Comparison of the L cr wave TOF and shear‐wave spectrum methods for the uniaxial absolute stress evaluation of steel members

2019 ◽  
Vol 26 (6) ◽  
pp. e2348 ◽  
Author(s):  
Jingbo He ◽  
Zuohua Li ◽  
Jun Teng ◽  
Ying Wang
Keyword(s):  
Shear Wave ◽  
Wave Spectrum ◽  
Stress Evaluation ◽  
Steel Members

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

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 492
Author(s):  
Zuohua Li ◽  
Jingbo He ◽  
Diankun Liu ◽  
Nanxi Liu ◽  
Zhili Long ◽  
...  
Keyword(s):  
Shear Wave ◽  
Wave Amplitude ◽  
Stress Measurement ◽  
Wave Spectrum ◽  
Amplitude Spectrum ◽  
Uniaxial Stress ◽  
Phase Spectrum ◽  
Great Promise ◽  
Steel Members ◽  
Phase Spectra

Structural health monitoring technologies have provided extensive methods to sense the stress of steel structures. However, monitored stress is a relative value rather than an absolute value in the structure’s current state. Among all the stress measurement methods, ultrasonic methods have shown great promise. The shear-wave amplitude spectrum and phase spectrum contain stress information along the propagation path. In this study, the influence of uniaxial stress on the amplitude and phase spectra of a shear wave propagating in steel members was investigated. Furthermore, the shear-wave amplitude spectrum and phase spectrum were compared in terms of characteristic frequency (CF) collection, parametric calibration, and absolute stress measurement principles. Specifically, the theoretical expressions of the shear-wave amplitude and phase spectra were derived. Three steel members were used to investigate the effect of the uniaxial stress on the shear-wave amplitude and phase spectra. CFs were extracted and used to calibrate the parameters in the stress measurement formula. A linear relationship was established between the inverse of the CF and its corresponding stress value. The test results show that both the shear-wave amplitude and phase spectra can be used to evaluate uniaxial stress in structural steel members.

scholarly journals Absolute stress measurement of structural steel members with ultrasonic shear-wave spectral analysis method

2017 ◽  
Vol 18 (1) ◽  
pp. 216-231 ◽  
Author(s):  
Zuohua Li ◽  
Jingbo He ◽  
Jun Teng ◽  
Qin Huang ◽  
Ying Wang
Keyword(s):  
Spectral Analysis ◽  
Structural Steel ◽  
Shear Wave ◽  
Wave Amplitude ◽  
Stress Measurement ◽  
Amplitude Spectrum ◽  
Uniaxial Stress ◽  
Wave Pulse ◽  
Steel Members ◽  
Pulse Echo

Absolute stress in structural steel members is an important parameter for the design, construction, and servicing of steel structures. However, it is difficult to measure via traditional approaches to structural health monitoring. The ultrasonic time-of-flight method has been widely studied for monitoring absolute stress by measuring the change in ultrasonic propagation time induced by stress. The time-of-flight of the two separated shear-wave modes induced by birefringence, which is particular to shear waves, is also affected by stress to different degrees. Their synthesis signal amplitude spectrum exhibits a minimum that varies with stress, which makes it a potential approach to evaluating uniaxial stress using the shear-wave amplitude spectrum. In this study, the effect of steel-member stress on the shear-wave amplitude spectrum from the interference of two shear waves produced by birefringence is investigated, and a method of uniaxial absolute stress measurement using shear-wave spectral analysis is proposed. Specifically, a theoretical expression is derived for the shear-wave pulse-echo amplitude spectrum, leading to a formula for evaluating uniaxial absolute stress. Three steel-member specimens are employed to investigate the influence of uniaxial stress on the shear-wave pulse-echo amplitude spectrum. The testing results indicate that the amplitude spectrum changes with stress and that the inverse of the first characteristic frequency in the amplitude spectrum and its corresponding stress exhibit a near-perfect linear relationship. On this basis, the uniaxial absolute stress of steel members loaded by a test machine is measured by the proposed method. Parametric studies are further performed on three groups of steel members made of 65# steel and Q235 steel to investigate the factors that influence the testing results. The results show that the proposed method can measure and monitor steel-members uniaxial absolute stress on the laboratory scale and has potential to be used in practical engineering with specific calibration.

scholarly journals Cross-correlation-based algorithm for absolute stress evaluation in steel members using the longitudinal critically refracted wave

2018 ◽  
Vol 14 (10) ◽  
pp. 155014771880331 ◽  
Author(s):  
Zuohua Li ◽  
Jingbo He ◽  
Jun Teng ◽  
Ying Wang
Keyword(s):  
Cross Correlation ◽  
Stress Measurement ◽  
Time Of Flight ◽  
Noise Signal ◽  
Theoretical Formula ◽  
Stress Monitoring ◽  
Stress Evaluation ◽  
Steel Members ◽  
Practical Engineering ◽  
The Absolute

