Strain rate effect on the mechanical behavior of polyamide composites under compression loading

Abstract

This paper presents an experimental study on the effect of strain rate on the compressive behavior of polyamide composites. Contrary to thermoset woven reinforced composites, thermoplastic woven reinforced composites have always received less interest despite its excellent damage and impact resistances. In this context, this work aims to study the behavior of fiber reinforced thermoplastic composites submitted to high strain rate in compression. The tested material is a thermoplastic composite made of armor tissue of equilibrate glass fiber and the matrix is composed of Polyamide 6 (PA6/Glass). The material is prepared with the fibers woven in 0/90 direction.The compressive mechanical response of PA6/Glass composite was determined in the transverse and longitudinal fibers directions at quasi-static and high strain rates.The hydraulic machine and Split Hopkinson Pressure Bar experiments were conducted to determine the dynamic and quasi static compressive deformation and fracture of the PA6/Glass at strain rates from 10 -5 s -1 to 1 s -1 and 100 s -1 to 2500 s -1 , respectively.In this work, the main goals were to determine the strain rate effect on: elastic modulus, failure stress and failure energy as a function of the loading direction. The strain rate sensitivity of the failure stress level and failure energy were observed. In addition, the failure mechanism was characterized by examining the fracture surfaces using the scanning electron microscopy (SEM) method.In quasi-static conditions of loading, the material reached its capacity due to the formation of shear bands, that concerned all three tested compression directions. In dynamics, the failure took place by 2 shearing followed by delamination. In case of dynamic loading in the direction perpendicular to fibers, the observations made by SEM showed that the failure of the composite had a fragile nature.

Review of Strain Rate Effects of Fiber-Reinforced Polymer Composites

“…Both the compressive strength and modulus were found to increase with increasing strain rates, and the compressive strain to failure was approximately insensitive to strain rates. Massaq et al [ 35 ] investigated the compressive mechanical response of PA6/glass composite in the transverse and longitudinal fibers directions at strain rates from 10 to 2500 s . Positive rate-sensitivity for the elastic modulus and failure stress were observed and the loading direction, viz.…”

Hazard Assessment of Abraded Thermoplastic Composites Reinforced with Reduced Graphene Oxide

“…Previous studies have shown that the release of fillers from polymer composites could be related to intrinsic failure mechanism. Release of rGO either as protruding or as free-standing from the PA6-rGO composite, during the abrasion process, could be explained by an interfacial debonding between the rGO and PA6 molecules or an adhesive failure as a result of the weak interaction between the rGO and PA6 matrix, as reported by previous studies (Massaq et al, 2019;Zaman et al, 2012;Zheng et al, 2019;. In addition, failure of graphene sheets is also highly possible, i.e., graphene layer breakage.…”

Material Characterization of PMC/TBC Composite Under High Strain Rates and Elevated Temperatures

“…In their simulations they used the value of 0.1 referring to experimental data; however, they also reported their initial research, where the friction coefficient varied in the range of 0.1 to 1, and the results changed by 6%. Friction reduction can be achieved by applying grease to the sample surface; its impact can also be taken into account analytically, as in [34]. In [19], a geometrically advanced RVE model with additional reinforcement in the z axis is shown; however, the authors point out technical problems with contact.…”