| The sled crash test is a very important method for automotive passive safety research and has low cost, good repeatability, so it is commonly used for appraising the performance of the safety system through reappearing special waveform. The crash energy-absorbing device is the key component in the sled crash test, it should not only absorb the energy generated in the collision process, but also acquire the deceleration curve which is specified by the regulation or a certain vehicle’s deceleration required in particular. For a good development of sled crash test, It is necessary to study and design a crash energy-absorbing device that having advantages of excellent repetition, low cost and adjustable waveform.In order to acquire the deceleration curve which is specified b y the regulation, this paper designs two kinds of crash energy-absorbing device which are based on the PU-pipes after analyzing the various crash energy-absorbing devices at home and abroad and considering the existing equipment in the laboratory(one way is that sled knocks leading block, another way is that sled knock connecting rod). Second, trial production and sled crash test s are used to explore that if the device could meet the test strength requirement and reappear special waveform. Then the effective crash energy-absorbing device’s computational model is established by finite element method and verified by comparing the results of test and simulation. Mooney-Rivlin is chosen to be the material constructive model of PU-pipes in computational model, because it is widely used and has a very high forecasting precision. Some key parameters in this material constructive model are determined with uniaxial compression test of PU-pipes. Finally effects of sled’s weigh, the maximum outside diameter of olive head and the number of connecting rod on deceleration curve are studied and hardness of rubber bearings installed in the sled is optimized, thus deceleration curves meeting the requirement of the regulation are achieved by simulation.The research result shows that two kinds of crash energy-absorbing device based on the PU-pipes could meet the test strength requirement, but the device knocking connecting rod is applied to follow-on test and simulation for little disturbing wave. The validity of simulation on computational model of crash energy-absorbing device and the correctness of simulation result are proved, and deceleration curves meeting the requirement of the regulation are achieved by simulation. |
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