Maximum stiffness topology optimization and dynamic response of a lightweight sandwich arch under impact load

Based on the bi-directional evolutionary structural optimization method (BESO), the nested loop structure of the traditional dynamic load optimization method was introduced into the ABAQUS-MATLAB platform integrated optimization to improve the dynamic load topology optimization process. Topological optimization design and dynamic response analysis of sandwich arch structure under the impact of projectile with initial velocity of 100 m/s were carried out. After optimization, the deformation mode of the core for sandwich arch can be divided into three symmetrical part: the compression dominated deformation occurs in the middle and the upper part of the mid-span region, which like the triangular lattice truss structure; the tensile and compression dominated deformation occurs in the upper and the lower part of the boundary region respectively, which presents the C-shaped structure; and the transition region, which presents the Y-shaped structure, between the mid-span and the boundary is dominated by the combination of tension and bending deformation. The dynamic response of the optimization results under the impact load was analyzed. The deflections of top and bottom sheets and energy absorption of core of two comparison models with equal mass (Voronoi aluminum foam sandwich arch and solid arch) and optimization arch structure under the impact load with the initial velocity of 100 m/s were compared. The deflection and specific energy absorption of the cores of the three models under the impact of the projectiles with the initial velocities of 100, 80, 50 and 20 m/s were compared. The results show that: under the same impact velocity, the optimization structure has the minimum deflection and the maximum specific energy absorption capability; while with the low impact velocity, the impact-resistance advantage of the optimization structure is not obvious. Furthermore, in the range of the impact velocity which has been studied, the optimization structure shows the better impact-resistance performance with the higher velocity. The dynamic responses of the two optimization structures with symmetric load and asymmetric load (the offset of impact point is 100%) under different load conditions were compared. The deflection of top and bottom sheets and the specific energy absorption of core of four models (symmetric optimization result, asymmetric optimization result, Voronoi aluminum foam sandwich arch and solid arch) were compared. The results show that: under different load conditions, the final optimization results are slightly different, and the different of structural responses under the same load is relatively small. The optimization results obtained under each working condition show slightly better mechanical properties under the corresponding condition, but optimization structures are significantly better than the traditional structures. Therefore, the structure optimized by symmetrical impact load has a certain universality. © 2022 Explosion and Shock Waves. All rights reserved.