针对柔顺机构中柔性铰链在受到连续变载荷反复加载的情况下,其最小厚度处容易产生应力集中并导致疲劳裂纹的产生,最终使得柔性铰链疲劳失效这一问题,以柔顺机构中典型的椭圆型柔性铰链为研究对象,分析其在最小厚度处所产生的最大应力,通过引入田口方法对其所产生的最大应力进行特性分析,找出影响其最大应力的可控因子以及噪声因子进而对其进行正交试验,并采用基于正交试验的灵敏度分析方法,定量地分析各决策变量对其最大应力的影响程度。计算结果表明:椭圆型柔性铰链最大应力的变化是由多个设计变量共同作用的结果,铰链的最小厚度t对其影响最大。基于田口方法的灵敏度分析因其不依靠优化算法,所以可用于分析不可微、离散或隐式表达式的结构灵敏度,从而为柔性铰链的稳健设计提供指导,以提高柔性铰链的疲劳寿命。
The flexible hinges in the compliant mechanism,when the cyclic loading with continuous and variable loads,are easily to induce the fatigue crack initiation in its thinnest place due to stress concentration. It ultimately causes fatigue failure in the flexible hinges. Using the elliptical hinge as the research object,this paper analyzed the characteristics of the maximum applied stress in the thinnest place of flexible hinges by using Taguchi Method. Orthogonal experiments were performed upon finding out the controllable factors and noise factors affecting the maximum stress. Sensitivity analysis based on Orthogonal experiments was applied loading to quantitatively analyze the effect of each design variable parameter on the maximum stress. The calculation showed that the change of the maximum stress depends on several design variables parameters,and the geometric parameter plays an important role. This method does not depend on optimization algorithm,can be employed for sensitivity analysis of discrete,non-differential or implicit-expression structures,and provides favorable reference to the robust design of the flexible hinges by improving its fatigue life.