Comparative study of the thermomechanical properties of natural fiber reinforced thermoplastic composites: A structural application for quadcopter design

Abstract

The growing global demand for sustainability has led bio-sourced fibers to be identified as an alternative to synthetic fibers. In this paper, micromechanics and multiscale modeling approaches are used to predict the thermomechanical behavior of thermoplastic (polypropylene PP matrix) composites reinforced with four different natural fibers: flax, vegetal-technic, woodforce and a hybrid of flax and vegetal-technic, for random and aligned fiber orientations. Different microstructural orientations (0°, 45°, 90° and random) are generated and computed using the finite element method. Besides, an analytical modeling based on the Mori-Tanaka homogenization scheme is used to validate numerical results. The thermomechanical results showed a good agreement between the numerical computation and analytical approach for the aligned fiber orientations. In addition, the mechanical results obtained for the random fiber orientation remain in agreement with the experimental and analytical results reported in the literature. Besides, a user-defined material (UMAT) is implemented on tensile, compression and shear specimens. Through a virtual characterization, a material card for a 50% volume fraction of fiber is established for a flax-PP composite. Finally, an application made on a quadcopter frame, gives the failure indicators under thermomechanical loads at −20 °C and 55 °C, demonstrating the capability of plant fibers composites to withstand extreme conditions.