Study of organic matrix composite behavior under dynamic loadings [document électronique

Abstract

The investigation of dynamic mechanical behavior of E-Glass/Epoxy composite for naval applications is performed in this thesis. Firstly, the effect of hygrothermal aging on water diffusion and degradation of thick E-glass/epoxy laminates for both in-plane and through thickness is studied under immersion in tab water at 60°C. The amount of water uptake was affected by the orientation angle for both in-plane and through thickness laminates. Apart ±60°IP, ±55°IP and ±55°(XY)TT laminates that exhibited a Fickian behavior, the others followed a two phases model. Furthermore, new algorithms were developed for delimiting SHPB pulses and validated through typical in-plane dynamic compressive loading tests on [±55°]20 laminates. For most laminates, absorption of tab water at 60°C provoked a decrease of compressive modulus and maximum stress and an increase of strain at maximum stress except the slight increases in maximum stress for [90°]40 IP, [0°]40 TT and [90°]40 TT. The highest amount of water uptake of 6.52% for [90°]40 IP resulted in strain rate independency of compressive modulus at lower strain rates and of maximum stress at higher strain rates. However, the higher amount of water uptake of about 4.25% for [±30°]20 TT resulted in strain rate independency of strain at maximum stress.