Flat Stiffened CFRP Panel Design and Analysis

Flat Stiffened CFRP Panel Design and Analysis | 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 Flat Stiffened CFRP Panel Design and Analysis Gayathri R, Suresh Kumar R, Ponmary Puspha Latha D, Rajkumar Sivanraju, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8772666/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 The aim of this paper is to analyze the behavior of stiffened Carbon Fiber attached to a flat plate stiffener. The structural behavior of a composite plate with a flat plate stiffener has been studied in this research work. The aim is to investigate the effects of the stiffener on the stiffness and strength of the plate. The composite plates were made of layers of carbon fiber and the flat plate stiffener and it was made of aluminum alloy. The FEA results showed that the stiffener had a significant effect on the stiffness and strength of the composite plate. The addition of the stiffener increased the stiffness and reduced the deflection of the plate. The stiffener also increased the maximum stress and strain values in the plate, indicating an increase in the plate's strength. Flat stiffener CFRP stiffness FEA strength Figures Figure 1 Figure 2 1. INTRODUCTION Composite materials are formed by combining two or more materials and that have quite different properties, and they do not dissolve or blend Into each other. The different materials in the composite work together to give the composite unique properties[ 1 , 2 ]. Researcher refer to Fiber Reinforced Polymer (FRP) composites, usually with carbon, glass, aramid, polymer or natural fibers embedded in a polymer matrix. Composite materials based on graphite and boron fiber systems are recognized as the most promising [ 3 , 4 ]. At present, the use of graphite/epoxy materials enables one to reduce structural weight by 20–25%. Further weight reduction can be attained by increasing the percentage of composites in the total amount of applied materials, as well as by improving the design methodology and fabrication technology used for composite structures [ 5 , 6 ]. It was impossible to use the new degrees of freedom given by composite materials without the development of the corresponding science of composite structures. This science has been developed in Russia for many years with the support of government. Stiffeners are employed to resist lateral loading of the plate and are usually made from the rolled shapes integrally welded to the plate. Such stiffeners are distinct from the other stiffeners and it is used to prevent plate buckling. Typically, stiffeners run continuously through the supporting frames. Spot welding also gives some control over dimensional stability. Polymer dispersions are applied by padding, slop padding, foam, spray and knife coating [ 7 , 8 , 9 ]. Thermoplastic binders are important in the manufacture of nonwoven fabrics intended for moulding operations. Other binding chemical finishes include anti-dust finishes, which bind and depress dust in applications such as mats. The final goal of application of any material is its rational utilization in a structure. Composite materials based on graphite and boron fibre systems are recognized as the most promising. At present, the use of graphite/epoxy materials enables one to reduce structural weight by 20–25%. Further weight reduction can be attained by increasing the percentage of composites in the total amount of applied materials, as well as by improving the design methodology and fabrication technology used for composite structures. Initially, composites were used in secondary structures, like the interior details and floors; next, they were used in less critical load-bearing components, i.e., the landing gear well doors, doors of the hatches, etc. At present, composite materials are being introduced into such primary structures of the airframe as the wing, fuselage and control surfaces. It was impossible to use the new degrees of freedom given by composite materials without the development of the corresponding science of composite structures. The linear buckling theory is no longer useful to analyze the post buckling behavior of a thin plate and the buckling strength cannot be used as a design criterion for such structures. Since the problem is too complicated to be treated mathematically, In general, several empirical formulae have been put forward based on GALCIT and MIT tests. The linear buckling theory of the plate in the strain hardening range based on the effective moduli of the material after yielding can furnish the appropriate design criterion which predicts the ultimate strength of the panels. Most of the stiffened plates have used stiffeners in the two mutually orthogonal constant directions. Earlier, these directions used to coincide with the length and breadth of the plate. However, there are now some examples of stiffeners being placed in geodesic fashion depending upon the loads that are applied to the panel. By continuously varying the stiffener orientation, Researcher can align the stiffeners along the load paths for the static case and in a way that can drive the natural frequencies away from the resonance frequencies for a dynamic case. This was the motivation behind the study and making of this paper. Hence the objective of this paper is to analyze a stiffened panel subjected to static and modal analysis [ 10 , 11 ]. 