Propeller Shaft Research Articles

Resistance performance simulation of remotely operated vehicle in deep sea considering propeller rotation

In order to predict the resistance performance and movement stability of deep-sea remotely operated vehicle quickly and accurately, the steady-state Reynolds-averaged Navier–Stokes method is used to simulate the force of open-frame remotely operated vehicle with propeller in motion. Volume force model is adopted to simulate the interaction between the propeller and the remotely operated vehicle, solving the force of remotely operated vehicle under the continuous work of two or four screw propellers in the horizontal and vertical motion, as well as the propeller thrust and shaft torque. In addition, according to the simulation result, the shaft torque of the symmetrical distributed propeller is almost equal, so it will not affect the movement stability of remotely operated vehicle. Since no experimental results of these drags and torques have not been performed in this study, it is important to validate the computational fluid dynamics methodology with experimental data and associated motion phenomena by means of numerical simulation. This is the preliminary design stage where extensive hydrodynamic test facilities are not available.

Exploration of Hybrid Materials for a Propeller Shaft in Aerospace Applications

This paper is a comprehensive analysis of the different composite materials that can withstand the maximum load to be used in shaft instead of the conventional steel which is currently in use. The research focuses on developing a laminated composite propeller shaft for a two-seater aircraft that can withstand maximum load with least deflection. The mathematical model for the shaft of the two-seater aircraft is developed using classical laminate theory. The in-plane forces concerning the applied torque, the strain and stress relations are evaluated for the laminated shaft which is exposed to the in-plane forces. The code is developed in Matlab for the analysis. The results obtained from the Matlab are analysed and the analysis determines that the hybrid material consisting of low carbon steel, epoxy, S glass and T700 fibres is the best suitable for the propeller shaft to withstand maximum load with the least deflection. The orientation angle is considered to be 45 degrees.

Design and Analysis of Propeller Shaft

Design and Analysis of Propeller Shaft

Failure and Thermal Examination of Hybrid Materials for a Propeller shaft in Aerospace Applications

Hybrid materials are an attractive option in case of aerospace and aviation applications since they are exceptionally strong. The current study presents the failure analysis of the hybrid material in ANSYS software. The main aim of this study is to check the suitability of the MATLAB results obtained from the previously selected composite material comprising of carbon steel + epoxy + S glass + T700 fibres using ANSYS software by creating a solid three-dimensional meshed model of the shaft. Layerwise shaft theory and finite element analysis have been employed for developing the model. The thermal analysis, delamination and buckling failure studies are conducted and found that increasing the thickness of the material will increase its load withstandability. The load failure point is found to be 8.4mm from the delamination studies. From analysis it was understood that the chosen composite material could be used for the propeller shaft of an aircraft.

Inverse modeling approach for transformation of propeller shaft angular deformation and velocity to propeller torque load

In full-scale trials or model-scale tests, the propeller torque load is typically measured indirectly on the propeller shaft. Due to structural flexibility and mass of the propeller and propeller shaft, the measured propeller shaft torque response includes a time delay and amplitude difference compare to the propeller load. These differences are usually small during propeller operation, but may be significant during transient states (i. e. starting of the engine, rough sea, or operation in ice-covered waters). In this paper, an inverse model is used to calculate propeller load based on the propeller shaft response. The results indicate that the inverse model can be less complex than the complete propulsion machinery model and consider only the propeller and propeller shaft. Several modeling approaches are tested based on four proposed measuring setups and three forms of system discretization. Out of five inverse modeling approaches, two approaches showed the ability to transform measured propeller shaft angular deformation and velocity responses, colored with noise, into the corresponding rule-based propeller torque load with acceptable accuracy. Furthermore, the robustness of the inverse approaches to the random ice-propeller interaction, sampling frequency, measuring location along the propeller shaft and starting time (before and during ice-propeller interaction), is discussed.

Marine Propeller Shaft Bearings under Low-Speed Conditions: Water vs. Oil Lubrication

The bearings used in shipbuilding, hydropower, and water pumps have undergone a metamorphosis in recent decades. Due to environmental regulations, lubrication with grease or mineral oil is prohibited. Thus, the standard solutions include water-lubricated bearings with polymer bushings or sealed systems lubricated with oil. When properly designed, assembled, and operated, bearings can operate reliably for years. However, specific operating conditions, such as a low rotational speed of the shaft, may result in intensive wear and premature failure. In this study, four sliding bearings approved for use in shipbuilding were experimentally tested. The test results showed that the choice of the bearing type has a key effect on friction during low-speed operation. Some of the tested bearings had significant static friction with intense slip–stick phenomena; they should not be used in applications requiring low-speed operation.

