Finite Element Analysis Of Important Mechanism Of Automobile Crane And Lightweight Design Of Its Frame Chassis

Automobile crane is a crane mounted on a common chassis or special automobile chassis,which has the advantages of flexible operation, high degree of integration, high power, goodstability, convenient operation, automobile crane is an important equipment widely used invarious engineering construction, playing an important role in the construction ofinfrastructure, the reliability of automobile crane is an important measure of its quality.The force on the frame is very complicated during the use of the crane.When we usetraditional mechanical analysis methods to analyze the frame, we will find there is a largedeviations between the analysis results and the actual use situation.If we use the test methodto analyze the frame, firstly, the test cost is high. Secondly, it needs a long time, especiallywhen we develop a new product, it will greatly increase the research and development cycle.However, when we use finite element analysis techniques to analyze the frame, it will greatlyreduce costs and shorten the development cycle. Therefore, we should pay more and moreattention on using the finite element analysis in automotive design and verification of theframe. Lightweight technology refers to the way of using optimization structure, materialselection, processing methods, reduce the quality of mechanical parts or the whole machine,so as to achieve a comprehensive benefits to improve product performance, reduce the cost,energy saving and emission reduction. The finite element method is an effective, efficient toolof modern engineering. The finite element method is applied to the crane frame structuredesign, which can optimize the design of the frame, shorten the development cycle of newcranes and has important significance for saving research and development costs etc.This paper introduces the finite element theory, development trend and the analysis step,introduced emphatically the shell structure used in this subject, and theory of plate shellstructure, thick plate theory and the shell element theory, node force, the unit shell-63of thenode displacement, stress and strain matrix equation were researched, from the theoreticalunderstanding of the analysis and calculation of finite element, laid the foundation for furtherfinite element analysis.Turntable structure and the leg are main structure of truck crane, which have a significantimpact on the performance of automobile crane. The failure would have serious consequences:insufficient strength would lead to deformation and damage of structures; insufficient rigidityleads to unstable task, even collapse. By using the finite element software ANSYS12to analyze the turntable in three dangerous working conditions, results show that the stress andstrain are in the allowable stress range, at rated load and the maximum lifting momentconditions the maximum stress appears in the luffing cylinder hinge ear plate, at the main armfully extended the biggest crane load conditions, the maximum stress value appears in thehead inside plate, the maximum stress values were less than300MPa, fully meet the actualrequirements; Add node degree of freedom coupling at the movable supporting leg and afixed supporting leg box, results show that the stress and strain are in the range of materialsunder the maximum load, meet the requirements.Using the finite element analysis software ANSYS, the crane turntable, legs and framesection is analyzed by finite element calculation, providing a theoretical basis for designingand improving of the crane. Through the analysis of the frame in four kinds of dangerousworking conditions (crane load straight ahead, crane load right behind, crane load positiveside and crane load behind45°direction) of the stress and deformation and then localoptimization of the frame. Analyzing the causes of large stress point appears in differentconditions, and partial strength this region, the frame should be simplified where the force ordeformation is small, the mass of the frame should be reduced to bottom without sacrificingthe stiffness and strength of the frame maximum. It could be found that the maximum stresswere reduced in varying degrees, the distribution of stress was more uniform, and thestructure was more reasonable by comparing the frame stress contours in each conditionbefore and after the frame was optimized. There was no failure quality feedback after23highly optimized sets were put into the market. After optimization, the single frame weightwas reduced by about180kg and the material cost was about900￥reduced, and then theframe lightweight design was achieved.