Damage identification method of beam structure based on support reaction force and deflection curvature

A support reaction force and damage identification technology, applied in the testing of machines/structural components, elastic testing, instruments, etc., can solve the problems of not being able to identify the degree of structural damage and requiring information before damage

Active Publication Date: 2021-01-22
XIANGTAN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a damage identification method for beam structures based on support reaction force and deflection curvature in view of the fact that the existing deflection and curvature methods cannot identify the degree of structural damage and require information before damage

Method used

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  • Damage identification method of beam structure based on support reaction force and deflection curvature
  • Damage identification method of beam structure based on support reaction force and deflection curvature
  • Damage identification method of beam structure based on support reaction force and deflection curvature

Examples

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Effect test

Embodiment 1

[0174]Example 1: seeFigure 17 , The span of the simply supported beam is 100cm, 5cm is divided into a unit, a total of 20 units, 21 measuring points (the numbers in the upper row of circles in the figure are the unit numbers, and the numbers in the lower row are the numbers of the measuring points). The section size of the board is b×h=4.5cm×1.5cm, and the elastic modulus of the material is 2.7×103MPa, Poisson's ratio is 0.37, density is 1200kg / m3.

[0175]The damage in the actual engineering structure, such as the occurrence of cracks, material corrosion, or the decrease of elastic modulus, generally only causes a large change in the stiffness of the structure, and has a small effect on the quality of the structure. Therefore, in the finite element calculation, it is assumed that the structural element damage only causes the decrease of the element stiffness, but does not cause the element quality to change. The damage of the element is simulated by the decrease of the elastic modulus...

Embodiment 2

[0184]Example 2: seeFigure 22 , The cantilever beam span is 100cm, 5cm is divided into a unit, a total of 20 units, 21 measuring points (the numbers in the upper row of circles in the figure are the unit numbers, and the numbers in the lower row are the numbers of the measuring points). The section size of the board is b×h=4.5cm×1.5cm, and the elastic modulus of the material is 2.7×103MPa, Poisson's ratio is 0.37, density is 1200kg / m3.

[0185]Considering that the fixed end unit 1, the mid-span unit 10, and the free end unit 20 have different degrees of damage together, the damage conditions are shown in Table 2.

[0186]Table 2 Multiple damage conditions of cantilever beam

[0187]

[0188]The specific implementation steps are as follows:

[0189]Step 1: Apply a concentrated load of 10N at the 21st measuring point at the cantilever end of the damaged cantilever beam to obtain the measured deflection curve of the cantilever beam after damage. The reaction force of the support is equal to the load ...

Embodiment 3

[0195]Example three: seeFigure 27 , The three-span continuous beam span is arranged as 100+150+100cm, 10cm is divided into a unit, a total of 35 units, 36 measuring points (the numbers in the upper row of circles in the figure are the unit numbers, and the numbers in the lower row are the support numbers) . The section size of the board is b×h=4.5cm×1.5cm, and the elastic modulus of the material is 2.7×103MPa, Poisson's ratio is 0.37, density is 1200kg / m3.

[0196]Unit 7 is located near the 0 point of the side span bending moment (ie the inflection point of deflection curvature) under uniform load, unit 13 is located near the 0 point of the bending moment of the concentrated load in the middle span, unit 18 is the middle span unit, and unit 26 is the third span The maximum negative bending moment unit, the damage conditions are shown in Table 3.

[0197]Table 3 Damage conditions of three-span continuous beam

[0198]

[0199]The specific implementation steps of condition 1 are as follows:

[0200]...

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Abstract

The invention discloses a beam structure damage identification method based on support counterforce and deflection curvature. The method mainly comprises the steps of applying load to a damaged back beam structure to obtain an actually measured deflection curve and support counterforce; solving the curvature of the actually measured deflection curve; calculating the bending moment value of each position of the beam structure through the support counterforce and the load; obtaining the stiffness of each position of the beam structure by dividing the bending moment value of the corresponding position by the deflection curvature, and identifying the damage position through the sudden change of the stiffness curve of the damage state; eliminating the stiffness of the damaged position, and fitting the residual stiffness curve to obtain a stiffness curve of an undamaged state; and calculating the damage degree according to the stiffness curves of the damaged state and the undamaged state toobtain the structural stiffness of the damaged position. If the beam structure is a statically indeterminate structure, loads are applied to different positions of the structure for multiple times, damage positions, damage degrees and stiffness results under the action of multiple loads are obtained, and damage judgment is comprehensively conducted. The method can accurately position and quantifythe damage of the beam structure, and is applied to damage evaluation of the beam structure.

Description

Technical field[0001]The invention belongs to the technical field of structural health monitoring, and specifically relates to a beam structure damage identification method based on support reaction force and deflection curvature of a beam structure nondestructive detection technology.Background technique[0002]As the core content of the bridge health monitoring system, structural damage identification has many identification methods. The overall damage identification methods developed at home and abroad mainly include: structural damage identification methods based on dynamic response and static response. The dynamic response parameter index mainly judges the structural damage through the change of the structural mode (vibration frequency and mode shape). This method has high requirements on the number of measuring points, the measurement accuracy of the sensor, and the method of modal parameter identification. The other type of method is a damage identification method based on stat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01M5/00
CPCG01M5/0008G01M5/0033
Inventor 唐盛华刘宇翔张学兵秦付倩楚加庆罗承芳杨文轩
Owner XIANGTAN UNIV
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