hybrid sisal-glass reinforced HDPE composite, this study aims to fill a significant gap in the literature and contribute valuable insights for designing durable adhesive joints for automotive applications.\u003c/p\u003e\n\u003cp\u003eBackground Gap of the study,Despite the extensive research on adhesive joints, there is a noticeable gap in the understanding of fatigue-induced debonding in joints involving steel and hybrid natural fiber composites. Previous studies have focused mainly on static loading or quasi-static conditions, with limited emphasis on cyclic loading behavior and the associated damage evolution in hybrid composite-metal joints (Xu et al., 2017). Furthermore, the influence of key parameters such as adhesive thickness, cohesive fracture toughness, moisture exposure, and temperature effects on fatigue performance has not been thoroughly investigated.\u003c/p\u003e\n\u003cp\u003eThis study aims to address these gaps by employing numerical simulations based on cohesive zone modeling to analyze the debonding behavior of adhesive joints under fatigue loading. The objective is to provide a comprehensive understanding of the fatigue failure mechanisms, with a focus on the impact of material and geometric parameters on joint durability, thus enhancing the design and optimization of adhesive joints in lightweight automotive structures.\u003c/p\u003e\n\u003cp\u003eThe motivation behind this study arises from the growing demand for lightweight and durable materials in the automotive industry, particularly in the design of automobile body panels. Hybrid composites, such as the combination of natural fibers like sisal and glass with HDPE, have shown promise due to their favorable mechanical properties, cost-effectiveness, and environmental benefits (Ramesh et al., 2020). However, for these materials to be effectively utilized in automotive applications, the adhesive bonding between metal substrates (like steel) and hybrid composites must be thoroughly understood, especially under challenging operating conditions like fatigue loading. While ABJ have been widely used in automotive and aerospace structures, the complex behavior of these joints under cyclic loading, particularly the debonding mechanisms, remains underexplored. Most studies have focused on static or quasi-static loading conditions, with little attention given to the fatigue behavior of adhesive joints under real-world operational stress conditions. This study aims to fill this gap by conducting numerical simulations of adhesive bonded single-side strap joints (ABSSSJ) under fatigue loading, using advanced models like Cohesive Zone Modeling (CZM). The ultimate goal is to enhance the durability of adhesive joints and provide design guidelines for their implementation in lightweight automotive structures.\u003c/p\u003e\n\u003cp\u003eThe literature review presents an overview of the key literature related to the analysis of adhesive bonded joints, focusing on the fatigue behavior of steel-to-hybrid sisal-glass reinforced HDPE composites and the use of numerical methods such as Cohesive Zone Modeling (CZM) to predict debonding and failure under cyclic loading.\u003c/p\u003e\n\u003cp\u003eAdhesive Bonding in Structural Joints, The adhesion between materials such as steel and composite materials, specifically hybrid sisal-glass reinforced HDPE, has been investigated in several studies due to the potential of this hybrid composite for automotive applications (Leal et al., 2020). These materials offer a good balance of mechanical properties, such as high strength and stiffness, along with relatively low density.\u003c/p\u003e\n\u003cp\u003eFatigue Behavior of Adhesive Bonded Joints, Several studies has investigated the effects of cyclic loading on the mechanical integrity of adhesive joints (Ferrante et al., 2018). The fatigue behavior of adhesive joints is complex, often involving a combination of adhesive failure, cohesive failure, and interface debonding (Vazquez et al., 2019). Previous studies suggest that adhesive thickness, the quality of the bonding interface, and material properties significantly influence fatigue resistance. The development of fatigue crack growth models for adhesive joints under cyclic loading is essential for predicting the lifespan of these joints (Li et al., 2021).