Damage and failure in carbon fiber-reinforced epoxy filament-wound shape memory polymer composite tubes under compression loading

In this paper, axial and radial compression tests of carbon fiber/epoxy filament wound shape memory polymer (SMP) composite tubes were carried out to investigate the corresponding mechanical response. Carbon fibers impregnated with epoxy resin matrix were wound with ±45° layers. The effects of temperature, compression times, defect hole area, shape, and distribution on the mechanical properties of composite tubes were studied and analyzed, respectively. Meanwhile, the mechanical model of stress distribution about the defect hole, under axial compression loading, was established via using the method of complex function. Furthermore, the failure factors of specimens were analyzed. As a result, the defect with sharp angle would result in lower buckling load and Young's modulus. In addition, the failure area, where the delamination of materials, was predominantly located in the middle of specimen. The more times of compression to failure would result in the lower buckling load and Young's modulus of specimens, and the relationship was mainly in form of a specific power function. According to Hashin failure criteria, the effect of axial compression times on buckling load and equivalent modulus was investigated.