机械结构系统中存在大量的结构，其固有频率会随着激振力幅的不同而改变，称之为刚度非线性结构，例如螺栓法兰联接结构、涂层复合结构等。由于存在刚度非线性，经典的半功率带宽法无法准确辨识这些结构的阻尼参数。本文在修正经典半功率带宽法的基础上，提出了一种适用于弱刚度及强刚度非线性系统的阻尼辨识方法，称为频域带宽法。首先，基于刚度非线性结构系统的运动方程，分别推导了弱刚度非线性及强刚度非线性系统的阻尼辨识公式。进一步，提出了基于频域带宽法测试具有刚度非线性结构系统的阻尼参数的方法及流程，并讨论了扫频方向、扫频速度对测试结果的影响。最后，以具有软式非线性特征的硬涂层薄板为对象进行实例研究，获得了该薄板不同激励幅度下的阻尼参数。本文的研究可为精确建立类似结构的动力学响应分析模型提供参考。
Abstract
There are a large number of structures, their natural frequencies will vary with the exciting levels and can be named as the stiffness nonlinear structures, such as the bolted joint structure, composite laminated plate structure, etc. Due to the effect of stiffness-nonlinear, the classical time domain and frequency domain methods of damping test will not be suitable to these structures. Therefore, on the basis of modified the classical half-power bandwidth method, this paper presented a method used to identify damping of the weak and strong stiffness-nonlinear structure systems. Based on the movement equation of the stiffness-nonlinear system, damping identifying formulas were derived respectively for the weak and strong stiffness-nonlinear structure systems. Then, damping test procedure was proposed for the above mentioned nonlinear structure systems. At last, a test case has demonstrated the practicability and effectiveness of this method, which was applied on damping test of a hard-coating cantilever thin plate with soft nonlinear characteristic and damping parameters were obtained under different exciting levels by sweep test.
关键词
刚度非线性 /
结构系统 /
阻尼测试 /
测试流程 /
频域带宽法
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Key words
stiffness-nonlinear /
structure system /
damping test /
test procedure /
frequency bandwidth method
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参考文献
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