Exploration of NDE Properties of AMB Supported Rotors for Structural Damage Detection

Sawicki, Jerzy T.; Storozhev, Dmitry L.; Lekki, John

doi:10.1115/1.4002908

Cited by 25 publications

(9 citation statements)

References 10 publications

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“…If the force is harmonic, then the presence of the crack generates responses containing frequen cies at combinations of the angular speed, applied forcing fre quency, and the rotor natural frequencies [14]. It has been shown that the appearance of the combinational frequencies is a very strong signature of the shaft crack [14,15]. However, the research conducted so far has focused on applying the harmonic force, act ing in one fixed direction only [13][14][15].…”

Section: Controlled Deflection Approach For Rotor Crack Detectionmentioning

confidence: 97%

“…It has been shown that the appearance of the combinational frequencies is a very strong signature of the shaft crack [14,15]. However, the research conducted so far has focused on applying the harmonic force, act ing in one fixed direction only [13][14][15].…”

Section: Controlled Deflection Approach For Rotor Crack Detectionmentioning

confidence: 99%

“…A relatively new approach to the problem of rotor crack detec tion employs the use of a specially designed diagnostic force applied to the rotating shaft [12][13][14][15]. If the force is harmonic, then the presence of the crack generates responses containing frequen cies at combinations of the angular speed, applied forcing fre quency, and the rotor natural frequencies [14].…”

Section: Controlled Deflection Approach For Rotor Crack Detectionmentioning

confidence: 99%

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Controlled Deflection Approach for Rotor Crack Detection

Kulesza

Sawicki

2012

Volume 7: Structures and Dynamics, Parts a and B

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A transverse shaft crack is a serious malfunction that can occur due to cyclic loading, creep, stress corrosion, and other mechanisms to which rotating machines are subjected. Though studied for many years, the problems of early crack detection and warning are still in the limelight of many researchers. This is due to the fact that the crack has subtle influence on the dynamic response of the machine and still there are no widely accepted, reliable methods of its early detection. This paper presents a new approach to these problems. The method utilizes the coupling mechanism between the bending and torsional vibrations of the cracked, non-rotating shaft. By applying an external lateral force of constant amplitude, a small shaft deflection is induced. Simultaneously, a harmonic torque is applied to the shaft inducing its torsional vibrations. By changing the angular position of the lateral force application, the position of the deflection also changes opening or closing of the crack. This changes the way the bending and torsional vibrations are being coupled. By studying the coupled lateral vibration response for each angular position of the lateral force one can assess the possible presence of the crack. The approach is demonstrated with a numerical model of a rotor. The model is based on the rigid finite element method (RFE), which has previously been successfully applied for the dynamic analysis of many complicated, mechanical structures. The RFE method is extended and adopted for the modeling of the cracked shafts. An original concept of crack modeling utilizing the RFE method is presented. The crack is modeled as a set of spring-damping elements (SDEs) of variable stiffness connecting two sections of the shaft. By calculating the axial deformations of the SDEs, the opening/closing mechanism of the crack is introduced. The results of numerical analysis demonstrate the potential of the suggested approach for effective shaft crack detection.

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Section: Controlled Deflection Approach For Rotor Crack Detectionmentioning

confidence: 97%

Section: Controlled Deflection Approach For Rotor Crack Detectionmentioning

confidence: 99%

Section: Controlled Deflection Approach For Rotor Crack Detectionmentioning

confidence: 99%

See 1 more Smart Citation

Controlled Deflection Approach for Rotor Crack Detection

Kulesza

Sawicki

2012

Volume 7: Structures and Dynamics, Parts a and B

Self Cite

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show abstract

“…The rotor is a part of a crack detection test rig utilized at the Center for Rotating Machinery Dynamics and Control (RoMaDyC) at Cleveland State University [13]. Main dimensions and the schematic diagram of the rotor are presented in Fig.…”

Section: Equations Of Motionmentioning

confidence: 99%

“…Grabowski's model can be applied, when the weight dominance of the external load is assumed [11][12][13]. In this situation, the constant static deflection of the rotor may be neglected, and only the dynamic, vibration response is calculated, simplifying the analysis.…”

Section: Introductionmentioning

confidence: 99%