Optimum Design Of The Equipment Of Car Crashes Using Thread Cutting

Improve the vehicle’s crashworthiness requirements make impact energy absorbing device is widely used in automotive safety design technology. the cutting the Screw Thread type car crash energy absorption device is a new concept of intelligent vehicle collision absorption structure. Threaded rod is the most important bearing pieces of the entire device. the device has a certain capacity to absorb the enormous energy when full impact is happened. But whether the threaded rod can maintain a very low bending rate or don’t bended ,it is essential for the capacity of the energy absorption device when degree impact is happened. while the quality of threaded rod account for two-thirds of the total device. So to achieve the optimum result of the device have important engineering practical significance and value.In reading a great deal of information and documentation, this paper take the cutting the Screw Thread type low-cost energy-absorbing structures as the research object, the work has done by are as follows:1)Firstly, the author makes a summary of the present research situation discussing faults of the cutting the Screw Thread type energy-absorbing structures in theory and structure. Later, Through analyzing the mechanical properties , the author finds the designing idea of energy absorbing equipment, and make out a flow chart for the optimization of the equipment . Orthogonal experiment method is a non-traditional optimum design method, opened a new road for the optimization of the car crash’s energy absorbing equipment.2)In order to design the thread -cutting energy to satisfy collision safety request, Firstly, the mechanical properties of thread cutting in static state are analyzed. And a mechanical formula of rectangle thread -cutting energy absorbing are brought forward, At the same time the rerationship of diameter , pitch and force are achieved. It is pointed that only 3 design variables are independence variables in all design variables for the thread -cutting energy, i.e. diameter, pitch, the length of section. Later, this paper makes the design by the method of orthogonal experiment method and dynamic finite element. 3)Taking threaded rod with hollow in the cutting the Screw Thread type low-cost energy-absorbing structures as the research object, The load under 30o Angular Impact and the finite element model of the screw are discussed . an equivalent column is selected for mechanical model . the results show that only 3 design variables are independence variables in all design variables for the screw with hollow in the cutting the Screw Thread type energy-absorbing structures, i.e. L1 , L3 , d , L2 .Later, this paper makes the design by the method of orthogonal experiment method and dynamic finite element.4) This paper make a choice of bolt by calculating it Under design conditions. At the same time , the device light-weight design and material selection be described. Finally completed the Optimal design of the cutting the Screw Thread type car crash energy absorption device .