\u003c/p\u003e\n\u003cp\u003eCohesive Zone Modeling (CZM) in Adhesive Joint Analysis\u003cstrong\u003e,\u0026nbsp;\u003c/strong\u003eIt involves defining a cohesive law that describes the relationship between the traction (stress) and separation (displacement) at the interface between two adherends (Xu and Needleman, 2016).The use of CZM enables the prediction of damage initiation and growth in adhesive joints, which is particularly important in the design of joints subjected to cyclic loading (Tvergaard and Hutchinson, 2020). Studies have shown that CZM can accurately simulate the initiation of cracks and the subsequent propagation through the adhesive layer, providing valuable insights into the failure mechanisms (Wang et al., 2022).\u003c/p\u003e\n\u003cp\u003eFatigue Analysis of Composite Adhesive Joints, Research has shown that the mechanical properties of these composites, such as their strength, stiffness, and fatigue resistance, can be influenced by factors such as the fiber-to-matrix ratio and the orientation of fibers (Gon\u0026ccedil;alves et al., 2019). These studies are essential for understanding how the hybrid composite material behaves under fatigue conditions and for optimizing adhesive joint designs for improved performance and longevity (Mahamid et al., 2018).\u003c/p\u003e\n\u003cp\u003eNumerical Simulation of Adhesive Bonding under Fatigue Loading,When combined with CZM, FEA simulations can capture the initiation and propagation of damage within the adhesive and the adherends (Ulm et al., 2020).The application of CZM to study fatigue loading in ABJ has proven to be a reliable method for simulating damage evolution, predicting failure modes, and assessing the durability of adhesive bonds under real-world loading conditions (Zhang et al., 2021).\u003c/p\u003e\n\u003cp\u003eGaps in Literature, while there is substantial research on adhesive bonding and fatigue analysis in adhesive joints, several gaps remain in the literature.One significant gap is the lack of comprehensive studies on the fatigue behavior of steel-to-hybrid composite adhesive joints, particularly involving materials such as sisal-glass reinforced HDPE. Additionally, the influence of environmental factors, such as temperature, humidity, and cyclic loading rates, on the long-term durability of these joints is not fully understood. Furthermore, while CZM has been widely used for static failure analysis, there is limited research applying CZM specifically for fatigue crack growth in adhesive joints.\u003c/p\u003e\n\u003cp\u003eFinally as a Conclusion, the literature reveals that while significant progress has been made in understanding the mechanical behavior of adhesive joints, especially under static loading, there is a need for more focused research on the fatigue performance of adhesive bonded joints, particularly in composite materials. The use of numerical modeling techniques such as CZM offers a promising approach to simulate the complex behavior of adhesive joints under cyclic loading, including fatigue damage initiation and propagation. The research gap identified in the fatigue analysis of steel-to-hybrid sisal-glass reinforced HDPE composite adhesive joints under cyclic loading provides the foundation for the current study.\u003c/p\u003e\n\u003cp\u003eProblem statements of the study focus on the automotive industry faces challenges in ensuring the reliability and durability of adhesively bonded joints, especially when subjected to cyclic loading conditions. Current research lacks comprehensive studies on the fatigue-induced debonding behavior of adhesive joints in hybrid composite-steel configurations, particularly with natural fiber composites like sisal-glass reinforced HDPE. Adhesive failure due to fatigue loading could significantly compromise the structural integrity and performance of automotive side body panels, leading to potential safety concerns.\u003c/p\u003e\n\u003cp\u003eFurthermore, the influence of critical parameters such as adhesive thickness, cohesive fracture toughness, moisture exposure, and temperature effects on fatigue performance has not been fully understood. These gaps in knowledge hinder the optimization of adhesive joints for automotive applications, leading to suboptimal designs that may not meet the required performance standards.\u003c/p\u003e\n\u003cp\u003eThe main objectives of this study are: To investigate the fatigue-induced debonding behavior of adhesive joints in steel-to-hybrid sisal-glass reinforced HDPE composite configuration, To develop a numerical model based on Cohesive Zone Modeling (CZM) to simulate the initiation and propagation of debonding under cyclic loading conditions, To assess the effects of key parameters, such as adhesive thickness, cohesive fracture toughness, moisture exposure, and temperature variations, on the fatigue performance of the adhesive joints, and to provide insights into the impact of fatigue loading on the long-term durability and performance of adhesively bonded joints, specifically for automobile side body panel applications.