Experimental Study of the Shaft Penetration Factor on the Torsional Dynamic Response of a Drive Train

Abstract

Typical rotating machinery drive trains are prone to torsional vibrations. Especially those drive trains that comprise one or more couplings which connect the multiple shafts. Since these vibrations rarely produce noise or vibration of the stationary frame, their presence is hardly noticeable. Moreover, unless an expensive torsional-related problem has become obvious, such drive trains are not instrumented with torsional vibration measurement equipment. Excessive levels can easily cause damage or even complete failure of the machine. So, when designing or retrofitting a machine, a comprehensive and detailed numerical torsional vibration analysis is crucial to avoid such problems. However, to accurately calculate the torsional modes, one has to account for the penetration effect of the shaft in the coupling hub, indicated by the shaft penetration factor, on the torsional stiffness calculation. Many guidelines and assumptions have been published for the stiffness calculation, however, its effect on the damping and the dynamic amplification factor are less known. In this paper, the effect of the shaft penetration factor, and hence coupling hub-to-shaft connection, on the dynamic torsional response of the system is determined by an experimental study. More specifically, the damping is of major interest. Accordingly, a novel academic test setup is developed in which several configurations, with each a different shaft penetration factor, are considered. Besides, different amplitude levels, along with both a sweep up and down excitation, are used to identify their effect on the torsional response. The measurement results show a significant influence of the shaft penetration factor on the system’s first torsional mode. By increasing the shaft penetration factor, and thus decreasing the hub-to-shaft interference, a clear eigenfrequency drop along with an equally noticeable damping increase, is witnessed. On the contrary, the influence of the sweep up versus down excitation is less pronounced.

Active Torque Control for Speed Ripple Elimination: A Mechanical Perspective

“…This is In line with the elastic model. The reduction is performed with Rivin's algorithm [48], with the results listed in Table 2 and (repeated in) Table A3. The drivetrain can be represented by a 12-Degree of Freedom (DOF) torsional model, as depicted in Figure 5.…”

“…This is In line with the elastic model. The reduction is performed with Rivin's algorithm [48], with the results listed in Table 2 and (repeated in) Table A3. When Equation ( 6) is solved for the present drivetrain in both the 12-and 3-DOF versions, the mode shapes of Figure 6 The reduction in the model to a 3-DOF model has only a small impact on the location of the resonance frequencies.…”

Mitigation of Torsional Vibrations in a Modular Drivetrain with Interleaving Control

“…The driveshaft of a weaving loom is driven by one or more motors [11]. A common issue with these machines is torsional vibration across the shaft, resulting in desynchronization of the weaving process; [35,36] studied the shaft's torsional dynamics regarding the shaft penetration factor and transient stability, while [37,38] have proposed reducing the vibrations across a shaft by modeling a predictive control and adjustable speed control. However, this research involves a single input-single output drivetrain, and thus is not directly applicable to a modular drivetrain.…”

Application of D-Decomposition Technique to Selection of Controller Parameters for a Two-Mass Drive System

“…Due to the progress of microprocessor technique and power electronics, which allows to generate the electromagnetic torque with a very small delay, nowadays this problem is also evident in different drive applications [7][8][9][10][11]. Torsional vibrations are recognised in servo systems, robot arm drives, CNC machines, hard disc drives, MEMS (micro electromechanical systems) [12][13][14][15][16][17][18][19], as well as in different industrial branches [20][21][22][23].…”