Development Of Automotive High-Strength Bolt Research And Analysis Platform Based On VDI-2230 Standard

In recent years,with the rapid development of aviation,automobile,shipbuilding and other industries,various industries have put forward higher requirements for the safety performance of bolts.Therefore,it is of great practical significance to carry out the corresponding safety analysis of bolts.At present,the strength fatigue safety analysis of bolts is based on the engineering algorithm of VDI-2230 issued by the German Association of Engineers.However,due to the complexity of the engineering algorithm,it will cost a lot of time and manpower to calculate and check the strength fatigue of bolts manually.In addition,VDI-2230 theory does not make corresponding research on the loss of bolt preload under high temperature creep,that is,it has certain limitations to use this theory to check and study bolts under high temperature.In order to solve the above problems,this paper combines VDI-2230 theory with bolt creep theory.By developing a bolt verification platform,the whole process integration of bolt finite element parametric modeling,automatic extraction of bolt simulation data,automatic bolt verification and automatic generation of bolt verification report is completed.The main work of this paper is as follows:(1)The VDI-2230 engineering algorithm is studied theoretically,and the connecting bolts between the lower front control arm of the chassis and the shock absorber are taken as the research object,so as to obtain the checking algorithm of various safety factors of the bolts and the bolt load parameters required in the checking process,which provides the corresponding theoretical basis for the extraction of subsequent finite element simulation data.(2)The attenuation of bolt pretightening force under high temperature creep is studied.The connecting bolts between the engine cylinder block and the cylinder head are taken as the research object.Based on the creep theory and the finite element analysis method,the change curve of bolt pretightening force with time under high temperature creep and thermal expansion is studied.At the same time,it is clear how to extract the change curve of bolt pretightening force under high temperature creep in Abaqus to prepare for the subsequent secondary development.(3)The Hyper Mesh is redeveloped,and Tcl/Tk script is compiled to complete the parametric modeling of bolt mesh and the assignment of material properties.At the same time,Python is used to compile the Abaqus script to extract the load data required in the bolt verification process and the change curve of bolt preload under high temperature creep.(4)The bolt verification platform is developed using Python language,and Tcl/Tk script and Abaqus script are integrated into the verification platform to complete the interaction between the platform and Hyper Mesh and Abaqus.At the same time,VDI-2230 theory is integrated into the verification platform,and the overall process integration of bolt finite element modeling,automatic extraction of bolt simulation data,automatic bolt verification and automatic generation of bolt verification report is finally completed.(5)The bolt checking platform is used to carry out parametric modeling for chassis bolts,suspension bolts and engine bolts,automatic extraction of finite element calculation results,automatic verification of safety factors for bolts based on VDI-2230 theory,and automatic generation of bolt verification reports.Finally,the feasibility of the bolt verification platform is verified.