Analysis of Puncture Resistant Steel for Tank Cars

A new puncture resistant steel is developed to improve the safety of tank cars transporting flammable liquids. The puncture behavior of the tank cars is simulated using a ductile damage model available in the finite element program, ABAQUS. The damage model assumes that, for a given stress‐state (triaxiality), failure initiates at the maximum load‐carrying capacity. The subsequent damage evolution is defined by its fracture energy. To investigate a range of triaxiality conditions, uniaxial tensile tests are performed on notched, round‐bar specimens for both current and new steel grades. Numerical simulations of each test are performed and validated with the test data. The relation between the equivalent plastic strain at failure initiation and the stress triaxiality (damage initiation) is obtained from the test data and the simulations, as is the fracture energy (damage evolution). Impact simulations are performed on the tank car and the results show that the new steel absorbs more impact energy, thereby delaying puncture. The outline of this paper is as follows. In Section 2, the experimental details of tensile tests are discussed. In Section 3, the numerical simulations of tensile tests, the damage model, and the puncture simulations are presented. In Section 4, the tank car simulation results for various impact velocities are discussed. Section 5 provides the conclusions of this study.