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

Damage Detection Method Based on Fractal Correlation Dimension for Steel Truss Structure

2014 ◽  
Vol 578-579 ◽  
pp. 1228-1232
Author(s):  
Shou Jun Du ◽  
Li Bin Shi ◽  
Li Mei Zhang
Keyword(s):  
Correlation Dimension ◽  
Detection Method ◽  
Fractal Theory ◽  
Sudden Change ◽  
Truss Structure ◽  
Structural Vibration ◽  
Damage Location ◽  
Damage Degree ◽  
Steel Truss ◽  
Fractal Correlation Dimension

Damage of steel truss structure can be determined by the sudden change of correlation dimension which was obtained from the structural vibration response through fractal theory. The streel truss structure was as exampled to verify this method. The results show that: this method can determine the damage location of the structure whether single damage or multi damage and can preliminarily judge the damage degree.

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.

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.

A Coupled Sensitivity Method for Structural Damage Detection

2013 ◽  
Vol 681 ◽  
pp. 271-275
Author(s):  
Jing Li ◽  
Pei Jun Wei
Keyword(s):  
Damage Detection ◽  
Mode Shape ◽  
Structural Damage ◽  
Damage Identification ◽  
Perturbation Approach ◽  
Structural Damage Detection ◽  
Beam Structure ◽  
Flexibility Matrix ◽  
Eigenvalue Sensitivity ◽  
Sensitivity Method

Based on the vibration information, a mixed sensitivity method is presented to identify structural damage by combining the eigenvalue sensitivity with the generalized flexibility sensitivity. The sensitivity of structural generalized flexibility matrix is firstly derived by using the first frequency and the corresponding mode shape only and then the eigenvalue sensitivity together with the generalized flexibility sensitivity are combined to calculate the elemental damage parameters. The presented mixed perturbation approach is demonstrated by a numerical example concerning a simple supported beam structure. It has been shown that the proposed procedure is simple to implement and may be useful for structural damage identification.

Spectral indicators in structural damage identification: A case study

1999 ◽  
Vol 213 (4) ◽  
pp. 411-415 ◽  
Author(s):  
J. A. Brandon ◽  
A. E. Stephens ◽  
E. M. O. Lopes ◽  
A. S. K. Kwan
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Vibration Signal ◽  
Open Crack ◽  
Severe Damage ◽  
Closed Crack ◽  
Spectral Signatures ◽  
Linear Behaviour ◽  
Systematic Effects

A pre-loaded cracked cantilever beam was excited vising a random vibration signal. Excitation levels were within the range of amplitudes that caused no suspicion of non-linear behaviour in an undamaged specimen of identical dimensions and material. Spectral signatures were acquired which made it possible to discriminate between open crack, closed crack and breathing conditions. Systematic effects relating to variations in resonant frequency were largely consistent with the literature for a lightly damaged beam but were unsupported for a beam with more severe damage.

scholarly journals Optimal Placement of Virtual Masses for Structural Damage Identification

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 340
Author(s):  
Jilin Hou ◽  
Zhenkun Li ◽  
Qingxia Zhang ◽  
Runfang Zhou ◽  
Łukasz Jankowski
Keyword(s):  
Structural Damage ◽  
Natural Frequencies ◽  
Damage Identification ◽  
Pso Algorithm ◽  
Optimal Placement ◽  
Beam Structure ◽  
Sensitivity Matrix ◽  
Swarm Optimization ◽  
Placement Optimization ◽  
Mutual Independence

Adding virtual masses to a structure is an efficient way to generate a large number of natural frequencies for damage identification. The influence of a virtual mass can be expressed by Virtual Distortion Method (VDM) using the response measured by a sensor at the involved point. The proper placement of the virtual masses can improve the accuracy of damage identification, therefore the problem of their optimal placement is studied in this paper. Firstly, the damage sensitivity matrix of the structure with added virtual masses is built. The Volumetric Maximum Criterion of the sensitivity matrix is established to ensure the mutual independence of measurement points for the optimization of mass placement. Secondly, a method of sensitivity analysis and error analysis is proposed to determine the values of the virtual masses, and then an improved version of the Particle Swarm Optimization (PSO) algorithm is proposed for placement optimization of the virtual masses. Finally, the optimized placement is used to identify the damage of structures. The effectiveness of the proposed method is verified by a numerical simulation of a simply supported beam structure and a truss structure.

scholarly journals A two-step method for damage identification in beam structures based on influence line difference and acceleration data

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401878740 ◽  
Author(s):  
D Tan ◽  
ZR Lu ◽  
JK Liu
Keyword(s):  
Objective Function ◽  
Structural Damage ◽  
Damage Identification ◽  
Dynamic Responses ◽  
Beam Structure ◽  
Modal Assurance Criterion ◽  
Beam Structures ◽  
Influence Line ◽  
Acceleration Data ◽  
Bird Mating Optimizer

