Research On The Cab Of Engineering Vehicle Based On Finite Element Method

The finite element method,which develops rapidly with the development of computer, is a modern calculation method. It is widely used in various fields of scientific calculation, design and analysis. And it solves many complex problems of design and analysis. It has already become an important tool in the analysis and engineering design. Meanwhile, the finite element method relate to many fields, like engineering vehicle, car and lathe, etc. In the field of engineering vehicles, sales are growing every year. But the poor working conditions often lead to the cab local cracking. So we must ensure the quality of vehicle’s requirements as well as the low cost. That makes the improved design with the finite element method particularly important. Thereinto, the strength, stiffness and fatigue life of the vehicle body are three basic requirements to ensure the safety of cab’s structure.In this paper, a cracking problem of the heavy truck cab is taken as a research object. After analyzing the cracking reason, it is known that low fatigue strength is the main factor leading to the crack. Finally the improvement is proposed. Comparing with the original model to verity the feasibility of the improved scheme. The specific research contents are as follows:Firstly, after studying the parts of the cab, body-in-white and front wall, the cracking phenomenon of the engineering vehicle cab in the road test is described.And then, the cracking reasons can be raised. The process of the reasons is created.Secondly, the basic principles and main solving steps of the finite element method are studied. Then using the finite element pre-processing software Hyper Mesh build a finite element model of the cab CAD geometry model. After understanding the theory of stiffness analysis, the bending stiffness and torsional stiffness of BIW is calculated with a Radioss solver. Then the Z variable displacement curve of the measuring points in the left and right stringers is drewaccording to the base of the analysis results. Based on the value of BIW’s bending and torsional stiffness, the reasonableness of its structural configuration can be determined. And the cracking problem is not caused by the lack of stiffness.Then, after studying the basic theory of static analysis, the additional quality is completed based on the original BIW finite element model. Meanwhile,the static strength of the cab is calculated in cornering, braking and shock conditions to simulate the actual work situation. After contrasting with the results, the safety coefficient of the material of the major components is higher than 1.0. This shows that the structural design and cab parts material is selected to meet the requirements of the static strength. And the cracking problem is not caused by the lack of intensity.Finally, the basic theory of fatigue life analysis is learned. Then, using the FEMFAT fatigue analysis software to predict the fatigue life of the cab based on the unit load stress field calculations, material S-N curve and load spectrum of Belgian road from businesses. The results show that most fatigue life of the structure is designed to meet the requirements of the cab. But the corner of A-pillar in the front wall planking is the region of high-cycle fatigue, which accords with the damage location. The fatigue life has increased after optimizing.And it indicates that the method of the fatigue life analysis is correct. It can also verifies that the improved option is feasible.