• Journal of Advanced Marine Engineering and Technology
• /
• v.14 no.2
• /
• pp.35-47
• /
• 1990

The natural frequency of lateral vibration for ship's propulsion shafting tends to become lower as the relative stiffness of supproted system of the propulsion shafting decreases and the weight of shafting increases. Especially, the propulsion shafting of high-power ships such as car ferries, roll-on/roll-off, and container ships are susceptible to lateral vibration for their resonant speeds are happened to be in ordinary operating speed ranges. So far, many papers on the lateral vibration of ship's propulsion shaftings are published but they treated mainly special cases and not explained explicitly the calculation process. In this paper, the calculation processes of undamped and also forced damped lateral vibration by the transfer matrix method are presented and the calculation programs are developed. With the developed computer programs, a ship's propulsion shafting which was introduced on the published paper is analyzed for its lateral vibration and also the lateral vibration of the main drive shaft for a lathe is calculated to show the availiability of developed computer programs.

• Journal of Advanced Marine Engineering and Technology
• /
• v.24 no.1
• /
• pp.18-24
• /
• 2000

As ship's propulsion shafting system has been complicated, many linear methods that have been used until now are not sufficient enough to produce proper solutions and these solutions are ofter unreasonable. So we need to solve nonlinear systems, and many methods for solving nonlinear vibration system have been developed. In this study, the propulsion shafting system was modeled with Duffing's nonlinear vibration system and multi-degree-of-freedom, and analyzed by using Quasi-Newton method. And for the purpose of confirming the reliability of the calculating results for nonlinear forced torsional vibration of the propulsion shafting system, the nonlinear calculated results were compared with the linear calculated ones for ship's propulsion shafting system. In the result, for analysis of the forced torsional vibration of the propulsion systems with nonlinear elements, the modified Newton's method is confirmed reasonable.

• Journal of the Society of Naval Architects of Korea
• /
• v.38 no.4
• /
• pp.48-55
• /
• 2001

In this paper, sensitivity analysis for the coupled axial and torsional undamped free vibration of ship propulsion shafting is proposed. The purpose of this study is to effectively and optimally design the resonance frequencies of propulsion shafting affecting barred speed range of main engine by modifying the diameters of intermediate and propeller shafts. The presented method is validated by the sensitivity analysis for the natural frequencies of propulsion shafting of two real large merchant ships. In addition, the changes of natural frequency and resonance main engine speed are discussed in case that the diameter is varied within the range regulated by the rule of shipping register.

• Journal of Advanced Marine Engineering and Technology
• /
• v.8 no.1
• /
• pp.37-48
• /
• 1984

For the designing propulsion shafting of ship, shaft diameters are usually calculated according to the Society's rules and other scantlings such as a shaft length, coupling and taper parts, etc., are decided according to calculated diameters. And then, the torsional vibration, the lateral vibration and shaft alignment should be reviewed to check whether the resonance points of torsional or lateral vibration appear within the normal operating speed range and the shaft alignment is reasonable. If the results of calculations are unsatisfactory, this process should be repeated until the final condition is determined and the process of this work takes much time to carry out. To simplify the above tedious processes, authors have developed a computer program to fulfill the above design processes at once. This program takes aim at reducing the manual calculating work associated with the propulsion shafting of ship. To confirm the availability of developed computer program, several propulsion shaftings which are driven by diesel engines, have been analysed. The results calculated by authors developed computer program show comparatively good agreements with those of the actual propulsion shafting.

• Journal of KSNVE
• /
• v.9 no.5
• /
• pp.936-942
• /
• 1999

Unstable torsional vibration on the marine ship's propulsion shafting system with diesel engine occurred due to a slippage of multi-friction clutch which was installed between increasing gear and shaft generator. In this paper, the mechanism of this vibration was verified via torsional, whirling, axial and structural vibration measurements of shafting system and noise measurement of gear box. And it was also identified by the theoretical analysis method.

• Journal of Power System Engineering
• /
• v.22 no.6
• /
• pp.11-19
• /
• 2018

In this study, the authors examine the propulsion shafting of the training ship SAEDONGBAEK and perform modeling to analyze the torsional free vibration of the shafting. In this paper, the computational algorithm for analyzing the torsional free vibration of the shafting with a reduction gear is formulated by the sylvester-transfer stiffness coefficient method (S-TSCM) that is a recently developed and a powerful method in free vibration analysis. According to the state of the controllable pitch propeller of the shafting and the temperature of the elastic coupling, the torsional free vibration of the shafting is performed by the S-TSCM. The authors examine the changes of the natural frequencies and natural modes which are the results of the torsional free vibration analysis of the shafting.

