Dynamic response of clamped all-metallic corrugated core sandwich cylindrical shell under localized lateral shock loading

Abstract

While cylindrical shells having corrugated or honeycomb sandwich walls exhibit attractive properties such as high stiffness/strength at low density and enhanced energy absorption, existing studies focused primarily on axial loading conditions. In reality, however, such sandwich cylindrical shells frequently face the threat of lateral impacts like in the case of high-speed railways and tube/pipeline systems. To explore the dynamic response of a fully-clamped sandwich cylindrical shell under lateral shock loading, a combined experimental and numerical study is carried out. Specimens of aluminum (Al) corrugated core sandwich cylindrical shells as well as thin-walled Al cylindrical shells are fabricated using the method of extrusion. Impact tests on these specimens are conducted using closed-cell Al foam projectiles launched via a light-gas gun. For each specimen, dynamic structural evolution, final deformation mode, and quantitative deflection are comprehensively measured and analyzed. Subsequently, a finite element (FE) model is established to simulate the lateral impact test, with good agreement against experimental measurements achieved. The validated FE model is then employed to quantify the effect of the number of corrugations in the core and explore energy absorption characteristics of individual components in the sandwich shell. In comparison with a thin-walled cylindrical shell of equal mass, the corrugated core sandwich cylindrical shell exhibits elevated lateral shock resistance (particularly so in the case of outer surface mid-point deflection on the impact side and inner diameter crushing), due mainly to energy absorption via core compression. However, within the studied range of impact momentum, the sandwich shell experiences consistently more significant bulging on the rear side than its thin-walled counterpart. A circumferential stress distribution map is constructed to reveal that the introduction of a corrugated core interrupts the continuous transmission path of circumferential stress along the shell’s circumferential direction. As a result, the contribution of circumferential membrane force to rear-side deformation is reduced while the influence of bending moment becomes dominant, leading to more significant bulging deformation on the rear side of the sandwich shell.