内置式平面抗拉柔性铰链的建模及分析

Modeling and analysis of planar tension inside flexure hinge

针对内置式LET(Lamina Emergent Torsion)柔性铰链轴向抗拉刚度低的问题,提出了一种内置式平面抗拉柔性铰链。首先全面考虑铰链各部分的变形特点,设计了内置式平面抗拉柔性铰链的结构形式;其次利用弹簧刚度模型推导了该柔性铰链弯曲等效刚度与抗拉等效刚度的理论计算模型,并通过设计实例的有限元仿真分析结果和理论计算值的对比,验证了上述理论模型的正确性;最后,将内置式LET柔性铰链和内置式平面抗拉柔性铰链的弯曲刚度及抗拉刚度进行比较。结果表明,在结构参数相近的前提下内置式平面抗拉柔性铰链的弯曲刚度仅是内置式LET柔性铰链的1.179倍,但抗拉刚度在其57.821~89.496倍之间。这意味着,内置式平面抗拉柔性铰链的抗拉刚度在弯曲刚度没有明显变化的情况下有显著提高。该铰链的性能完全与预期相符。

A new planar tension inside flexure hinge is proposed in lamina emergent mechanisms（LEMs） to increase the axial stiffness of inside LET flexure hinge. Firstly, the structure of the planar tension inside flexure hinge is designed considering deformation characteristic of flexure hinge. Secondly, the theoretical calculating model of the equivalent tensile stiffness and equivalent bending stiffness is presented respectively using spring model. The correctness of the theoretical models is verified by the comparison of the theoretical calculation and finite element analysis. Finally, the bending stiffness and tensile stiffness of the planar tension inside flexure hinge is compared with that of inside LET flexure hinge, separately. Research result shows that bending stiffness of planar tension inside flexure hinge is only 1.179 times of that for inside LET flexure hinge, but the tensile stiffness is between 57.821 to 89.496 times of that for inside LET flexure hinge in the case of the flexure hinges with similar structure parameters. That means the tensile stiffness of planar tension inside flexure hinge is increased significantly without obvious change of the bending stiffness, and the performance of the planar tension flexure hinge meets expectation.