\u003c/p\u003e\n\u003cp\u003eThis study answer the following Research Questions\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003eWhat is the effect of cyclic loading on the fatigue-induced debonding of adhesive joints in steel-to-hybrid sisal-glass reinforced HDPE composite ABSSSJs?\u003cbr\u003e\u003cbr\u003e\u003c/li\u003e\n \u003cli\u003eHow do critical factors such as adhesive thickness, cohesive fracture toughness, moisture exposure, and temperature affect the fatigue resistance of ABSSSJs?\u003cbr\u003e\u003cbr\u003e\u003c/li\u003e\n \u003cli\u003eWhat are the dominant failure mechanisms (e.g., adhesive failure, cohesive failure, or mixed-mode failure) under fatigue loading conditions?\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"2. Method and Materials","content":"\u003cp\u003eThis section outlines the approach used to model the adhesive-bonded single-side strap joint (ABSSSJ) between steel and hybrid sisal-glass reinforced HDPE composite under fatigue loading using numerical techniques.\u003c/p\u003e\u003cdiv id=\"Sec2\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Finite Element Modeling (FEM)\u003c/h2\u003e\u003cp\u003eThe analysis of the ABSSSJ was conducted using a 2D finite element model (FEM) implemented in ANSYS. The lower adherend (hybrid sisal-glass reinforced HDPE composite) was modeled using orthotropic shell elements (SHELL181), while the upper adherend (steel) was modeled with isotropic solid elements (SOLID185). The adhesive layer (Araldite 2020, Araldite 2015 and AV138) was modeled using cohesive zone elements (INTER202) to represent the interface between the two adherends. The material properties for the adhesive and adherends were selected based on the values obtained from literature and experimental data.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Cohesive Zone Model (CZM)\u003c/h2\u003e\u003cp\u003eA cohesive zone model (CZM) was used to simulate the debonding behavior at the adhesive interface. The interface properties, including the adhesive\u0026rsquo;s cohesive strength and fracture toughness, were defined using a bilinear traction-separation law. The model was calibrated to replicate both tensile and shear failure modes under fatigue loading conditions.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Fatigue Loading Conditions\u003c/h2\u003e\u003cp\u003eFatigue loading was applied to the joint using cyclic loading conditions, where the load was varied between minimum and maximum values to simulate real-world fatigue behavior. The loading conditions were chosen to match typical operational conditions for automotive body panels, with stress ratios and frequencies defined based on experimental studies. The fatigue damage was modeled using the Paris law for crack growth under mixed-mode loading conditions.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Boundary Conditions and Simulation Setup\u003c/h2\u003e\u003cp\u003eThe boundary conditions were applied to the FEM model to replicate the loading and support conditions for a typical adhesive-bonded joint under bending. Fixed supports were applied at the ends of the steel adherend, while cyclic loading was applied at the free end. The simulation was run under various loading cycles until failure was observed in the adhesive layer, with the crack propagation monitored at each step.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.5 Post-Processing\u003c/h2\u003e\u003cp\u003eStress and strain distributions across the adhesive thickness were analyzed at different load steps. The results from the simulation were post-processed to examine the stress concentration areas, fatigue crack initiation points, and failure modes. The results were compared with experimental data available in the literature to validate the model.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results and Discussion","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n \u003ch2\u003e3.1 Stress Distribution\u003c/h2\u003e\n \u003cp\u003eThe FEM simulation revealed significant stress concentrations in the adhesive layer, particularly at the edges of the adhesive bondline. The shear stress was found to be highest near the adhesive interface, especially in the region of the overlap. The stress distribution showed in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ea gradual decrease across the adhesive thickness, with the maximum stress occurring at the steel-Hybrid sisals-Glass- HDPE composite interface. This observation is consistent with the findings of previous studies on adhesive joints under similar loading conditions.