A Random Dynamic Load Identification Method Based on Spectral Stochastic Finite Element Model

Abstract

The invention discloses a random dynamic load recognition method based on a spectrum random finite element model. The method comprises the following steps: S1, carrying out modal tests repeatedly under the same working condition on a structure which contains uncertain parameters, and establishing a spectrum random finite element model of an uncertain system; S2, measuring a random dynamic responsesample of the structure which contains the uncertain parameters under the effect of a random dynamic load; S3, recognizing a mean value of the random dynamic load on the structure by using a mean value of a random dynamic response sample; S4, solving a random dynamic response covariance of the structure when only uncertainness of the parameters of the system is considered by using the recognizedmean value of the random dynamic load; S5, calculating an approximate value of the random dynamic response covariance caused by the reason that only dynamic load randomness is considered; and S6, recognizing a statistical characteristic of the random dynamic load. Uncertainness of a dynamic load and system parameters can be considered simultaneously, and by a dynamic response sample of a measuredstructure, the statistical characteristic of the random dynamic load acting on the system of the structure is recognized.

Description

Technical field: [0001] The invention relates to a random dynamic load identification method based on a spectral random finite element model, and belongs to the technical field of dynamic load indirect identification. Background technique: [0002] Dynamic loads on engineering structures are crucial to the design and safety assessment of structures. In many cases, the external loads on some engineering structures are difficult to obtain by direct measurement methods, such as the aerodynamic loads on the aircraft during flight, the wind and wave loads on the offshore platform, and the contact loads between the wheels on the vehicle and the ground, etc. Therefore, using Obtaining dynamic load information indirectly by measuring the dynamic response of the structure has become a widely used technology, also known as the dynamic load indirect identification technology. [0003] The current indirect identification methods for dynamic loads can be mainly divided into frequency do...

AI Technical Summary

Problems solved by technology

The existing indirect dynamic load identification methods generally assume that the dynamic model of the structural system is accurate enough, and there is no or only a small uncertainty, that is, the dynamic load identification is limited to the deterministic structure, and it is impossible to consider the variable parameters of the structural system. Certainty

However, in actual engineering, due to manufacturing or measurement errors and the discreteness caused by the material itself, the structural system parameters are often not suitable to be described by a definite value, regardless of the uncertainty of the system parameters will be It will cause errors or even errors in the dynamic load identification results

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