Modeling Method And Dynamic Analysis Of Bolted Composite Structure System Modeling Method And Dynamic Analysis Of Bolted Composite Structure System

Bolt connection has been widely used in mechanical manufacturing,civil construction,land and water transportation,aerospace and other engineering fields.Bolt plays a role of transferring force and motion in the structure,and its mechanical characteristics have an important influence on the dynamic behavior of the structure.If the influence of bolt connection is ignored in the process of structural dynamic modeling,it will lead to significant errors in the model results and experimental results,especially when the structure is strongly excited.Because of the nonlinearity and complexity of bolted connections,it is a challenging problem to predict the dynamic characteristics of such structures by using numerical models such as finite element.In this paper,the bolted composite structure is taken as the research object,the numerical modeling method of bolted connection is studied,and the model updating based on certainty is discussed.The main contents are as follows:First of all,the current situation of modeling methods and model updating of bolted composite structure is fully investigated.The characteristics of constitutive model and finite element model of bolted composite structure are sorted out.Six common modeling methods of finite element model are briefly introduced.The advantages and disadvantages of different finite element models of bolted composite structure are compared and discussed,including fine three-dimensional finite element model,rigid element model and spider-net model,composite model,thin-layer element model,spring damping model and so on.Taking the three-layer frame bolt connection structure as an example,based on the modal results,the effectiveness of different simplified methods for structural simulation is studied and analyzed,which provides research means and basis for the following modeling selection and optimization analysis of bolt connection structure.Secondly,the equivalent linear model of bolt connection structure is established and applied to the low-speed machine of large-scale composite structure to carry out the deterministic load analysis of the structure.In order to establish the equivalent linear analysis model of the composite structure,the stiffness of the bolt connection substructure should be calculated according to the actual characteristics of the bolt.The cone pile method and the appropriate element are used to simulate the bolt connection area,which are used to simulate the through bolt and the fuselage connection bolt in the low-speed machine.The working load of the low-speed machine is given,and the transient dynamic analysis under the working load is carried out.The dynamic response of the connecting area of the through bolt and the fuselage connecting bolt is discussed.At last,the model updating of bolted structure based on PSD is developed by Pseudo-excitation method.By using the Pseudo-excitation method,a cantilever structure is analyzed in ANSYS and MATLAB respectively,which verifies the feasibility of Matlab using ANSYS to realize the Pseudo-excitation method.On this basis,the model updating of bolted shell structure based on PSD is carried out,and the influence of noise and excitation form on parameter identification is discussed.The results show that the method has better effect,and comparing with the usual method the CQC method of random vibration,the Pseudo-excitation method greatly improve the calculation efficiency.