Dynamic behavior of composite joints in hydrodynamic ram simulator

Abstract

The fracture behavior of carbon/epoxy composite joint structures under highly dynamic pressure loading was studied experimentally and numerically. The considered dynamic pressure loading, called hydrodynamic ram (HRAM), potentially causes fractures in structures filled with fluid. First, experiments using the HRAM simulator method were carried out to monitor the fracture behavior of the composite joint structure. In the experiment, highly dynamic pressure loading was generated which propagated and initiated the fracture of the composite joint. Next, numerical simulation was performed through finite element analysis using LS-DYNA. The dynamic pressure loading inside the fluid was predicted using the arbitrary Eulerian Lagrangian (ALE) method and the fracture behavior of the composite joint structure was simulated using cohesive zone modeling (CZM). The analysis was validated by comparing the predicted results with those from the experiment. The predicted pressure loadings were well-matched with the experimentally measured ones. The strain histories and failure strain values obtained by the analysis also agreed reasonably well compared to those in the experiment for selected points in the composite structure. Finally, the effects of impact velocity and the stiffness of the joint structure on the fracture behavior were examined.