Damage of woven composite under tensile and shear stress using infrared thermography and micrographic cuts

Abstract

Infrared thermography was used to study damage developing in woven fabrics. Two different experiments were performed, a ±45°tensile test and a rail shear test. These two different types of tests show different damage scenarios, even if the shear stress/strain curves are similar. The ±45°tension test shows matrix hardening and matrix cracking whereas the rail shear test shows only matrix hardening. The infrared thermography was used to perform an energy balance, which enabled the visualization of the portion of dissipated energy caused by matrix cracking. The results showed that when the resin is subjected to pure shear, a larger amount of energy is stored by the material, whereas when the resin is subjected to hydrostatic pressure, the main part of mechanical energy is dissipated as heat.

Deviation-based calibration for progressive damage analysis in pultruded glass fiber reinforced composites

“…It is well known that fiber reinforced composites exhibit a nonlinear response under pure shear loadings (Kaddour et al., 2013). Off-axis tensile tests of [±45] laminates are required to determine the relevant stress-strain curves (Lisle et al., 2015). Due to the lack of experimental data on the four pultruded GFRP laminates, nonlinear shear was not considered here.…”

STAR: Visual Computing in Materials Science

“…Aside specific properties and characteristics of materials such as flow stress, strain and strain rate, surface strain and temperature under strain, also their deformation behavior during the targeted usage are of interest. An example for stress and deformation analysis is found in the work of Lisle et al [LBP*15], investigating the damage of woven composites under tensile and shear stress using infrared thermography and micrographic cuts. The authors computed stress‐strain curves as well as temperature variation fields of the specimens encoded in 2D colormaps and used 2D scanning electron micropcopy (SEM) micrographs for verification.…”

Thermography-based approaches for multi-scale damage assessment in woven composite materials

“…If the macroscale damage, such as intra-yarn cracking and delamination, can be spotted and located by IR thermography because of the heat it generates when it appears [2], it is much more complex when it comes to microscale matrix cracking. Some authors proposed an energy approach aiming at visualizing the portion of dissipated energy caused by damage [3]. As far as non-destructive inspection is concerned, conventional techniques such as active thermography or ultrasonic testing have shown their limits: even macroscale cracks become uneasy to detect once they are closed back up when the composite material is not under load anymore.…”