• Journal of Power System Engineering
• /
• v.7 no.3
• /
• pp.29-34
• /
• 2003

Genetic algorithm is a optimization technique based on the mechanics of natural selection and natural genetics. Global optimum solution can be obtained efficiently by operations of reproduction, crossover and mutation in genetic algorithm. The authors developed a computer program which can optimize marine propulsion shafting by using binary-coded genetic algorithm and modal analysis method. In order to confirm the effectiveness of the developed computer program, we apply the program to a optimum design problem which is to obtain optimum diameters of intermediate shaft and propeller shaft in marine propulsion shafting. Objective function is to minimize total mass of shafts and constraints are that torsional vibration stresses of shafts in marine propulsion shafting can not exceed the permissible torsional vibration stresses of the ship classification society. The computational results by the program were compared with those of conventional design technique.

• Journal of Advanced Marine Engineering and Technology
• /
• v.9 no.4
• /
• pp.307-316
• /
• 1985

Nowadays, the natural frequencies and their relative amplitudes of torsional vibration for the marine diesel engine shafting are usually calculated by the Holzer method and also its resonant amplitudes are estimated by the energy method, that is, by equating the exciting energy to the damping one. Therefore, the forced vibration amplitudes out of the resonant points can not be calculated by the above-mentioned method. And so, the reasonable barred-ranges of torsional vibration can not be set and also the flank of resonant point which locates near the calculation limit can not be estimated. For such problems, the equation of forced vibration with damping must be solved directly and these results can be utilized to derive the synthesized torsional vibration of the marine diesel engine propulsion shafting. In this study, the equation of forced vibration with damping for the marine diesel engine propulsion shafting is derived and its steady-state vibration is calculated by the mechanical impedance method. For numerical calculation of the actual propulsion shafting a computer program is developed. In order to prove the reliability of this program, an actual ship's propulsion shafting whose torsional vibration was measured is analyzed and the calculated propulsion shafting whose torsional vibration was measured is analyzed and the calculated results are compared with the measured ones. And also, they are compared with the calculated results which were obtained by the modal analysis.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2002.05a
• /
• pp.129-134
• /
• 2002

This study is focused on the layout design with sizing for the main propulsion shafting with controllable pitch propeller system. For appropriate design and successful manufacturing of controllable pitch Propeller system, it is based on specifications to be required from the customer as well as the stresses calculation and analysis of main propulsion system for hollow shafting. And it must be performed according to the U.S military specifications MIL-STD-2189(SH) with drawing of NAVSHIPS 803-2145807, and also the stress analysis by applying safety factor. The results are as follows : 1. For the main propulsion system with controllable pitch propeller, it is designed the following items propeller diameter, hub diameter, dimensions of oil distribution or actuating unit based on shaft mounting type, diameters of propeller and intermediate shaft, dimension of split muff coupling, coupling flange thickness and of coupling bolt diameter. 2. As the results, we can get complete our own design ability for the main propulsion shafting with controllable pitch propeller system with critical data which are necessary to establish shafting arrangement from the ship building companies.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2008.09a
• /
• pp.54-61
• /
• 2008

With the development of computer program in calculation for torsional vibration of ship's propulsion shafting it has become possible to calculate all order's vibratory amplitude, vibratory torque, vibratory stress and synthesis value at all concerned revolutions by way of solving the vibratory equation directly. Though this kind of propulsion shafting vibration calculation method makes it possible to get generalized and precise result of calculation, the unexpected critical crankshaft torsional vibration has still appeared in maneuvering range of the engine. A close investigation has been carried out to find out the cause for the 2-node propulsion shafting torsional vibration of the crankshaft that exceeded the limitation value near the MCR 104rpm on the sea trial of the recently delivered 6000TEU class container vessel from HHIC. In conclusion, as the latest super-output engine with heavy crankshaft and propeller mass seems to be liable to 2-node torsional vibration of crankshaft, it is recommend that, in the design stage of propulsion shafting, its torsional vibration condition must be more carefully checked.