The exponential model versus a modified Chamis model and applications to sustainable particulate composites

Abstract

AbstractThe Exponential model is introduced to predict the modulus of particulate or short‐fiber reinforced composites. The model allows the prediction of Young's modulus, bending modulus, shear modulus, and bulk modulus in a series of composites from a single experimental point. Subsequently, a modification of the widely used Chamis model is introduced, also allowing the prediction of particulate composite moduli from a single experimental point. The predictions of each model are compared with original experimental data derived from tension tests on sustainable and bio‐based composites, covering common cases of thermosets and thermoplastics, as well as different chemical treatments and sizes of the reinforcing materials, and are plotted against the predictions of the rule of mixtures, the inverse rule of mixtures and the Chamis model. Two different matrices (PLA and Ecopoxy) and six different reinforcements (chemically treated and untreated Luffa cylindrica short fibers, acetylated and untreated cotton flocks, and olive pits of 1–5 μm or 50–150 μm diameter) are used. The comparisons show that both the proposed models are capable of achieving much higher prediction accuracy (2.28–59.51 times less root mean square error) than the three models already in use, and easily adapting to the matrix and/or reinforcement changes.