Failure behavior of a composite T-joint subjected to hydrodynamic ram

The Hydrodynamic ram (HRAM) phenomenon is one of the main types of ballistic battle damages of a military aircraft and has great importance to airframe survivability design. The HRAM phenomenon occurs in aircraft wing structures with internal fuel tanks. HRAM can generate approximately 690 bar (10000 psi) of pressure in the fuel tank. It causes significant damage to the wing fuel tank, which contains the fluid, and the connection structure of the wing fuel tank. The HRAM effect occurs due to the interaction between the fluid and structure, and damage can be investigated by measuring the pressure of the fluid and the dynamic strains on the structure. In this paper, a static test and an HRAM test of a composite T-joint were performed. The HRAM test utilized a ram simulator which can generate HRAM pressure. When a high speed cylindrical puck was fired to the ram simulator filled with water, HRAM pressure was generated, and the pressures of the fluid was measured. The failure behavior of the composite T-joint due to HRAM pressure was examined using the strain gauges and a PVDF sensor which were attached to the surface of the composite T-joint.