A Prediction Method of Coupling Loss Factor in Complex Structures

Abstract

The present invention provides a method for predicting a coupling-loss factor of a complex structure; a system is cut into continuously coupled subsystems, and the boundary conditions of a subsystem on a coupling edge are approximated; a finite element model of each coupled subsystem is established; boundary conditions are imposed, and a modal analysis of a structural finite element model is performed; modal data are extracted; the work of modal interaction is calculated by using the stress modal mode and displacement modal mode of the coupled edges of two subsystems, and the coupling loss factor of the structure is predicted by using a dual modal equation method. The present invention combines a finite element method and a dual modal equation method to predict the coupling loss factor of the complex structure; a finite element method is used to obtain the displacement and stress modal modes at the coupling edges, and the natural frequencies and modal quality of the subsystems; by means of calculating the interaction work of the coupling subsystems and then combining with a dual modal equation method, the coupling-loss factor is obtained, and the coupling-loss factor of a complex structure can be accurately and highly effectively predicted.

Description

technical field [0001] The invention relates to a statistical energy analysis method, in particular to a prediction method of coupling loss factor. Background technique [0002] The statistical energy analysis method can well describe the average vibration characteristics of each component of the system. It is a powerful tool for solving complex structural dynamics problems in high-frequency environments. It has been successfully applied in aerospace, ships, automobiles and other fields. When using statistical energy analysis to predict the high-frequency dynamic response of complex structures, the key is to determine the parameters of statistical energy analysis, especially to accurately predict the coupling loss factors between subsystems. [0003] At present, the acquisition of coupling loss factor often adopts test method, wave method, power input method, etc. For some actual engineering structures, the coupling loss factor is often obtained through experiments. However...

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Problems solved by technology

For some actual engineering structures, the coupling loss factor is often obtained by experiments. However, the experimental analysis has the disadvantages of high cost, limited test conditions and test conditions, etc.

The wave method is also one of the traditional methods to obtain the coupling loss factor, but this method is only suitable for simple structures, such as coupled beams, coupled plates, plate T-connections, etc., and cannot give corresponding theoretical solutions for complex structures

The power input method is one of the most classic methods for obtaining the coupling loss factor. However, for the prediction of the coupling loss factor of complex structures, the steps are cumbersome, and the vibration energy of the subsystem needs to be obtained by using the modes of the overall structure and the mode shapes of all nodes. In addition, it is necessary to calculate the input power, and obtain the coupling loss factor of the coupling system through the overall power balance equation of the subsystem; and with the increase in the number of structural subsystems, the loss factor matrix appears ill-conditioned, which greatly reduces the accuracy and calculation efficiency of the coupling loss factor prediction , it is difficult to meet the actual needs of the project

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