单螺栓连接梁的非线性连接层建模与参数识别

Nonlinear connection layer modeling and parametric identification for single bolt connected beam

针对线性的螺栓连接层等效模型无法表征进入微观滑移状态后结合部动力学行为的问题,用Voce本构关系对线性连接层等效模型做出了改进,使其能表征螺栓结合部的非线性动力学行为。以单螺栓连接梁为研究对象,试验探究了不同预紧扭矩对其固有频率的影响,测试了其在不同幅值谐波激励力下的频响函数。通过遗传算法对连接层等效模型的四个非线性参数进行了识别,分别包括初始屈服应力、切线模量和两个形状参数,识别了参数后模型频响函数计算值与试验值的误差在10%以内,表明改进后模型的准确性与可行性。改进后连接层等效模型可以用于装配结构非线性行为的预测。

Here,aiming at the problem of linear equivalent model of bolted connection layer not able to characterize dynamic behavior of the joint after entering micro slip state,the equivalent model of linear connection layer was improved by using Voce constitutive relation to be able to characterize nonlinear dynamic behavior of bolted joint.Taking a single bolt connected beam as the study object,effects of pre-tightening torque changes on beam natural frequencies were experimentally investigated,and its frequency response functions(FRFs)under harmonic excitation forces with different amplitudeswere tested.4 nonlinear parameters of initial yield stress,tangent modulus and two shape parametersin the equivalent model of connecting layer were identified with genetic algorithm.It was shown that the error between calculated value of the model’s FRF and its experimental value is within 10%after identifying parameters,the correctness and feasibility of the improved model is verified;the improved equivalent model of connecting layer can be used to predict nonlinear behavior of assembly structure.