MODELLING AND SIMULATION OF THE AUTOMOBILE DYNAMICS MOVEMENT USING MATLAB SIMULINK SOFTWARE

As the car moving, the power of the engine is transmitted to the active wheel through the transmission system. In such a transmission, the power is lost due to friction in the powertrain and the power of the active wheel will be less than the output of the engine. The transmission system consists of components such as clutches, transmissions, propeller shaft, active bridge, differential and active wheels. During the working process, each of these parts is affected by the individual factors that reduce their performance. This article is to analyze the structure, function, task and modeling of the vehicle transmission system components, building the dynamics movement model of the transmission system according to D’Alambert principle, in which the dynamics of the wheel and the axle as well as the rigidity of the powertrain and chassis are mentioned. The Matlab Simulink software is used to simulate the automobile drive system. Thereby, the factors affecting the operation of the transmission system are analysed and evaluated in order to clarify the law of motion, and propose solutions that improve the quality of the transmission system on automobile.

Design and analysis of the propulsion shafting system in a ship with single stern tube bearing

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. Therefore, in the past, the bearing was arranged to support the propeller shaft with two forward and afterward stern tube bearings. However, when the main engine and the stern bulkhead are installed as far aftward as possible to minimize the volume of the engine room, it is necessary to provide shaft flexibility by removing the forward stern tube bearing. As a result, the resonance revolution of the propeller blades during whirling vibration of the propulsion shafting system falls within the range of normal operating revolutions. This means that abnormal wear of the stern tube bearing, damage to the stern tube sealing device, and hull structure vibration may occur due to the whirling vibration. In this paper, the characteristics of shafting alignment and whirling vibration of a ship supporting a propeller shaft with double and single stern tube bearings are compared. Moreover, the changes in shaft flexibility and the characteristics of the whirling vibration of a corresponding shafting system in a 50 K-DWT petroleum product tanker were explored by applying a single stern tube bearing. In addition, the shafting alignment and whirling vibration are determined according to the installation position of the intermediate shaft bearing. A method is suggested for selecting the optimal shafting arrangement by which to secure the shaft flexibility of a ship to which a single stern tube bearing is applied, and to avoid resonance from the whirling vibration.

Improvement of lubrication performance of water lubricated polymer bearing via enlarged axial end bearing diameter

Purpose The purpose of this paper is to improve the lubrication performance of a water-lubricated polymer bearing with axial grooves, especially enlarge the minimum film thickness. Design/methodology/approach The bearing diameter is enlarged near the axial ends of the journal, with axial openings of a trumpet shape. A numerical model is developed which considers the proposed trumpet-shaped openings, bush deformation and grooves. The generatrix of the trumpet-shaped opening is assumed to be a paraboloid. Three different variations are covered, and the influences of the trumpet-shaped openings’ parameters on the bearing performance are analyzed. Findings The appropriate trumpet-shaped openings at the axial ends effectively increase the minimum film thickness, and the impact of trumpet-shaped openings on load carrying capacity is very small or even negligible. For the water-lubricated polymer bearing with axial grooves analyzed in this paper, the appropriate trumpet-shaped openings increase the minimum film thickness from 0.53 to 11.14 µm and decrease the load carrying capacity by 2.48 per cent. Practical implications The results of this study can be applied to marine propeller shaft systems and other systems with polymer bearings. Originality/value This paper has presented an approach for significantly increasing the minimum film thickness of a water-lubricated polymer bearing. A study on the performance improvement of water-lubricated polymer bearings with axial grooves is of significant interest to the research community.

Experimental verification of the mechanism on stick-slip nonlinear friction induced vibration and its evaluation method in water-lubricated stern tube bearing

Water lubricated stern tube bearings are widely used to support the propeller shaft in marine applications. The material of the stern tube bearing is usually rubber or polymer. Since water creates the lubricating film at the shaft-bearing interface, the friction coefficient on the bearing in the boundary and mixed lubricating area where the friction induced vibration frequently occurs is usually higher than that of oil. Furthermore, the friction coefficient is reduced as the speed of the shaft revolution increases within the regime in which static friction is dominant. In this case, the shaft-bearing system can become unstable due to the stick-slip motion of the shaft-bearing system, and self-excited vibration can occur. In this study, the shaft-bearing system is described using a two degrees of freedom model, and a stability analysis is performed in accordance with system parameters such as normal load, damping on the bearing, and the natural frequency of the shaft system related to the stick-slip motion at the shaft-bearing interface. In addition, stick-slip nonlinear friction induced vibration is reproduced with a test unit that can simulate stick-slip nonlinear friction induced vibrationof the propulsion shaft of the ship. We attempt to how the stick-slip vibration is identified using signal processing of the test unit acceleration.

