3D数字路面底盘构件载荷分解研究

Load decomposition of vehicle chassis components based on 3D digital road

汽车底盘零部件载荷谱是分析构件疲劳性能的关键要素。传统采用虚拟迭代提取载荷谱的方法存在研发周期长、成本高等缺点。基于此,采集了试验场典型强化路不平度的高程数据,建立3D数字路面模型,开展了试验场典型强化道路试验,得到实车轮心六分力、悬架和车身关键点监测信号;基于ADAMS/CAR建立整车刚柔耦合多体动力学模型,并通过室内台架试验依次对整车模型和轮胎模型进行校验;采用3D数字路面法和虚拟迭代法开展整车多体动力学仿真,并将仿真数据与实车测试信号从时域、频域、RMS值、伪损伤比和穿级计数等数据统计角度分析对比。结果表明,基于3D数字路面仿真数据精度略低于虚拟迭代法,但两种方法在各典型路面工况下监测信号时域和频域曲线整体趋势基本一致,RMS值相对误差在30%以内,伪损伤比值均介于0.65~1.70,可满足后续疲劳分析的精度要求;3D数字路面仿真能够较为准确的反映强化路载荷工况,在零部件研发初期可进一步提高效率,降低成本。

The load spectrum of car chassis components is the key factor to analyze components’fatigue performance.The traditional extracting load spectrum method with the virtual iteration has disadvantages of long development period and high cost.Here,the elevation data of typical reinforced road surface roughness in test field were collected to establish a 3D digital road model,and the test field’s typical reinforced road tests were conducted.Monitoring signals of a real car wheel center force’s six components,suspension and car body key points were obtained.Based on the software ADAMS/CAR,the rigid-flexible coupled multi-body dynamic model of the whole vehicle was established,and the obtained whole vehicle model and tire model were verified using indoor bench tests.The 3D digital road method and the virtual iteration method were used to perform the whole vehicle multi-body dynamic simulation,and the simulation data and real vehicle testing signals were analyzed contrastively from data statistics angles of time domain,frequency domain,RMS value,pseudo damage ratio and penetration count.The results showed that the accuracy of simulation data based on 3D digital road is slightly lower than that based on virtual iterative method,but overall trends of time domain and frequency domain curves of monitoring signals obtained using the two methods are basically the same under various typical road surface conditions;the relative error of RMS value is less than 30%,and the pseudo damage ratio is within the range of 0.65-1.70 to meet accuracy requirements of subsequent fatigue analysis;3D digital road simulation can reflect load condition of reinforced road surface more accurately,and further improve efficiency and reduce cost in initial stage of car parts development.