论文标题
用新的强摩擦阻尼结构挑战实验非线性模态分析方法
Challenging an experimental nonlinear modal analysis method with a new strongly friction-damped structure
论文作者
论文摘要
在这项工作中，我们表明，基于扩展的周期性运动概念的最近提出的实验非线性模态分析方法非常适合提取强烈非线性系统的模态特性（即在存在大频移，高和非线性阻尼，模式形状的变化和更高谐波的情况下）。为此，我们设计了一个新的测试钻机，该钻机表现出很大程度的摩擦引起的阻尼（模态阻尼比最高15％），并且频率转移36％。该标本称为橡胶，是在干摩擦的影响下的悬臂梁，从满杆到主要滑动。借助标本的设计，对于受到干摩擦力的系统，测量值可以重复。然后，我们将方法应用于样品，并表明即使偏转形状随振幅变化，单点激发也足以跟踪模态性能。使用单个非线性模式振荡器的计算频率响应具有确定的模态性能非常吻合不同的激发水平的参考曲线，表明模态性质的重要性和准确性。
In this work, we show that a recently proposed method for experimental nonlinear modal analysis based on the extended periodic motion concept is well suited to extract modal properties for strongly nonlinear systems (i.e. in the presence of large frequency shifts, high and nonlinear damping, changes of the mode shape, and higher harmonics). To this end, we design a new test rig that exhibits a large extent of friction-induced damping (modal damping ratio up to 15 %) and frequency shift by 36 %. The specimen, called RubBeR, is a cantilevered beam under the influence of dry friction, ranging from full stick to mainly sliding. With the specimen's design, the measurements are well repeatable for a system subjected to dry frictional force. Then, we apply the method to the specimen and show that single-point excitation is sufficient to track the modal properties even though the deflection shape changes with amplitude. Computed frequency responses using a single nonlinear-modal oscillator with the identified modal properties agree well with measured reference curves of different excitation levels, indicating the modal properties' significance and accuracy.
