Abstract:
The vehicle safety test includes two types of real vehicle collision and sled collision test (car simulation collision). The expensive actual vehicle crash test has a long preparation cycle and poor waveform reproducibility which is generally used only for product certification. The sled crash test can obtain the test results similar to the actual vehicle collision, and it is therefore widely used. In recent years, hydraulic bumper crash has become an important research direction. In this work, the vehicle collision test device of hydraulic buff is taken as the research target. By using the mechanics and fluid mechanics theory, the force and movement of the sled and the hydraulic cylinder piston and hydraulic cylinder pressure changes are analyzed. According to the principle of conservation of energy, the mechanical model and the energy conservation model of the sled collision process are established. By using discrete solution method, the established model is solved numerically. For a specific example, the influences of the parameters such as mass of the sled, the initial collision speed and the diameter of the damp hole on the collision process are thoroughly studied and a series of regular curves are obtained. The acceleration of the sled increases with the initial collision speed and the length of the damp hole, but it decreases with the mass of the sled and the distance between the damping holes. During the collision process, the more the mass of sled is, the slower its speed gets; the longer the length of the damping hole is and the smaller the diameter of the damping hole is, the faster the speed changes. The sled displacement increases with the mass of the sled, the initial collision speed, the distance between the damp hole and the diameter of the damp hole, while it decreases with the length of the damp hole.