This article presents a two-step approach for structural damage identification in beam structure. Damages are located using the influence line difference before and after damage, the calculation of damage severity is accomplished by acceleration data and bird mating optimizer algorithm. Local damages are simulated as the reduction of both the elemental Young’s modulus and mass of the beam. The technique for damage localization based on displacement influence line difference and its derivatives for beam structure has been outlined. An objective function that comprises dynamic acceleration is utilized in bird mating optimizer. All data are originated from only a few measurement points. Two numerical examples, namely, a simply supported beam and a four-span continuous beam, are investigated in this article. Identification results from different objective functions are compared with results from objective function conventional modal assurance criterion, which shows the superiority of the proposed function. In addition, results of dynamic responses under different types of excitation are presented. The effect of measurement noise level on damage identification results is studied. Studies in the article indicate that the proposed method is efficient and robust for identifying damages in beam structures.

Strain modal-based damage identification method and its application to crane girder without original model

2018 ◽  
Vol 233 (4) ◽  
pp. 1299-1311 ◽  
Author(s):  
Huichao Yang ◽  
Feiyun Xu ◽  
Jiaxin Ma ◽  
Kai Huang
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Spline Interpolation ◽  
Moving Average ◽  
Original Data ◽  
Original Model ◽  
Difference Curve ◽  
Existing Structures ◽  
Damage Degree ◽  
Almost All

Although there are many methods to identify structural damage of the crane girder, almost all of them are used by means of comparing specific parameters of original and existing structures. And it leads to difficulties in practice. So, a method to identify damage of the crane girder is proposed based on strain modal without original model. First, the strain modal difference curve was obtained by using difference algorithm to deal with strain modal and cubic spline interpolation algorithm to fit the curve, and the damage location was realized by constructing and comparing damage sensitive index (IDSI). Then, the data of undamaged checkpoints adjacent to damaged checkpoints are stationary and modeled by Auto-Regressive Moving-Average Model, with this modeling the original data of the damaged checkpoints was predicted, and variation of the got strain modal difference curve was used to determine damage degree. Finally, the application of this method was implemented by some experiments and numerical calculations, and the results demonstrated that this method can effectively identify the damage of the crane girder.

Damage Orientation Method Based on the Modal Kinetic Energy

2012 ◽  
Vol 256-259 ◽  
pp. 1112-1116 ◽  
Author(s):  
Hai Ping Meng ◽  
Xin Yan Lin
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Mass Matrix ◽  
Kinetic Method ◽  
Element Model ◽  
Structural Vibration ◽  
Modal Strain Energy ◽  
Orientation Method ◽  
Vibration Responses ◽  
Damage Condition

Dynamic methods by structural vibration responses and system dynamic characteristic parameters are the main methods for structural damage identification. Based on the modal strain energy method and used unit location matrix instead of element mass matrix, modal kinetic method is proposed. Two kinds of typical damage condition were simulated and the results show that the method can reduce structural finite element model accuracy, calculate simply and realize the initial damage location.

On a hybrid use of structural vibration signatures for damage identification: a virtual vibration deflection (VVD) method

2016 ◽  
Vol 23 (4) ◽  
pp. 615-631 ◽  
Author(s):  
Hao Xu ◽  
Zhongqing Su ◽  
Li Cheng ◽  
Jean-Louis Guyader
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Numerical Study ◽  
Damage Index ◽  
Structural Vibration ◽  
Single Type ◽  
Structure Identification ◽  
Detection Accuracy ◽  
Beam Model ◽  
Vibration Signatures

A damage identification method named virtual vibration deflection (VVD) was developed, the principle of which was formulated based on the “weak” modality of the pseudo-excitation (PE) approach previously established. In essence, VVD is based on locating structural damage within a series of “sub-regions” divided from the entire structure under inspection, and each sub-region was considered as a “virtual” structure undergoing independent vibration. The corresponding vibration deflection of the “virtual” structure was then used to derive the damage index of VVD. Besides various advantages inheriting from the PE approach, for example, capability of detecting damage without baseline signals and pre-developed benchmark structures, VVD exhibits improved detection accuracy and particularly enhanced noise immunity compared with the PE approach, attributed to a hybrid use of multi-types of vibration signatures (MTVS). As a proof-of-concept investigation, a beam model was used in a numerical study to examine the philosophy of VVD. And the influences from different factors (i.e., level of measurement noise and measurement density) on the detection accuracy of VVD were discussed based on the numerical model. An experiment was carried out subsequently to identify the locations of multiple defects contained in an aluminum beam-like structure. Identification results constructed by the PE approach, VVD using single-type of vibration signatures, and VVD using MTVS, were presented, respectively, for the purpose of comparison.

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