直角切口柔性铰链串联支链的屈曲分析

利用材料力学弯曲变形理论的挠曲线近似微分方程,建立计算直角切口柔性铰链串联支链屈曲临界力的数学模型,在建模过程中定义平均屈曲临界挠度系数并给出其确定方法.采用商用有限元软件ANSYS8.0对大量不同参数的串联支链模型进行有限元屈曲分析,分析结果与根据数学模型计算得到的屈曲临界力十分接近,说明了所建数学模型的正确性.研制测试柔性铰链串联支链屈曲临界力的专用试验装置,针对加载载荷尺寸对柔性支链屈曲的影响,提出载荷等效长度的概念.试验结果表明:屈曲临界力的试验值与理论计算值相吻合,从而验证所建数学模型具有较高的参考价值,可以作为柔性铰链串联支链屈曲优化设计的指导理论.

BUCKLING ANALYSIS OF SERIAL CHAIN COMPOSED OF THE RIGHT-ANGLE-NOTCH FLEXURE HINGES

The mathematical model, which can be used to calculate the critical force of compliant serial mechanism com-posed of right-angle-notch flexure hinges, is established by employing the approximative differential equation of the flexi-ble curve of the material bending theory. The buckling critical coefficient of flexibility is defined, and the method is put for-ward, by which the value of the coefficient could be calculated. The finite element buckling analysis using commercial software ANSYS8.0 is carried out, and the result confirms the correct-ness of the mathematical model established above. The experi-mental equipment is developed to test buckling critical force of compliant serial mechanism. In order to reduce the influence of load dimension on buckling, the conception of load equivalent length is proposed. Experiments indicate that the experimental value is consistent with the theoretical one. Consequently, the mathematical model proposed above has high reference value, and it can be used as the directive theory for buckling optimiza-tion design of compliant serial mechanism.