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Zhao Z.,University of Jinan | Nie Z.H.,University of Jinan | Nie Z.H.,The Key Laboratory of Disaster Forecast and Control in Engineering | Ma H.W.,University of Jinan | Ma H.W.,The Key Laboratory of Disaster Forecast and Control in Engineering
Applied Mechanics and Materials | Year: 2014

A newdamage identificationmethodfor arch bridge structures under a moving load based on the difference of deflection is presented. The function ofthe deflection atthe midspanof thearch with the changing positions of the moving load is derived using the Moore integralmethod. It can be concluded from the results that when the moving load is in the areawithout damage,this target indicates to be linear functions with the cosine of an angle(θ) between moving load and horizontal. Nevertheless, this target is multinomial with the change of cos θin the damage area.In order to validate the proposed damage detection algorithm, a steel arch modal issimulated, which is proved to be practicable in projects.The results indicate that the location and degreeof single damage can be identified accurately. © (2014) Trans Tech Publications, Switzerland.

Cheng C.,University of Jinan | Nie Z.,The Key Laboratory of Disaster Forecast and Control in Engineering
Advanced Materials Research | Year: 2013

In this paper, the technology of attractor phase space in chaotic theory is introduced and applied in the structural damage detection. Firstly the phase plane is constructed with the displacement and acceleration responses. Using the changes of phase plane topology of intact and damaged responses, a new damage index is extracted, and the structural damage existence and severity are identified successfully. Since some of the state variables can not be measured, a method of phase space reconstruction is proposed using single dynamic response. The dynamic responses are directly displayed into phase space, realizing transforming the signals from time domain to space domain. Then using the reconstructed phase space, the damage is diagnosed. The results indicate that the phase space reconstruction method has good robustness to noise, and higher sensitivity compared with traditional modal-based methods. The phase space reconstruction method can calculate the value of the damage index using single dynamic response, so that a single sensor can monitor structural damage existence and severity. © (2013) Trans Tech Publications, Switzerland.

Nie Z.,Jinan University | Hao H.,University of Western Australia | Ma H.,Jinan University | Ma H.,The Key Laboratory of Disaster Forecast and Control in Engineering
Structural Health Monitoring | Year: 2012

Ideally, structural health monitoring of civil infrastructure consists of determining, by measured parameters, the location and severity of damage in the structure. Many structural vibration parameters have been used to identify and quantify damage. Using parameters based on structural vibration phase space features for damage detection is a new field in structural health monitoring. In this article, a new parameter based on topology changes of the phase space of vibration signals is proposed to identify structural damage, and an index named changes of phase space topology derived from vibration time history is used to locate the damage. A circular arch structure is used to demonstrate the method. Both numerical simulation and experimental tests of dynamic responses of a scaled arch structure to impact loads are carried out. The obtained structural response data are used to detect structural damage. Both the experimental and numerical results indicate that this method can successfully locate damage. It also demonstrated that this proposed method is more sensitive to damage but less sensitive to noise than modal-based parameters. The proposed damage index can be a good candidate in an online structural health monitoring system, as it depends on global vibration measurements but is more sensitive to structural damage than other global vibration-based parameters such as vibration frequencies and mode shapes. © The Author(s) 2012.

Zhong K.,Jinan University | Zhang W.,Taiyuan University of Science and Technology | Ma H.,Jinan University | Ma H.,The Key Laboratory of Disaster Forecast and Control in Engineering
Jixie Qiangdu/Journal of Mechanical Strength | Year: 2012

An experimental research based on the longitudinal guided wave performed to identify pipeline crack. To excite and record symmetrical mode L(0, 2), a PZT (the solid solution of PbZrO3 and PbTiO3) ring made from PZT-5 with the same size of the cross section of pipe was used as the excitation sensor, and 16 piezoelectric slices distributing uniformly on the pipe end as the receiving sensor. The propagation of the guided wave studied in intact pipelines. It could be found that the transmission distance of the guided wave can be about 50 meters, and 70 kHz can be used as the most suitable center frequency for damage detection. Keep the frequency as constant, increasing the periods number of the excitated guided wave can induce to high power output. But too many periods will lead to waveform superpositions. On this basis, the flaw of the pipe with single and double fracture can be detected and located by the receiving waves. Finally, the parameter influence of the crack parameter on reflection coefficients was studied. It can be found that the relationship between the reflection coefficients and crack circumference parameters satisfies approximately linear relationship.

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