Design and analysis of propeller shaft pdf
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- Top PDF Design, Failure Analysis and Optimization of a Propeller Shaft for Heavy Duty Vehicle
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- Journal of Engineering and Applied Sciences
- Design and analysis of the propulsion shafting system in a ship with single stern tube bearing
Journal of Vibroengineering, Vol.
Top PDF Design, Failure Analysis and Optimization of a Propeller Shaft for Heavy Duty Vehicle
Journal of Vibroengineering, Vol. Received 24 August ; received in revised form 18 November ; accepted 13 December ; published 15 February Zhang Cong, Tian Zhe, Yan Xinping Analytical analysis of the vibration of propulsion shaft under hull deformation excitations. An analytical method to solve vibration of the propulsion shaft under hull deformation excitations is introduced.
The model of shaft with the excitations at bearings is seen as a simplified propulsion shaft-ship hull system, as bearings could be assumed as the connection structures that transmit the forces from hull to shaft.
Vibration characteristics of shaft under hull excitations are gained. The effects of propeller, supports stiffness, the location of hull excitations, the amplitude of excitations and the size of shaft are discussed.
With the development of ship enlargement and economization, many researchers focus on the design of large ships and their propulsion systems . For the ships with large size, dynamic interaction of propulsion shaft and ship hull is more and more evident, especially when it is travelling in rough seas . Therefore, it is meaningful to work on the coupling interactions between the propulsion shaft and the ship hull in the sea wave during the analysis of vibration to guarantee the safety of navigation.
Xing and Price used numerical methods to deal with the coupled fluid-solid interactions  to solve the effects between ship hull and sea wave. Qiu  simplified the ship as a beam and built a finite model to simulate a flexible beam in finite depth water under moving loads in the ship-shaft coupled analysis. Lech Murawski  analyzed the effect of hull deformation on the shaft alignment. Low and Lim  presented an approach to determine the changing displacement of the propulsion shaft due to the hull deflection.
Tian  used a numerical two-dimensional model of large ship propulsion-hull coupling system to analyze the dynamic interactions of the vibration of the ship propulsion system and the vibration of the hull. In the analysis of shaft vibration, the model of shaft is always composed of propeller, beam, and rotor. Warikoo  built a propeller shaft assembly, including blades and shaft rotor.
Propeller could also be simplified as mass at the shaft end. Low  introduced a method to solve the natural frequencies of a beam-mass system in transverse vibration. Bearings, as the connection between propulsion shaft and ship hull, transmit the forces from ship hull to propulsion shaft.
They could be assumed as discontinuities structures of the propulsion shaft. There are many researches on the shaft model including discontinuities. Shahgholi  studied the free vibration analysis of a shaft with simple support conditions. Wang  researched on the vibration of beams with arbitrary discontinuities and boundary conditions. Lin and Change  considered the model of multi-span beams with intermediate flexible constraints.
Lin  utilized the numerical assembly method to solve mode of a multi-span Timoshenko beam with a number of concentrated elements, including masses, linear springs and rotation springs. Zhang  used a general analytical solution to study free vibration of non-uniform Timoshenko beams coupled with flexible attachments and multiply discontinuities in engineering application, based on separation of variable in conjunction with transfer matrix approach.
Based on these references, in this paper, a method to solve vibration of the propulsion shaft under hull deformation excitations is introduced. The model of shaft with the excitations at bearings is seen as a simplified propulsion shaft-ship hull system. Propeller is assumed as a mass at the end of the shaft. Added mass from the water around it is considered. Moreover, hull deformation excitations are considered in the continuity conditions equations at each support. The analytical solution of the propulsion shaft under hull deformation excitations is gained.
In Section 3, a finite element model is developed in ANSYS to validate the results obtained from analytical model presented in this work. Dynamic responses of propulsion shaft are gained by analytical method to discuss vibration characteristics of the propulsion shaft under hull deformation excitations. The effects of propeller, supports stiffness, the location of hull deformation excitations, the size of the shaft and the amplitude of excitations are considered.
