Research Based on Modal Curvature and Wavelet Transform for Identifying Damage of Reticulated Shell Structures

2014 ◽  
Vol 501-504 ◽  
pp. 905-910
Author(s):  
Meng Hong Wang ◽  
Chen Meng Ji ◽  
Shan Shan Luo
Keyword(s):  
Wavelet Transform ◽  
Damage Identification ◽  
Shell Structures ◽  
Scaled Model ◽  
Transform Method ◽  
Stiffness Reduction ◽  
Modal Curvature ◽  
Transform Coefficients ◽  
The Difference ◽  
Reticulated Shell Structure

In this paper, a research is carried on to identify damage of reticulated shell structures based on the combination of modal curvature method and wavelets transform method. Take a scaled model of the reticulated shell structure as an example to analyze, the cross section of one member supposed to have a slight damage of stiffness reduction. In order to locate the damage, modal curvatures of the structure are taken as damage indexes to perform continuous wavelet transform. Results of the numerical analysis indicate that the difference of wavelet transform coefficients of modal curvature can be used to locate damage roughly, while the wavelet transform coefficients of modal curvature difference can be used to locate damage more precisely with easier and more reliable data processing. So it is clear that the damage identification based on modal curvature and wavelet transform is quite effective.

TECHNOLOGY FOR THE DEVELOPMENT OF SOFTWARE ALGORITHMS FOR OPTOELECTRONIC MONITORING SYSTEMS FOR REMOTE OBJECTS

2021 ◽  
pp. 10-21
Author(s):  
V. E. Makhov ◽  
V. M. Petrushenko ◽  
A. V. Emel'yanov ◽  
V. V. Shirobokov ◽  
A. I. Potapov
Keyword(s):  
Wavelet Transform ◽  
Continuous Wavelet Transform ◽  
Monitoring Systems ◽  
Practical Implementation ◽  
Continuous Wavelet ◽  
Optoelectronic System ◽  
Transform Method ◽  
Software Algorithms ◽  
Optoelectronic Systems ◽  
Transform Coefficients

The issues of constructing algorithms for obtaining coordinate and non-coordinate information used to solve the problem of multiplexing images obtained from several optoelectronic systems are considered. A unique mathematical method for finding the corresponding points in images, based on algorithms for continuous wavelet transform of the brightness structure of an image, is proposed. The technology of development of algorithms intended for multi-position optoelectronic systems for monitoring remote objects based on software from National Instruments is considered. A technique for constructing software for obtaining information is proposed, which ensures high accuracy in determining the coordinates of the corresponding fragments in images. It is shown that the parallel use of several methods makes it possible to assess the reliability of the information obtained under conditions of changing observation parameters. The use of several methods makes it possible to assess the reliability of the information obtained under conditions of changing observation parameters. Computational experiments have confirmed that a more accurate search for image alignment regions is provided by the double wavelet transform method by increasing the number of extrema of the curves of the continuous wavelet transform coefficients, expanding the area from localization and additional filtering. An example of the practical implementation of the developed algorithms in a two-channel optoelectronic system is presented.

scholarly journals Non-Model Approach Based Damage Detection in RC Frame with Masonry Infill

Proceedings ◽  
2018 ◽  
Vol 4 (1) ◽  
pp. 56
Author(s):  
Himakshi Bhatia ◽  
Ajay Chourasia ◽  
Shilpa Pal
Keyword(s):  
Damage Detection ◽  
Damage Identification ◽  
Response Spectra ◽  
Mode Shapes ◽  
Rc Frame ◽  
Scaled Model ◽  
Masonry Infill ◽  
Building Research Institute ◽  
Time Histories ◽  
Modal Curvature

The paper focuses on real-time damage detection based on vibration studies carried out by the Central Building Research Institute (CBRI) structural health monitoring team. The experiment was performed on a 1:3 scaled model of a six- story reinforced concrete (RC) frame with masonry infill in the building dynamics laboratory of CBRI. The forward problem is attended by inducing step-by-step damage in infill to investigate the changes in dynamic response as a result of changes in the physical properties of the structure. Recorded time histories are processed for frequency response spectra (FRS) with fast fourier transform (FFT) and mode shapes are obtained. Changes in natural frequency and modal curvature for each of the five damage cases are analysed for damage detection and location in the structure. An algorithm for damage identification viz. curvature damage factor (CDF) approach is presented.