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\n \u003ch2\u003e3.2 Fatigue Behavior and Damage Evolution\u003c/h2\u003e\n \u003cp\u003eThe fatigue simulation revealed that the debonding of the adhesive layer initiated at the center of the adhesive bondline and propagated outward in both shear and tensile directions indicated in figure \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. The cohesive zone model accurately captured the damage evolution, with the damage initiation corresponding to regions of high stress concentrations. The results showed a significant difference in damage progression between the tensile and shear zones of the adhesive, highlighting the mixed-mode nature of the debonding process.\u003c/p\u003e\u003cspan\u003e\n \u003cp\u003e(b) Higher stress contour of a debonding displacement\u003c/p\u003e\n \u003c/span\u003e\n \u003cp\u003eThe fatigue life of the adhesive joint was found to be influenced by the adhesive thickness shows in Fig. 3 varying adhesive thickness from 0.2-1.00mm CZM Based FEM simulation results graph plotted ABSSSJ using ANSYS, with thinner adhesive layers experiencing earlier failure due to higher stress concentrations. The analysis also showed that the hybrid composite\u0026apos;s mechanical properties significantly affected the fatigue behavior, with the sisal-glass hybrid providing enhanced resistance to fatigue cracking.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\n \u003ch2\u003e3.3 Comparison with Experimental Results\u003c/h2\u003e\n \u003cp\u003eThe results indicated in Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e from the CZM Based FEM simulations were compared with available experimental data for adhesive-bonded joints under similar fatigue conditions. The numerical results showed good agreement with experimental data in terms of stress distribution and failure location. Minor discrepancies were observed in the exact fatigue life, which could be attributed to the simplifications in the numerical model, such as the idealization of material properties and boundary conditions (BCs).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\n \u003ch2\u003e3.4 Failure Modes\u003c/h2\u003e\n \u003cp\u003eThe failure mode analysis indicated that the adhesive layer experienced both cohesive failure (within the adhesive material) and adhesive failure (at the interface between the adhesive and the adherends). The results suggested that the fatigue life of the joint could be extended by optimizing the adhesive thickness and improving the interface bonding strength.\u003c/p\u003e\n \u003cp\u003eIncreasing the adhesive thickness from 0.2-1.0 mm results shows in the Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e an in an increase in the peak tensile load. However, beyond a certain thickness, the joints demonstrate a slight reduction in tensile strength due to the decrease in bond stiffness. This suggests an optimal adhesive thickness range for maximum performance.\u003c/p\u003e\n \u003cp\u003eThe results confirmed that an adhesive thickness of 0.5 mm provided the best mechanical performance also shown in Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e. Thicknesses below this value led to stress concentration and premature failure, while larger thicknesses introduced flexibility and reduced load transfer efficiency. The cohesive elements in the FEM model predicted this non-linear behavior effectively, validating optimal adhesive selection.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eThis study presented a numerical modeling approach to investigate the fatigue behavior and failure analysis of adhesive-bonded single-side strap joints (ABSSJ) between steel and hybrid sisal-glass reinforced HDPE composite under fatigue load. Using finite element modeling and cohesive zone modeling, the study successfully simulated the stress distribution and damage evolution under cyclic loading conditions. The key findings of this study are:\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eStress concentrations in the adhesive layer were identified as the primary factor influencing the fatigue behavior of the joint.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eFatigue crack initiation and propagation were primarily observed at the adhesive-steel interface and within the adhesive layer itself.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThe adhesive thickness significantly influenced the fatigue life, with thinner adhesives leading to premature failure.