Research On Numerical Simulation Of Small Cold Bending Mold Of Ambulance Overalies

Now a days the ambulance deep cover are small batch production automobile parts, generally using the large-scale die for one-time forming, or glass fiber reinforced plastic through pasting.The former measure costs too high, not meeting the enterprises’needs, and the latter has short life and low intensity, can’t meeting the higher demand of consumer. This paper studies the small continuous cold bending die.By sacrificing the production efficiency to reduce the one-time costs, sheet metal is made into tambulance deep cover through the local cold bending forming method.This paper introduces and summarizes the current studying situation of the automobile cover parts development, and the present developing situation of the theory for cold bending forming. So far, processing method for automobile cover parts is still mainly whole processing forming, while the present study on automobile cover parts are mostly optimization design, and cold bending forming theory has not yet been mastered by people, whose research are mainly on rolling cold bending forming theory. With the present developing situation of cover parts mold and the research situation of cold bending forming theory, the paper first established three-dimensional entity model of deep cover part based on the ambulance deep covers produced by golden cup car factory, then used the common process designing method of covering parts for the processing’s process design of deep cover part, and simply designed local continuous cold bending forming mold for the cold bending process. This paper made a mechanical analysise for the deep cover cold bending forming process, and determined related parameters which effected the forming performance and the forming quality. Took the large plastic deformation finite element theory as foundation, the paper reasonably simplified to deep cover’s local continuous cold bending forming process, and the finite element analysis model. Using Dynaform software,this paper made a three-dimensional display dynamic finite element numerical simulation analysis for the deep cover cold continuous bending forming process, and got the stress and strain distribution rule and the geometrical deformation of different dishes of the vertex angle and hypotenuse of the deep cover during forming process.,these relative parameters,the stress and strain distributions and variation of thickness and so on were being compareted under the following technological parameters,such as different forming angle、different overlap area、 different sheet thickness and different radius of round in same dishes of times and so on, the influence of these technological parameters on the deep cover cold bending forming were discussed as well.Through comparative analysis of forming limit diagram establishing methods, this article confirmed that the forming limit diagram established by K-B formula in Dynaform software were ture to reality,which showed that the simulation method is validity> reliability and accuracy in calculation of results. So the use of Dynaform software simulation to simulate local cold bending forming process for deep cover is feasible. The result of this paper provided reliable forming validate model for local continuous cold bending forming of sheet metal in the future,and provided believable evidence for practical production application, which is meanful in promoting local continuous sheet cold bending forming theory research and guiding real production.