典型柔性铰链和柔顺机构疲劳性能及损伤识别研究

发布时间：2018-12-08 12:09

【摘要】：本文研究了典型柔性铰链的疲劳性能以及柔顺机构的损伤识别。柔顺机构的运动是通过其柔性构件的变形来实现的。对一些柔顺机构来说,所需的动作可能只发生一次,因此静态失效理论就足以分析这类机构了。然而在设计时通常要求机构能进行多次运动,可能是上万次的往复循环,甚至是”无限”寿命。这种反复加载会使构件中产生交变应力,在应力远低于产生静态失效的应力值时就可能发生疲劳失效。因此,通过理论和实验来确定柔顺机构的疲劳失效是非常重要的。对于柔顺机构这种复杂并且成本高的机构,重复的疲劳实验非常困难。因此,以典型柔性铰链的疲劳分析为基础,建立基于特征参数分解的柔顺机构的损伤识别方法,可以预测柔顺机构的寿命。这对于柔顺机构的研究和发展具有重要意义。本文分析了直圆型和叶型两种典型柔性铰链的疲劳性能。利用基于临界平面法的疲劳准则,建立了柔性铰链疲劳分析模型。疲劳实验的结果证明了模型的正确性。通过疲劳实验给出了柔性铰链的寿命曲线以及考虑可靠性的寿命曲线簇。最后拟合出了柔性铰链疲劳寿命经验公式,分析了尺寸参数对铰链疲劳寿命的影响。结果表明,尺寸参数对铰链的疲劳寿命有较大影响,必须根据不同的寿命要求选择合适的尺寸参数。基于特征参数分解法,建立了柔顺机构的损伤识别方法。算例结果证明了方法的有效性。结果表明,本方法可以准确的识别损伤的单元个数、位置以及损伤程度,并且适用于多损伤以及大损伤情况。
[Abstract]:The fatigue performance of typical flexure hinge and damage identification of compliant mechanism are studied in this paper. The motion of compliant mechanism is realized by the deformation of its flexible member. For some compliant mechanisms, the required action may occur only once, so the static failure theory is sufficient to analyze such mechanisms. However, the mechanism is usually required to move many times, possibly tens of thousands of cycles, or even "infinite" life. This kind of repeated loading will result in alternating stress in the member, and fatigue failure may occur when the stress is far below the value of the stress that produces static failure. Therefore, it is very important to determine fatigue failure of compliant mechanism through theory and experiment. Repeated fatigue tests are very difficult for a complex and high cost compliant mechanism. Therefore, based on the fatigue analysis of typical flexure hinge, the damage identification method of compliant mechanism based on characteristic parameter decomposition is established, which can predict the life of compliant mechanism. This is of great significance to the research and development of compliant mechanism. In this paper, the fatigue properties of two typical flexure hinges, straight shape and blade shape, are analyzed. The fatigue analysis model of flexure hinge is established by using the fatigue criterion based on critical plane method. The fatigue test results show that the model is correct. The life curve of flexure hinge and the life curve cluster considering reliability are given by fatigue experiment. Finally, the empirical formula of fatigue life of flexure hinge is fitted, and the influence of dimension parameters on fatigue life of hinge is analyzed. The results show that the size parameters have great influence on the fatigue life of the hinge, and the appropriate dimension parameters must be selected according to the different life requirements. Based on the characteristic parameter decomposition method, the damage identification method of compliant mechanism is established. The numerical results show that the method is effective. The results show that the method can accurately identify the number, location and degree of damage, and is suitable for multiple and large damage cases.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH112

【引证文献】