Influence of Uniaxial Stress on the Shear-Wave Spectrum Propagating in Steel Members

Li, Zuohua; He, Jianping; Liu, Diankun; Liu, Nanxi; Long, Zhili; Teng, Jun

doi:10.3390/s19030492

Cited by 9 publications

(4 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In many LSTF tasks, feature extraction methods [27][28][29] have been applied to time series data, which are able to explain sequence relationships and help forecasting models learn the nonlinear characteristics of structural state data. Moreover, extracted features, which reflect the state of the structure to a certain extent, are also widely used in the SHM [30,31], especially the amplitude and phase of data [32,33]. Among them, FFT has been widely recognized for its characteristics of decomposing data to make them stable, fast convergence, and reflecting the trend to a certain extent [29,34].…”

Section: Introductionmentioning

confidence: 99%

Long-Term Structural State Trend Forecasting Based on an FFT–Informer Model

Dan

2023

Applied Sciences

View full text Add to dashboard Cite

Machine learning has been widely applied in structural health monitoring. While most existing methods, which are limited to forecasting structural state evolution of large infrastructures. forecast the structural state in a step-by-step manner, extracting feature of structural state trends and the negative effects of data collection under abnormal conditions are big challenges. To address these issues, a long-term structural state trend forecasting method based on long sequence time-series forecasting (LSTF) with an improved Informer model integrated with Fast Fourier transform (FFT) is proposed, named the FFT–Informer model. In this method, by using FFT, structural state trend features are represented by extracting amplitude and phase of a certain period of data sequence. Structural state trend, a long sequence, can be forecasted in a one-forward operation by the Informer model that can achieve high inference speed and accuracy of prediction based on the Transformer model. Furthermore, a Hampel filter that filters the abnormal deviation of the data sequence is integrated into the Multi-head ProbSparse self-attention in the Informer model to improve forecasting accuracy by reducing the effect of abnormal data points. Experimental results on two classical data sets show that the FFT–Informer model achieves high and stable accuracy and outperforms the comparative models in forecasting accuracy. It indicates that this model can effectively forecast the long-term state trend change of a structure and is proposed to be applied to structural state trend forecasting and early damage warning.

show abstract

Section: Introductionmentioning

confidence: 99%

Long-Term Structural State Trend Forecasting Based on an FFT–Informer Model

Dan

2023

Applied Sciences

View full text Add to dashboard Cite

show abstract

“…In this case, characteristic quantities in the echo spectrum are more sensitive to stress. 25,28,29 In addition, data of the unstressed state are no longer special. The combination of the spectrum analysis technique and ultrasonic method provides a possibility to improve the sensitivity of the stress measurement of steel members.…”

Section: Introductionmentioning

confidence: 99%

“…The stress measurement sensitivity is defined as the change in the physical parameters to be measured that is caused by a change in stress. In this case, characteristic quantities in the echo spectrum are more sensitive to stress 25,28,29 . In addition, data of the unstressed state are no longer special.…”

Section: Introductionmentioning

confidence: 99%

Measurement of the stress of steel members using the ultrasonic phase spectrum

Liu

et al. 2022

Structural Contr & Hlth

Self Cite

View full text Add to dashboard Cite

Summary The stress state of steel members is an important indicator in evaluating structural safety. The ultrasonic time‐of‐flight method of measuring the stress of steel members based on acoustoelastic theory has been fully developed. However, the time difference is hard to be measured. The present paper proposes a new method of measuring the uniaxial stress of steel members using the phase spectrum of the ultrasonic transverse wave. The effect of interference of the two wave components generated by shear‐wave birefringence under uniaxial stress is investigated. It is found that the derivative curve of the phase spectrum of the pulse‐echo comprising the two wave components reaches a maximum periodically, and the frequency corresponding to the maxima is sensitive to stress and relatively easy to be measured. On this basis, a theoretical formula for the measurement of the uniaxial stress of steel members based on the phase spectrum is derived. Results of calibration tests show a good linear relationship between the stress and the reciprocal of the first response frequency corresponding to the maximum of the derivative curve of the phase spectrum. The uniaxial stress can then be measured by obtaining the first response frequency of the phase spectrum of the in‐service structural steel member. In addition, the effects of the thickness of steel members and the sampling rate of the oscilloscope on the uniaxial stress measurement are investigated. The present paper also illustrates the correspondence between the amplitude spectrum method and phase spectrum method.

show abstract

“…The non-destructive measurement method gives information on the magnitude, direction, and position of stress without damaging or affecting the performance of the measured part. Among the non-destructive measurement methods, the ultrasonic method has many advantages such as no radiation damage to the human body, a high spatial resolution, and a large range of measurement depths [ 15 , 16 , 17 , 18 , 19 ], which has always been the focus of scholars’ research. Ultrasonic stress measurement mainly includes longitudinal and transverse wave methods, the surface wave method, guided wave method, non-linear method, and longitudinal critically refracted (LCR) wave method.…”

Section: Introductionmentioning

confidence: 99%

Study on Propagation Depth of Ultrasonic Longitudinal Critically Refracted (LCR) Wave

Liu

Chen

et al. 2020

Sensors

View full text Add to dashboard Cite

The accurate measurement of stress at different depths in the end face of a high-pressure compressor rotor is particularly important, as it is directly related to the assembly quality and overall performance of aero-engines. The ultrasonic longitudinal critically refracted (LCR) wave is sensitive to stress and can measure stress at different depths, which has a prominent advantage in stress non-destructive measurements. In order to accurately characterize the propagation depth of LCR waves and improve the spatial resolution of stress measurement, a finite element model suitable for the study of LCR wave propagation depths was established based on a wave equation and Snell law, and the generation and propagation process of LCR waves are analyzed. By analyzing the blocking effect of grooves with different depths on the wave, the propagation depth of the LCR wave at seven specific frequencies was determined in turn. On this basis, the LCR wave propagation depth model is established, and the effects of wedge materials, piezoelectric element diameters, and excitation voltages on the propagation depth of LCR waves are discussed. This study is of great significance to improve the spatial resolution of stress measurements at different depths in the end face of the aero-engine rotor.

show abstract

Influence of Uniaxial Stress on the Shear-Wave Spectrum Propagating in Steel Members

Cited by 9 publications

References 51 publications

Long-Term Structural State Trend Forecasting Based on an FFT–Informer Model

Long-Term Structural State Trend Forecasting Based on an FFT–Informer Model

Measurement of the stress of steel members using the ultrasonic phase spectrum

Study on Propagation Depth of Ultrasonic Longitudinal Critically Refracted (LCR) Wave

Contact Info

Product

Resources

About