Sommerfeld effect characterization in rotors with non-ideal drive from ideal drive response and power balance

Karthikeyan, M.; Bisoi, Alfa; Samantaray, Arun Kumar; Bhattacharyya, Ranjan

doi:10.1016/j.mechmachtheory.2015.04.016

Cited by 37 publications

(6 citation statements)

References 24 publications

(43 reference statements)

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“…During this same This figure shows that for misalignments greater than about δ 0 > 11 deg, the driveshaft rotational speed, ω L , becomes captured. This rotor speed capture phenomenon is the hallmark of the so-called Sommerfeld effect which has been found in other nonlinear rotor systems [18][19][20][21][22][23][24][25][26][27][28][29]. The key finding in this paper is that the rotor However, the suspension damping has little effect on the misaligned-induced speed capture phenomena shown in Figs.…”

Section: Driveline Spinup Responsementioning

confidence: 55%

“…Similar to the suspension stiffness, since δ is not restricted to a small angle, the suspension damping only reacts to the velocity component in the n2 direction giving rise to the Lcosδ term in Eq. (28). Since δ 0 is constant and considering Eq.…”

Section: Double U-joint Driveline Modelmentioning

confidence: 99%

“…They concluded that the torsional material damping had a significant effect on suppressing the Sommerfeld effect in this system. Karthikeyan et al [28] studied the Sommerfeld effect of rotor-motor using commercial software ANSYS. The regression equations of the steady-state transverse and rotating displacement were developed to fit the data point.…”

Section: Introductionmentioning

confidence: 99%

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Nonlinear Coupled Torsion/Lateral Vibration and Sommerfeld Behavior in a Double U-Joint Driveshaft

Yao

DeSmidt

2020

Journal of Vibration and Acoustics

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Many driveline systems are designed to accommodate angular misalignment by use of flexible couplings or Universal Joints (U-Joints) which link individual shaft segments. The Sommerfeld effect is a nonlinear phenomena observed in some rotor systems being driven through a critical speed when there is not enough power to accelerate the rotor through resonance. Previous studies have shown that rotor speed can become captured when transitioning through natural frequencies due to nonlinear interactions between a non-ideal driving input and rotor imbalance. This paper, for the first time, shows that this type of rotor speed capture phenomena can also be induced by driveline misalignment. During rotor spinup under constant motor torque it is found that misalignment-induced rotor speed capture phenomena can occur as the shaft speed approaches ½ the first elastic torsional natural frequency. Depending on misalignment level and motor torque, the shaft speed will either dwell near this speed and then pass through, or the speed will become trapped. Here a nonlinear rotordynamics model of a segmented driveshaft connected by two U-Joints including effects of angular misalignment and load torque is developed for the study. This analysis also determines the minimum driveline misalignment angle for which the shaft speed capture phenomena will occur for a given motor torque and load torque condition.

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Section: Driveline Spinup Responsementioning

confidence: 55%

Section: Double U-joint Driveline Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nonlinear Coupled Torsion/Lateral Vibration and Sommerfeld Behavior in a Double U-Joint Driveshaft

Yao

DeSmidt

2020

Journal of Vibration and Acoustics

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“…Investigation considering the modeling of a motor in a finite element model was performed by Karthikeyan et al. 14 in order to study the Sommerfeld effect. They analyzed the increase in drive power input near resonance due to the fact that it contributes to increasing the transverse vibrations not producing increasing of the rotor spin.…”

Section: Introductionmentioning

confidence: 99%

Remarks on optimization of impact damping for a non-ideal and nonlinear structural system

Silva

Wahrhaftig

Brasil

2020

Journal of Low Frequency Noise, Vibration and Active Control

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It is intended, in this work, to present some research results on the optimization of an impact damper for a structural system excited by a non-ideal power source. In the model, the impact vibration absorber is, basically, a small free mass inside a box carved in the structure that undergoes undamped linear motions colliding against the walls of the box. Whenever the mass shocks against the walls of the box, an exchange of kinetic energy between the mass and the structure may be used to control the amplitude of the dynamic response of the structure. In this work, the structure is excited by a non-ideal power source, a DC electric motor installed on it, which may present the Sommerfeld effect. A non-ideal power source is one that interacts with the motion of the structure as opposed to an ideal source whose amplitude and frequency are fixed, independent of the displacements of the structure. Here, the dynamic response of the system is computed using step-by-step numerical integration of the equations of motion derived via a Lagrangian formulation. The optimization problem is defined considering as the objective function the maximum amplitude of the structure displacement, while the design variables are the weight of the free mass and the width of the carved box. Using the augmented Lagrangian method, several optimization problems are formulated, and, solving them, the best design to maximize the efficiency of the impact damper is obtained.

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“…The effect is observed when the frequency of excitation gets near to the system’s natural frequency and the increase in the input power does not increase the shaft speed but rather the system’s amplitude of vibration. This continues till the power input is increased sufficiently, whereupon the rotor spin speed suddenly jumps to much higher value and the transverse vibration amplitude reduces appreciably (Karthikeyan et al., 2015). The Sommerfeld effect occurs because of the nonideal characteristic of the vibration source, which, different from the ideal ones, is influenced by the system’s response which it supplies power.…”

Section: Introductionmentioning

confidence: 99%

Remarks on the Sommerfeld effect characterization in the wavelet domain

Varanis

Balthazar

Silva

et al. 2018

Journal of Vibration and Control

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In many applications in engineering, a mechanical system operates in the nonstationary regime, either partially of fully, creating the possibility to generate nonlinearities in them. Great efforts have been made to better understand and characterize these phenomena. One of several methods that are being used for the processing of signals of a nonstationary nature, as well as for the characterization of nonlinearities in mechanical systems, is the wavelet transform. A particular phenomenon that is seen in systems operating in the nonstationary regime is the Sommerfeld effect, which occurs due to the nonlinear interaction between a nonideal energy source and a mechanical system. This phenomenon can lead to high amplitudes of vibration for the system that in turn can cause damage in it. Therefore, this work presents an application of the continuous wavelet transform and the wavelet packet transform for the characterization of the Sommerfeld effect in mechanical systems where only the time response is at hand. Experimental procedures were performed where a nonideal energy source (an unbalanced DC motor) was used to excite (a) a portal frame and (b) a three-story shear-building. The results showed the effectiveness and the potential of the methods proposed.

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Sommerfeld effect characterization in rotors with non-ideal drive from ideal drive response and power balance

Cited by 37 publications

References 24 publications

Nonlinear Coupled Torsion/Lateral Vibration and Sommerfeld Behavior in a Double U-Joint Driveshaft

Nonlinear Coupled Torsion/Lateral Vibration and Sommerfeld Behavior in a Double U-Joint Driveshaft

Remarks on optimization of impact damping for a non-ideal and nonlinear structural system

Remarks on the Sommerfeld effect characterization in the wavelet domain

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