柔性铰链的疲劳寿命评估方法研究

发布时间：2018-02-26 08:34

本文关键词： 柔性机构柔性铰链疲劳寿命名义应力法　出处：《西安电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：柔性机构是一种利用柔性构件本身的弹性变形来实现运动、力、能量的传递和转换的新型机构,能够减少零件数目、减少装配、提高精度、减少摩擦等,在微机电系统、仿生领域有着很高的价值。对一些柔性机构来说,所需的动作可能只发生一次,因此可以使用静态失效理论来分析这类机构。但是对于大多数柔性机构来说,在工作中需要承受循环载荷的作用,循环载荷会使构件中产生交变应力,交变应力使得柔性机构中最薄弱部位的应力在远低于屈服极限的情况下就发生疲劳失效。而柔性铰链是柔性机构中最薄弱的环节,因此对柔性铰链进行疲劳分析,进行寿命预测变得越来越重要。本文以圆型柔性铰链作为研究对象,利用名义应力法和有限元分析方法得到了圆型柔性铰链的疲劳寿命曲线,并拟合出疲劳寿命曲线的经验公式,分析了影响圆型柔性铰链疲劳寿命的因素。研究发现,圆型柔性铰链的曲率半径,最小厚度和表面状态对铰链的疲劳寿命影响较大。同时,分析了离心率对圆锥曲线型柔性铰链疲劳寿命的影响。因此,在设计和加工中应根据不同的寿命要求选用最合适的尺寸参数和加工方法。本文基于名义应力法和圆锥曲线型柔性铰链应力集中系数通用公式建立了圆锥曲线型柔性铰链的寿命预测方法,通过算例验证了该方法的有效性。该方法为柔性铰链的设计提供了支持。通过该方法可以在柔性铰链的初步设计时计算铰链的疲劳寿命,避免不合理的参数选择。
[Abstract]:Flexible mechanism is a flexible component using the elastic deformation to realize motion, force, energy transfer and conversion mechanism, can reduce the number of parts, reduce the assembly, improve accuracy, reduce friction, in MEMS, bionics has a very high value. Some of the flexible mechanism, required the action may occur only once, so we can use the theory to analyze the static failure mechanism. But for the most flexible mechanism, needs to work in under cyclic loads, the cyclic loading will cause stress generated in the AC component, alternating stress makes the flexible mechanism the weakest parts of the stress in the far below the yield limit under the condition of fatigue failure. The flexible hinge is the weakest link of flexible mechanism, the flexible hinge fatigue life prediction analysis, this paper has become more and more important. The circular flexure hinge as the research object, using the nominal stress method and the finite element analysis method to get the fatigue life curve of circular flexure hinge, and the fitted empirical formula of fatigue life curve, analyzed the influence factors of circular flexure hinge fatigue life. The study found that the radius of curvature of circular flexure hinge, fatigue the life of the minimum thickness and surface condition on the hinge effect. At the same time, analyzes the influence on the rate of centrifugal conic type flexible hinge fatigue life. Therefore, we should size parameters and processing method of the most suitable according to different life requirements in designing and processing. In this paper, the nominal stress method and conic type flexible hinge the stress concentration coefficient of general formula is established to predict method of conic flexure hinge based life, through an example to verify the effectiveness of the method. The method for the design of flexible hinge By this method, the fatigue life of the hinges can be calculated at the initial design of the flexure hinges to avoid the unreasonable selection of the parameters.

【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TH112

【共引文献】