The Effect of Lamb Wave Interaction with Fatigue Crack in Thin Al Sheet

Pavelko, Vitālijs; Pavelko, Igors; Ozolinsh, Eriks

doi:10.4028/www.scientific.net/kem.488-489.65

Cited by 2 publications

(4 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Effect of crack opening/closing was reliably fixed. The same effect for a relatively long fatigue crack in a thin flat samples of aluminum alloy was investigated in the articles [9][10][11]. It is demonstrated that there is a stable correlation between the size of the crack and the amplitude of the transmitted or reflected signal.…”

Section: Introductionmentioning

confidence: 86%

“…Here the essential results of FCOC effect are reproduced from [9][10][11]. The Al2024-T3 1 mm thickness sample equipped by two PZT was used.…”

Section: Some Main Regularities Of the Crack Opening / Closing To The...mentioning

confidence: 99%

“…Especially important that there is a perceptible difference of signal intensities at a crack opened and closed states. Note [10] that the mentioned effect is associated with the change of acoustic impedance of the damaged structure. The purpose of this article is to evaluate more details the effect of opening/closing of a fatigue crack to the electromechanical impedance (EMI) of the system " host structure/ PZT".…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Application of the Fatigue Crack Opening/Closing Effect for SHM Using Electromechanical Impedance Technology

Pavelko

2015

AMM

Self Cite

View full text Add to dashboard Cite

Earlier the effect of fatigue crack opening/closing (FCOC) to ultrasound guided wave propagation was investigated. The purpose of this article is to evaluate this effect to the electromechanical impedance (EMI) of the system "piezoelectric transducer / host structure. Experimental study performed using the flat samples of aluminum alloy. One of them had the 4 mm central hole. Other sample after fatigue testing had central fatigue crack of 40 mm length (including a 4 mm central hole for the initiation of a fatigue crack. Each sample was loaded by tensile axial static load from zero to 12 kN and the EMI measurement after eacn 2 kN incrementat of load. The EMI was measured in the frequency range of 20-40 kHz. It is established that the FCOC effect to magnitude and reactance of EMI mainly associated with variation of the capacitance of PZT under mechanical load. But the effect to the PZT resistance is more complex and more significant. The result of the study is the base of some procedure of fatigue crack detecting by the EMI method without baseline use. The developed model of EMI of ’host structure – PZT’ that is based on the modal decomposition of dynamic response of this system allows to solve main problems of the SHM system designing and optimizing of its parameters.

show abstract

Section: Introductionmentioning

confidence: 86%

“…Here the essential results of FCOC effect are reproduced from [9][10][11]. The Al2024-T3 1 mm thickness sample equipped by two PZT was used.…”

Section: Some Main Regularities Of the Crack Opening / Closing To The...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Application of the Fatigue Crack Opening/Closing Effect for SHM Using Electromechanical Impedance Technology

Pavelko

2015

AMM

Self Cite

View full text Add to dashboard Cite

show abstract

“…6 The interaction of Lamb waves with fatigue crack opening and closing effect due to the differential loading was investigated by Pavelko et al in an aluminium panel, where they found a significant decrease in Lamb wave amplitude (peak to peak voltage) in the loaded versus the unloaded state. 7 Pavelko also used experimental and numerical techniques to study the interaction of Lamb waves excited at 250 kHz with the opening/closing effect of the fatigue crack due to differential loading on an aluminium panel. He found the presence of a threshold load above which the intensity of the transmitted signal did not change with increased loading.…”

Section: Concepts Of Damage Index and Damage Matrix Are Not New Ihnmentioning

confidence: 99%

A novel damage detection methodology using multi-frequency guided waves for SHM applications

Pant¹,

Martinez²,

Yanishevsky³

et al. 2019

AAOAJ

View full text Add to dashboard Cite

This paper studies the effect of fatigue crack growth on the propagation characteristic of multi-frequency anti-symmetric Lamb wave modes in a C-Channel type aerospace structure through a Damage Response Factor (DRF) approach based on experimental testing with numerical verification. The approach is based on an algorithm for analyzing guided wave data excited at different frequencies, providing a method for identification of damage along an actuator-sensor path in a pitch-catch scenario. Computation of the DRF is based on the changes in the wave amplitude ratio, energy ratio, and cross correlation coefficient between the current and a baseline signal taken at the beginning of the test or at lowest load level. In addition to the commonly used threshold value, the DRF approach uses the upper and lower bounds on the average DRF value along with the separation of the DRF based on excitation frequency. By combining these criteria, a method for damage detection was developed. The approach presented here was experimentally and numerically verified for a C-Channel manufactured from aluminium alloy 7075-T651. A constant amplitude fatigue cyclic loading was applied to the C-Channel in order to grow a crack from a 3.2 mm diameter hole with a ~0.4 mm saw-cut starter notch. Multiple piezoelectric sensors were utilized to generate and capture a series of guided Lamb waves at different excitation frequencies to evaluate the presence of damage along each sensor path. Both the experimental measurements and the Finite Element Method (FEM) provide good agreement on the application of the DRF as a means for detecting damage. A "cycle-free baseline" damage detection method is also presented, which is based on interrogating the structure during the same cycle, but at different loading conditions.

show abstract

The Effect of Lamb Wave Interaction with Fatigue Crack in Thin Al Sheet

Cited by 2 publications

References 4 publications

Application of the Fatigue Crack Opening/Closing Effect for SHM Using Electromechanical Impedance Technology

Application of the Fatigue Crack Opening/Closing Effect for SHM Using Electromechanical Impedance Technology

A novel damage detection methodology using multi-frequency guided waves for SHM applications

Contact Info

Product

Resources

About