螺栓结合部切向动力学行为辨识方法

Tangential Dynamic Behavior Identification of Bolt Joints

首先,以螺栓结合部切向动力学特性为研究对象,基于频响函数的子结构综合法为理论主线,建立结合部切向动力学行为辨识基本方程,推导其切向动刚度Za的理论表达式;其次,联合奇异值分解与最小二乘法,优化辨识结合部切向等效刚度ka与阻尼ca,由此建立螺栓结合部切向动力学数值模型;最后,利用该模型计算结构测点频响函数,进而将其与实测值进行对比。结果表明,二者吻合程度较高,且特征峰对应频率误差分别为1.38%,1.51%和0.84%,验证了所提方法能有效辨识螺栓结合部切向动力学行为,所得等效动力学参数精度较高,可为机械系统整机精准建模提供理论参考与数据支撑。

Identification of joints dynamic behaviors has become a universal issue,which is critical for accurate modeling of mechanical system.In this paper,a thorough methodology is presented to investigate bolt joint tangential dynamic characteristics.Substructure synthesis,based on structure frequency respond functions(FRFs),is employed as the theory mainline to construct the fundamental equation for identifying bolt joint tangential dynamic behaviors.Tangential dynamic stiffness of bolt joint,Za,is deduced afterwards.By virtue of singular value decomposition and least squares approaches,equivalent tangential stiffness parameters,ka,and damping parameter,ca,utilized for bolt joint tangential dynamic modeling in the following step,are identified.Validity of the proposed tangential dynamic model is demonstrated by comparing FRFs obtained numerically and experimentally.Comparison results indicate that frequencies errors of first three characteristic peaks are 1.38%,1.51% and 0.84%,respectively.It is sufficient to prove that the proposed methodology is efficient for identifying bolt joint tangential dynamic behaviors and the resulting equivalent dynamic parameters are highly accurate so that they can be regarded as theory and data supports for accurate modeling of mechanical system.