Efficiency of crack detection based on damping characteristics

Bovsunovsky, A.

doi:10.1016/j.engfracmech.2019.04.005

Cited by 17 publications

(10 citation statements)

References 17 publications

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“…As crack detection methods usually analyze the response at a low level of excitation force, in this study, it is assumed that damping changes because of the nonlinear geometric stiffness parameter are negligible and only changes to damping value owing to the presence of a breathing crack are investigated. For this purpose, the model proposed by Bovsunovsky (2019) is exploited to calculate the damping value of the cracked beam. According to this model, the energy loss in the structure ψ(σm) is proportional to the amount of relative energy dissipated during a loading cycle ΔU(σm) and is expressed by (Bovsunovsky, 2019)…”

Section: Damping Of Breathing Crackmentioning

confidence: 99%

Nonlinear vibration analysis of a cantilever beam with a breathing crack and bilinear behavior

Kharazan

Irani

Salimi

2021

Journal of Vibration and Control

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Nonlinear phenomena widely occur in practical engineering applications. A typical example in aerospace structures is the creation of a breathing crack that opens and closes under cyclic loads, which causes bilinear behavior in the structural response. Late detection of such cracks can lead to a catastrophic failure that results in extensive structural damage. Therefore, analyzing the behavior of the structure because of the presence of a breathing crack is very important and needs to be investigated in detail. In this article, the nonlinear response of a single-degree-of-freedom nonlinear cantilever beam with a transverse breathing crack and bilinear behavior was studied. To investigate the nonlinear behavior, bilinear functions of the beam stiffness and nonlinear geometric stiffness were converted to polynomial functions. The proposed model is validated by comparing the time history responses of the approximated polynomials with the bilinear model of the cracked beam. Moreover, by considering damping changes because of the presence of the breathing crack, the nonlinear behavior was investigated. The results indicated that the proposed method is sensitive to the presence of a breathing crack. Also, the nonlinearity increases with an increase in the crack depth and location ratios associated with the jump phenomenon in the vibration response of the cracked beam.

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Section: Damping Of Breathing Crackmentioning

confidence: 99%

Nonlinear vibration analysis of a cantilever beam with a breathing crack and bilinear behavior

Kharazan

Irani

Salimi

2021

Journal of Vibration and Control

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“…Метод вищих гармонік [8] і метод, заснований на зміні характеристик демпфірування [9], останнім часом вважається найбільш перспективними для практичного використання. Ці методи при певних умовах мають високу чутливість до пошкодження типу тріщини [3,[7][8] (…”

Section: вібраційна діагностика втомних пошкоджень у конструктивних елементах газотурбінних двигунів на стадії ремонтуunclassified

Vibration Diagnostics of Fatifue Damage in Structural Elements of Gas Turbine Engines at the Repair Stage

Bovsunovsky¹

2021

Vibrations in Engineering and Technology

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Vibration diagnostics of damage belongs to the class of non-destructive methods, which usually do not take long time. However, the main problem of vibration diagnostics is relatively low sensitivity to the critical damage of fatigue crack type, which arises because of long time accumulation of plastic deformation. To improve the sensitivity and reliability of vibration diagnostics of damage two methods were considered. First method was based on the fact, that a characteristic feature of vibrations of structural elements with fatigue crack is the occurrence of non-linear resonances (sub- and super-harmonic) and significant non-linearity of vibration response at these resonances. Secon one – on the fact, that quite noticeable in certain cases increase of damping characteristic caused by a crack can be observed. Analytical and experimental studies of these methods were carried out as applied to the blades of aircraft gas turbine engines. As a result of the studies, the intensity of change in parameter of super-harmonic resonance and in damping characteristics at different parameters of crack was determined. Besides, the experimental techniques for vibration testing of turbine blades were developed. There was demonstrated, that the sensitivity of both considered methods of vibration diagnostics is several orders of magnitude higher than the sensitivity of conventional methods based on the change in natural frequencies and mode shapes, and they can be effectively used for the diagnostics of blades on the stage of engine repair. All the other conditions being equal, second-order superharmonic resonance demonstrates a higher sensitivity to the presence of cracks than the damping characteristic. The smallest crack with an area of 0.2% considered in the work causes a reliably recorded non-linearity of vibration response at superharmonic resonance of order of 2/1. At this the change of damping characteristic slightly exceeds the error of experiment.

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“…Перший метод заснований на тому, що характерною особливістю коливань елементів конструкцій з втомної тріщиною є виникнення нелінійних резонансів (суб-і супергармонічних) і значна нелінійність вібраційного відгуку на цих резонансах. Другий [4], амплітуди вимушених коливань [5], виникнення суб-і супергармонічних резонансів [6], а також зміна характеристик демпфірування [7].…”

Untitled

2021

Vibrations in Engineering and Technology

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Efficiency of crack detection based on damping characteristics

Cited by 17 publications

References 17 publications

Nonlinear vibration analysis of a cantilever beam with a breathing crack and bilinear behavior

Nonlinear vibration analysis of a cantilever beam with a breathing crack and bilinear behavior

Vibration Diagnostics of Fatifue Damage in Structural Elements of Gas Turbine Engines at the Repair Stage

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