1.1 FSDT Mesh-Free Method Bending and free vibration analysis of circular stiffened plates is done using the FSDT mesh-free method. Due to high strength-to-weight ratio, stiffened plates have been extensively found in civil and oceanographic engineering, transportation and aerospace industry, etc. The stiffeners in the structure enhance the stiffness of the whole structure without consuming too much material and significantly increasing its weight, which greatly improves the cost-effectiveness of the structure. In addition to the common rectangular stiffened plates, the circular stiffened plates have gradually been widely used. For example, the raft foundation of some structures such as water towers, chimneys, silos, etc. are mostly circular in shape; aerospace vehicles and large machinery in industry also have circular parts with stiffeners. Therefore, the study of circular stiffened plates has been highly valued. Many researches have been carried out on stiffened plates. The early researchers used an orthotropic model, which approximated stiffened plates with flat plates of equal thickness and the stiffeners were converted into another layer attached to the original plates. Another option was the grillage model [ 12 ]. These were the first to analyze the vibration behaviors of stiffened plates by using the orthotropic model or the grillage model. Although the principle of these models was clear and the formulation was simple, they had taken too many simplifications. They encountered difficulties in dealing with the general stiffened plate problems with sparse or uneven arrangement of stiffeners and failed to give satisfactory solutions. In order to improve it, subsequent researchers tended to consider the stiffeners and flat plate of a stiffened plate separately, In order to simulate the stiffeners with the beam model, and to combine the stiffeners and flat plate together by introducing the displacement compatibility between them [ 13 ]. 1.2 Impact of Stiffener Location on Buckling Strength The study analyses the buckling behaviour of a single open stiffener, two open stiffeners and a single closed stiffeners under pure bending and compression and recommends the use of two open stiffeners over single stiffener for longer spans and it has not contained more information for the various stiffener spacing [ 14 ]. The influence of stiffeners nearer to top flange plays a vital role in the stability of the plate [15]. The stiffeners at the optimal place enhances the critical load for all load cases such as pure bending, and combined bending and shear [ 16 ]. Many researchers focused on optimizing the stiffeners via modifying shape, size and location to increase the stability of the thin plates. But the flat stiffener has the simplest geometry in comparison with other forms of stiffeners such as L, T, Z, I, rectangular and box- section. The research focused on many parameters and its impact on buckling failure and it shows uncertainty analysis also [ 17 ]. This research uses two stiffeners and its effect in increasing the buckling strength to prevent the failure. 2. MATERIAL SELECTION FOR FLAT PLATE STIFFENER Aluminum is lightweight and has a high strength-to-weight ratio, making it an excellent choice for applications where weight is a critical factor. It is also corrosion-resistant, which makes it suitable for use in harsh environments. However, aluminum is more expensive than steel. Composite materials, such as carbon fiber-reinforced polymers (CFRP) are gaining popularity in the aerospace industry due to their high strength and low weight. However, they are more expensive than traditional materials like steel or aluminum. Carbon fiber is a lightweight and strong material that is made from thin strands of carbon. The carbon fibers are woven together and then impregnated with a resin to create a composite material that is strong and stiff. Carbon fiber is commonly used in applications that require high strength-to-weight ratios, such as aerospace, automotive, and sporting equipment. 2.1 Comparison of Properties Carbon fiber and aluminum are both commonly used materials in various industries, including aerospace, automotive, and sports equipment. Here are some key differences between these two materials. Weight: Carbon fiber is significantly lighter than aluminum. This makes it an ideal material for applications where weight reduction is critical, such as aerospace and high-performance sports equipment. Strength: Carbon fiber has a higher tensile strength than aluminum. Tensile strength refers to the maximum stress a material can withstand before breaking. However, aluminum has a higher compressive strength than carbon fiber, meaning it can withstand more pressure without deforming or breaking. Stiffness: Carbon fiber is stiffer than aluminum, meaning it doesn't bend or flex as much under load. This stiffness is desirable for applications where rigidity is important, such as high-performance bicycles or racing car frames. Corrosion Resistance: Aluminum is naturally resistant to corrosion, while carbon fiber can corrode under certain conditions. However, carbon fiber is not susceptible to galvanic corrosion, which is a type of corrosion that can occur when dissimilar metals come into contact with each other. The Table 1 given below shows the properties of carbon fiber and aluminum alloy especially Young’s modulus and ultimate strength for the same materials have been compared. Table 1 Mechanical Properties 3. MODELLING Solid Works is an solid modelling computer-aided design (CAD) and computer-aided engineering (CAE) computer program that runs on Microsoft Windows. Building a model in Solid Works usually starts with a 2D sketch (although 3D sketches are available for power users). The sketch consists of geometry such as