Experimental Study And Finite Element Analysis On A Commercial Frame

The frame is the core of the vehicle body, which suffers the load from the road and shipment. Besides frame serves as the carrier in many important assemblies, so the performance of the vehicle directly depends on it. The failure mode of the frame can be divided into two categories, namely strength fracture and durability fracture.Through the combination of engineering theory and practice, the thesis studies the frame structure of a commercial vehicle. Based on the perspective of static characteristic and endurance character, we made the assessment of endurance and reliability of the frame structure in commercial vehicle and accomplished the fatigue life optimization design of parts of frame structure, which provides the company with reference frame and accumulative data in actual production. The results are as follow:(1) Making models for the analysis of frame structure of a commercial vehicle based on HyperMesh. Under the condition of bending and torsion, we compute and analyze the static strength and stiffness of the frame. At the same time, we predict the distribution of the stress and deformation, the simulative results show that the design has met the requirement of the structural strength and stiffness.(2) Carrying out bench test for the structure of vehicle frame, whose bending rigidity is 86.47KN/mm. there is little difference in the torsional rigidity in the three frame, both of them are about 5000N*m/°. We make a comparison with the CAE results, which certificates the reliability and validity of the FEM. We also analyze the difference between the test results and CAE results.(3) We also accomplished Bench test for the torsional fatigue of the vehicle frame. According to the experiment, we made an analysis of simulative fatigue life. By comparison of the test and simulation, which verifies the reliability of the fatigue-life analysis. And we also make an optimization design of the fracture components. Through 500000 circles, the accumulative damage of the improved cross beam is 1/3 of the damage of initial structure. And the accumulative damage of the improved balance shaft is 1/11 of the damage of initial one.