Bearings are assumed as the important connections between propulsion shaft and hull in the shaft-hull vibration system, which transmit the forces from hull deformation due to sea wave to propulsion shaft, as shown in Fig. Thus, in this paper, propulsion shaft is simplified as a beam with hull excitations at the bearing supports.
The propeller is considered as a mass at the end of the shaft. Except for loading on the bearings of shaft via hull deformation, sea wave affects the running of propeller. This influence is consisted of gravity effects, damping effects and inertia effects, of which inertia effects are the most important.
Therefore, added mass on propeller due to water around it is introduced here. As the hull deformation have great effects on the bending direction, axial vibration is ignored and 2-dimensional system of motion is considered. The bearing supports B 1 , B 2 ,…, B n with stiffness S 1 , S 2 ,…, S n and the damping C 1 , C 2 ,…, C n respectively are modeled as intermediate flexible constraints.
For each segment of shaft beam, the bending dynamic equation of motion is as follows, according to the Euler-Bernoulli theory:. I i is the moment of inertia of each segment of shaft.
A i , B i , C i , D i are the coefficients of each segment. The continuities condition of displacement, slope, bending moment and shearing force at the junction of two segments across each support can be expressed respectively:. S i is the stiffness and C i is the damping factor of each support. When the propeller is considered as a mass at the end of the shaft, the boundary condition Eq.
The relationship between added mass m and propeller mass m 1 can be expressed approximately as :. Hull deformation excitations are applied as harmonic point forces at the supports. The point force at B i is described in terms of Dirac delta function by:. Thus, when the hull deformation excitation at the support is considered, excluding the time harmonic dependency, the continuity condition Eq. According to Eq. Thus, substituting Eq. For the i th part of shaft, the matrix block of the displacements and forces are:.
One end with propeller mass and one free end are considered here by:. When the hull deformation excitations are considered, the matrix form solution of dynamic responses of the shaft with propeller is as follows:. The force matrix [ F i ] for the continuity condition refers to the hull deformation excitation at each support as:.
Solving the system, the displacement of shaft at a certain frequency and the vibration characteristics can be gained. A simplified model of propulsion shaft of one typical ship with hull excitations at the bearings is presented in Fig. The length of the shaft is The shaft is divided into five segments by four supports with lengths of According to the ship real data and simulation, when the ship is in the case of sea wave length In this paper, this case is taken as an example to show how to use the mentioned analytical method to analyze the dynamic responses of a propulsion shaft under hull deformation excitations.
A finite element model is developed in ANSYS to validate the results obtained from the analytical model presented here. The shaft, the supports and the propeller are built by element Beam, Combin14 and Mass21, respectively. Table 1. Comparison of natural frequencies by two methods. Meanwhile, when the hull deformation excitations are considered, as shown in Fig.
These errors arise due to different precisions and solutions for two methods, which are more obvious when the vibration is more complex at higher frequency range. But the errors could be acceptable, as they have few effects on the analysis of the vibration characteristics. Comparison of dynamic responses by two methods. Dynamic responses of the shaft under hull excitations.
This part discusses the vibration characteristics of the shaft under the hull deformation excitations mentioned in the given case in the sea wave. The response displacements at these two points under hull deformation excitations are presented in Fig.
It can be observed in Fig. It also can be seen from the curves that the displacement of propeller reaches the peaks at every natural frequency while the excitations at 1st, 5th and 6th frequency do not excite the resonant vibration of the engine end.
From Fig. The shaft under the 10th frequency has largest deformation with the largest displacement 9. Thus, at Response shapes under hull excitations of natural frequencies. As the propeller is considered as a mass propeller mass and added mass at one end in this model, the effect of the propeller on the vibration characteristics of shaft under hull deformation excitations is discussed in this part.
