Impact Response and Structural Optimization of CSCS Sandwich Shells Under Vehicle Impact

In this study, curved steel-concrete-steel (CSCS) shells were employed as protective walls to resist vehicle impact, owing to its high resistance, small deformation and damage found in the former studies. LS-DYNA was employed to numerically study the behaviors of CSCS shells under vehicle impact. Impact force, displacement and internal energy of CSCS shell, displacement of supports and damage contours of concrete were obtained from the FE simulations and discussed in detail. The influences of concrete thickness, steel plate thickness, rise height and impact velocity on the impact response of CSCS shell were also numerically investigated. The results showed that the initial kinetic energy was mainly dissipated through the plastic deformation of the vehicle, and the failure mode was dominated by local deformation. Global deformation only occurred when the CSCS shell was subjected to a high-velocity vehicle impact (i.e., 120 km/h). The comparison between CSCS shell and flat SCS panel subjected to the same vehicle impact showed that the CSCS shell had better performance in terms of higher resistance, smaller deformation and damage level. In order to propose a guideline for designing CSCS shell against vehicle impact, the response surface models for determining displacements of CSCS shell and support were established. Multi-objective optimization method was utilized to obtain the Pareto solution sets between displacement ratio of CSCS shell and vertex displacement of support, as well as between displacement ratio and mass of CSCS shell, which provided the suggestions for the design and application of CSCS shell in protective engineering.