points, lines, arcs, conics (except the hyperbola), and splines. Dimensions are added to the sketch to define the size and location of the geometry. Relations are used to define attributes such as tangency, parallelism, perpendicularity and concentricity. The parametric nature of SolidWorks means that the dimensions in the sketch can be controlled independently, or by relationships to other parameters inside or outside of the sketch. In an assembly, the analog to sketch relations are mates. Just as sketch relations define conditions such as tangency, parallelism, and concentricity with respect to sketch geometry, assembly mates define equivalent relations with respect to the individual parts or components, allowing the easy construction of assemblies. Solid Works also includes additional advanced mating features such as gear and cam follower mates, which allow modelled gear assemblies to accurately reproduce the rotational movement of an actual gear train. Finally, drawings can be created either from parts or assemblies. Views are automatically generated from the solid model, and notes, dimensions and tolerances can then be easily added to the drawings as needed (Fig. 1). Figure 1 Modelling of Flat Plate Stiffener ANSYS develops and markets finite element analysis software used to simulate engineering problems. The software create simulated computer models of structures, electronics, or machine components to simulate strength, toughness, elasticity, temperature distributions, electromagnetism, Fluid flow and other attributes. ANSYS is used to determine how a product will function with different specifications, without building test products or conducting crash tests. For example, ANSYS software may simulate how a bridge will hold up after years of traffic, how to best process salmon in a cannery to reduce waste, or how to design a slide that uses less material without scarifying safety. Most ANSYS simulations are performed using the ANSYS Workbench software, which is one of the company’s main products. Typically ANSYS users break down larger structures into small components that are each modelled and tested individually. A user may start by defining the dimensions of an object, and the adding weight, pressure, analyses movement, fatigue, fractures, fluid flow, temperature distribution, electromagnetic efficiency and other effects over time (Fig. 2). Figure 2 Meshing of the plate Table 2 Analysis of Material Result Table 2 from the analysis for total deformation, shear stress, strain energy, normal stress, tensile deformation and tensile equivalent stress is tabulated. From the analysis it can be concluded that carbon fiber is the best material for the consider of flat plate stiffener, as it has less deformation low density and also has high normal stress compared to other material. 4. CONCLUSION This project mainly concentrates on analyzing the structural integrity of the considered geometry. The static structural analysis is carried out to analyze the strength of the flat plate stiffener for two different materials i.e., carbon fiber and Aluminum using ANSYS. It is concluded that carbon fiber can be used as a replacement for present day material having less structural properties. It can be used to increase the range of the aircraft. These materials are the future of Aerospace industry. From the experimental analysis, it is found that carbon fiber is the best material for the consideration of flat plate stiffener, and it has less deformation, low density and also high normal stress compared to other material. Declarations Author Contributions: Conceptualization, G.R., R.S. and J.W.M.; methodology, G.R. and J.W.M.; validation, R.S. and S.K.; formal analysis, G.R. and R.S.; data curation, R.S., S.K., P.P.L. and J.W.M.; writing—original draft preparation, G.R. and J.W.M.; writing—review and editing, G.R., J.W.M., R.S. and S.K.; supervision, R.S. and G.R. All authors have read and agreed to the published version of the manuscript. Funding: This research received no external funding. Institutional Review Board Statement: Not applicable. Data Availability Statement: The data can be obtained from the corresponding author on request. Acknowledgments: We acknowledge the institutional management and family members for their immense support. Conflicts of Interest: The authors declare no conflict of interest. References Bo Wang, Musen Yang, Dengyu Zhang, Dachuan Liu, Shaojun Feng, Peng Hao , Alternative approach for imperfection-tolerant design optimization of stiffened cylindrical shells via energy barrier method, Thin-Walled Structures (2022), 172 , 108838. Koiter,W.T., M., Pignataro, An alternative approach to the interaction between local and overall buckling in stiffened panels Buckling of Structures/Proc. of IUTAM Symposium, Cambridge (1974), pp.133-148. Teter, Kolakowski, Z., Interactive buckling and load carrying capacity of thin-walled beam-columns with intermediate stiffeners Thin Wall Struct. (2004),42, pp.211-254 Hoppmann, W. H. and Magness, L. S., Nodal patterns of the free flexural vibrations of stiffened plates, Journal of Applied Mechanics (1957), 24, pp.526-530. Kirk, C. L., Vibration characteristics of stiffened plates, Journal of Mechanical Engineering Science (1960), pp. 242-253. Amar, N. Nayak, Laren Satpathy, Prasant K. Tripathy, Free vibration characteristics of stiffened plates, International Journal of Advanced Structural Engineering (2018), 10, pp.153-167. Matsunaga, H., Vibration of cross-ply laminated composite plates subjected to initial in-plane stresses, Thin-Walled Structures (2002), 40(7-8), pp.557–571. Mazin