三自由度半正定系统随机振动仿真与试验研究

目的研究三自由度半正定系统在随机振动条件下的加速度动态响应以及加速度功率谱密度。方法以运输包装中常见的三自由度半正定系统为原型,建立了三自由度半正定系统的质量-弹簧-阻尼系统。依据美国ASTM-D4728随机振动标准,利用Matlab/Simulink仿真平台,建立仿真模型,并输入模型参数,得到了三自由度半正定系统随机振动下的动态响应。基于相同试验标准进行试验,对比分析试验结果与仿真结果的差异。结果在低频段内(小于80 Hz),Simulink仿真模拟随机振动的加速度功率谱密度值与随机振动试验的加速度功率谱密度值的相关性系数达到0.983,加速度功率谱密度值最大处仅相差8.8%。在高频段内(大于80 Hz),Simulink仿真模拟随机振动的加速度功率谱密度值与随机振动试验的加速度功率谱密度值的相关性系数只达到0.745,加速度功率谱密度值最大处相差13.1%。结论利用Matlab/Simulink仿真平台分析包装系统的低频随机振动是一种简单可行的方法,一定程度上可以作为随机振动试验的代替手段。

Random Vibration Simulation and Experimental Study of Three-degree-of-freedom Semi-definite System

The paper aims to study dynamic acceleration response and acceleration power spectral density of a three-degree-of-freedom semi-definite system under random vibration. The mass-spring-damping system of the three degrees of freedom semi-positive definite system is established. According to the ASTM-D4728 random vibration standard in the United States, using the Matlab/Simulink simulation platform, the simulation model is established, and the parameters of the model are input, and the dynamic response under the random vibration of the three-degree of freedom semi-positive definite system is obtained. Based on the same test standard, the difference between the test results and the simulation results is compared. In the low frequency band (less than 80 Hz), the correlation coefficient between the acceleration power spectral density value of Simulink simulation and random vibration experiment reached 0.983; and the maximum difference between the two measured acceleration power spectral density values was only 8.8%. In the high frequency band (greater than 80 Hz), the correlation coefficient between the acceleration power spectral density value of Simulink simulation and the random vibration experiment only reached 0.745. However, the maximum difference between the two measured acceleration power spectral density values was 13.1%. Analyzing low frequency random vibration of packaging system with Matlab/Simulink simulation platform to analyze the low frequency random vibration of packaging system is a simple and feasible method. To some extent, it can be used as a substitute for random vibration test.