scholarly journals Damage Identification Method of Beam Structure Based on Modal Curvature Utility Information Entropy

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Chang-Sheng Xiang ◽  
Ling-Yun Li ◽  
Yu Zhou ◽  
Zi Yuan
Keyword(s):  
Information Entropy ◽  
Damage Identification ◽  
Local Mode ◽  
Beam Structure ◽  
Damage State ◽  
Entropy Index ◽  
Damage Degree ◽  
Curvature Index ◽  
Modal Curvature ◽  
Utility Information

Generally, the damage of the structure will lead to the discontinuity of the local mode shape, which can be well reflected by the modal curvature of the structure, and the local information entropy of the beam structure will also change with the discontinuity of the mode. In this paper, based on the information entropy theory and combining the advantages of modal curvature index in damage identification of beam structure, the modal curvature utility information entropy index is proposed. The modal curvature curves of nondestructive structures were obtained by fitting the modal curvature curves of damage structures with the gapped smoothing technique to avoid dependence on the baseline data of nondestructive structures. The index comprehensively reflects the damage state of the structure by calculating mutual weight change matrix and the weight-probability coefficient. The performance of the new index was verified by the finite element simulation and model test of simply supported beam, respectively. The results show that the modal curvature utility information entropy index takes advantage of the modal curvature index which is sensitive to damage and can overcome its shortcomings effectively. The index proposed can identify the damage location and damage degree accurately and has certain noise immunity, which provides an effective damage identification indicator for beam structures.

Damage Identification for Beam Structure Based on Correlation Dimension

2012 ◽  
Vol 193-194 ◽  
pp. 1342-1345
Author(s):  
Mao Jiang ◽  
Ling Zhou ◽  
Ying Tao Li ◽  
Hai Qing Zhou ◽  
Jun Shao
Keyword(s):  
Structural Damage ◽  
Correlation Dimension ◽  
Damage Identification ◽  
Fractal Theory ◽  
Vibration Signal ◽  
Structural Vibration ◽  
Damage Analysis ◽  
Beam Structure ◽  
Damage Degree ◽  
System Output

In order to explore the effective damage identification method for structure, the structural vibration signal is directly correlation dimension analyzed according to fractal theory, and structural damage is identified by measuring the singularity in system output, then the method for structural damage identification based on correlation dimension of vibration response is proposed. The damage analysis results of a simply supported beam demonstrate that, the proposed method can accurately detect single and multi different degree damage’s location of beam structure, and alteration of correlation dimension will increase along with the damage degree

Study on Box Girder Damage Identification of Cable-Stayed Bridges

2011 ◽  
Vol 101-102 ◽  
pp. 1156-1160
Author(s):  
Hua Wei Zhu ◽  
Hong Mou Wang ◽  
Wei Peng
Keyword(s):  
Damage Identification ◽  
Stress Index ◽  
Bending Stress ◽  
Box Girder ◽  
Cable Tension ◽  
Flexibility Matrix ◽  
Tension Index ◽  
Modal Flexibility ◽  
Curvature Index ◽  
Modal Curvature

A comparative study of the girder damage identification of Jintang Cable-stayed Bridge in Zhoushan Island-Land Project using the deflection index, the cable tension index, the beam bottom bending stress index, the modal curvature index and the modal flexibility matrix is introduced. By means of finite element method, a series of damage cases associated with the box girder are analyzed. The result shows that, for different damage types, the best effect of the girder damage identification is the modal curvature index, followed by the cable tension index, the beam bottom bending stress index is nearly of the same effect as the modal flexibility matrix index, and the worst is the deflection index.

Damage Quantitative Investigation of Beam Structure Based on Changing Ratio of Modal Curvature

2011 ◽  
Vol 255-260 ◽  
pp. 654-658
Author(s):  
Ji Ping Ge
Keyword(s):  
Linear Increase ◽  
Beam Structure ◽  
Quantitative Investigation ◽  
Supporting System ◽  
Damage Recognition ◽  
Modal Curvature ◽  
Damage Extent ◽  
Extent Of Damage ◽  
The Relationship

The changing ratio of modal curvature is proposed for damage recognition, and its ability of damage localization and damage quantitative has been studied in this paper. For testing the effect of damage recognition, two research parameters, the different section rigidity and the scope of damages, are included. And changing rules of the index with structure rigidity, constraints, and structure supporting system have been studied at the same time. The numerical analysis results indicated: The relation of linear increase exists between the changing ratio of modal curvature and the extent of damage, the changing slope of the index is bigger with the increase of damage extent; The boundary condition and the structure supporting system will affect the value of index; In the view of one special structure, case study should be carried to establish the relationship between value of index and the extent of damage.