Victor Yousif, Nazar Kais M. Naief, Yahya M. Hamad, Optimum height of plate stiffener under pressure effect, First Regional Conference of Eng. Sci. NUCEJ Spatial ISSUE (2008),11(3),pp.459-468. Do Kyun Kim, Su Young Yu,Hui Ling Lim and Nak-Kyun Cho, Ultimate compressive strength of stiffened panel: An empirical formulation for flat-bar type, Journal of Marine Science and Engineering (2020),8(8), 605; https://doi.org/10.3390/jmse8080605. Sheikh, I. A., Elwi, A. E., Stiffened steel plates under combined compression and bending, Journal of constructional steel research (2003), 59(7), pp.911–930. Grondin G.Y., Chen Q., Elwi A.E., Cheng, J. J., Stiffened steel plates under compression and bending. J Construct Steel Res 1998; 45(2), pp.125–48. Paik, J.K., Thayamballi AK, Kim D.H., An analytical method for the ultimate compressive strength and effective plating of stiffened panels, J Construct Steel Res 1999; 49, pp.43–68. Paik, J.K., Thayamballi A.K., Park Y.I., Local buckling of stiffeners in ship plating, J Ship Res (1998), 42(1), 56–67. Ghaith A. Abu Reden., & Sandor Adany. (2021). On the Optimal Shape and Placement of Longitudinal Stiffeners in Longitudinally Stiffened Plates. Proceedings in Civil Engineering, 6(3-4), 1805-1809. https://doi.org/10.1002/cepa.2438 ] Bedair, O. K. (1997). Influence of stiffener location onthe stability of stiffened plates under compression andin-plane bending. International journal of mechanicalsciences, 39(1), 33-49. Vu, Q. V., Papazafeiropoulos, G., Graciano, C., & Kim,S. E. (2019). Optimum linear buckling analysis of lon-gitudinally multi-stiffened steel plates subjected tocombined bending and shear. Thin-Walled Structures,136, 235-245. AASHTO LRFD bridge design specifications. (2008).Washington, D.C.: American Association of StateHighway and Transportation Officials. Tables Tables 1 and 2 are available in the supplementary files section Additional Declarations No competing interests reported. Supplementary Files Table1.jpg Table 1 Mechanical Properties Table2.jpg Table 2 Analysis of Material Result 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8772666","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":599148587,"identity":"e5a10ef3-c36c-4e8b-ab62-3934b01273b0","order_by":0,"name":"Gayathri R","email":"","orcid":"","institution":"Karunya Institute of Technology and Sciences","correspondingAuthor":false,"prefix":"","firstName":"Gayathri","middleName":"","lastName":"R","suffix":""},{"id":599148588,"identity":"2f34d0fd-c86a-40d8-85f0-c1cf3b0db469","order_by":1,"name":"Suresh Kumar R","email":"","orcid":"","institution":"Sri Eshwar College of Engineering and Technology","correspondingAuthor":false,"prefix":"","firstName":"Suresh","middleName":"Kumar","lastName":"R","suffix":""},{"id":599148589,"identity":"5a30d9e5-63be-444c-9103-7f371464a6aa","order_by":2,"name":"Ponmary Puspha Latha D","email":"","orcid":"","institution":"Karunya Institute of Technology and Sciences","correspondingAuthor":false,"prefix":"","firstName":"Ponmary","middleName":"Puspha Latha","lastName":"D","suffix":""},{"id":599148591,"identity":"a8b8e3d2-ab12-48f1-8079-8428a938d20e","order_by":3,"name":"Rajkumar Sivanraju","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAw0lEQVRIiWNgGAWjYPACNjkQeeABkcoZG4BajMFaEkjQwpAIIhiI0sLffvj444oavvT5YYcfAm2xk9NtIKBF4kxaYuOZY2y5G2+nGQC1JBubHSCgxUCCx7CxgQ2oZXYCSMuBxG2EtfB/bGz4x5ZuODv9A7FaeBgbG9vYEuSlc4i0BegXw5mNfWyGG6RzCg4kGBDhF2CIPfjY8O2YvPzs9M0fPlTYyRHUAgXHGAzAKg2IUw4CNQzyDcSrHgWjYBSMghEGAI9MRV9agZxoAAAAAElFTkSuQmCC","orcid":"","institution":"Hawassa University","correspondingAuthor":true,"prefix":"","firstName":"Rajkumar","middleName":"","lastName":"Sivanraju","suffix":""},{"id":599148593,"identity":"63930c3f-3ce7-4ed5-869f-f400101da948","order_by":4,"name":"John Weslin M","email":"","orcid":"","institution":"Karunya Institute of Technology and Sciences","correspondingAuthor":false,"prefix":"","firstName":"John","middleName":"Weslin","lastName":"M","suffix":""}],"badges":[],"createdAt":"2026-02-03 07:55:02","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8772666/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8772666/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":103903215,"identity":"cd529f2a-a9b3-42e0-9103-a27f5d29f31f","added_by":"auto","created_at":"2026-03-04 10:22:46","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":15583,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eModelling of Flat Plate Stiffener\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Fig1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8772666/v1/c5f48cc9318530ad91b2cd39.jpg"},{"id":103903217,"identity":"af504736-30d7-4649-a309-5a3efd6b612c","added_by":"auto","created_at":"2026-03-04 10:22:46","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":43732,"visible":true,"origin":"","legend":"\u003cp\u003eMeshing of the plate\u003c/p\u003e","description":"","filename":"Fig2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8772666/v1/263842a4cfd10e20703d4249.jpg"},{"id":104004286,"identity":"2ff59181-49b4-4be3-bbd5-e3e07bd75694","added_by":"auto","created_at":"2026-03-05 14:41:06","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":415185,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8772666/v1/890323bf-a32c-4521-b469-ea26ec84bba7.pdf"},{"id":103903216,"identity":"ae84c7e2-f2f7-456c-a342-6e1cf26a4e52","added_by":"auto","created_at":"2026-03-04 10:22:46","extension":"jpg","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":43738,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTable 1 Mechanical