Modeling And Verfication Of Nonlinear Dynamic Characterstics Of Bolted Joints

The casing is an important part of the aviation engine,bolt connection structure mainly rely on to connect,positioning and sealing between the sections of casing.Because of the binding site in the bolt joint structure,the dynamic characteristics of the whole structure will be affected by the nonlinearity of the joint.But in the face of structural dynamic problems of bolt connection,most of the time linearization is usually done,the contact relationship of all parts directly ignored,and put all the parts as a whole.Neglecting the influence of nonlinear behavior,the accuracy of analysis results is greatly reduced.So,to predict the response of bolted joint structures accurately in complex vibration condition,the complex nonlinear behavior must be tested and establish nonlinear dynamic finite element model.The finite element model of simplified casing is established,the dynamic influence of bolt connection structure on the casing is studied,and through the finite element calculation and test to analyze the bolt connection structure on the whole structure.Several testing methods for nonlinear structures are presented,and the nonlinear experiments are carried out on bolted connection beam and simplified box.The influence of local nonlinear characteristics of bolt connection structure on the mode of the casing is studied,and the nonlinear finite element model is established by using spring damping element and nonlinear contact setting in ANSYS,the calculation and analysis are carried out under the same experimental conditions.The results show that the nonlinear modeling method can better simulate the actual bolt connection structure.It has a certain reference value for the calculation and analysis of bolt connection structure.