Modal Material Identification Method Using a Dissipative Finite Element Model

Structural damage identification technology is of great significance to improve the reliability and safety of civil structures and has attracted much attention in the study of structural health monitoring. In this paper, a novel structural damage identification method based on transmissibility in the time domain is proposed. The method takes the discrepancy of transmissibility of structure response in the time domain before and after damage as the basis of finite element model updating. The damage is located and quantified through iteration by minimizing the difference between the measurements at gauge locations and the reconstruction response extrapolated by the finite element model. Taking advantage of the response reconstruction method based on empirical mode decomposition, damage information can be obtained in the absence of prior knowledge on excitation. Moreover, this method directly collects time-domain data for identification without modal identification and frequent time–frequency conversion, which can greatly improve efficiency on the premise of ensuring accuracy. A numerical example is used to demonstrate the overall damage identification method, and the study of measurement noise shows that the method has strong robustness. Finally, the present work investigates the method through a simply supported overhanging beam. The experiments collect the vibration strain signals of the beam via resistance strain gauges. The comparison between identification results and theoretical values shows the effectiveness and accuracy of the method.

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Damage Identification of High-speed Maglev Guideway Girder Based on Modal Identification

Structural Health Monitoring ◽

10.21741/9781644901311-34 ◽

2021 ◽

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Health Monitoring ◽

High Speed ◽

Damage Identification ◽

Element Model ◽

High Tech ◽

Maglev Train ◽

Identification Method ◽

The Finite Element Model

Abstract. As a modern high-tech rail vehicle, the maglev train realizes the non-contact suspension and guidance between the train and the guideway, which greatly reduces the resistance of the system. Due to the high-speed operation characteristics of maglev trains, the structural health monitoring of guideway girders is particularly important for the safety and stability of maglev train operation. This paper takes the maglev train guideway girder as the monitoring target, and the finite element model of the maglev vehicle-guideway is established to simulate the running state of the train passing through the guideway girder. The dynamic response data of the guideway girder is obtained in the finite element model, considering healthy states and different damage states of the guideway girder. Then, a modal-based damage identification method is proposed, which obtains the guideway girder damage sensitive characteristics by decomposing the guideway girder acceleration response signal. Finally, based on the measured guideway girder acceleration data, this paper verifies the effectiveness of the damage identification method in guideway girder structure health monitoring, which provides reference and guidance for the future maintenance of the maglev guideway girder.

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Statistical damage identification method based on dynamic response sensitivity

Journal of Low Frequency Noise Vibration and Active Control ◽

10.1177/1461348418784828 ◽

2018 ◽

Vol 39 (3) ◽

pp. 560-571 ◽

Cited By ~ 3

Author(s):

Ling Mao ◽

Shun Weng ◽

Shu-Jin Li ◽

Hong-Ping Zhu ◽

Yan-Hua Sun

Keyword(s):

Finite Element ◽

Dynamic Response ◽

Finite Element Model ◽

Damage Identification ◽

Element Model ◽

Measured Data ◽

Response Sensitivity ◽

Identification Method ◽

The Finite Element Model ◽

Statistical Damage

The traditional deterministic damage detection method is based on the assumption that the measured data and the finite element model are accurate. However, in real situation, there are many uncertainties in the damage identification procedure such as the errors of the finite element model and the measurement noise. Since the uncertainties inevitably exist in the finite element models and measured data, the statistic method which considers the uncertainty has wide practical application. This paper proposes a statistical damage identification method based on dynamic response sensitivity in state-space domain. Considering the noise of the finite element model and measured acceleration response, the statistical variations of the damaged finite element model are derived with perturbation method which is based on a Taylor series expansion of the response vector and verified by Monte Carlo technique. Afterward, the probability of damage existence for each structural element is estimated using the statistical characteristic of the identified structural parameters. A numerical simply supported beam under the moving load is applied to demonstrate the accuracy and efficiency of the proposed statistical method.

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