Until recently, laboratory testing of packaged systems has been undertaken by simulating vertical vibrations alone. However, with increasing demand for a reduction in packaging waste, the use lightweight systems, such as stretch film, is increasing. Such containment systems are susceptible to the lateral forces generated by the pitch and roll vibratory motion of vehicles due to road surface unevenness. If laboratory simulation is to be realistic, multi‐axial motion must be taken into account and an understanding of the relationships between the random heave, pitch, and roll vibrations is essential. This paper uses vibration data collected from a number of transport vehicles traveling along typical urban and suburban routes to establish the nature and level of the multi‐axial vibrations that exist. These are presented with average Power Density Spectra (PDS) as well as statistical distributions of the moving root‐mean‐square (rms). The paper analyses the data for correlation of the rms levels with respect to nonstationarity. This is important when simulating nonstationary (randomly fluctuating rms) vibrations for heave, pitch and roll. These statistical correlation functions are used to manage the relative rms levels of each of the three Degrees of Freedom (DoFs) when undertaking vibration simulations using multi‐axis vibration test systems. The results show that the relationships between the moving rms of heave, pitch and roll vibrations are not strongly correlated but can be characterized statistically as joint distributions to enable realistic simulation of multi‐axial random vibrations of road transport vehicles under controlled laboratory conditions.

中文翻译：

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城市运输路线中升沉，俯仰和横摇振动的某些特征

直到最近，仅通过模拟垂直振动就对封装系统进行了实验室测试。然而，随着减少包装浪费的需求增加，诸如拉伸膜的轻质系统的使用也在增加。由于道路不平整，这种封闭系统容易受到由车辆的俯仰和侧倾振动运动产生的侧向力的影响。如果要进行真实的实验室模拟，则必须考虑多轴运动，并且必须了解随机波动，俯仰和横摇振动之间的关系。本文使用从沿典型城市和郊区路线行驶的许多运输车辆收集的振动数据来确定存在的多轴振动的性质和水平。这些均以平均功率密度谱（PDS）以及移动均方根（rms）的统计分布表示。本文分析了数据的均方根值与非平稳性之间的相关性。当模拟起伏，俯仰和横摇的非平稳（均方根波动）振动时，这一点很重要。当使用多轴振动测试系统进行振动模拟时，这些统计相关函数可用于管理三个自由度（DoF）的相对均方根值。结果表明，升沉运动均方根之间的关系，。