Mathematical Modelling of Tensile Mechanical Behavior of a Bio-Composite Based on Polybutylene-Succinate and Brewer Spent Grains

A model based on the fitting of stress-strain data by tensile tests of biocomposites made of a bioplastic (polybutylene succinate, PBS) and spent brewer's grain filler (BSGF) is developed. The model is suitable to describe the elastic-plastic behavior of these materials in terms of two mechanical parameters (tensile stress and tensile stiffness or Young's modulus) depending on the filler concentration. The mechanical characteristics, derived from the fitting parameters, show a good agreement with the experimental data. The mathematical model used here could be an important aid for the experimentation and the manufacturing process as it allows to predict the mechanical tensile parameters of a mixture with different filler concentrations, avoiding the long and complex preparation cycle of bio-composites, as well as the specific mechanical tests. The physical properties required by the objects created with the PBS-BSGF bio-composite by the partners/stakeholders of the research project co-financing this research, can be quite different. Therefore, a mathematical model that predicts some of the mechanical properties in terms of the mixture composition may be useful to speed up the selection of the required amount of BSGF in the mixture.