A Modified Sensitivity Structural Damage Identification Method Based on Joint Index and Limited Information

Abstract

The present invention discloses a corrected sensitivity structural damage recognition method based on a joint index and finite information. The method comprises: firstly, characterizing a damage and an error by setting an element stiffness coefficient and a modeling error coefficient; secondly, calculating a displacement-frequency joint index based on a static and dynamic result and correcting the joint index; afterwards, extracting finite information to construct a displacement-frequency sensitivity matrix and correcting the matrix; then, calculating a change amount of element stiffness by using the corrected sensitivity matrix and the joint index; and finally, changing a model error coefficient to calculate results of different errors. The corrected sensitivity structural damage recognition method based on the joint index and the finite information provided by the present invention is based on a static and dynamic joint index, considers the finite information and by correcting a sensitivity equation, ensures that each term of a sensitivity matrix can reflect joint information of a degree of freedom in static displacement sampling and a natural frequency sampling order. The method provides a reference for a recognition operation on a dynamic and static information joint damage of a large and complex structure, and explores a new solution for a damage recognition operation where a plurality of degrees of freedom only have finite sample information.

Description

technical field [0001] The invention relates to a modified sensitivity structural damage identification method based on joint indicators and limited information, and is especially suitable for damage identification and health monitoring of large and complex structures with many degrees of freedom. Background technique [0002] With the advancement of space science, the development of aerospace technology and the future demands of human beings on the space field, the structure of modern spacecraft is developing in the direction of large-scale and complex. Spacecraft structures, including manned spacecraft, deep space exploration satellites, space solar power plants, and solar sails, face the problem of structural damage accumulation under the influence of design loads and various sudden external factors in complex space service environments. Thus the safety of the structure is threatened. The problem of damage identification, which uses non-destructive methods to detect whet...

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Problems solved by technology

[0003] The frequency-based damage identification method can realize the health monitoring of the structure to a certain extent, especially because the frequency measurement is convenient and accurate, and the error is low, so it can be used for damage identification with more accurate frequency input parameters, but the disadvantage is that the frequency is Global quantities, which are not sensitive to local damage, or different damages will cause the same frequency change, prone to damage recognition "misdiagnosis"

The identification of static displacement can achieve local damage diagnosis to a large extent, because static displacement can realize the fine description of the local information of the structure, but due to the large number of sampling points of the static displacement degree of freedom, all freedom can be realized. The sampling of degree information is extremely unrealistic

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