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThe hybrid sisal-glass reinforced HDPE composite adherend provided enhanced resistance to fatigue damage compared to pure HDPE composites.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003cp\u003eThe CZM Based FEM simulation highlights that debonding in ABSSSJ is driven by stress concentration at the bond edges, particularly where shear and peel stresses are high. The findings provide insight into optimizing adhesive thickness, overlap dimensions, and material properties to enhance joint strength and durability. Further validation through experimental testing and variational analytical methods is necessary to refine the predictive accuracy of the FEM model.\u003c/p\u003e\u003cp\u003eThe model developed in this study provides valuable insights into the design and optimization of adhesive-bonded joints under fatigue loading. The findings can guide future research into improving the durability of adhesive-bonded joints in automotive and aerospace applications.\u003c/p\u003e\u003cp\u003eFinally in Future studies should take into account environmental factors such as moisture, temperature variations, and aging effects, which can significantly influence the performance of adhesive-bonded joints in real-world applications.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eABJ\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eAdhesively Bonded Joint\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eABSSSJ\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eAdhesively bonded single-side strap joints\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eBC\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eBoundary conditions\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eCZM\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eCohesive zone model\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eFEM\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eFinite Element Method\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eHDPE\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eHigh density poly ethylene\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eInstitutional Review Board Statement:\u003c/strong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003cstrong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.This study is a review of previously published literature and does not involve any human participants or animal studies requiring ethical approval. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformed Consent Statement:\u003c/strong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNot applicable.No human subjects were involved in this study, hence informed con sent was not required.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflicts of Interest:\u003c/strong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability:\u003c/strong\u003e The datasets generated and analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003eNot applicable.This article is a comprehensive review based on publicly available data and previously published studies. No new data were generated or analyzed during the preparation of this review. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration Competing of Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding Statement:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. However, institutional resources and laboratory infrastructure from Bahir dar institute of technology were utilized throughout the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSamuel Tesfaye: conceptualized the study, designed and conducted the experiments, performed the data analysis, and drafted the manuscript. Assefa Asmare Tsegaw: Supervision, project administration, funding acquisition, Teshome Mulatie Bogale: Data collection and Analysis, formal analysis, Addisu Negashi Ali, Asmamaw Tegegne Abebe: Conceptualization, methodology, investigation, All authors have read and approved the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgment\u003cbr\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to express their sincere gratitude to Bahir dar Institute of Technology for providing laboratory access and technical support. Special thanks to the materials testing unit lab team for their assistance in mechanical testing also not stated name individuals and organization who supports, and contributes directly and indirectly.