Structure health monitoring method based on distributed strain dynamic test

Abstract

The invention discloses a method for monitoring the structure health based on a distributed strain dynamic test; the invention adopts a distributed strain transducer to build a distributed sensing network and selects to arrange a reference transducer, carries out structure system simulation state analyzing to obtain a distributed strain simulation state vector DMSV, originally takes whether a target characteristic vector Alpha changes or not as a criterion to identify structural damage, obtains the effects of being capable of rapidly, accurately and effectively capturing the structural damage and locating, and simultaneously adopts the reasonable measures of real time image display and deleting redundant data on time, thereby having the advantages of small errors, high precision, simple process and intuitionistic monitoring; the method can eliminate the interference of noise and environment under the conditions of uncertain loading and an unknown mathematical model, carry out on-line structural damage detecting and diagnosing in real time and is suitable for long period monitoring of various engineering structures, especially for the civil structure.

Description

Technical field: [0001] The invention relates to a method for monitoring engineering structures, in particular to a structural health monitoring method based on distributed strain dynamic testing. Background technique: [0002] With the continuous improvement of people's requirements for the safety and reliability of engineering structures, monitoring and diagnosing structural performance, discovering structural damage in time, predicting possible disasters, and evaluating its safety have become important tasks for future structural design and manufacturing. , The inevitable requirements in construction and management work. In recent years, due to the progress of science and technology in all aspects and the needs of practical engineering, the technology called "structural health monitoring" in this field has been developed rapidly. The related products, systems and engineering applications are well known at home and abroad. Also emerge in endlessly. The so-called Structur...

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Problems solved by technology

[0005] (1) On-site detection method based on static test: it must be carried out under the premise of specifying the applied load. This method needs to strictly control the conditions of the applied static load. It not only consumes a lot of manpower and material resources when loading, but also must stop the structure. normal working condition

[0006] (2) Detection methods based on dynamic testing: There are too many parameters to be identified using model update or system identification structural analysis methods, and the structural mathematical model may be distorted. At the same time, the algorithm is difficult to converge and its effectiveness is easily affected by actual measurement noise and errors; The detection of the analysis method that does not require the structural mathematical model also has its own defects: the frequency domain method based on vibration testing can only obtain a few first few order frequencies and mode shapes of the structural response under actual test conditions, and cannot be directly used for small damage diagnosis The modal curvature method is easily disturbed by noise and errors, and requires enough measuring points to ensure accuracy; the flexibility matrix method is not easy to reflect the information of local damage in multiple parts of the structure or adjacent positions, etc.

[0007] (3) Measurements using accelerometers, speedometers or displacement sensors are all responses to the translational degree of freedom at a certain point of the structure. These responses have no direct and clear relationship with the local damage of the structure, and the damage at a certain position will vary in degree. The measurement value of the sensors arranged in a certain area near the position is greatly affected, and multiple damages at different positions will be reflected in the measurement value of a sensor to varying degrees. This coupling relationship makes the structural response analysis based on these sensor measurements facing great difficulties

[0008] (4) For the traditional "point" strain gauge, if the local damage in the structure does not appear within the test range of the installed sensor, it is difficult to be detected accurately; If placed in the area, the sensor will often fail due to local stress concentration or cracks in the area

Therefore, it is difficult for the "point" distributed strain sensor to effectively capture the unpredictable structural damage in advance, but it is also unrealistic to arrange the sensors densely on a large structure, so the "point" strain sensor cannot adapt to the detection area as large as possible. "Distributed measurement" covering the entire structure

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