The Development Of Vehicle Body Structural Analysis Solver On The Basis Of Triangular Plate And Shell Element

With the great progress of automobile industry,Computer Aided Engineering(CAE)tecnology become an indispensable tool in the process of automobile development due to its efficiency,low-cost and so on.However,Most CAE software used in domestic automobile industry currently are imported from abroad,which makes a few multinational corporations dominant in domestic CAE software market.These software get the recognition from many engineers by virtue of generality and simplicity,but they have high price and some key functions and modules of them are limited or prohibited.Therefore,developing CAE software with intellectual property can fundamentally break the situation and decrease the cost of vehicle development and manufacturing.Among CAE projects of automobile,vehicle body structural analysis is an important and necessary part because reliability of its result has decisive influence on vehicle body design.As the most complicated assembly of automobile,the general structure of vehicle body is welded or riveted by plate and shell structures,hence the accuracy and convergency of plate and shell element will directly affect reliability of results in structural or modal analysis of vehicle body.Structural mesh is generally used in analysis of plate and shell structures to improving accuracy,but it is difficult to approximate complex shell geometry.Thus the presented high-accuracy triangular plate and shell element and the architecture of open source FEA software are combined in this thesis,and the main parts of it are listed as follows:(1)The foumula with nonlinear part of Central point based Discrete Shear Gap of triangular plate and shell element(CP-DSG3)is deduced.Based on the Ressiner-Mindlin theory and Timoshenko beam hypothesis,this method reconstructs the shear strain to overcome anisotropy of traditional DSG3 by integrating from the geometrically central point of triangle.A series of linear and nonlinear benchmarks are processed and the result shows that CP-DSG3 can comparatively obatin better accuracy and stability.(2)CP-DSG3 is also realized in commercial software Abaqus through its user subroutine UEL,analysis on dent resistance of vehicle roof is conducted using contact module and numerical solver of Abaqus.Compared to the results of general analysis with structural meshes,CP-DSG3 is applicable to complex engineering problems.(3)The architecture of object oriented FEA software OOFEM is analyzed using reverse engineering method,on the basis of this architecture and many popular linear algebra packages,a structural analysis solver of vehicle body using triangular plate and shell elements is developed by integrating presented CP-DSG3,and a related engineering problem is studied to verify the accuracy and efficiency of this solver.