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Damage identification method of axial functionally graded beam

A functional gradient and damage recognition technology, which is applied in special data processing applications, instruments, electrical digital data processing, etc., can solve the problems of low recognition efficiency, reduced precision, damage misjudgment, etc., and achieve good robustness, high precision, The effect of improving recognition accuracy and calculation efficiency

Inactive Publication Date: 2017-11-17
SUN YAT SEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the application to modal data, there are certain requirements for the number of measuring points, and the accuracy is reduced when using incomplete modal
Similarly, because the damage location is not predicted first, it will cause problems such as low recognition efficiency and misjudgment of damage.

Method used

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  • Damage identification method of axial functionally graded beam
  • Damage identification method of axial functionally graded beam
  • Damage identification method of axial functionally graded beam

Examples

Experimental program
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Effect test

Embodiment 1

[0051] Example 1: Damage identification for axially functionally graded simply supported beams

[0052] Such as image 3 The simply supported beam with a rectangular cross-section is shown, the geometric parameters are shown in the figure, and the structural parameters are: the material on the left is pure aluminum, Young’s modulus E l =6.9×10 10 N / m 2 , material density ρ l =2700kg / m 3 , the material on the right is pure steel, Young’s modulus E r =2.1×10 11 N / m 2 , material density ρ r =7800kg / m 3 , the power rate of the functionally graded beam is 1.5, that is, the change of elastic modulus and density from left to right is: E(x)=(E L -E R )(1-x / L) θ +E R , ρ(x)=(ρ L -ρ R )(1-x / L) θ +ρ R . Decompose the simply supported beam into image 3 Twelve functionally graded beam elements are shown. Assume that the loss factor of unit No. 1 is 0.05, that of unit No. 1 is 0.1, that of unit No. 6 is 0.15, and that of unit No. 10 be 0.2.

[0053] The RFV values ​​of ...

Embodiment 2

[0055] Example 2: Damage identification for a four-span functionally graded beam

[0056] Such as Figure 6 In the four-span beam structure shown, the length of each span is l=3m. The structure is divided into 60 functionally graded beam units, the material on the left is Ti-6Al-4V alloy, Young's modulus E l =1.05×10 11 N / m 2 , material density ρ l =4429kg / m 3 , the material on the right is zirconia ZrO2, Young's modulus E r =1.68×10 11 N / m 2 , material density ρ r =3000kg / m 3 , the power rate of the functionally graded beam is 1.5. Assume a 5% loss in unit 2, a 10% loss in unit 8, a 15% loss in unit 18, a 20% loss in unit 28, and a 5% loss in unit 33 , Unit 38 suffered a 10% loss and Unit 48 suffered a 15% loss.

[0057] The RFV value of each node is as follows Figure 7 As shown, it can be seen that units 2, 8, 18, 28, 33, 38, and 48 are suspicious units that may be damaged.

[0058] Dynamic loads applied at nodes 8, 17, 34 and 36 Extract the displacement res...

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Abstract

The invention discloses a damage identification method of an axial functionally graded beam. The implementation process as follows: (1) establishing a finite element model of a functionally graded beam damage structure through a finite element method, and extracting inherent frequency, modality and other parameters of the structure; (2) calculating and comparing residual strain energy values of nodes, and selecting a suspicious unit; (3) calculating a hybrid sensitivity matrix S and a response difference delta H of a to-be-corrected model and a real model based on a damage parameter alpha of the suspicious unit; (4) solving a correction equation S delta alpha = delta H; (5) updating the damage parameter alpha of the suspicious unit =alpha +delta alpha; and (6) if preset precision requirements are not satisfied, returning to the loop iteration in (3), and otherwise, outputting the damage parameter to serve as an identification result. By adoption of the method, the concept of the residual force vector is defined, the damage is located, and the number of to-be-identified parameters is reduced; and the hybrid sensitivity matrix containing frequency and dynamic response is adopted, compared with the ordinary sensitivity matrix, relatively high identification precision is still available in a noise condition, and the functionally graded beam, which is a relatively complex structure, can also be successfully identified.

Description

technical field [0001] The invention relates to the technical field of structural health detection damage identification, and more specifically, to a damage identification method for an axially functionally graded beam. Background technique [0002] With the rapid development of our society, the number of various engineering facilities has been increasing, and large-scale and complex buildings have sprung up. During the service period of these structures and infrastructure, due to the influence of environmental loads, corrosion, material aging and other adverse factors, structural fatigue and damage will inevitably accumulate over time. If these damages are ignored, once the damage of the key parts of the structure accumulates to a certain extent, the damage will expand rapidly, leading to the destruction of the entire structure. The tragedies caused by the failure to detect structures in time are numerous, not only causing significant economic damage, but also threatening ...

Claims

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Application Information

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IPC IPC(8): G06F17/50
CPCG06F30/13G06F30/23
Inventor 谭栋吕中荣
Owner SUN YAT SEN UNIV
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