The absolute stress in the in-service steel members is a critical indicator employed for the evaluation of structural performance. In the field of structural health monitoring, the stress is usually monitored by the stress monitoring system. However, the monitored stress is the relative value, rather than the absolute value. The longitudinal critically refracted wave has shown potential for use in absolute stress measurement. The accurate measurement of the longitudinal critically refracted wave time-of-flight is the core issue with this method. In this study, a cross-correlation-based algorithm is presented for stress evaluation using the longitudinal critically refracted wave. Specifically, a cross-correlation theoretical formula is derived and a five-step framework is proposed for the longitudinal critically refracted wave time-of-flight measurement. Four steel members are employed to investigate the parametric calibration using the longitudinal critically refracted wave to measure the stress. On this basis, the proposed cross-correlation-based algorithm is used to evaluate the stress of a steel member. The results indicate that the cross-correlation-based algorithm can measure the longitudinal critically refracted wave time-of-flight without filtering the noise signal, and the stress measurement results are better than those of the traditional peak value method. The proposed method provides a potential way to measure the absolute stress in practical engineering applications.

Determining formation shear‐wave transverse isotropy from borehole Stoneley‐wave measurements

Geophysics ◽  
2003 ◽  
Vol 68 (1) ◽  
pp. 118-126 ◽  
Author(s):  
Xiaoming Tang
Keyword(s):  
Shear Wave ◽  
Transverse Isotropy ◽  
Wave Spectrum ◽  
Weighted Average ◽  
Stoneley Wave ◽  
Fast Method ◽  
Actual Structure ◽  
Stoneley Waves ◽  
Wave Data ◽  
Shale Formation

Many rocks exhibit transversely isotropic (TI) characteristics. For determining the TI property using acoustic logging, Stoneley waves are the only borehole wave mode that has a significant sensitivity to TI effects, especially when the formation is acoustically slow compared to the borehole fluid. This study describes a method for deriving the formation shear‐wave TI parameter from the Stoneley wave data acquired by a logging tool. It is shown that the presence of the tool in the borehole can substantially affect the Stoneley wave propagation. Fortunately, for low‐frequency Stoneley waves, the tool effect can be satisfactorily modeled using an effective modulus, regardless of the actual structure of the tool. The modulus can be determined from a calibration procedure. In the inversion processing of the Stoneley wave data, the Stoneley wave slowness is related to the weighted average of the wave's dispersion curve over the frequency range occupied by the wave spectrum. This provides a fast method for the inversion. As a processing example, this method has been applied to estimate the shear‐wave TI parameter profile for the Lewis shale formation in Braggs, Wyoming. The resulting profile delineates the shear‐wave anisotropy magnitude and variation for this shale formation.

Millimetre-wave spectrum of the Ar-CO complex: the K = 2 ← 1 and 3 ← 2 subbands

1997 ◽  
Vol 92 (2) ◽  
pp. 229-236 ◽  
Author(s):  
M. HEPP ◽  
R. GENDRIESCH ◽  
I. PAK ◽  
Y.A. KURITSYN ◽  
F. LEWEN ◽  
...  
Keyword(s):  
Wave Spectrum ◽  
Millimetre Wave

Liver Elastography in Healthy Children Using Three Different Systems – How Many Measurements Are Necessary?

2020 ◽  
Author(s):  
Anders Batman Mjelle ◽  
Anesa Mulabecirovic ◽  
Roald Flesland Havre ◽  
Edda Jonina Olafsdottir ◽  
Odd Helge Gilja ◽  
...  
Keyword(s):  
Shear Wave ◽  
Transient Elastography ◽  
Intraclass Correlation ◽  
Age Groups ◽  
Liver Stiffness ◽  
Shear Wave Elastography ◽  
Healthy Children ◽  
Significant Difference ◽  
Pediatric Liver Disease ◽  
Liver Elastography

Abstract Purpose Liver elastography is increasingly being applied in screening for and follow-up of pediatric liver disease, and has been shown to correlate well with fibrosis staging through liver biopsy. Because time is of the essence when examining children, we wanted to evaluate if a reliable result can be achieved with fewer acquisitions. Materials and Methods 243 healthy children aged 4–17 years were examined after three hours of fasting. Participants were divided into four age groups: 4–7 years; 8–11 years; 12–14 years and 15–17 years. Both two-dimensional shear wave elastography (2D-SWE; GE Logiq E9) and point shear wave elastography (pSWE; Samsung RS80A with Prestige) were performed in all participants, while transient elastography (TE, Fibroscan) was performed in a subset of 87 children aged 8–17 years. Median liver stiffness measurement (LSM) values of 3, 4, 5, 6, 7, and 8 acquisitions were compared with the median value of 10 acquisitions (reference standard). Comparison was performed for all participants together as well as within every specific age group. We investigated both the intraclass correlation coefficient (ICC) with absolute agreement and all outliers more than 10 %, 20 % or ≥ 0.5 or 1.0 kPa from the median of 10 acquisitions. Results For all three systems there was no significant difference between three and ten acquisitions, with ICCs ≥ 0.97. All systems needed 4 acquisitions to achieve no LSM deviating ≥ 1.0 kPa of a median of ten. To achieve no LSM deviating ≥ 20 % of a median of ten acquisitions, pSWE and TE needed 4 acquisitions, while 2D-SWE required 6 acquisitions. Conclusion Our results contradict recommendations of 10 acquisitions for pSWE and TE and only 3 for 2D-SWE.

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