Blast response and optimization of cylindrical sandwich shells with toroidal tubular cores

Experimental, theoretical and numerical simulations were carried out to investigate the dynamic response and blast resistance for the cylindrical sandwich shells with toroidal tubular cores under internal blast loading. The typical deformation modes of internal/external shells and toroidal tubular core layers were observed through experiments. A theoretical model considering the circumferential plastic membrane forces and the axial moment components was performed to predict the blast response of sandwich shells. The mid-points deflections and velocities of internal/external shells obtained by theoretical predictions are consistent with the experimental and numerical results. Influences of wall thicknesses of internal/external shells and the axial/radial gradient of toroidal tubular cores on the blast resistance of single and triple layers sandwich shells were investigated by numerical simulations. The results show that the negative gradient structures have the smallest normalized deflection, while the hybrid gradient structures have the highest energy absorption. On this basis, multi-objective optimization of the sandwich shells was carried out by combining the response surface method (RSM) and the multi-objective genetic algorithm (MOGA). The optimization results yielded a trade-off between deformation, energy absorption and structural mass, and demonstrated the advantages of the "Pareto front" in these design cases.