The response displacements at propeller end and engine end of the shaft with and without propeller mass are compared in Fig. As shown in Fig.
However, the peaks of the curve do not shift, which means the resonant frequencies has no change. To conclude, the propeller mainly constrains the amplitude of displacement of the response points near the propeller end. Comparison of results for the shaft with and without propeller. As the hull deformation excitations are set at the supports, this part discusses the effect of the stiffness of supports on the vibration characteristics of shaft under hull deformation excitations.
It is observed in Fig. In other words, the resonant frequencies decrease when there is no stiffness at the supports. Moreover, for corresponding peaks, the amplitude of the results for the shaft with stiffness are lower than that for the shaft without stiffness, especially at the lower frequency range, which is because there is less constraint for the no stiffness supports. Comparison of results for the shaft with and without support stiffness.
This part discusses the effect of the location of hull excitations on the vibration characteristics of shaft under hull deformation excitations.
Set only one support is excited by hull deformation excitation only in this part. The amplitude of this excitation is the average of the hull deformation excitations, which is Four cases are considered here, which are hull deformation excitation at support B1, B2, B3, and B4, respectively. The comparisons of these four cases are presented in Fig.
Show all documents Design, Failure Analysis and Optimization of a Propeller Shaft for Heavy Duty Vehicle rotational diameter, low weight, and versatile flange connections these features provide an ideal base for standardized drive train design and new power transmission concepts. Depending on application of vehicle where the engine and axles are separated from each other, as on four-wheel-drive and rear wheel-drive vehicles, it is the propeller shaft that serves to transmit the drive force generated by the engine to the axles. Sagging causes vibration and results in an increase in noise, to such an extent that the shaft is likely to break when the critical speed is exceeded. Design and optimization of automobile propeller shaft with composite materials using FEM Analysis Amol B Rindhe and S R Wagh  They investigate heavy duty vehicles driveshaft is one of the important components.
Show all documents The design parameters were optimized with the objective of minimizing the weight of composite drive shaft. The design optimization also showed significant potential improvement in the performance of drive shaft. This project deals with propeller shaft of MARUTHI OMNI to design the shaft for its minimum dimensions to satisfy current problem specification and then replace conventional steel material with composite material. Then they can be created as a part model for respective dimensions in NX 8.
Warikoo, Raman Analysis of propeller shaft transverse vibrations. Masters thesis, Memorial University of Newfoundland. The aim of this project was to find a simple, practical and sufficiently accurate method for finding the natural frequencies of a propeller shaft assembly. The need for such methods is felt at the early design stages when sufficient data about the system is not available and the need to restrict the cost of analysis is of importance. Due to these facts it is clear that the methods based on the discretization of the continuum, which can estimate the natural frequencies accurately may not be advisable to go in for in the initial stages. The propeller was considered to be a flexible rotor mounted with blades.
An automotive propeller shaft, or drive shaft, transmits power from the engine to differential gears of rear wheel-driving vehicle. In present work an attempt has.
Journal of Engineering and Applied Sciences
The propeller shaft transmits drive from the gearbox output to the final drive in the rear axle. A hollow steel tube is used for the propeller shaft. It is lightweight but will still transfer considerable torque and resist to bending forces. The von-Mises stress and shear stress are within the allowable limit.
In recently constructed vessels, minimization of engine room volume is required to maximize the volume of cargo to be shipped. Therefore, the main engine and the stern bulkhead mounted on the ship are installed as far as possible in the aftward direction. As a result, the length of the propeller shaft is reduced, along with the stern tube bearing span used to support it. In this case, the shaft flexibility is reduced, the reaction influence number is increased, and the point load of each bearing is easily influenced by change in displacement. Because the point load of each bearing is susceptible to hull deformation and thermal expansion, it is difficult to adjust the shaft arrangement and the bearing load change after large adjustment of the shaft arrangement.
Design and analysis of the propulsion shafting system in a ship with single stern tube bearing
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