Damage Location in Beam and Plate Structures by Wavelet Analysis of Experimentally Determined Mode Shapes

2005 ◽  
Vol 293-294 ◽  
pp. 313-320 ◽  
Author(s):  
Magdalena Rucka ◽  
Krzysztof Wilde
Keyword(s):  
Wavelet Analysis ◽  
Wavelet Transforms ◽  
Mode Shapes ◽  
Engineering Structures ◽  
Plate Structures ◽  
Continuous Wavelet Transforms ◽  
Damage Location ◽  
Structural Mode ◽  
Crack Position ◽  
Fixed Boundary Condition

In this paper a method for estimating the damage location in beam and plate structures is presented. A plexiglas cantilever beam and a plexiglas plate with one fixed boundary condition are tested experimentally. The dynamic response of the structures is analyzed using one and twodimensional continuous wavelet transforms of the structural mode shapes. The location of the crack is indicated by a peak in the spatial variation of the transformed response. The proposed wavelet analysis can effectively identify the crack position without knowledge of either the structure characteristics or its mathematical model. The practical application of the technique for civil engineering structures requires only the response of the structure.

scholarly journals Wavelet Scalogram for Detection of R-peaks in Noisy ECG Signal

2019 ◽  
Vol 8 (10) ◽  
pp. 132-136
Keyword(s):  
Wavelet Analysis ◽  
Wavelet Transforms ◽  
Ecg Signal ◽  
Continuous Wavelet ◽  
Signal Design ◽  
Two Dimensional ◽  
Qrs Complex ◽  
Continuous Wavelet Transforms ◽  
Valuable Data ◽  
Ecg Signals

The ECG (electrocardiography) which reports heart electrical action is capable to supply with valuable data almost the sort of cardiac disarranges endured by the patient based on the fluctuations obtained from the ECG signal design. In this paper, we considered noisy ECG signals [MIT-BIH database] and their different wavelet scalograms. Wavelet analysis performed in the ECG signals with continuous wavelet transforms and it has allowed to graphically identifying scalograms energy two-dimensional characteristics of the heartbeat QRS complex.

scholarly journals A discrete wavelet analysis of freak waves in the ocean

2004 ◽  
Vol 2004 (5) ◽  
pp. 379-394 ◽  
Author(s):  
En-Bing Lin ◽  
Paul C. Liu
Keyword(s):  
Wavelet Analysis ◽  
Wavelet Transforms ◽  
Discrete Wavelet ◽  
Continuous Wavelet ◽  
Freak Waves ◽  
Freak Wave ◽  
Continuous Wavelet Transforms ◽  
Basic Properties ◽  
Discrete Wavelet Analysis

A freak wave is a wave of very considerable height, ahead of which there is a deep trough. A case study examines some basic properties developed by performing wavelet analysis on a freak wave. We demonstrate several applications of wavelets and discrete and continuous wavelet transforms on the study of a freak wave. A modeling setting for freak waves will also be mentioned.

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.

COMPARATIVE ANALYSIS OF SPECTRA OF THE 2000-YEAR NORTHERN HEMISPHERE AVERAGE SURFACE AIR TEMPERATURE RECONSTRUCTIONS

2021 ◽  
pp. 5-13
Author(s):  
N. M. DATSENKO ◽  
◽  
D. M. SONECHKIN ◽  
B. YANG ◽  
J.-J. LIU ◽  
...  
Keyword(s):  
High Resolution ◽  
Northern Hemisphere ◽  
Air Temperature ◽  
Wavelet Transforms ◽  
Spectral Composition ◽  
Low Frequency ◽  
Surface Air Temperature ◽  
Temporal Variations ◽  
Continuous Wavelet Transforms ◽  
Stable Estimation

The spectral composition of temporal variations in the Northern Hemisphere mean surface air temperature is estimated and compared in 2000-year paleoclimatic reconstructions. Continuous wavelet transforms of these reconstructions are used for the stable estimation of energy spectra. It is found that low-frequency parts of the spectra (the periods of temperature variations of more than 100 years) based on such high-resolution paleoclimatic indicators as tree rings, corals, etc., are similar to the spectrum of white noise, that is never observed in nature. This seems unrealistic. The famous reconstruction called “Hockey Stick” is among such unrealistic reconstructions. Reconstructions based not only on high-resolution but also on low-resolution indicators seem to be more realistic, since the low-frequency parts of their spectra have the pattern of red noise. They include the “Boomerang” reconstruction showing that some warm periods close to the present-day one were observed in the past.

scholarly journals Crack Identification and Localization In Structural Beams Using Numerical and Experimental Modal Analysis- A Review

2020 ◽  
pp. 62-68
Keyword(s):  
Modal Analysis ◽  
Natural Frequency ◽  
Structural Damage ◽  
Experimental Modal Analysis ◽  
Mode Shapes ◽  
Crack Identification ◽  
Engineering Structures ◽  
Aircraft Wings ◽  
Crack Location ◽  
Damaged Beams

This article presents a critical review of recent research done on crack identification and localization in structural beams using numerical and experimental modal analysis. Crack identification and localization in beams are very crucial in various engineering applications such as ship propeller shafts, aircraft wings, gantry cranes, and Turbo machinery blades. It is necessary to identify the damage in time; otherwise, there may be serious consequences like a catastrophic failure of the engineering structures. Experimental modal analysis is used to study the vibration characteristics of structures like natural frequency, damping and mode shapes. The modal parameters like natural frequency and mode shapes of undamaged and damaged beams are different. Based on this reason, structural damage can be detected, especially in beams. From the review of various research papers, it is identified that a lot of the research done on beams with open transverse crack. Crack location is identified by tracking variation in natural frequencies of a healthy and cracked beam

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