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor\u0026rsquo;s information:-\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDr Assefa Asmare Tsegaw\u003cstrong\u003e\u003csup\u003e1\u0026nbsp;\u003c/sup\u003e\u003c/strong\u003e(PHD, Associate Professor), published more than 27 papers, Chair Head of Manufacturing engineering in Bahirdar Institute of Technology (BIT), and lecture and Senior Researcher. Now he is Main and Co Advisor for Msc and PHD Candidate Students\u003c/p\u003e\n\u003cp\u003ee-mail: [email protected], Phone no:+251918703107\u003c/p\u003e\n\u003cp\u003eORCID: https://orcid.org/0000-0002-5453-3764\u003c/p\u003e\n\u003cp\u003eDr Teshome Mulatie Bogale\u003cstrong\u003e\u003csup\u003e1\u003c/sup\u003e\u003c/strong\u003e (PHD, Associate Professor), published more than 24 papers, Co-ordinator of Post graduate studies of Faculty of mechanical and industrial, lecture and Senior Researcher. Now he is Main and Co Advisor for Msc and PHD Candidate Students engineering (FMIE) in Bahirdar Institute of Technology (BIT)\u003c/p\u003e\n\u003cp\u003ee-mail: teshomemul@gmail or [email protected], Phone no:+251929467952\u003c/p\u003e\n\u003cp\u003eORCID: https://orcid.org/0000-0003-0576-3261\u003c/p\u003e\n\u003cp\u003eDr Addisu Negash Ali\u003cstrong\u003e\u003csup\u003e1\u003c/sup\u003e\u003c/strong\u003e, (PHD, Associate Professor), published more than 25 papers , Chair Head of Mechanical Design engineering in Bahirdar Institute of Technology (BIT), lecture and Senior Researcher. Now he is Main and Co Advisor for Msc and PHD Candidate Students\u003c/p\u003e\n\u003cp\u003ee-mail: [email protected], Phoneno:+251930524952\u003c/p\u003e\n\u003cp\u003eORCID: https://orcid.org/0000-0002-7380-6780\u003c/p\u003e\n\u003cp\u003eDr Asmamaw Tegegne Abebe\u003cstrong\u003e\u003csup\u003e2\u003c/sup\u003e\u003c/strong\u003e, (PHD, Associate Professor), published more than 23 papers, Lecturer and Head of Manufacturing Technology in Faculty of Mechanical Technology (FTVTI), lecture and Senior Researcher . Now he is Main and Co Advisor for Msc and PHD Candidate Students in and out side the institution/university\u003c/p\u003e\n\u003cp\[email protected], Phoneno: +251912685576\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eArouche, M., Belec, L., and Bernhart, G. (2020). Fatigue behavior of adhesively bonded composite joints: A numerical and experimental study. International Journal of Adhesion and Adhesives, 98, 102552.\u003c/li\u003e\n \u003cli\u003eCampilho, R. D. S. G., Banea, M. D., Neto, J. A. B. P., and da Silva, L. F. M. (2019). Advances in numerical modeling of adhesive joints. Journal of Adhesion Science and Technology, 33(5), 485\u0026ndash;515.\u003c/li\u003e\n \u003cli\u003eD\u0026rsquo;Amore, A., Frendo, F., and Iannace, S. (2021). Structural performance of adhesive bonding in automotive lightweight structures. Composites Part B: Engineering, 215, 108770.\u003c/li\u003e\n \u003cli\u003eda Silva, L. F. M., and Öchsner, A. (2008). Modeling of adhesively bonded joints. Springer Science and Business Media.\u003c/li\u003e\n \u003cli\u003eKhoramishad, H., Crocombe, A. D., Wahab, M. A., and Ashcroft, I. A. (2010). Predicting fatigue damage in adhesive joints using a cohesive zone model. International Journal of Fatigue, 32(7), 1146\u0026ndash;1158.\u003c/li\u003e\n \u003cli\u003ePires, F., Marques, E. A. S., da Silva, L. F. M., and Carbas, R. J. C. (2022). Numerical modeling of adhesive joints: A review on techniques and challenges. Journal of Adhesion, 98(6), 612\u0026ndash;635.\u003c/li\u003e\n \u003cli\u003eRamesh, M., Palanikumar, K., and Reddy, K. H. (2020). Evaluation of mechanical and tri bological properties of hybrid natural fiber composites. Materials Today: Proceedings, 27, 2052\u0026ndash;2057.\u003c/li\u003e\n \u003cli\u003eXu, W., Zhao, X., \u0026amp; Zhang, J. (2017). Fatigue failure analysis of adhesively bonded composite joints using CZM and XFEM. Composite Structures, 180, 571\u0026ndash;579.\u003c/li\u003e\n \u003cli\u003eFerrante, L., et al. (2018).\u0026quot;Fatigue behavior of adhesive bonded joints: A review of experimental and numerical studies.\u0026quot; International Journal of Fatigue, 111, 102-115. https://doi.org/10.1016/j.ijfatigue.2018.01.005\u003c/li\u003e\n \u003cli\u003eGon\u0026ccedil;alves, S. J., et al. (2019).\u0026quot;Fatigue of hybrid fiber-reinforced polymer composite adhesive joints under cyclic loading. \u0026quot;Composite Structures, 227,111341. https://doi.org/10.1016/j.compstruct.2019.111341\u003c/li\u003e\n \u003cli\u003eLeal, S. D., et al. (2020). \u0026quot;Adhesive bonding of hybrid composite materials: A review on the influence of interface conditions and material properties.\u0026quot; Materials Science and Engineering: A, 778, 139104. https://doi.org/10.1016/j.msea.2019.139104\u003c/li\u003e\n \u003cli\u003eLi, X., et al. (2021). \u0026quot;Fatigue crack growth prediction in adhesive joints under variable amplitude loading.