摘要
针对处于悬臂态的螺栓联接梁,采用线性弯曲刚度和立方刚度等参数来表征该系统联接部位的非线性特性,结合边界条件和联接部位的连续性条件,建立其二自由度非线性动力学模型。采用多尺度法对该系统进行求解,获得其非线性频率响应函数。在非线性解的基础上,推导出系统的线性和非线性参数的表达式。以某悬臂螺栓联接梁为例,实测不同预紧力矩下的固有特性和响应特性,进而辨识出不同预紧力矩下该系统的线性和非线性参数。结果表明:本文提出的螺栓联接梁二自由度非线性模型以及相应的参数辨识方法具有合理性,螺栓联接梁具有典型的软式非线性特性。
For the cantilever bolted joint beam, parameters including linear bending stiffness and cubic stiffness were introduced to represent the nonlinear characteristics of the joint part. Combined with the boundary conditions and the continuity of joint part, a two degree of freedom(DOF) nonlinear dynamic model was constructed and the nonlinear frequency response function was obtained by means of multiple scales method. Based on the nonlinear solutions,expressions of linear and nonlinear parameters were deduced. A cantilever beam with bolted joint was taken as example to identify the linear and nonlinear parameters by measuring its natural characteristics and response characteristics at different preloads. The results show that the two DOF model and the identification method are reasonable. Typical"softening" nonlinearities can be also observed in the results.
引文
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