Evaluation of pile defects using complex continuous wavelet transform analysis

Ni, Sheng Huoo; Yu, Yang; Tsai, Pei Hsun; Chou, Wei Hsiang

doi:10.1016/j.ndteint.2017.01.007

Cited by 24 publications

(21 citation statements)

References 7 publications

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“…Schilder et al [3] developed a device for detecting pile integrity by arranging the Fabry-Perot interferometer sensor and the fiber Bragg grating sensor outside the pile body. Ni et al [4] used field tests to study the wavelet transform technology in the identification of defective piles. Singh et al [5] discussed the advantages and disadvantages of the low-strain method and cross-hole acoustic logging method through the field bridge foundation integrity identification test.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Bearing Characteristics and Soil Deformation of Necking Pile with Cap Using Transparent Soils Technology

Guo

2021

Advances in Civil Engineering

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This paper will employ the transparent soil experiment technology to explore the influences of shallow necking on the vertical bearing capacity of single pile with cap. Model experiment is carried out on one intact pile and nine shallow necking piles. The load-settlement curves of all piles are obtained, which are used to study bearing characteristics of piles. The displacement fields of soil around piles are employed to investigate the reasons for the loss of vertical bearing capacity of piles with shallow necking. The vertical bearing capacity is greatly reduced which is caused by shallow necking. When the axial dimension of necking is the same, the larger the radial size is, the greater the loss of vertical bearing capacity is. When the radial dimension of necking is the same, the greater the axial size is, the greater the loss of vertical bearing capacity is. The soil near the pile shaft and under the pile cap produces a large area of vertical downward deformation, which causes the relative displacement between the pile shaft and the soil to greatly reduce. Therefore, it is easy that the necking piles with caps develop negative friction, which causes the vertical bearing capacity of piles to reduce. When the radial dimension of the shallow necking is 80% of pile diameter, the pile is easy to be damaged.

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Section: Introductionmentioning

confidence: 99%

Experimental Study on Bearing Characteristics and Soil Deformation of Necking Pile with Cap Using Transparent Soils Technology

Guo

2021

Advances in Civil Engineering

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“…Zheng et al [11] proposed an analytical method to localize damage of a thin-walled pipe pile based on LST, in which the coupling of the pile and viscoelastic soil vibrations are considered. Up to now, the LST methods, including sonic echo (SE) and impulse response (IR) approaches, have been developed rapidly for damage localization on a basis of one-dimensional wave theory [12,13].…”

Section: Introductionmentioning

confidence: 99%

“…e complex continuous wavelet transform (CCWT) was also employed to estimate the lengths and damage positions of piles by extracting phase angles [12]. However, the CCWT-based damage localization method is only demonstrated via laboratory tests on pile specimens and its application on actual piles has not been investigated yet.…”

Section: Introductionmentioning

confidence: 99%

Damage Localization of Piles Based on Complex Continuous Wavelet Transform: Numerical Example and Experimental Verification

Zheng

Wang

Lin

et al. 2020

Shock and Vibration

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A new signal processing method called complex continuous wavelet transform (CCWT) is introduced in this paper to localize pile damage because it clearly reveals inherent characteristics of response signals. In this method, CCWT is first performed on the response signal to obtain the wavelet coefficient matrix. The resultant coefficients are then employed to calculate phase angles at different frequency bands with an aim of pile damage localization. However, the CCWT method is only demonstrated via laboratory tests on pile specimens, and its application on actual piles has not been examined. Moreover, various factors such as pile-soil interaction need to be considered when the CCWT method is applied on actual piles. To address these issues, a numerical example of 3D finite element pile model followed by a parameter analysis and an experimental verification on an actual pile are investigated. The results demonstrate that the CCWT method is capable of localizing pile damage under different damage scenarios. However, there are still some interference points in the grayscale images of phase angles and the reduction of interference points needs to be addressed by mutual verification with other pile damage detection methods and engineering experience.

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“…In the application of STFT, the time domain and frequency domain resolution cannot be optimized simultaneously. However, it requires a more flexible method, which can adaptively change the window size to receive more accurate time or frequency [42].…”

Section: Introductionmentioning

confidence: 99%

An Improved Cyclic Modulation Spectral Analysis Based on the CWT and Its Application on Broken Rotor Bar Fault Diagnosis for Induction Motors

Zhen

Wang

et al. 2019

Applied Sciences

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Induction motors (IMs) are widely used in many manufacturing processes and industrial applications. The harsh work environment, long-time enduring, and overloads mean that it is subjected to broken rotor bar (BRB) faults. The vibration signal of IMs with BRB faults consists of the reliable modulation information used for fault diagnosis. Cyclostationary analysis has been found to be effective in identifying and extracting fault feature. The estimators of cyclic modulation spectrum (CMS) and fast spectral correlation (FSC) based on the short-time fourier transform (STFT) have higher cyclic frequency resolution, which has proven efficient in demodulating second order cyclostationary (CS2) signals. However, these two estimators have limitations of processing the maximum cyclic frequency αmax that is smaller than Fs/2 (Fs is the sampling frequency) according to Nyquist’s Theorem. In addition, they have lower carrier frequency resolution due to the fixed window size used in STFT. In order to resolve the initial shortcomings of the CMS and FSC methods, in this paper, we extended the analysis of CMS algorithm based on the continuous wavelet transform (CWT), which enlarged the maximum cyclic frequency range to Fs/2 and provides higher carrier frequency resolution because the CWT has the advantage of multi-resolution analysis. The reliability and applicability of the proposed method for fault components localization were validated by CS2 simulation signals. Compared to CMS and FSC methods, the proposed approach shows better performance by analyzing vibration signals between healthy motor and faulty motor with one BRB fault under 0%, 20%, 40%, and 80% load conditions.

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Evaluation of pile defects using complex continuous wavelet transform analysis

Cited by 24 publications

References 7 publications

Experimental Study on Bearing Characteristics and Soil Deformation of Necking Pile with Cap Using Transparent Soils Technology

Experimental Study on Bearing Characteristics and Soil Deformation of Necking Pile with Cap Using Transparent Soils Technology

Damage Localization of Piles Based on Complex Continuous Wavelet Transform: Numerical Example and Experimental Verification

An Improved Cyclic Modulation Spectral Analysis Based on the CWT and Its Application on Broken Rotor Bar Fault Diagnosis for Induction Motors

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