Partial Frequency Assignment for Torsional Vibration Control of Complex Marine Propulsion Shafting Systems

Abstract

With the large-scale and complexity of ship propulsion shafting, it is more difficult to analyze and control the torsional vibration of shafting. Therefore, an effective control method for the torsional vibration of shafting is of great significance in the field of ship engineering. The main strategy of torsional vibration control adopted in this paper is to keep the natural frequency of a shaft system away from the excitation frequency through structural modifications. In addition, because the basic parameters of much of the equipment in engineering applications cannot be changed, this restriction cannot be ignored when seeking solutions related to structural modifications. This paper studies the partial eigenvalue assignment for the torsional vibration control of complex ship propulsion shafting using the gradient flow method, which can shift a “dangerous” natural frequency to a safe value, while satisfying complex physical constraints. The models of a ship propulsion system and a diesel generator set are established to demonstrate several different desired modification schemes and constraint conditions in practice. In particular, close frequencies are shifted. The numerical simulation results demonstrate that it is effective and feasible to make a partial frequency assignment of torsional vibration, which provides a reliable approach for the control of torsional vibration for complex shaft systems in practical engineering.

Noise and Vibration Recorded on Selected New Generation DP Class Shuttle Tankers Operated in the Arctic Offshore Sector

“…The main sources of vibration on sea vessels [10][11][12][13][14][15][16]24,25]: − main engine and mechanical transmission assemblies, − screw and drive shaft arrangement, − engine exhaust system, − combustion and electric motors − exhaust systems of internal combustion engines, − electricity generators, − compressors, ventilation and air conditioning systems, − flow installations, − ship propellers (propellers and thrusters), − propeller unbalance: dynamic, hydrodynamic, static, − machines and auxiliary devices, − the undulation of the sea.…”

Application of a Thermo-Hydrodynamic Model of a Viscous Torsional Vibration Damper to Determining Its Operating Temperature in a Steady State

“…Ship engines are multi-cylinder units and thus their crankshafts are relatively long. Therefore, engineers develop increasingly effective methods and algorithms for the detection of torsional vibrations of crankshafts and other power transmission elements in marine propulsion systems with a view to avoiding operating conditions that increase the risk of damage due to failure [ 9 , 10 , 11 ]. When selecting a torsional vibration damper, efforts are made not only to increase the durability and eliminate torsional vibrations of the crankshaft which are dangerous for the engine design, but also to take into account transient states and reduction in the time delay at step acceleration of the engine rotational speed [ 12 ].…”

Pole Assignment for Active Vibration Control of Linear Vibrating Systems through Linear Matrix Inequalities

“…The assignment of the dynamic response of vibrating mechanical systems, such as structures, mechanisms, or multibody systems, is often performed by properly assigning the poles of the controlled systems. Both active feedback control [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] and passive approaches (i.e., parameter modifications, see e.g., [19][20][21]) or are exploited to accomplish this important task. Indeed, the system poles, which are often denoted as the eigenvalues, define the system stability as well as the properties of the transient response such as the damping ratio, the rise time, and the settling time.…”