scholarly journals Locating and Quantifying Damage in Beam-like Structures Using Modal Flexibility-based Deflection Changes

2020 ◽  
Vol 20 (10) ◽  
pp. 2042008
Author(s):  
N. T. Le ◽  
A. Nguyen ◽  
D. P. Thambiratnam ◽  
T. H. T. Chan ◽  
T. Khuc
Keyword(s):  
Strain Energy ◽  
Damage Identification ◽  
Real Life ◽  
Detection Methods ◽  
Beam Model ◽  
Structural Components ◽  
Modal Strain Energy ◽  
Modal Flexibility ◽  
Modes Of Vibration ◽  
Identification Tool

This paper presents an enhanced method to locate and quantify damage in beam-like structures using changes in deflections estimated from modal flexibility (MF) matrices. The method is developed from explicit relationship between a series of MF-based deflection change vectors and the damage characteristics. Based on this, three damage locating criteria are defined and used to detect and locate damage. Once the damage is located, its severity is estimated conveniently from a closed-form function. The capability of the proposed method is examined through numerical and experimental verifications on a steel beam model. The result shows that the method accurately locates and quantifies damage under various scenarios using a few modes of vibration, with satisfactory or even better results compared to those obtained from traditional static deflection-based method. The performance of the proposed method is also compared with three well-known vibration-based damage detection methods using changes in MF and modal strain energy. It is found that the proposed method outperformed the other three methods, especially for multiple damage cases. As beams can represent various structural components, the proposed method provides a promising damage identification tool targeting the application to real-life structures.

Infrastructure Sustainability

2011 ◽  
pp. 186-201
Author(s):  
Hoi Wai Shih ◽  
David Thambiratnam ◽  
Tommy Chan
Keyword(s):  
Energy Method ◽  
Strain Energy ◽  
Health State ◽  
Modal Strain Energy ◽  
Structural Health ◽  
Modal Strain Energy Method ◽  
Modal Flexibility ◽  
Before And After ◽  
Composite Bridges ◽  
Strain Energy Method

Assessing the structural health state of urban infrastructure is crucial in terms of infrastructure sustainability. This chapter uses dynamic computer simulation techniques to apply a procedure using vibration-based methods for damage assessment in multiple-girder composite bridges. In addition to changes in natural frequencies, this multi-criteria procedure incorporates two methods, namely, the modal flexibility and the modal strain energy method. Using the numerically simulated modal data obtained through finite element analysis software, algorithms based on modal flexibility and modal strain energy change, before and after damage, are obtained and used as the indices for the assessment of structural health state. The feasibility and capability of the approach is demonstrated through numerical studies of a proposed structure with six damage scenarios. It is concluded that the modal strain energy method is capable of application to multiple-girder composite bridges, as evidenced through the example treated in this chapter.

scholarly journals Structural damage identification based on gray cloud rule generator algorithm

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401881990 ◽  
Author(s):  
Hui-Yong Guo ◽  
He-Fa Yuan ◽  
Qi Huang
Keyword(s):  
Energy Dissipation ◽  
Structural Damage ◽  
Strain Energy ◽  
Damage Identification ◽  
Cloud Model ◽  
Structure Model ◽  
Cloud Droplets ◽  
Modal Strain Energy ◽  
Energy Dissipation Ratio ◽  
Better Than

It is difficult for the traditional methods to identify uncertain damage problems caused by noise. Therefore, a gray cloud rule generator algorithm based on cloud model and modal strain energy is presented to solve the problems. Cloud model can simulate both randomness and fuzziness with fixed parameters. Therefore, it is applicable for the uncertain damage problems. First, modal strain energy and modal strain energy dissipation ratio index are introduced. Then, numerical characteristics of a cloud model are described and some cloud generators are analyzed. Finally, a gray cloud rule is proposed and the gray cloud rule generator algorithm based on the gray cloud rule generator and modal strain energy is developed. The interference of uncertain noise is reduced through a large number of cloud droplets. A two-dimensional truss structure model has been used to verify the effectiveness of the algorithm. The results indicate that the proposed gray cloud rule generator algorithm is applicable to identify the uncertain damage caused by noise, and the identification results of the proposed method are relatively better than those of modal strain energy dissipation ratio index.

Pseudo Strain Energy Density-Based Structural Damage Identification

2009 ◽  
Vol 413-414 ◽  
pp. 71-78
Author(s):  
Xiao Qiang Chen ◽  
Hong Ping Zhu ◽  
Dan Sheng Wang
Keyword(s):  
Energy Density ◽  
Strain Energy Density ◽  
Structural Damage ◽  
Strain Energy ◽  
Damage Identification ◽  
Wavelet Packet ◽  
Damage Index ◽  
Dynamic Strain ◽  
Beam Model ◽  
Measured Strain

In this paper, a new time-domain method for detecting structural local damage has been developed, which is based on the measured strain signals. The “pseudo strain energy density (PSED)” is defined and used to build two major damage indexes, the “average pseudo strain energy density” (APSED) and the “average pseudo strain energy density changing rate” (APSEDR). A probability and mathematical statistics technique is utilized to derive a standardized damage index. Afterwards, these indexes are used to establish the damage identification strategies for beam structures and plate structures respectively. Furthermore, the wavelet packet transform is used to pre-process the measured dynamic strain signals. Then, the effectivity of the new damage identification method is confirmed by numerical simulations. Finally, a laboratory beam model experiment is conducted to verify this method examine the feasibility and applicability of the new method.

Research on Detection of Distribution and Collision of Wireless Sensor Nodes Based on Radio-Frequency Technique

2014 ◽  
Vol 602-605 ◽  
pp. 2089-2092
Author(s):  
Jin Cheng Zhou ◽  
Zhen Yang
Keyword(s):  
Energy Method ◽  
Strain Energy ◽  
Large Scale ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Detection Accuracy ◽  
Structural Components ◽  
Modal Strain Energy ◽  
Wireless Sensor Nodes ◽  
Modal Strain Energy Method

many factors need to be considered in layout and distribution of wireless sensor nodes; in addition to the general features of common monitoring sensors, such as economic factors, environmental factors, detection accuracy factor, etc, some particular features should be fully considered, such as intensity, large-scale rapid layout, early warning and monitoring of critical structural components and important areas, as well as its redundancy. Basing on the Modal Energy Method, the paper proposes an optimal sensor layout algorithm available in improvement of modal strain energy method, and such the method is simple and quick, with certain practical value.

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