Properties\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Table1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8772666/v1/3615d3a9d639d8ab1f3d21b3.jpg"},{"id":103903218,"identity":"71efa966-3140-417c-9308-ecd85e3b582f","added_by":"auto","created_at":"2026-03-04 10:22:46","extension":"jpg","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":65825,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTable 2 Analysis of Material Result\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Table2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8772666/v1/6daa09a77322ae1cd861f4fe.jpg"}],"financialInterests":"No competing interests reported.","formattedTitle":"Flat Stiffened CFRP Panel Design and Analysis","fulltext":[{"header":"1. INTRODUCTION","content":"\u003cp\u003eComposite materials are formed by combining two or more materials and that have quite different properties, and they do not dissolve or blend Into each other. The different materials in the composite work together to give the composite unique properties[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Researcher refer to Fiber Reinforced Polymer (FRP) composites, usually with carbon, glass, aramid, polymer or natural fibers embedded in a polymer matrix. Composite materials based on graphite and boron fiber systems are recognized as the most promising [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. At present, the use of graphite/epoxy materials enables one to reduce structural weight by 20\u0026ndash;25%. Further weight reduction can be attained by increasing the percentage of composites in the total amount of applied materials, as well as by improving the design methodology and fabrication technology used for composite structures [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. It was impossible to use the new degrees of freedom given by composite materials without the development of the corresponding science of composite structures. This science has been developed in Russia for many years with the support of government. Stiffeners are employed to resist lateral loading of the plate and are usually made from the rolled shapes integrally welded to the plate. Such stiffeners are distinct from the other stiffeners and it is used to prevent plate buckling. Typically, stiffeners run continuously through the supporting frames. Spot welding also gives some control over dimensional stability. Polymer dispersions are applied by padding, slop padding, foam, spray and knife coating [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThermoplastic binders are important in the manufacture of nonwoven fabrics intended for moulding operations. Other binding chemical finishes include anti-dust finishes, which bind and depress dust in applications such as mats. The final goal of application of any material is its rational utilization in a structure. Composite materials based on graphite and boron fibre systems are recognized as the most promising. At present, the use of graphite/epoxy materials enables one to reduce structural weight by 20\u0026ndash;25%. Further weight reduction can be attained by increasing the percentage of composites in the total amount of applied materials, as well as by improving the design methodology and fabrication technology used for composite structures. Initially, composites were used in secondary structures, like the interior details and floors; next, they were used in less critical load-bearing components, i.e., the landing gear well doors, doors of the hatches, etc. At present, composite materials are being introduced into such primary structures of the airframe as the wing, fuselage and control surfaces. It was impossible to use the new degrees of freedom given by composite materials without the development of the corresponding science of composite structures.\u003c/p\u003e \u003cp\u003eThe linear buckling theory is no longer useful to analyze the post buckling behavior of a thin plate and the buckling strength cannot be used as a design criterion for such structures. Since the problem is too complicated to be treated mathematically, In general, several empirical formulae have been put forward based on GALCIT and MIT tests. The linear buckling theory of the plate in the strain hardening range based on the effective moduli of the material after yielding can furnish the appropriate design criterion which predicts the ultimate strength of the panels. Most of the stiffened plates have used stiffeners in the two mutually orthogonal constant directions. Earlier, these directions used to coincide with the length and breadth of the plate. However, there are now some examples of stiffeners being placed in geodesic fashion depending upon the loads that are applied to the panel. By continuously varying the stiffener orientation, Researcher can align the stiffeners along the load paths for the static case and in a way that can drive the natural frequencies away from the resonance frequencies for a dynamic case. This was the motivation behind the study and making of this paper. Hence the objective of this paper is to analyze a stiffened panel subjected to static and modal analysis [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cdiv id=\"Sec2\" class=\"Section2\"\u003e \u003ch2\u003e1.1 FSDT Mesh-Free Method\u003c/h2\u003e \u003cp\u003eBending and free vibration analysis of circular stiffened plates is done using the FSDT mesh-free method. Due to high strength-to-weight ratio, stiffened plates have been extensively found in civil and oceanographic engineering, transportation and aerospace industry, etc. The stiffeners in the structure enhance the stiffness