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Local bridge damage quantification method based on deflection influence lines

A quantification method and influence line technology, applied in the direction of instruments, complex mathematical operations, calculations, etc., can solve problems such as difficulty in constructing sensitivity matrix, iteration non-convergence, and large amount of calculation

Active Publication Date: 2016-11-23
XIAMEN UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, (1) the construction of the sensitivity matrix is ​​often difficult, and the iterative non-convergence is prone to occur; (2) the optimization iteration process is computationally intensive, and the correction efficiency cannot be improved

Method used

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  • Local bridge damage quantification method based on deflection influence lines
  • Local bridge damage quantification method based on deflection influence lines
  • Local bridge damage quantification method based on deflection influence lines

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0185] Example 1: Damage quantification of numerical models of simply supported beams and continuous beams

[0186] The design dimensions of simply supported beam model are as follows: figure 1 As shown (the node numbers are 1~41), the length is 2m, and the rectangular cross-sectional size is 0.03m×0.05m. Other material parameters include: elastic modulus E = 205GPa; density ρ = 7800kg / m 3 . The finite element modeling adopts the Euler-Bernoulli beam unit, and the beam is divided into 40 units (1~40), numbered sequentially from left to right.

[0187] In order to verify the ability of this method to identify one damage and multiple damages, the following two damage cases are designed: (1) Damage case 1: the stiffness of No. 8 unit of the simulated simply supported beam is reduced by 30%; (2) Case 2: The stiffnesses of No. 8, No. 22 and No. 36 units of the simulated simply supported beam are reduced by 20%, 25% and 15% respectively. Due to the objective existence of measure...

Embodiment 2

[0197] Example 2: Quantification of damage to simply supported aluminum beams in the laboratory

[0198] The simply supported aluminum beam adopts a box section with a length of 3.16m, a height of 0.025m, a width of 0.15m, and a box wall thickness of 0.0015m. The front view and cross section of its finite element model are as Figure 11 shown. The Young's modulus after model update is E=6.9×10 10 Pa, using a 2.47Kg mass block to carry out static loading according to a specific spacing (the unit spacing of the model division) to simulate the moving vertical unit force. Selectively arrange displacement meters at the 1 / 4 span, 1 / 2 span, 5 / 8 span and 3 / 4 span of the beam, and the sampling frequency is 50Hz.

[0199] In addition, in order to simulate damage and locate damage, the whole beam is divided into 32 areas, which are numbered from left to right, except for the area at the starting end, which is 8 cm, and the rest are 10 cm. This is also to facilitate subsequent model p...

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Abstract

The invention discloses a local bridge damage quantification method based on deflection influence lines and relates to the field of health monitoring of an engineering structure. The method comprises steps as follows: 1) decomposition and combination of an eigenvalue of a stiffness matrix; 2) construction of an influence line matrix; 3) quantification of the injury degree. By means of a characteristic parameter decomposition method, damage is quantified by the use of the influence lines, a matrix with similar sensitivity is acquired more conveniently, the solving process cannot be iterated, and the solving speed is higher. On the basis of the deflection influence lines of a bridge, the damage degree can be more accurately quantified while local damage is positioned. Compared with existing damage indexes, the damage index based on the influence lines is more sensitive to local damage of the bridge and is not sensitive to change of the environment factor, and the method is more suitable for detecting the local damage of the bridge in the operation environment. Compared with a conventional damage positioning method based on a sensitivity matrix, the matrix with the similar sensitivity is simpler and more convenient to construct, the solving process cannot be iterated, the problem about no convergence of iteration of numerical solution is solved, and the solving speed is increased.

Description

technical field [0001] The invention relates to the field of health monitoring of engineering structures, in particular to a bridge local damage quantification method based on deflection influence lines in a structural health monitoring system. Background technique [0002] In the past few decades, China has built a large number of bridges, including many long-span bridges with a span of one kilometer. Considering environmental corrosion, material aging, long-term and fatigue effects of loads, and sudden disasters such as typhoons and earthquakes, bridges are accompanied by structural deterioration from the beginning of their construction. Damage starts locally, but local damage of bridges often does not cause significant changes in the overall properties of the structure, which brings great difficulties to damage identification. Structural damage identification generally refers to the detection of reductions in the stiffness of structural members. Rytter divides damage id...

Claims

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Application Information

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IPC IPC(8): G06F19/00G06F17/16
CPCG06F17/16G16Z99/00
Inventor 陈志为朱松晔蔡亲霖
Owner XIAMEN UNIV