Sensitivity analysis-based variable screening and reliability optimisation for composite fuselage frame crashworthiness design

During the impact process, fuselage frame structures often experience severe crushing-induced kinematic deterioration. To improve cabin safety, this paper developed an analysis and design algorithm to optimise 2D triaxially-braided composite (2DTBC) frame under dynamic crush-type load. The design methodology integrates three concepts coming from several different communities including numerical simulation, sensitivity analysis-based variable screening and reliability optimisation. Based one continuous medium mechanics theory, a basic finite element (FE) model coupled with multiple failure modes is built at the macroscopic level previously. Afterwards, the Sobol' global sensitivity analysis is performed to derive a design variable importance hierarchy. Finally, differential evolution (DE) algorithm is implemented to identify the optimum frame geometry that has maximum energy-absorption capacity. The investigation demonstrates that appropriate redistribution of shape parameters of the frame could enhance its design reliability and crashworthiness, and the higher number of design variables often performs better from the energy-absorption viewpoint.