of the whole structure without consuming too much material and significantly increasing its weight, which greatly improves the cost-effectiveness of the structure. In addition to the common rectangular stiffened plates, the circular stiffened plates have gradually been widely used. For example, the raft foundation of some structures such as water towers, chimneys, silos, etc. are mostly circular in shape; aerospace vehicles and large machinery in industry also have circular parts with stiffeners. Therefore, the study of circular stiffened plates has been highly valued. Many researches have been carried out on stiffened plates. The early researchers used an orthotropic model, which approximated stiffened plates with flat plates of equal thickness and the stiffeners were converted into another layer attached to the original plates. Another option was the grillage model [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. These were the first to analyze the vibration behaviors of stiffened plates by using the orthotropic model or the grillage model. Although the principle of these models was clear and the formulation was simple, they had taken too many simplifications. They encountered difficulties in dealing with the general stiffened plate problems with sparse or uneven arrangement of stiffeners and failed to give satisfactory solutions. In order to improve it, subsequent researchers tended to consider the stiffeners and flat plate of a stiffened plate separately, In order to simulate the stiffeners with the beam model, and to combine the stiffeners and flat plate together by introducing the displacement compatibility between them [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e1.2 Impact of Stiffener Location on Buckling Strength\u003c/h2\u003e \u003cp\u003eThe study analyses the buckling behaviour of a single open stiffener, two open stiffeners and a single closed stiffeners under pure bending and compression and recommends the use of two open stiffeners over single stiffener for longer spans and it has not contained more information for the various stiffener spacing [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. The influence of stiffeners nearer to top flange plays a vital role in the stability of the plate [15]. The stiffeners at the optimal place enhances the critical load for all load cases such as pure bending, and combined bending and shear [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Many researchers focused on optimizing the stiffeners via modifying shape, size and location to increase the stability of the thin plates. But the flat stiffener has the simplest geometry in comparison with other forms of stiffeners such as L, T, Z, I, rectangular and box- section. The research focused on many parameters and its impact on buckling failure and it shows uncertainty analysis also [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. This research uses two stiffeners and its effect in increasing the buckling strength to prevent the failure.\u003c/p\u003e \u003c/div\u003e"},{"header":"2. MATERIAL SELECTION FOR FLAT PLATE STIFFENER","content":"\u003cp\u003eAluminum is lightweight and has a high strength-to-weight ratio, making it an excellent choice for applications where weight is a critical factor. It is also corrosion-resistant, which makes it suitable for use in harsh environments. However, aluminum is more expensive than steel. Composite materials, such as carbon fiber-reinforced polymers (CFRP) are gaining popularity in the aerospace industry due to their high strength and low weight. However, they are more expensive than traditional materials like steel or aluminum. Carbon fiber is a lightweight and strong material that is made from thin strands of carbon. The carbon fibers are woven together and then impregnated with a resin to create a composite material that is strong and stiff. Carbon fiber is commonly used in applications that require high strength-to-weight ratios, such as aerospace, automotive, and sporting equipment.\u003c/p\u003e \u003cp\u003e \u003cb\u003e2.1 Comparison of Properties\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eCarbon fiber and aluminum are both commonly used materials in various industries, including aerospace, automotive, and sports equipment. Here are some key differences between these two materials.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eWeight: Carbon fiber is significantly lighter than aluminum. This makes it an ideal material for applications where weight reduction is critical, such as aerospace and high-performance sports equipment.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eStrength: Carbon fiber has a higher tensile strength than aluminum. Tensile strength refers to the maximum stress a material can withstand before breaking. However, aluminum has a higher compressive strength than carbon fiber, meaning it can withstand more pressure without deforming or breaking.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eStiffness: Carbon fiber is stiffer than aluminum, meaning it doesn't bend or flex as much under load. This stiffness is desirable for applications where rigidity is important, such as high-performance bicycles or racing car frames.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eCorrosion Resistance: Aluminum is naturally resistant to corrosion, while carbon fiber can corrode under certain conditions. However, carbon fiber is not susceptible to galvanic corrosion, which is a type of corrosion that can occur when dissimilar metals come into contact with each other.