Crushing Responses and Design of CF/EP Composite Structures

Abstract

By virtue of their excellent properties of specific strength-to-mass and stiffness-to-mass ratios, carbon fibre reinforced epoxy (CF/EP) structures are becoming increasingly important in various transportation tools and industrial machines. Many studies have investigated the damage responses of CF/EP composite structures. However, there are still outstanding issues associated with failure-mechanism investigation and design for CF/EP composite structures under crushing loading. First, specific experimental approaches and advantageous models remain inadequate. Second, systematic study of the crushing responses of CF/EP composite structures is necessary. Third, the structural design of CF/EP materials are meaningful but seldom. Transverse impact is a common and important crushing scenario for CF/EP composite sandwich panels (CSPs). This study developed a specific FEA model addressing intralaminar damage, interlaminar and adhesive delamination, and honeycomb core (HC) failure of CF/EP CSPs, and designed an optimal structure under both transverse normal and oblique impact. Next, in-plane crushing responses of the CF/EP CSPs were investigated. Both in-plane localised and globalised crushing tests were conducted to characterise the failure responses and mechanisms of CSPs. CF/EP composite tubes are very promising for crushing energy absorption. This study investigated the failure mechanism and energy absorption of CF/EP tubes under three triggering initiators subjected to both quasi-static and dynamic crushing. This study characterised the failure responses and mechanisms of CF/EP composite structures under different crushing scenarios, and numerical techniques were applied. Optimisation theories with mathematic algorithms were utilised to improve the models’ comprehensive performance. The findings provide a series of valuable data for potential engineering applications.