LS-DYNA® Impact Simulation of Composite Sandwich Structures with Balsa Wood Core

The impact damage response of balsa core sandwich composite plates with S2-glass/ epoxy reinforced facesheets is evaluated by impacting them with a spherical steel projectile at single impact locations. The impact damage can significantly reduce the structural integrity and load bearing capacity of a composite structure. Under high velocity impact loading, laminated composites experience significant damage causing fiber breakage, matrix cracking and delamination. Energy absorption and delaminations from high velocity impacts with spherical projectile of .30 caliber is discussed. Finite element modeling was used to gain insight into failure modes, energy absorption, and damage prediction. During high velocity impact, composite laminates undergo progressive damage and hence, Material Model 162, a progressive failure model based on Hashin’s criteria, has been assigned to predict failure of the laminates. The laminates, the projectiles and the balsa wood core are meshed using brick elements with single integration points. These results were then compared with experimental data obtained from three layer S-2 glass/epoxy facesheets balsa core sandwich structures. An excellent correlation between experimental and numerical results had been established.