A Modal Parameter Identification Method for Output-Only Linear Time-Varying Structural Structures

Abstract

The invention discloses an output-only linear time-varying structure modal parameter identification method and belongs to the technical field of structural dynamics. Firstly, a cost function of a least squares support vector machine vector time-varying autoregressive model is deduced; secondly, a function space is built by means of a Wendland compactly supported radial basis function; a regular factor is determined through the non-parameter method based on Gamma testing, and a basis function width reduction coefficient is given on the basis of actual experiences; a time-varying autoregressive model order is determined according to the Bayesian information criterion and the Akaike information criterion; a function space order is determined according to the ratio of residual sum of squares to sequence sum of squares; finally, the matrix expression of the least squares support vector machine vector time-varying autoregressive model is solved according to the cost function, modal frequency of a system is solved according to a time freezing method, and linear time-varying structure modal parameter identification is finished. The method can improve calculation efficiency, improves system robustness, and is widely used in linear time-varying structure modal identification in structural dynamic engineering application.

Description

technical field [0001] The present invention relates to an identification method of only outputting linear time-varying structural modal parameters, in particular to a method for identifying only outputting linear time-varying structural modal parameters based on a vector time-varying autoregressive model and a least squares support vector machine, belonging to the structure The field of kinetic technology. Background technique [0002] In daily life and industrial production, due to different reasons such as changes in working conditions, structural aging, and normal wear and tear, the modal parameters of many engineering structures will change with time, showing time-varying characteristics. For example, the vehicle-axle system under the excitation of moving vehicles, the launch vehicle whose fuel quality changes with time, the aircraft under the additional aerodynamic effect during flight, and the expandable geometrically variable space agency all exhibit time-varying cha...

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Problems solved by technology

[0013] In short, since the solution of support vector machine technology is a constrained convex quadratic programming problem, the calculation amount is huge in the actual solution process, the calculation efficiency is low, and the calculation cost is high

Moreover, it is highly sensitive to the order of the model and samples, and the selection of parameters such as the order of the model and the regularization factor adopts a cross-validation method. There is no simple and easy method, and it is very complicated for users to apply.

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