Damaged state uniform load surface curvature-based simply supported beam damage identification method

A damage identification, surface curvature technology, used in special data processing applications, instruments, electrical digital data processing, etc.

Active Publication Date: 2018-03-27
XIANGTAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Xu Dian and Yang Youfa used polynomial least squares to fit the flexibility curvature curve before damage, and used the damage effective area to identify the damage degree. This method can only qualitatively evaluate the damage degree

Method used

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  • Damaged state uniform load surface curvature-based simply supported beam damage identification method
  • Damaged state uniform load surface curvature-based simply supported beam damage identification method
  • Damaged state uniform load surface curvature-based simply supported beam damage identification method

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Embodiment Construction

[0082] The technical solution of the present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

[0083] 1 Damage identification method

[0084] 1.1 Curvature of uniform load surface in damage state

[0085] The flexibility matrix F of the structure can be obtained from the mode shape normalized by mass as follows:

[0086]

[0087] Where: Φ=[φ 1 ,φ 2 ,…,φ m ] is the mode matrix, m is the mode order, φ i =[φ i1 φ i2 … φ in ] T is the i-th mode shape vector, n is the number of extracted mode shape nodes, is a diagonal matrix, ω i is the natural frequency of the i-th mode.

[0088] The flexibility matrix of the damaged state structure is:

[0089]

[0090] The displacement of the structure under load can be calculated by the flexibility matrix:

[0091] w=F·P (29)

[0092] In the formula: w is the displacement, P is the load column vector.

[0093] When P is taken as the unit of unif...

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Abstract

The invention discloses a damaged state uniform load surface curvature-based simply supported beam damage identification method. The method comprises the following steps of obtaining a uniform load surface curvature of a damaged state; obtaining a displacement curve equation of a simply supported beam; obtaining a uniform load surface curvature of an undamaged state; and identifying a damage level. According to the method, the simply supported beam is subjected to damage level identification by only utilizing a flexibility matrix of structure damage states; the uniform load surface curvature of the damaged state is fitted by adopting a quadratic polynomial least square method based on a condition that the displacement curve equation of the undamaged simply supported beam under the effect of a uniform load is a quartic polynomial; and a fitted curve is used for replacing the uniform load surface curvature of the undamaged state to perform damage identification. A relationship between the uniform load surface curvature and the unit damage level is theoretically inferred; single-damage and multi-damage working conditions are considered; reasons for generating errors during use of thefitted curve for performing the damage level identification are analyzed; a corresponding correction method is given; and the corrected method can realize relatively accurate damage level quantification of the simply supported beam.

Description

technical field [0001] The invention relates to a method for identifying damage of a simply supported beam, in particular to a method for identifying damage of a simply supported beam based on the curvature of a uniform load surface in a damaged state. Background technique [0002] In recent years, the use of structural flexibility matrix construction indicators for damage diagnosis has attracted widespread attention from scholars at home and abroad, and a variety of damage identification indicators based on structural flexibility matrices have also been developed. Curvature technology can amplify the discontinuity of the curve and make the small changes of the curve easier to detect. Therefore, many scholars have conducted research on the flexibility curvature. Most damage indicators require information before damage and can only be used for structural damage location and Qualitative response damage degree. For the case of no pre-damage information, Wang and Qiao proposed ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCG06F30/20G06F2119/06
Inventor 唐盛华苏彬建秦付倩周楠楚加庆简余罗承芳
Owner XIANGTAN UNIV
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