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eThe Table\u0026nbsp;1 given below shows the properties of carbon fiber and aluminum alloy especially Young\u0026rsquo;s modulus and ultimate strength for the same materials have been compared.\u003c/p\u003e \u003cp\u003e \u003cb\u003eTable\u0026nbsp;1 Mechanical Properties\u003c/b\u003e \u003c/p\u003e"},{"header":"3. MODELLING","content":"\u003cp\u003eSolid Works is an solid modelling computer-aided design (CAD) and computer-aided engineering (CAE) computer program that runs on Microsoft Windows. Building a model in Solid Works usually starts with a 2D sketch (although 3D sketches are available for power users). The sketch consists of geometry such as points, lines, arcs, conics (except the hyperbola), and splines. Dimensions are added to the sketch to define the size and location of the geometry. Relations are used to define attributes such as tangency, parallelism, perpendicularity and concentricity. The parametric nature of SolidWorks means that the dimensions in the sketch can be controlled independently, or by relationships to other parameters inside or outside of the sketch.\u003c/p\u003e \u003cp\u003eIn an assembly, the analog to sketch relations are mates. Just as sketch relations define conditions such as tangency, parallelism, and concentricity with respect to sketch geometry, assembly mates define equivalent relations with respect to the individual parts or components, allowing the easy construction of assemblies. Solid Works also includes additional advanced mating features such as gear and cam follower mates, which allow modelled gear assemblies to accurately reproduce the rotational movement of an actual gear train. Finally, drawings can be created either from parts or assemblies. Views are automatically generated from the solid model, and notes, dimensions and tolerances can then be easily added to the drawings as needed (Fig.\u0026nbsp;1).\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003e \u003cb\u003eFigure\u0026nbsp;1 Modelling of Flat Plate Stiffener\u003c/b\u003e \u003c/p\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eANSYS develops and markets finite element analysis software used to simulate engineering problems. The software create simulated computer models of structures, electronics, or machine components to simulate strength, toughness, elasticity, temperature distributions, electromagnetism, Fluid flow and other attributes. ANSYS is used to determine how a product will function with different specifications, without building test products or conducting crash tests. For example, ANSYS software may simulate how a bridge will hold up after years of traffic, how to best process salmon in a cannery to reduce waste, or how to design a slide that uses less material without scarifying safety.\u003c/p\u003e \u003cp\u003eMost ANSYS simulations are performed using the ANSYS Workbench software, which is one of the company\u0026rsquo;s main products. Typically ANSYS users break down larger structures into small components that are each modelled and tested individually. A user may start by defining the dimensions of an object, and the adding weight, pressure, analyses movement, fatigue, fractures, fluid flow, temperature distribution, electromagnetic efficiency and other effects over time (Fig.\u0026nbsp;2).\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;2 Meshing of the plate\u003c/p\u003e \u003cp\u003e \u003cb\u003eTable\u0026nbsp;2 Analysis of Material Result\u003c/b\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;2 from the analysis for total deformation, shear stress, strain energy, normal stress, tensile deformation and tensile equivalent stress is tabulated. From the analysis it can be concluded that carbon fiber is the best material for the consider of flat plate stiffener, as it has less deformation low density and also has high normal stress compared to other material.\u003c/p\u003e"},{"header":"4. CONCLUSION","content":"\u003cp\u003eThis project mainly concentrates on analyzing the structural integrity of the considered geometry. The static structural analysis is carried out to analyze the strength of the flat plate stiffener for two different materials i.e., carbon fiber and Aluminum using ANSYS. It is concluded that carbon fiber can be used as a replacement for present day material having less structural properties. It can be used to increase the range of the aircraft. These materials are the future of Aerospace industry. From the experimental analysis, it is found that carbon fiber is the best material for the consideration of flat plate stiffener, and it has less deformation, low density and also high normal stress compared to other material.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAuthor Contributions: Conceptualization, G.R., R.S. and J.W.M.; methodology, G.R. and J.W.M.; validation, R.S. and S.K.; formal analysis, G.R. and R.S.; data curation, R.S., S.K., P.P.L. and J.W.M.; writing\u0026mdash;original draft preparation, G.R. and J.W.M.; writing\u0026mdash;review and editing, G.R., J.W.M., R.S. and S.K.; supervision, R.S. and G.R. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cp\u003eFunding: This research received no external funding.\u003c/p\u003e\n\u003cp\u003eInstitutional Review Board Statement: Not applicable.\u003c/p\u003e\n\u003cp\u003eData Availability Statement: The data can be obtained from the corresponding author on request.\u003c/p\u003e\n\u003cp\u003eAcknowledgments: We acknowledge the institutional management and family members for their immense support.\u003c/p\u003e\n\u003cp\u003eConflicts of Interest: The authors declare no conflict of interest.