\u0026quot;International Journal of Adhesion and Adhesives, 105, 102744. https://doi.org/10.1016/j.ijadhadh.2020.102744\u003c/li\u003e\n \u003cli\u003eMahamid, I., et al. (2018). \u0026quot;Fatigue behavior of adhesive joints in composite materials: A review.\u0026quot; Composite Part B: Engineering, 144, 116-134. https://doi.org/10.1016/j.compositesb.2018.02.030\u003c/li\u003e\n \u003cli\u003eTvergaard, V., and Hutchinson, J. W. (2020). \u0026quot;The cohesive zone model: A critical review.\u0026quot; Engineering Fracture Mechanics, 233, 107030. https://doi.org/10.1016/j.engfracmech.2020.107030\u003c/li\u003e\n \u003cli\u003eUlm, F. J., et al. (2020).\u0026quot;The use of finite element methods in the analysis of adhesive bonded joints. \u0026quot;International Journal of Solids and Structures, 118, 25-40. https://doi.org/10.1016/j.ijsolstr.2020.04.022\u003c/li\u003e\n \u003cli\u003eVazquez, M. R., et al. (2019). \u0026quot;Fatigue of adhesive joints under mixed mode loading: A comprehensive review.\u0026quot; International Journal of Adhesion and Adhesives, 92, 92-112. https://doi.org/10.1016/j.ijadhadh.2018.11.012\u003c/li\u003e\n \u003cli\u003eWang, D., et al. (2022).\u0026quot;Fatigue analysis of adhesive bonded joints under cyclic loading using cohesive zone modeling.\u0026quot; Fatigue and Fracture of Engineering Materials and Structures, 45(8), 1863-1880. https://doi.org/10.1111/ffe.13626\u003c/li\u003e\n \u003cli\u003eXu, Y., and Needleman, A. (2016). \u0026quot;Cohesive zone modeling of fracture in adhesive joints.\u0026quot; International Journal of Fracture, 199(1), 3-15. https://doi.org/10.1007/s10704-016-0171-x\u003c/li\u003e\n \u003cli\u003eZhang, X., et al. (2021). \u0026quot;Numerical modeling of fatigue crack growth in adhesive joints under cyclic loading using cohesive zone model.\u0026quot; Computers, Materials and Continua, 66(3), 1785-1805. https://doi.org/10.32604/cmc.2021.017650\u003c/li\u003e\n \u003cli\u003eZhang, X., and Liu, Z. (2021). \u0026quot;Nonlinear Finite Element Analysis of Adhesive Bonded Joints Under Fatigue Loading.\u0026quot; Journal of Mechanical Engineering Science, 235(6), 1064-1077. https://doi.org/10.1177/09544062211007778\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Adhesively bonded joints, fatigue loading, cohesive zone model, finite element analysis, debonding mechanics","lastPublishedDoi":"10.21203/rs.3.rs-7472044/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7472044/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study presents a numerical modeling approach for analyzing the debonding behavior of adhesively bonded single-side strap joints made of steel-to-hybrid sisal-glass reinforced HDPE composite under fatigue loading. The objective of the study is to investigate the fatigue-induced debonding behavior of adhesively bonded joint. Methods employed in this study are a cohesive zone model based finite element method employed to simulate the progressive damage and failure mechanisms at the adhesive interface. The study investigates the effects of key parameters, including adhesive thickness, cohesive fracture toughness, fiber-to-matrix weight ratio, temperature, and moisture exposure on fatigue life and damage progression. The numerical results are validated against experimental data and analytical solutions, demonstrating the model's accuracy in predicting fatigue-induced debonding. Sensitivity analyses are performed to assess the influence of varying material and geometric parameters on joint durability. The findings provide insight into optimizing adhesive joint design for automotive applications, particularly for lightweight composite structures. It is recommended that future research incorporate detailed experimental testing under fatigue loading to confirm the predictive accuracy of the FEM simulations and CZM approach.\u003c/p\u003e","manuscriptTitle":"Numerical Modeling of Adhesively Bonded Single-Side Strap Joints: Steel-to-Hybrid Sisal-Glass Reinforced HDPE Composite Debonding Under Fatigue Loading","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-08 08:11:16","doi":"10.21203/rs.3.rs-7472044/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"10a57d33-bc29-477f-bf8c-729fe92f1687","owner":[],"postedDate":"September 8th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-08T08:11:17+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-08 08:11:16","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7472044","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7472044","identity":"rs-7472044","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}