抗压内LET柔性铰链的建模及分析

Modeling and analysis of compressive inside LET flexure hinge

针对内LET（Lamina emergent torsion）柔性铰链存在轴向刚度低这一问题,基于倒置原则提出了一种抗压内LET柔性铰链.首先,综合考虑各柔顺片段的变形特点,设计了抗压内LET柔性铰链的结构;其次,利用等效弹簧刚度模型推导了该铰链的弯曲等效刚度及抗压等效刚度,并用有限元分析实例验证了2种理论计算模型的正确性;最后,将内LET柔性铰链和抗压内LET柔性铰链弯曲变形及压缩变形的有限元仿真结果进行比较.结果表明,在外形尺寸一致的情况下抗压内LET柔性铰链的弯曲刚度是内LET柔性铰链的1.195倍,而抗压刚度却是其24.532-28.141倍.在弯曲刚度无明显变化的前提下,抗压内LET柔性铰链的抗压刚度大幅提升,该铰链的结构设计完全符合预期要求.

Based on the inversion principle,a new compressive inside LET flexure hinge is presented to improve the axial compressive stiffness of inside LET flexure hinge.Firstly,the structure of compressive inside LET flexure hinge was designed considering the deformation characteristics of compliant segments comprehensively.Secondly,the theoretical calculating models of the equivalent compressive stiffness and the equivalent bending stiffness for the compressive inside LET flexure hinge were set up respectively by using spring model.Meanwhile,correctness of two theoretical calculating models was validated by finite element analysis.Finally,the finite element simulation results were demonstrated by comparing the compression deflection and bending deflection of the compressive inside LET flexure hinge with that of the inside LET flexure hinge.The results showed that bending stiffness of the compressive inside LET flexure hinge was only1.195 times of that for the inside LET flexure hinge,but the compressive stiffness was 24.532-28.141 times of that for inside LET flexure hinge.The compression stiffness of compressive in-side LET flexure hinge is significantly increased in the case that the bending stiffness does not change obviously,which also proves the superiority and the reasoning of the design of the compressive inside LET flexure hinge.