Abstract:
Engineering structures like those with applications in aerospace industry, marine industry and sports industry etc. have composite materials under impact loads. Understanding of failure characteristics of composite materials under various loading condition is essential to ensure a reliable design and to avoid catastrophic failure. The damage behaviour of composites has been under research for different loading conditions. Most of the research studies have focused the failure under quasi-static loading and low velocity impact loading. However, damage behaviour under high-energy impact is a completely different phenomenon than the former. In addition, very few studies are available on the damage modelling of fibre-ceramic sandwich structures. This thesis is an attempt to further extend the understanding of failure of composite materials by investigating the damage behaviour under high-energy impact loading.
The research methodology adopted utilizes an analytical modelling and numerical simulations of composite materials under impact loading. The analytical model is derived using laminate theory and fracture mechanics as a strength based and energy-based approach respectively. Finite element analysis (Explicit dynamic) is carried out using a commercially available software ABAQUS 6.13. Simulation model is benchmarked with published literature and showed good correlation.
It is observed that energy absorption increases with increase in interface area by changing the tile configuration of core for a range of impact energy (0-40J). While, solid core shows dominant energy absorbing behaviour at high-energy impacts (>40J). However, placing the ceramic core results in increased damage energy value throughout as compared to pure composite panel.
Moreover, as the impact energy increases the material behaviour tend to be more brittle in nature and delamination at the interface of tiles in ceramic core is no longer a dominant failure mode, which is the result of high rate of loading. In addition, the core shatters as soon as the projectile hits the panel and tensile failure of fibre is now predominant.
