基于虚拟试验台的驾驶室边界载荷谱研究

Research on Boundary Load Spectrum of Cab Based on Virtual Test Rig

以某型商用车驾驶室为研究对象,考虑车架大变形及刚度影响,利用虚拟台架技术搭建驾驶室-车架刚柔虚拟台架模型,建立车架7通道等效位移激励复现驾驶室实际工作状态。将虚拟台架模型与实车试验内部响应信号相结合,选择信噪比较高的信号为目标信号进行迭代分析,基于系统传递函数迭代获取车架位置等效位移激励。以小圆凸起路面为例,经过9次迭代后,响应值与目标值在时域范围内曲线峰值、趋势及相位上有很高的重合度,频域范围内重合度也较高,各通道相对损伤值均在1左右,迭代精度较高,然后分解获取驾驶室各工况边界载荷谱,为后续驾驶室疲劳寿命预估提供可靠时域载荷谱。

Aiming at the problem of the boundary load spectrum of the commercial vehicle cab,taking a certain type of commercial vehicle cab as the research object andconsidering the large deformation and stiffness of the frame,the cab-frame rigid-flexible virtual bench model is built by using the virtual platform technology.The seven-channel equivalent displacement excitation of the frame is established to reproduce the actual working state of the cab.The virtual bench model is combined with the internal response signal of the actual vehicle test,and the signal with high signal-to-noise ratio is selected as the target one for iterative analysisand the equivalent displacement excitation of the frame position is obtained iteratively based on the system transfer function.Taking the small round bump road as an example,after 9 iterations,the response value and the target value have a high degree of coincidence in the curve peak,trend and phase in the time domain,and the degree of coincidence in the frequency domain is also high.The relative damage value of each channel is around 1,and the iteration accuracy is high.Then the boundary load spectrum of each operating condition of the cab is decomposed to provide a reliable time-domain load spectrum for subsequent fatigue life prediction of the cab.