Finite Element Analysis And Optimization Research Of The Ladder Fire Truck

YT32Aerial ladder fire truck is the first ladder products of Xuzhou heavymachinery Co., Ltd., It is a special fire-fighting vehicle on rescue and quenching.With the development of science and technology, the buildings in the cities becomemore and more dense,and more and more high, Aerial ladder fire truck will becomethe main force of fire-fighting.This thesis is based on the project-YT32(two bridge/three bridge) ladder truckmodeling and analysis software development,which is cooperated by Jilin universityand Xuzhou Heavy Machinery Co., Ltd. Analyse the ladders with the classical finiteelement software-ANSYS, and provide a theoretical basis to the enterprise designers.First and foremost, I calculated the upper structural performance with thesimplified BEAMs to simulate ladder structure, under the control standard of theallowable stress. Then extracted the internal force of the oil cylinders and leaf chainfor reference. Because there might be some problems to build the model, I revised theresult of calculation by the mathematical formulas. As a result the structureperformance is close to the actual product. Then I built a particular model for detailedcalculation by large deformation, the main output were the positions of big stress area.I used the contact to simulate the joints of the ladders, then I could simulate thetransmission of the force more accurately. The detailed calculation is aimed at thelimits of the operating mode of scheme calculation, calculated the mises stress of thedangerous parts and the displacement of the model, and extracted the internal force ofthe oil cylinders and leaf chains. In order to acquaint the corresponding of the ladderstructure under external loads, as well as to avoid the resonance of the ladderstructure in the working state, this paper also carried out prestressed modal analysis,to get the frequency and mode of vibration of ladder structure.In order to verify the correctness of the results of detailed calculation, Iformulated the corresponding test plan. We measured the stress and the strain in thecorresponding position and corresponding condition by the dynamic stress straintester. Then I compared the test results and detailed calculation results, to verify the correctness of finite element simulation.I established the models, which were used in scheme calculation, detailedcalculation and modal calculations, divided elements and gave unit to elements withHypermesh; I processed the boundary of models, calulated and checked results withAnsys; Finally, I worked out the program of batch processing with APDL and DOSlanguage, to automatically calculate and extract results in quantity. Through thetheories and practices of this text, the finite element analysis offers some guidelinesfor the design and production of the ladder fire truck. It can greatly reduce the designcycle, improve the product performance, and avoid the risk of the structural damages.