Dynamical Modeling Of Periodically Supported Bolt Connection Structure And Damage Identification Based On Probability

Bolt connection structures are widely used in the field of engineering,but the dynamical modeling of bolt connection is complex and difficult.Modeling methods based on finite element method require fine meshes to capture the dynamical characteristics of bolt connection structures.Hence,a dynamical modeling method of bolt connection structures based on spectral finite element method is presented in this paper.The proposed method formulates the dynamical stiffness matrix in frequency domain of bolt connection structures and by further considering the displacement and force boundary conditions,the frequency responses and modal parameters can be obtained.Supported by the National Natural Science Foundation of China(NO:51778506),combining with Bayesian model class selection theory,the dynamical modeling is used in periodically supported bolt connection beams in order to obtain a relatively simple parameterization scheme for keeping the similar model-data matching.In the meantime,the particle filter method is utilized to identify the damages in bolt connection beams based on probability.The specific research contents are as follows:(1)Based on spectral finite element method and thin-layer element,this paper proposed a dynamical modeling of bolt connection structures.The dynamical stiffness matrix of bolt element is derived and the frequency responses and modal parameters are obtained by considering the displacement and force boundary conditions.Through comparing the modal parameters got from spectral finite element method with experimental results,it is verified that the proposed dynamical modeling method is valid and applicable.(2)The formulated dynamical model is utilized in the numerical simulation and experimental verification of periodically supported bolt connection beams.Based on Bayesian model class selection theory,a simplified model parameterization scheme,which can keep the similar model-data matching,is selected from a series of modeling schemes.In addition,particle filter is used to locate the damaged bolt in periodically supported beams.The validity of Bayesian model class selection theory is verified through analyzing the results of particle filter.(3)The formulated dynamical model is also utilized to study the wave propagation characteristics of periodically supported bolt connection beams.The localization factor is implemented to analyze the influence of disorder in stop frequency band and pass frequency band of periodic structures.