Quasi-static numerical study of the breathing mechanism of an elliptical crack in an unbalanced rotating shaft

Rubio, Lourdes; Muãoz-Abella, MÂa Belãn; Rubio, P.; Montero, Laura

doi:10.1590/s1679-78252014001300002

Cited by 13 publications

(11 citation statements)

References 33 publications

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“…For this transient breathing model, the crack status remains fully open and fully closed at two singles positions, where the crack points downwards and upwards, respectively. However, it was demonstrated that the crack actually remains fully open or fully closed for a range of shaft rotation angles [13]. A new crack breathing mechanism was proposed by Al-Shudeifat et al [14] where the crack was no longer seen to be fully open or fully closed at a single rotation angle.…”

Section: Introductionmentioning

confidence: 99%

“…A few studies have been recommended where the weight-only breathing models may not be suitable for lightweight rotors, vertical rotors or rotors operating around their critical speed of rotation [21,22], as there is significant influence from dynamic loads. Rubio et al [13,17] highlighted the influence of the eccentricity on the breathing behavior in a rotating cracked shaft in terms of crack opening percentage and stress intensity factor. It was found that addition of an unbalance force has a large influence on the crack breathing mechanism.…”

Section: Introductionmentioning

confidence: 99%

“…The results obtained from the unbalanced shaft model are also compared with the balanced shaft, where only rotor weight is considered. It should be mentioned that Rubio's [13] work employed a classical Jeffcott rotor simply supported at both ends, with a massless shaft and a disc at the mid-span of the shaft. In this rotor and unbalance force configuration, crack breathing will remain the same regardless of the crack location.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Crack breathing behavior of unbalanced rotor system: A Quasi-static numerical analysis

Hossain¹,

Wu²

2018

J. vibroeng.

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Abstract. Crack opening and closing during shaft rotation of a cracked rotor system have long been a focus of many previous studies. Previously published modeling work in the literature uses weight-governed crack breathing model for very large rotor systems. However, for lightweight or vertical or lightly damped rotors the opening and closing statuses of a crack are not always weight dominated as there is significant influence from dynamic loads. Further, the dependence of the breathing mechanism on the crack location has not been investigated yet. In this paper, the crack breathing behavior of an unbalanced shaft at the different crack location of a rotating shaft is investigated. A three-dimensional finite element model, consisting of a two-disk rotor with a transverse crack, is used. Finite element model is simulated using ABAQUS/Standard. Crack breathing behavior is found to strongly depend on its axial position, angular position, depth ratio, unbalanced force ratio and angular position. Two different crack breathing regions along the shaft length are identified, where unbalanced shaft stiffness may be larger or smaller than the balanced shaft, depending on the unbalance force orientation, magnitude and crack location. Further, four specific crack locations along the shaft length have been identified, where the crack remains fully closed or open or just behaves like in the balanced shaft. The results suggest that more accurate prediction of the dynamic response of cracked rotors can be expected when the effects of unbalance force and individual rotor physical properties on the crack breathing have been taken into account.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Crack breathing behavior of unbalanced rotor system: A Quasi-static numerical analysis

Hossain¹,

Wu²

2018

J. vibroeng.

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“…They made their calculation with aim of MATLAB software. Rubio (2014) in order to keep a shaft safe from abruptly crack failure, they studied the effect of the crack breathing with existence of eccentric mass in different position. They used their result at the trend of crack propagation and evaluation of Stress Intensity Factor (SIF).…”

Section: Introductionmentioning

confidence: 99%

Fault Detection in High Speed Helical Gears Considering Signal Processing Method in Real Simulation

Adnani

Dokami

Morovati

2016

Lat. Am. j. solids struct.

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In the present study, in order to detect the fault of the gearmeshs, two engaged gears based on research department of a major automotive company have been modeled. First off, by using the CAT-IA software the fault was induced to the output gear. Then, the faulty gearmesh and non-faulty gearmesh is modeled to find the fault pattern to predict and estimate the failure of the gearmesh. The induced defect is according to the frequently practical fault that takes place to the teeth of gears. In order to record the acceleration signals to calculate the decomposition algorithm, mount the accelerometer on accessible place of the output shaft to recognize the pattern. Then, for more realistic simulation, noise is added to the output signal. At the first step by means of Butterworth low pass digital, the noise has to be removed from signals after that by using the Empirical Mode Decomposition (EMD), signals have decomposed into the Instinct Mode Function (IMF) and every IMF were tested by using the Instantaneous Frequency (IF) in way of Hillbert Transform (HT). For this purpose a code was developed in MATLAB software. Then, in order to detect the presence of the fault the frequency spectrum of IMF's are created and defect is detected in gearmesh frequency of the spectrum.

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“…Moreover, almost all existing models are not applicable near the shaft's critical speed because equations of motion developed under the assumption of rotor static load dominance are no longer suitable for analysis near the critical speed. As such, a few studies have examined some facets of nonlinear crack breathing [9][10][11][12][13]. Bachschmid et al [12] studied the nonlinear breathing mechanism by significantly reducing the damping of the cracked rotor system so as to amplify the influence of the breathing behavior of the crack.…”

Section: Introductionmentioning

confidence: 99%

Effect of Unbalanced Force on the Crack Breathing Mechanism

Mobarak¹,

Wu²,

Yang³

2016

IJMERR

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The dependence of crack breathing behaviors on the crack location was investigated under the effect of unbalanced force. A parameter known as the effectual bending angle is introduced to describe the nonlinear relationship between crack direction and bending direction for balanced and unbalanced shafts along the shaft length. The breathing behavior of cracks was visualized by examining the duration of each crack status (open, closed, and partially open/closed) during a full shaft rotation. It is shown that a crack in an unbalanced shaft has more breathing patterns than a crack in a balanced shaft, including a single status (fully open/never closed or fully closed/never open) and dual statuses. Two pairs of interesting locations along the shaft length were identified, where the crack shows specific breathing behaviors. Further, the angular range, during which a crack remains fully closed, partially open/closed, or fully open, changes significantly with the crack location. The analytical model developed in this work can be further utilized to obtain the time-varying stiffness matrix of the cracked shaft element under the influence of unbalanced force. 

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Quasi-static numerical study of the breathing mechanism of an elliptical crack in an unbalanced rotating shaft

Cited by 13 publications

References 33 publications

Crack breathing behavior of unbalanced rotor system: A Quasi-static numerical analysis

Crack breathing behavior of unbalanced rotor system: A Quasi-static numerical analysis

Fault Detection in High Speed Helical Gears Considering Signal Processing Method in Real Simulation

Effect of Unbalanced Force on the Crack Breathing Mechanism

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