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBo Wang, Musen Yang, Dengyu Zhang, Dachuan Liu, Shaojun Feng, Peng Hao\u003cstrong\u003e,\u003c/strong\u003e Alternative approach for imperfection-tolerant design optimization of stiffened cylindrical shells via energy barrier method, Thin-Walled Structures (2022), 172\u003cstrong\u003e, \u003c/strong\u003e108838.\u003c/li\u003e\n\u003cli\u003eKoiter,W.T., M., Pignataro, An alternative approach to the interaction between local and overall buckling in stiffened panels Buckling of Structures/Proc. of IUTAM Symposium, Cambridge (1974), pp.133-148.\u003c/li\u003e\n\u003cli\u003eTeter, Kolakowski, Z., Interactive buckling and load carrying capacity of thin-walled beam-columns with intermediate stiffeners Thin Wall Struct. (2004),42, pp.211-254\u003c/li\u003e\n\u003cli\u003eHoppmann, W. H. and Magness, L. S., Nodal patterns of the free flexural vibrations of stiffened plates, Journal of Applied Mechanics (1957), 24, pp.526-530.\u003c/li\u003e\n\u003cli\u003eKirk, C. L., Vibration characteristics of stiffened plates, Journal of Mechanical Engineering Science (1960), pp. 242-253.\u003c/li\u003e\n\u003cli\u003eAmar, N. Nayak, Laren Satpathy, Prasant K. Tripathy, Free vibration characteristics of stiffened plates, International Journal of Advanced Structural Engineering (2018), 10, pp.153-167. \u003c/li\u003e\n\u003cli\u003eMatsunaga, H., Vibration of cross-ply laminated composite plates subjected to initial in-plane stresses, Thin-Walled Structures (2002), 40(7-8), pp.557\u0026ndash;571.\u003c/li\u003e\n\u003cli\u003eMazin Victor Yousif, Nazar Kais M. Naief, Yahya M. Hamad, Optimum height of plate stiffener under pressure effect, First Regional Conference of Eng. Sci. NUCEJ Spatial ISSUE (2008),11(3),pp.459-468.\u003c/li\u003e\n\u003cli\u003eDo Kyun Kim, Su Young Yu,Hui Ling Lim and Nak-Kyun Cho, Ultimate compressive strength of stiffened panel: An empirical formulation for flat-bar type, Journal of Marine Science and Engineering (2020),8(8), 605; https://doi.org/10.3390/jmse8080605.\u003c/li\u003e\n\u003cli\u003eSheikh, I. A., Elwi, A. E., Stiffened steel plates under combined compression and bending, Journal of constructional steel research (2003), 59(7), pp.911\u0026ndash;930.\u003c/li\u003e\n\u003cli\u003eGrondin G.Y., Chen Q., Elwi A.E., Cheng, J. J., Stiffened steel plates under compression and bending. J Construct Steel Res 1998; 45(2), pp.125\u0026ndash;48.\u003c/li\u003e\n\u003cli\u003ePaik, J.K., Thayamballi AK, Kim D.H., An analytical method for the ultimate compressive strength and effective plating of stiffened panels, J Construct Steel Res 1999; 49, pp.43\u0026ndash;68.\u003c/li\u003e\n\u003cli\u003ePaik, J.K., Thayamballi A.K., Park Y.I., Local buckling of stiffeners in ship plating, J Ship Res (1998), 42(1), 56\u0026ndash;67.\u003c/li\u003e\n\u003cli\u003eGhaith A. Abu Reden., \u0026amp; Sandor Adany. (2021). On the Optimal Shape and Placement of Longitudinal Stiffeners in Longitudinally Stiffened Plates. Proceedings in Civil Engineering, 6(3-4), 1805-1809. https://doi.org/10.1002/cepa.2438\u003c/li\u003e\n\u003cli\u003e] Bedair, O. K. (1997). Influence of stiffener location onthe stability of stiffened plates under compression andin-plane bending. International journal of mechanicalsciences, 39(1), 33-49.\u003c/li\u003e\n\u003cli\u003eVu, Q. V., Papazafeiropoulos, G., Graciano, C., \u0026amp; Kim,S. E. (2019). Optimum linear buckling analysis of lon-gitudinally multi-stiffened steel plates subjected tocombined bending and shear. Thin-Walled Structures,136, 235-245.\u003c/li\u003e\n\u003cli\u003eAASHTO LRFD bridge design specifications. (2008).Washington, D.C.: American Association of StateHighway and Transportation Officials.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 and 2 are available in the supplementary files section\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"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":"Flat stiffener, CFRP, stiffness, FEA, strength","lastPublishedDoi":"10.21203/rs.3.rs-8772666/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8772666/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe aim of this paper is to analyze the behavior of stiffened Carbon Fiber attached to a flat plate stiffener. The structural behavior of a composite plate with a flat plate stiffener has been studied in this research work. The aim is to investigate the effects of the stiffener on the stiffness and strength of the plate. The composite plates were made of layers of carbon fiber and the flat plate stiffener and it was made of aluminum alloy. The FEA results showed that the stiffener had a significant effect on the stiffness and strength of the composite plate. The addition of the stiffener increased the stiffness and reduced the deflection of the plate. The stiffener also increased the maximum stress and strain values in the plate, indicating an increase in the plate's strength.\u003c/p\u003e","manuscriptTitle":"Flat Stiffened CFRP Panel Design and Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-04 10:22:41","doi":"10.21203/rs.3.rs-8772666/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":"06d2906b-2a5a-413c-9a75-79fe7d1fa6eb","owner":[],"postedDate":"March 4th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-05T14:38:16+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-04 10:22:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8772666","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8772666","identity":"rs-8772666","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}