EMD (empirical mode decomposition)-based stress-strain reconstruction method

Abstract

The invention provides an EMD (empirical mode decomposition)-based stress-strain reconstruction method and belongs to the technical field of structural health monitoring. The method is mainly based on the information of three aspects of measured data of a strain gauge, a structural model, and the position information of measurable points and immeasurable points. The method comprises the steps of decomposing the actual measurement structural response of the measurable points of a monitoring system or a sensor into a group of modal responses; obtaining the modal response relationship between the measureable points and the immeasurable key points by establishing a finite element model-based conversion equation to obtain a group of modal responses of the immeasurable points and reconstructing the structural responses of the immeasurable points by superposing the obtained modal responses. The method enables the strain gauge to be directly used for measurement of the stress-strain of the key points under the condition of no direct sensor measurement, and is high in accuracy and analysis speed.

Description

technical field [0001] The invention belongs to the technical field of structural health monitoring, and in particular relates to a stress-strain reconstruction method based on empirical mode decomposition (EMD) of key unmeasurable points. Background technique [0002] Structural health monitoring (SHM) is a key issue in engineering systems, civil infrastructure, and smart structures in recent years. For most mechanical systems subjected to fatigue loading, fatigue crack growth is a major failure path, and fatigue damage mainly depends on the stress loading history under actual working conditions. The difficulty of fatigue life prediction is that it is difficult to infer the stress and fatigue load near the fatigue crack. Since the location of the damage is unknown, it is difficult to directly measure the stress or strain at the damage site. Therefore, inferring the stress and strain field at the hazard point from the measurement data at a remote location becomes an essent...

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Problems solved by technology

[0004] Aiming at the existing problem that the strain and stress in fatigue crack growth cannot be directly measured, the present invention provides a stress-strain reconstruction method based on empirical mode decomposition, which reconstructs the stress-strain of key unmeasurable points, and is suitable for evaluating structures Estimation of stress loading history of damage during fatigue damage life of parts

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