High fidelity residual strength assessment for composite aircraft sustainment

The sustainment of composite aircraft requires analysis tools and knowledge suitable to support airworthiness decision-making. High-fidelity simulation tools have significant potential to address this challenge, though further study is required on incorporating the complex damage introduced via low velocity impact such as a tool drop during maintenance. In this paper, a methodology for compressive residual strength assessment is investigated that uses the highfidelity computational analysis tool BSAM. The tool represents fibre fracture, matrix cracking and delamination, and progression and interaction of these modes. The experimental impact damage was mapped and modelled, which included the geometry of the impact indentation, fibre fracture in the plies and delamination in ply interfaces. It was found that inclusion of the fibre fracture in the impact region has a significant effect on the development of damage modes, due to the interaction with the fibre fracture region. The results support improved sustainment of defence platforms, through enhanced predictive capability and material understanding.