Simulation of a CMVSS 215 bumper pendulum test series with LS-DYNA

In the course of an increasing automotive development for international markets many new loadcases have to be tested. The Canadian bumper pendulum test (CMVSS215) is one of these loadcases that form a special challenge for the simulation with LS-DYNA due to its sequential process. For this test four different bumper pendulums have to impact the vehicle, while with each new test the prior damages have to be taken over. Until now the simulation had to be interrupted after each impact due to the necessity of repositioning the vehicle to the initial state. This demands personal intervention of an engineer after each of the first three impacts costing useful time. In some cases complex scripts are run between the impacts to reposition the car, which has the advantage of being independent of human intervention, but still these are time-consuming methods. Much more practicable and feasible is a solution directly using the possibilities of LSDYNA which neither cost any script processing time nor affords human intervention. At Ingenieurbüro Huß & Feickert a method was developed which links the motion of the impactors to the movement of the car so that each pendulum can start in the right initial position for the specific loadcase. Thus the test can be performed in one single run saving useful time for development.