Fine Simulation Analysis Of Car Door Structure Basing On KMAS/one-step And ABAQUS

Automobile is one of the most important products in industrial development of our country. Thanks to the policy that encourages the development of auto bodies', as well as its key parts, shaping and structure performance, our country's automotive industry has been effectively promoted. Currently, computer simulation is the most active field of forming technology and structure design and analysis.Using simulation technology to do the forming simulation can predict the stress and strain of stamping parts and the potential defects of stamping parts.So, it provides an extremely favorable tool for the optimization of process parameters and the properties of structure and it is of great significance for ensuring the quality, reducing material consumption, shortening vehicle products development cycles and lowering manufacturing costs.There are so many factor can affect the accuracy of simulation analysis, such as finite element theory, mesh, computer'performance, forming factors and so forth.The initial stress and strain of stamping parts in structure have a great impact on the accuracy of the structural analysis.This paper verifies the feasibility of Fine Simulation Analysis by joining the result of the simulation analysis'effect of the initial stress and strain of the entire door structure with door plate stamping parts inside and outside.Combined with one practical project, the automobile's front door, supplied by Chang'an Automobile Group, this paper uses technology of finite element simulation and builds that type model by the software named ABAQUS. Inputing the project into software KMAS/one-step through the programmes of conversion between mesh datas and then simulate the inverse forming simulation analysis of the door one step.Using the stress and strain of the analysis result as the initial stress and strain file in the ABAQUS structure analysis and then computing them in three operating situations. Comparing the forming factors'effects on Structural stiffness and strength to reflect the simulation accuracy of Fine analysis. Details are as followings:Firstly, develop procedures to achieve datas conversion between software KMAS /one-step and ABAQUS. KMAS/one-step is a software about sheet metal forming developed independently by Institute of body and die engineering in Jilin University. It develops the technology of forming simulation; especially can give a fast and accurate calculation result of the one step forming. ABAQUS doesn't have output format *.inp file which KMAS/one-step supports at present so to program separately to achieve the interface between these two software's data. In comparing various conversion methods, choose the approach of one-to-one corresponding of mesh node and element number to achieve the data interface of mesh model and build one solid foundation for the aspect of data in and output.Secondly, using software KMAS/one-step to do the inverse forming simulation analysis of the door plate stamping parts inside and outside one step and gain their stress and strain results to be the initial stress and strain of structure analysis. Modifying stress and strain documents to the data files ABAQUS software can read and add the initial stress, strain statements and calculate in the ABAQUS software. In order to verify the feasibility of this method, an example of a separate car outside the board has been taken, to compare the shaping factors to the impact of analysis of the structure.Finally, on the basis of the feasibility test before using this method to carry out further analysis of the whole door's structure and properties. As the inside plate and outside are the main door stampings, here consider only the effects of the door panels and the outer plate forming and other components are not considered. Outcome the document stress, strain derived documents of the door panels, boards forming simulation analysis, modify the format of element number, combine and edit the stress and strain files of plate inside and outside as input documents used as analysis of the overall structure by ABAQUS. Then in the ABAQUS software, add order statements of initial stress and strain documents reader of the overall structure of the door and compute. To comparative analysis, taking into account four initial conditions totally, namely: not considering forming factors; considering isolatedly initial stress, considering isolatedly initial strain and at the same time considering the initial stress and strain Application of the four initial conditions, analyzing the reverse powered respectively of structure of the door mainly. By analyzing the results is: there is no change in the results between initial strain considered only and the initial factors not considered. Considering initial stress only, doors stiffness increases and taking into account the initial stress and strain at the same time, the door will have a larger stiffness than considering the initial stress only. To sum up, considering the factors of forming the stiffness is larger than that not considering and that is closer to the actual situation and so that shows the fine simulation method in which the factors of forming are considered improves the accuracy of the simulation.