The Damage Identification of Bridges Based on Structural Deflection and Wavelet Transform

2011 ◽  
Vol 374-377 ◽  
pp. 2533-2537
Author(s):  
Ying Hui Xue ◽  
Hai Qing Liu
Keyword(s):  
Wavelet Transform ◽  
Signal Analysis ◽  
Structural Damage ◽  
Damage Identification ◽  
Structural Response ◽  
Wavelet Function ◽  
Deflection Curve ◽  
Damage Location ◽  
Transform Coefficients ◽  
The Time Domain

Wavelet transform can characterize the local features of the signal in the time domain and frequency domain, enlarges and identifies the mutation signal of the structural response at different scales as a new signal analysis tools. In this paper, based on the structural deflection curve, propose a wavelet-based method to identify the beam structural damage. Use wavelet function to decompose the deflection curve of the structure after injury. Determine the existence of damage by the change and distribution of wavelet transform coefficients, determine the damage location, and simulate a cantilever bridge to verify this method.

Research of Socket Welds Vibration Fatigue Resistance and Application of Wavelet Transform Method in Damage Detection

2013 ◽  
Vol 300-301 ◽  
pp. 1214-1221
Author(s):  
Lei Lin ◽  
De Cheng Xu ◽  
Fei Xue ◽  
Wen Xin Ti
Keyword(s):  
Wavelet Transform ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Damage Identification ◽  
Response Signal ◽  
Acceleration Response ◽  
Transform Method ◽  
Vibration Fatigue ◽  
Vibrating Table

Socket welds are widely used in nuclear power plants. According to industry experiences, vibration fatigue of socket welds is becoming one of the major ageing issues. It is very important for the operating engineers to monitor the vibration condition and detect the damage before leak occurs. This paper studies the damage identification technology applying wavelet transform method. Small bore pipes with socket welds are installed on the vibrating table and vibrate at the frequencies that near its first natural frequency. The acceleration response signal is acquired and decomposed by wavelet method. The energy of decomposition signal shows a suddenly variation when crack occurs. From this study, a parameter that is sensitive to vibration fatigue is defined and has the potential application value in the nuclear power plants to identify the vibration fatigue damage.

Damage Identification of Multi-Box Steel-Concrete Composite Bridges Based on Modal Curvature Difference Method

2012 ◽  
Vol 226-228 ◽  
pp. 1689-1692 ◽  
Author(s):  
Yi Qiang Xiang ◽  
Li Si Liu ◽  
Yu Liang He
Keyword(s):  
Difference Method ◽  
Structural Damage ◽  
Damage Identification ◽  
Damage Index ◽  
Element Model ◽  
Before And After ◽  
Composite Bridges ◽  
Modal Curvature ◽  
Composite Bridge ◽  
The Difference

Based on the data from dynamic analysis of a 40m-span multi-box steel-concrete composite bridge and the difference value of its modal curvature before and after the structural damage, this paper detects the damage locations in steel-concrete composite bridge by modal curvature difference method (MCDM). Here we adopt the updated finite element model in last work as analytical model, taking concrete density and elastic modulus as updating parameters and modal frequency+MAC as reference data. The results indicate that the modal curvature difference method can well locate the damages in steel-concrete composite bridge, especially the damage in concrete. But the change rate of frequency as damage index is insensitive to the bridge damage and the method can’t be applied solely for practical.

Demodulation of single interferograms using a sliding 2-D continuous wavelet transform method

2015 ◽  
Vol 62 (8) ◽  
pp. 633-637 ◽  
Author(s):  
Jésus Villa ◽  
Ismael de la Rosa ◽  
Rumen Ivanov ◽  
Daniel Alaniz ◽  
Efrén González
Keyword(s):  
Wavelet Transform ◽  
Continuous Wavelet Transform ◽  
Continuous Wavelet ◽  
Transform Method

Study on Damage Detection of Bridge Based on Wavelet Multi-Scale Analysis

2013 ◽  
Vol 639-640 ◽  
pp. 1010-1014 ◽  
Author(s):  
Ke Ding ◽  
Ting Peng Chen
Keyword(s):  
Wavelet Transform ◽  
Damage Detection ◽  
Detection Method ◽  
Mode Shapes ◽  
Scale Analysis ◽  
Multi Scale ◽  
Damage Location ◽  
Transform Coefficients ◽  
Beam Bridge ◽  
Multi Scale Analysis

The damage detection method based on wavelet multi-scale analysis is presented in the paper. The damage location can be identified by analyzing the multi-scale wavelet transform coefficients of curvatures of mode shapes. The extreme value of wavelet transform coefficients indicates the damage location. But it is difficult to detect the location of defect if the defect is near to the equilibrium position of vibration. In order to solve this problem, we put forward a method which is to add the wavelet transform coefficients of multi modals together. The method can effectively overcome the above problem. Three damage situations of simply supported beam bridge are discussed in the paper. The results show that the peaks of wavelet transform coefficients indicate the damage location of structural. It is possible to pinpoint the damage location based on wavelet multi-scale analysis on curvatures of mode shapes.

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