Impact simulation of elastic fuel tanks reinforced with exoskeleton for aerospace applications

Abstract: The main subject of the thesis is impact simulation of an elastic fuel tank reinforced with a polymer exoskeleton. Thanks to its light weight and failure resistance, this type of design shows potential to be used in aerospace applications. The simulation imitates a drop test from the height of 20 m on a rigid surface, in accordance with Military Handbook testing guidelines for fuel tanks. The focus is on establishing the best practices for modelling and solving this type of problems. The computational methods are tested on a generic model of a rectangular prismatic tank with rounded edges. The walls of the tank are made of a combination hyperelastic rubber material orthotropic fabrics. The simulation is performed for the 70% and 100% water lled tank. All calculations are performed using the Altair HyperWorks 13.0 software suite, in particular the RADIOSS solver and OptiStruct Solver and Optimiser. The criteria for evaluation of model and simulation quality are suggested. Comparison is made between various uid (ALE and SPH) and solid (composite and hyperelastic) modelling approaches. Material parameters are found using the least-squares t to the experimental measurements. The nal, most robust and accurate model serves as a basis for establishing a design optimisation procedure, aiming at reduction of mass of tank components while ensuring the structural integrity. Furthermore, the advantages and drawbacks of di erent modelling approaches are discussed. The main conclusions from the study are summarised and suggested directions for future work are given.