Impact damage and compression behaviours of three-dimensional angle-interlock woven composites after thermo-oxidation degradation

Abstract

This paper reports impact and compression behaviours of three-dimensional angle interlock woven composites after the thermal ageing degradation in both experimental and finite element analyses. The composite coupons have been aged in atmospheric environment for 4, 8, 16 and 32 days at 180℃. Barely visible impact damage was induced by low velocity impact test and the residual strength was evaluated by following compression test. The results show a substantial decline in compression after impact properties after thermal ageing. After aging at 180℃ for 32 days, the compression after impact stress and modulus retention rates of three-dimensional woven composites are 59% and 82.2%, respectively. Such degradation is attributed to interface damage and matrix degradation. The fracture morphologies observed by microscopy revealed that the failure of the original specimen was dominated by matrix crack, while for long time aged specimens interface degradation became main damage mechanism. The numerical study was used to unveil the influence of matrix crack and interface degradation on failure developments of composites. The results indicate a variation from a brittle failure mode to a progressive failure model after long time ageing.

Low-velocity impact and residual flexural behaviors of 2.5-D woven composite under accelerated thermal ageing: Experiment and numerical modelling

“…The degradation of the epoxy matrix was experimentally characterized by previous study (Cao et al., 2018) and implemented into material model.…”

“…The micro-cracks provide additional paths for oxygen diffusion, thus accelerating the degradation rate. Many studies (Cao et al., 2018; da Silva et al., 2016; Fan et al., 2016; Mouzakis et al., 2014; Wang et al., 2017) have demonstrated that the deterioration of the fiber–matrix interface and consequent fiber debonding caused by thermal oxidation ageing had a significant influence on the failure mechanism of composites.…”

Failure mechanism of Ω-shape 3D orthogonal woven composite component under transverse low-velocity impact and subsequent axial compression load

“…It needs to be considered that LVI history which retain the final deformation and damage excluding the internal stress state as the initial conditions for the subsequent CAI analysis. More importantly, few studies (Cao et al., 2018, 2020) have analyzed the LVI and CAI behavior of 3 D woven composites at mesoscopic scale. And different failure modes will play an important role in the stress state and failure behavior of warp, weft and Z-yarn under progressive compression after impact, which should be further studied in detail when the profile of composite is not a planar structure, such as the Ω-shape configuration.…”