车辆振动加速度响应分析的速度—频域方法

为直接从车辆振动加速度响应中提取车辆特性和车辆激励特性,引入车辆速度参量,构成系统响应—特性—激励关联方程组；由空间输入功率不变的物理特性得到并论证车辆激励特性随车辆速度变化的频域数值规律:激励频率与车辆速度成正比,随机激励加速度等效功率谱与车辆速度的3次方成正比,周期激励加速度等效功率谱与车辆速度的4次方成正比；车辆特性随车辆速度变化较小,即使发生蛇形,只要振动传递路径不发生变化,轮对以上部件间的振动传递关系也基本与车辆速度无关.据此,给出车辆加速度响应分析的速度—频域方法,通过对速度—频谱和速度—名义传递三维图中基本不随车辆速度变化、随车辆速度线性变化和高速低频区突变3类局部峰值的识别,实现对系统响应—特性—激励关联方程组的工程求解.运用结果表明:该方法有效实现了车辆特性与车辆激励的解耦及耦合分析.

Speed-Frequency Domain Method for the Response Analysis of Vehicle Vibration Acceleration

To directly get both vehicle system and excitation characteristics from vehicle vibration acceleration response,system response-characteristics-excitation relevant equations were built through introducing vehicle speed parameter.The numerical correlation of vehicle excitation characteristics changed with vehicle speed in frequency domain was obtained and demonstrated through the physical characteristics of consistent space input power.Excitation frequency is linear to vehicle speed.The stochastic excitation acceleration equivalent power spectrum is linear to the third power of vehicle speed.The periodic excitation acceleration equivalent power spectrum is linear to the forth power of vehicle speed.Vehicle characteristics vary little with vehicle speed.The vibration transmission relationship between components above wheelset basically has nothing to do with vehicle speed as long as the path of vibration transmission remains unchanged even if vehicle is in hunting state.Accordingly,the speed-frequency domain method for the response analysis of vehicle acceleration is given.By analyzing 3D graphs of speed-frequency domain and speed-nominal transmission,the local peaks are recognized under three circumstances,namely,basically no change with speed,change linear with speed,and abrupt change in high speed and low frequency region.Engineering solution for system response-characteristics-excitation relevant equations is thus achieved.Application results indicate that speed-frequency domain method has effectively realized the decoupled and coupling analysis between the vehicle characteristics and vehicle excitation.