An Approach to Non-linear Experimental Modal Analysis
An Approach to Non-linear Experimental Modal Analysis
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非线性实验模态分析方法
DOI：
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发表时间：
2011
期刊：
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通讯作者：
A. Calvi
中科院分区：
文献类型：
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作者：
M. Link;M. Boeswald;S. Laborde;M. Weiland;A. Calvi
这是DYNAMITED（测试数据的动态评估和改进）研究项目的目标，该项目由欧洲航天局（ESA）资助，与EADS ASTRIUM相关的欧洲工业和大学团队开展，旨在评估和改进动态测试程序。在试验后活动中，空间结构非线性行为的检测、识别、量化和预测是至关重要的。现有的航天器振动试验评估方法是基于线性结构特性假设的。在非线性结构行为的情况下，观察到的共振位移和频响峰变化通常不能通过非线性评估程序反映在实践中。在振动台试验中，为了避免结构超载，通常采用输入缺口控制结构的动力响应在规定的水平和位置。这种方法在不同的输入水平上产生了有效的准线性结构行为，使得经典的线性模态提取工具可以在每个水平上单独应用。然而，测量的动态响应（透射率）显示峰值移位和振幅变化取决于输入水平的基础激励。在本文中，我们提出了一种使用三种不同输入电平的方法，其中响应电平被控制在主导共振周围的窄频带频率范围内恒定。我们描述了一种技术的前提，目的是预测对测量输入水平以外的响应。这是通过将插值和外推技术应用于从三个不同输入水平测量的透射率中提取的模态数据来实现的。将该技术应用于典型STM卫星结构（结构试验模型）试验过程中测量的振动试验数据，给出了结果。
It was the aim of the DYNAMITED (DYNamics AssessMent and Improvment of TEst Data) research project conducted by a European industrial and university team associated around EADS ASTRIUM and funded by the European Space Agency (ESA) to assess and improve dynamic test procedures. In the field of post test activities, the detection, identification, quantification and prediction of the non-linear behavior of space structures is of prime importance. Present evaluation methods for spacecraft vibration tests are based on the assumption of linear structural behaviour. The resonance shifts and FRF peak variations observed in the case of non-linear structural behavior are generally not reflected in practice by non-linear evaluation procedures. In order to avoid overloading of the structure during the qualification test on a shaking table the dynamic response is generally controlled at specified levels and locations by input notching. This approach generates an effectively quasi linear structural behavior at the different input levels which enables the utilization of classical linear modal extraction tools to be applied separately at each level. However, the measured dynamic responses (transmissibilities) reveal peak shifts and amplitude changes depending on the input level of the base excitation. In the paper we present an approach using three different input levels where the response levels are controlled to be constant within a narrow band frequency range around the dominant resonances. We describe the premises of a technique with the aim of predicting the responses to other than the measured input levels. This is achieved by applying interpolation and extrapolation techniques to the modal data extracted from the transmissibilities measured at three different input levels. Results are presented from an application of the technique to the vibration test data measured during a typical STM satellite structure (Structural Test Model) test campaign.