筋腱连接器球形橡胶轴承刚度仿真与试验

Simulation and experiment of the stiffness of tendon connector flexjoint

为深入研究橡胶材料及结构参数对球形橡胶轴承刚度性能的影响,采用有限元方法对5种不同材料或结构的球形橡胶轴承进行分析研究,完成了球形橡胶轴承的压缩与摆动试验.对相应橡胶材料进行了材料试验,使用Abaqus/Standard建立橡胶轴承的二维轴对称模型和1/2三维模型,用Neo-Hooke、Mooney-Rivlin和Yeoh超弹性本构模型进行仿真.进行橡胶轴承的压缩与摆动试验,对有限元仿真进行对比验证.试验结果表明:丁腈橡胶、氢化丁腈橡胶与天然橡胶制造的球形轴承,压缩刚度均会随着压缩位移上升而上升,摆动刚度均会随着摆动角度上升而下降;球形橡胶轴承金属层数量的上升会提高其竖直刚度,但对摆动刚度几乎没有影响; Yeoh本构模型在两种变形情况下均可以很好地拟合试验结果;在变形较小时,用MooneyRivlin本构模型进行仿真也可以得到较为准确的仿真结果;在压缩仿真中,形变较大时,Mooney-Rivlin本构模型无法表现出刚度迅速上升的阶段,因此仿真结果会小于试验结果;使用Neo-Hooke本构模型的仿真结果误差最大,在摆动仿真中完全无法使用.

Five flexjoints of tendon connector with different rubber material or structure were simulated by FEM to study the effect of parameters on the stiffness of flexjoint.The flexjoints were also tested under compression and rotation load.The material tests are taken on the specified rubber,and a half 3D model and a 2D model are built by Abaqus/Standard software.Neo-Hooke,Mooney-Rivlin and Yeoh constitutive model are used in the simulation.The experiments and simulation results are compared to analyze the validity and accuracy of different constitutive models,and the results show that the compression stiffness of flexjoints will increase as displacement increases,and the rotational stiffness will decrease as the angle increases.The increase in the number of the rubber layers will improve the compression stiffness but has little effect on the rotation stiffness.The results of simulation with Yeoh model can fit the experimental results very well.The Mooney-Rivlin model can also provide a relative accurate results under small deformation.The compression simulation results of Mooney-Rivlin model will be smaller than test results because that model cannot reflect the“upturn”of rubber material.The Neo-Hooke model provides the biggest error.