Study On Topology Optimization Technologies Of Heavy Vehicle Frame

Recently, topology optimization has become a hotspot in structure optimization globally. It can acquire the best distribution of material while containing or improving the performances. It makes the complicated structures being neatly and reasoningly selected in concept design stage. This paper discusses its application in the field of heavy vehicle frame, the main works include:Firstly, 3D topology optimization model was built according to the trim size, loads, and constraints by HyperWorks, take the distortion energy under several load steps as objective function, and the volume fraction as constraint function, using the method of changing density, carry out several topology optimizations on a same model , then a set of results were got.Secondly, one topology structure of the lowest constraint function has been switch to shell, which is easier manufactured, and homogeneous on density as well as the thickness. After size optimization and shape optimization the concept design was turned out, and the new frame was lighter 315kg than primary design.Lastly, analyze the intensity and stiffness of the frame being optimization. Results show that both bending stiffness and torsion stiffness were improved, especially the torsion stiffness was enhanced over one time; both bending mode frequency and torsion mode frequencies were increased; the structure satisfy the static intensity demand in utmost load steps; and the simulate results indicate that it will not has fatigue problems when running 6000km through 160mm deep notch road at 5.4km/h.Some conclusions about topology optimization technique and the structure of heavy vehicle frame were brought through the study:①3D topology optimization design on a heavy vehicle frame, which take the lowest distortion energy of several load steps as objective function, and the volume fraction as constraint function could acquire an optimum design with better stiffness and intensity with lighter mass.②The surface of frame is more useful. The topology structure shows the top and nether surface on the middle frame was more reserved, while the middle layer between surfaces was hollow. It shows the top surface and nether surface could greatly improve the torsion stiffness.③The material topology is greatly related to the position of frame brackets and the loads on the brackets. The crossbeam is thin with more holes distribute on the carling at the frontal frame, because of the lighter loads, while the crossbeam is huge without hole on the carling in the middle frame, because of the heavier loads.④The result of free mode analysis show that local modes on front and rear carling appeared in low frequency range, because topology optimization deleted the crossbeam at the front and rear of frame, which contribute little to the stiffness, but are necessary in the frame to avoid carling swing.⑤The lower the volume fraction constraint function is , the more deleted material of the frame in the topology optimization process are , and the more difficulty the iterative calculating is. So how to set the constraint function is a key technique to balance the efficiency of topology optimization process.