Free Vibration of Damaged Beam Structure with a Notch Defect

2012 ◽  
Vol 226-228 ◽  
pp. 44-47 ◽  
Author(s):  
Jiang Yi Chen ◽  
Li Ge Fan ◽  
Dong Chen Qin
Keyword(s):  
Damage Identification ◽  
Delta Function ◽  
Theoretical Background ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Beam Structure ◽  
Arbitrary Boundary ◽  
Numerical Examples ◽  
Elastically Supported ◽  
Universal Expression

In this paper, we derive the universal expression of the modal parameters for a damaged beam under arbitrary boundary conditions. The delta function is first employed to describe a notch damage in the beam and consequently to derive the governing equation for the damaged beam. Second, by virtue of the perturbation method, the eigenvalues and the corresponding mode shapes are obtained for the damaged beam. Finally, numerical examples are given for an elastically supported beam. It is believed that the proposed approach could provide the necessary theoretical background for damage identification in beam structures.

scholarly journals Damage Identification of Plate Structure Based on the Method of Modal Flexibility Curvature Difference

2019 ◽  
Vol 256 ◽  
pp. 02015
Author(s):  
Jiangang Zhao ◽  
Yuxiang Zhang ◽  
Jiazhao Chen
Keyword(s):  
Numerical Analysis ◽  
Lower Order ◽  
Damage Identification ◽  
Higher Order ◽  
Plate Structure ◽  
First Order ◽  
Flexibility Matrix ◽  
Damage Degree ◽  
Higher Order Modes ◽  
Modal Flexibility

According to the higher order modes of the structure are difficult to extract and the lower order are easy to obtain in practice, it is put forward that only uses the parameters of lower or first-order modal to constitute the modal flexibility curvature difference (MFCD) as the index of damage identification, which based on the flexibility matrix of structure being sensitive to the structure modal characteristics. Numerical analysis is made on different damage conditions of a plate structure, and the result shows that the MFCD can not only accurately identify the single-damage and multi-damage position of plate structure, but also reflect the size of damage degree. It has a great significance to apply the index into the range of damage identification of actual structures.

scholarly journals Study on the Measurement Method of the Crack Local Flexibility of the Beam Structure

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Yumin He ◽  
Siyu Guo ◽  
Xiaolong Zhang
Keyword(s):  
Natural Frequency ◽  
Cross Sections ◽  
Measurement Method ◽  
Vibration Signal ◽  
Beam Structure ◽  
Crack Location ◽  
Influence Curves ◽  
Damage Degree ◽  
Local Flexibility ◽  
Sample Points

The crack which appears in the structure can be described by a local flexibility. With the occurrence and propagation of crack, the local flexibility will change. The change can effectively reflect the damage degree of the structure. In this paper, the measurement method of the crack local flexibility of the beam structure is presented. Firstly, a series of sample points are selected at the crack location and the possible value range of the crack local flexibility, and then these sample points are used as input parameters for the dynamic analysis of the beam structure. The vibration equation of beam structure is solved, and the frequency influence surface is drawn. In addition, the vibration signal of the beam is tested, and the first three order natural frequencies can be obtained. Thirdly, these frequencies measured are adopted to cut the natural frequency influence surfaces, and then the first three order natural frequency influence curves are drawn. The intersection points of these frequencies influence curves can indicate the crack local flexibility and the corresponding crack location. This method is suitable for measuring the local flexibility of crack with different shapes and types in the beam structure which have various cross sections.

scholarly journals Application of Genetic Fuzzy System for Damage Identification in Cantilever Beam Structure

2016 ◽  
Vol 144 ◽  
pp. 215-225 ◽  
Author(s):  
Deepak K. Agarwalla ◽  
Abdul Sadik Khan ◽  
Subham Kumar Sahoo
Keyword(s):  
Cantilever Beam ◽  
Fuzzy System ◽  
Damage Identification ◽  
Beam Structure ◽  
Genetic Fuzzy System
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