Geometry and temperature effects on the tensile modulus of randomly oriented short fibers reinforced biocomposites using finite elements method

Abstract

In this study, the effect of the fiber’s geometry and the temperature on the tensile modulus of biocomposite materials is investigated. Digimat® software is used, which applies the numerical finite elements method to obtain the tensile modulus of the biocomposites C1, C2, and the biocomposite (PP+30%Hemp). The first modeled biocomposite material C1 consists of (PHBV/PBAT) matrix reinforced by 30% of randomly oriented short natural Switchgrass fibers, while the second biocomposite material C2 is built of polypropylene (PP) matrix reinforced with 30% of randomly oriented short natural Miscanthus fibers. To validate the approach, a comparison between the conducted modeling results and previous experimental results is done, and the possibility to evaluate the tensile modulus of the biocomposites C1 and C2 by using Digimat® software is confirmed. Regarding the effect of fiber geometries, it is found that the essential factor in cylindrical fibers is the ratio L/D. When the length of the fibers increases, the ratio L/D increases, and this leads to a higher modulus. The same pattern is confirmed for the rectangular fibers, when the length of the rectangular fibers increases, it also leads to a higher tensile modulus. Additionally, it is noticed that after a certain value of fiber length, the tensile modulus becomes stable. The results show that the tensile modulus remains relatively constant after a certain value of fiber length. The effect of the fiber length on the tensile modulus of biocomposites was discussed for both Miscanthus and Switchgrass fibers with cylindrical and rectangular cross-section, and follows the same pattern for both uses. As for the effect of temperature on the tensile modulus of biocomposite materials, it is confirmed that the modulus of both matrix and fibers decreases with increasing temperature, consequently the modulus of the biocomposite material reduces.

Date	18 Oct 2023
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Anh Dung Ngô (Supervisor)