Mechanical properties and low-velocity impact analysis of camel hair and hybrid camel hair/flax fibre-reinforced epoxy

Abstract

Composite plates structures are subjected to many damage problems under low-velocity impacts such delamination and matrix cracking, in order to know the importance of hybridisation on improving mechanical properties. This study explores the low-velocity impact behaviour of two composites: one reinforced with camel hair fibre/epoxy (CHF/Epoxy) and the other with a hybrid of camel hair and flax fibres camel hair fibre–flax fibre/epoxy (CHF-Flax/Epoxy). Static tests (tensile, compression, and bending) were conducted to characterise the mechanical properties of the composites. Impact tests were performed using a drop weight impact machine at three energy levels (3, 7, and 20 J). Particularly, the hybrid composite plate (camel hair fibre/epoxy) exhibited superior mechanical properties in static tests, leading to enhanced impact resistance compared to the composite plate (camel hair fibre/epoxy). Additionally, a numerical study was conducted using a 3D finite elements model. The Hashin criteria and the progressive damage model were used to predict intralaminar damage, and surface-based cohesive behaviour with quadratic stress failure criteria was used to predict delamination. The progressive damage model was coded and its implementation is conducted with a user-defined material subroutine (VUMAT) for Abaqus/Explicit. The damage mechanism and energy dissipation were observed at each energy level. Matrix cracking occurred first, followed by delamination. The 3D damage model was able to simulate the damage initiation and damage evolution until failure. The results of the model showed good agreement with experimental results in term of force, displacement and energy dissipation curves.