Non-linear ultrasonic technique to assess fatigue damage in structural steel

Sagar, S Palit; Das, Swapan Kumar; Parida, N; Bhattacharya, D. K.

doi:10.1016/j.scriptamat.2006.03.037

Cited by 74 publications

(10 citation statements)

References 9 publications

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“…The interpolation method in the spline is piecewisepolynomial interpolation that reduces the interpolation error compared to polynomial interpolation [56]. The second approach to identify the acoustic nonlinearity parameter using the time histories of wavelet coefficients for the first and second harmonics is based on obtaining the wave envelopes at each frequency, and applying equation (4) to the entire time-history data as shown in Figure 14 for the pristine specimen. While the peak amplitudes of each frequency component do not occur at the same time, the acoustic nonlinearity parameter shows a constant regime within the time interval 2.0 -5.5 µs.…”

Section: Nonlinear Ultrasonic Results Using the Wt-based Methodsmentioning

confidence: 99%

“…The requirement that the wavelength of ultrasonic signal should be smaller than the size of defects when the linear UT is implemented limits the capability of assessing material conditions involving microstructural defects, such as early stages of fatigue and creep damage. On the other hand, on account of the advancement of UT instrumentation and the theory of nonlinear wave propagation, the nonlinear characteristics of the wave motion has been utilized to investigate microstructural defects [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

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Wavelet based harmonics decomposition of ultrasonic signal in assessment of plastic strain in aluminum

et al. 2017

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In nonlinear ultrasonics, the correlation between microstructural change and ultrasonic properties is investigated by the acoustic nonlinearity parameter, calculated by experimentally measuring the first and second harmonic amplitudes of ultrasound signals. The most prevalent signal processing method is to transform the time-domain signal into the frequency domain and acquire the amplitudes of each frequency from the frequency spectrum. However, the major drawback of this approach is that temporal information is not preserved and the transformation errors increase dramatically in analyzing nonlinear signals with discontinuities. In this study, two wavelet-based algorithms are introduced to analyze the waveform in nonlinear ultrasonic testing. The algorithms are applied to correlate the acoustic nonlinearity parameter and the plastic deformation of aluminum 1100 specimens, for the purpose of validation. The results showed that the acoustic nonlinearity parameter calculated through the proposed algorithms is not influenced by the signal processing variables, and the signal processing error is reduced when the waveletbased decomposition is applied.

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Section: Nonlinear Ultrasonic Results Using the Wt-based Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Wavelet based harmonics decomposition of ultrasonic signal in assessment of plastic strain in aluminum

et al. 2017

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“…The degradation of early performance of fatigue-damaged engineering components accounts for more than 80% of the entire fatigue life. 10,11 Although existing non-destructive testing technology including linear ultrasonic testing technology is ideal for detecting macroscopic defects in materials, and it can prevent early damage of materials (such as dislocation structure, microcracks, and pores) before macroscopic cracks appear in the fatigue process, inclusions cannot be detected. 12 In recent years, nonlinear ultrasonic non-destructive testing technology has been a research hotspot.…”

Section: Introductionmentioning

confidence: 99%

Research on high cycle fatigue damage characterization of FV520B steel based on the nonlinear Lamb wave

Wang

Zhou

Chen

et al. 2021

The Journal of Strain Analysis for Engineering Design

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In this study, high-strength steel FV520B sheets were subjected to high-cycle tensile-tension fatigue experiments at room temperature in order to obtain fatigue-damaged specimens. Then Lamb waves were used to perform nonlinear ultrasonic testing on them to obtain the normalized relative nonlinear coefficients, β′/ β0. The corresponding relationship between β′/ β0 and the percentage of fatigue life was obtained. Finally, the microstructural changes of the damaged samples were observed by a scanning electron microscope in order to explore the correlation mechanism between β′/ β0 and the degree of micro-defects and fatigue damage. The experimental results showed that as the number of fatigue cycles increased, β′/ β0 first slowly rose, then quickly rose to reach a peak, and finally declined, which was consistent with the generation and propagation of dislocations and cracks during fatigue damage. As the length and number of microcracks increased, β′/ β0 also increased, especially in the initial stage of fatigue crack initiation. β′/ β0 was very sensitive to the size of fatigue cracks, so the change of β′/ β0 can be used to detect the degree of early fatigue damage of the material.

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“…Metal materials are widely used in practical engineering applications, but long-term in-service work makes them prone to failure due to fatigue damages. The linear acoustic method is invalid for detecting fatigue damages of materials, while the finite amplitude sound wave can produce obvious waveform distortion when it propagates through a medium with fatigue damages, which has been proven to be an effective method for evaluating fatigue damages in metal materials [ 1 , 2 , 3 , 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Acoustic Modeling and Measurements during the Fatigue Process in Metals

2019

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The nonlinear spring model combined with dislocation dipole theory was applied to describe the acoustic nonlinearity during the fatigue process in metals. The spring stiffness changes with fatigue degree. For the early stage, spring stiffness approaches infinity, and the heavier nonlinearity mainly results from the increase of dislocation density. Further fatigue leads to the occurrence of micro-cracks, during which spring stiffness begins to decrease. Abundant micro-crack sprouting accelerates the crack’s expansion, and spring stiffness drops quickly, which causes the obvious decline in the transmitted harmonic amplitudes. Solutions obtained from the nonlinear wave equation with dislocation terms were added into the spring model. Varying spring stiffness was chosen for simulating the fatigue process. Then, nonlinear harmonic variation during this process was observed, which was classified into three stages: (I) the early dislocation fatigue stage; (II) the micro-crack sprouting stage; (III) the crack expansion stage. Nonlinear acoustic measurements were carried out on an aluminum alloy specimen during its fatigue process until cracks could be seen clearly. Harmonic variations in experiments can also be classified into the same three stages as the numerical results, which provides a theoretical and experimental reference for fatigue evaluation in metals using the nonlinear acoustic method.

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Non-linear ultrasonic technique to assess fatigue damage in structural steel

Cited by 74 publications

References 9 publications

Wavelet based harmonics decomposition of ultrasonic signal in assessment of plastic strain in aluminum

Wavelet based harmonics decomposition of ultrasonic signal in assessment of plastic strain in aluminum

Research on high cycle fatigue damage characterization of FV520B steel based on the nonlinear Lamb wave

Nonlinear Acoustic Modeling and Measurements during the Fatigue Process in Metals

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