Research On The Ride Comfort For Heavy-duty Truck With Flexible Frame

Heavy-duty truck is an important tool for highway transportation. The ride comfort is always the research focus in automobile manufacturing enterprises at home and abroad. However, the former research only considered the suspension system, and does not take into account the influences of the frame flexible characters. Heavy-duty truck has large load quality and long wheelbase. The frame suffers multiple assembly weights and transfers much the forces and moments. Simple rigid frame model, in the designing of the suspension system cannot be accepted. In a word, the flexible characters of the frame cannot be ignored in the study of ride comfort for heavy vehicles.The paper studied on the ride comfort of an 8×4 type heavy-duty truck. Firstly, The finite element analysis was carried out on the frame in Hypermesh software. Neutral file was obtained by analysis. Secondly, templates of the whole vehicle assembly were built by using the module of ADAMS/Car. Thirdly, component subsystems are built by these templates, which were assembled into the coupled model of truck. According to the vehicle design parameters, adjust the quality and rotational inertia of established model. Finally, the road simulation file was established. Ride comfort simulation were conducted based on random road excitation and pulse road excitation. Evaluate frame flexible impact on vehicle ride comfort by compared the above two kind simulation results.The vertical accelerations of the cargo mass center and the driver center were analyzed in B level road simulations at the vehicle speeds of 20km/h,40km/h and 60km/h respectively. Based on the contrast of the two kind model simulation results, we learn that the main vibration frequency of the two kind frame model is between 0 to 10 Hz. Acceleration values of rigid frame model is greater than flexible frame. In pulse road simulation, at the speed of 20km/h,40km/h,60km/h and 80km/h, vertical acceleration of the center mass of the tank and driver. Acceleration values are less than 43.02m/s2. It has no harm both to the driver’s health and cargo’s intact.At the same speed, the acceleration of the flexible frame model is lower than the rigid frame model. And the frequency of the flexible frame model is lower than rigid frame. Therefore, the flexible of frame absorb the part of the vibration energy, which will more realistic response of real vehicle driving conditions. If, however, did not consider the flexible of frame in the vehicle design, the actual performance of the vehicle is greatly different from the performance of the vehicle design, which is not conducive to the design of the vehicle. In short, the flexible of frame has a significant impact on the ride comfort. In the process of vehicle researching and designing, the flexible of frame should give full consideration.