Measurement of axial stress using mode-converted ultrasound

Kim, Nohyu; Hong, Min-Sung

doi:10.1016/j.ndteint.2008.09.005

Cited by 107 publications

(46 citation statements)

References 13 publications

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“…Due to the effect of the friction between the bolt and the clamped parts and the screw thread, the torque wrench cannot accurately control the pre-tightening force. Acousto-elastic effect based ultrasonic methods are alternatives to estimate the bolt axial load by measuring the time-of-flight (TOF) [2,3], the velocity ratio of longitudinal waves and transverse waves [4,5], and the resonant frequency shift of the bolt [6]. The velocity change of waves in the bolt resulted from the bolt stress is very small, so specialized precision instruments are required to measure the variations of the TOF, velocity and frequency shift, which hinders the application of the method.…”

Section: Introductionmentioning

confidence: 99%

Bolt Looseness Detection Based on Piezoelectric Impedance Frequency Shift

et al. 2016

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Abstract:In this paper, a piezoelectric impedance frequency shift method is developed to estimate the bolt preload for the detection of bolt looseness in engineering structures. An experimental device that allows the precision control of the axial preload force on a bolt is designed and fabricated. A universal testing machine is used to preload accurately on the bolt in the experiments. Under different bolt preload conditions, the impedance analyzer measures the admittance (inverse of the impedance) signal of the PZT (Lead ZirconateTitanate) patches which are bonded on the bolt head. Firstly, a wide frequency band is swept to find a sensitive frequency band of the piezoelectric admittance with the imaginary part. Then in the sensitive frequency band, a specified peak frequency of the admittance signature is chosen to investigate the frequency shift with different bolt preloads. The relationship between the specified frequency shift and the bolt preload is established. The experimental results show that the specified peak frequency decreases as the bolt preload increases for both M16 and M12 bolts, and the frequency shift has a linear relationship with the preload on the bolt. The frequencies of the real and imaginary parts of the admittance signature have the same results. Therefore, the bolt preload can be determined by measuring the specified frequency shift and this method has a good application prospect.

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Section: Introductionmentioning

confidence: 99%

Bolt Looseness Detection Based on Piezoelectric Impedance Frequency Shift

et al. 2016

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“…Some research already exists on methods that do not require the bolt to be measured beforehand. These use the difference between shear and pressure waves to determine the actual stress state in the bolt [Jhang 2006, Kim 2009, Toda 2000, Walaszek 2006]. Some of these use electromagnetic (EMAT) instead of piezoelectric transducers.…”

Section: Methods For Determining Bolt Pretensionmentioning

confidence: 99%

Workshop on quantitative tools for condition assessment of aging infrastructure :

Terry¹,

Siewert²,

McColskey³

et al. 2010

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“…Papers [15,16] analyze the use of surface waves to determine longitudinal and transverse stresses of welded elements under conditions of instability of the acoustoelastic effect and measurement error for this method. Examples of estimation of components of a general error that affects the result of control of physical-mechanical characteristics of different objects are presented in [17].…”

Section: Correcting the Position Of Piezoelectric Transducers During mentioning

confidence: 99%