Analysis and Redesign of Connection Part in Cargo Truck Chassis for Fatigue Durability Performance 2023-01-0599

With the growing prosperity of the long-distance freight and urban logistics industry, the demand for cargo trucks is gradually increasing. The connecting bracket is the critical connecting part of the truck chassis, which bears the load transmitted by the road excitation and reduces the damage to the frame caused by the load. However, the occurrence of rough road conditions is inevitable in heavy-duty transportation. In this paper, road durability tests and fatigue life analysis are carried out on the original structure to ensure the safety of the vehicle. Based on the known boundary and load constraints, a lightweight and high-performance structure is obtained through size optimization, as the original structure cannot meet the performance requirements. Firstly, the road test was conducted on the truck where the original bracket structure is located. The stress response spectrums under fatigue simulation were obtained by combining the road test load spectrums at the excitation points. Moreover, according to the von Mises yield criterion or Tresca yield criterion, the stress-strain in the multiaxial state is equated to the stress-strain in the uniaxial state and made as the fatigue damage parameter. Then the cumulative damage value was carried out by adopting the fatigue damage accumulation theory based on Miner's rule. Secondly, a new connecting bracket layout is designed and optimized by size optimization with multiple performance constraints. Finally, fatigue life prediction and road durability tests were conducted based on the optimized design. The fatigue analysis and road durability test results show that the optimized bracket has better stiffness, strength, and fatigue performance than the original bracket.