Optimisation of thin-walled hybrid vertical struts for crashworthy aircraft designs

This research concerns the crashworthiness enhancement of a model of a Boeing 737-200 fuselage section. Using a validated numerical specimen, four thin-walled crushable hybrid energy absorbers are added to the aircraft to work as vertical struts. The absorbers are composed of a hollow aluminium tube, a star-shaped glass fibre–reinforced polymer inner matrix and foam extrusions. The absorbers—with variable tube edge and thickness, composite thickness and core height—are single- and multi-objectively optimised. Surrogate models and genetic algorithms are used for the minimisation of acceleration loads, injury levels and the strut’s weight. Results yield a more efficient frames’ collapse evolution with plastic dissipation increased by over 50%. Consequently, acceleration peaks are up to 50% lower at the two measured locations while maintaining low mass values. Injury levels were also reduced from severe to moderate according to an Eiband diagram.