Experimental research on marine oil-lubricated stern tube bearing

Bearings of propeller shafts are very crucial elements of the propulsion system of each of the ships. The safety of shipping depends on their durability and reliability. The new legal restrictions mean that today we are looking for environmentally friendly solutions. That is why water-lubricated bearings are becoming more and more popular. So, will oil-lubricated shaft bearings belong to the past? The bearing with a white metal bushing lubricated with mineral oil, which was subjected to experimental tests, has a number of advantages. First of all, it works in the area of full fluid friction, and in typical shipbuilding conditions it has a significant excess of hydrodynamic load capacity. Therefore, replacing mineral oil with an environmentally friendly lubricant with a similar viscosity seems to be a promising solution. Motion resistance larger than that in water-lubricated bearings compensates for the reliability and durability of this solution.

Review and Analysis of Various Composite Propeller Shaft

The replacement of conventional steel driveshaft of automobiles with an appropriate composite driveshaft with different combinations of fibers at a time. For reducing the bending natural frequency the conventional steel shafts are made in two pieces, where to reduce the overall weight the composite material drive shaft is made in single piece. Various composites can be designed and analyzed for their appropriateness in terms of torsional strength, bending natural frequency and torsional buckling by comparing them with the conventional steel driveshaft under the same grounds of design constraints and the best-suited composite will be recommended. Light has been thrown upon the aspects like mass saving, number of plies and ply distribution.

고용량 경사류용 동력계를 이용한 프로펠러 단독시험 특성의 실험적 연구

In order to investigate Propeller Open Water (POW) characteristics for the high-speed propeller in Large Cavitation Tunnel (LCT), the high-capacity inclined-shaft dynamometer was designed and manufactured. Its measuring capacities of thrust and torque are ±2200N and ±120N-m, respectively. The driving motor is directly connected to the propeller shaft. Inclined angle of the propeller shaft can be adjusted up to ±10°. As the pressure inside LCT can be adjusted in the range of 0.1~3.0bar, we can carry out the POW test at high Reynolds number (above 1.0×106) without propeller cavitation and the cavitation test in uniform flow. After the new dynamometer setup in LCT, the Reynolds number variation test and propeller open-water test were conducted at the inclined angle of 0°and 6°. The present POW results of the new dynamometer are compared with those of the existing high-capacity dynamometer in LCT and of the dynamometer in the towing-tank. Through systematic model tests and comparison with their results, the performance of the new inclined-shaft dynamometer was verified. It is thought the POW test for the high-speed propeller should be better conducted at high Reynolds number.

Design And Analysis Of An Open Differential

An automobile differential gear system is used to establish a differential motion between left and right driving axle which provides a smooth turning of the vehicle. When a vehicle takes a turn then the wheels at outermost position requires to cover a large distance than that of the innermost wheels. This speed variation can be achieved by using a differential gear system. It also transmits the power from the propeller shaft to each axle. A rear wheel drive vehicle requires a differential at the rear axle while all-wheel drive vehicle requires differential gear system for each and every axle. In this paper, an open differential is designed for a leading automobile and analysed the ability to work without failure. The analysis was done using the modified Lewis equation, Hertzian contact stress equation and AGMA equations. The analytical results were compared with results obtained by FEA. It is observed that results obtained from Lewis criterion are more conservative as compared to AGMA. The results obtained from modified Lewis, Hertzian contact stress and AGMA are in good agreement with the results obtained from FEA.

Coupled transverse and torsional vibrations of the marine propeller shaft with multiple impact factors

An appropriate assessment of the dynamic behavior of a ship's marine propeller shaft is essential to enable the optional power delivery to the propeller and to minimize various vibrations during the rotation. As the mechanism of coupled transverse-torsional vibrations for the shaft is not fully revealed, which seriously affect the stability and reliability of ship's navigation. An accurate and applicable numerical model for the coupled vibrations of marine propeller shaft is thus proposed to solve this problem. This non-linear model with ordinary differential equations is analytical calculated on the basis of high order Runge-Kutta method. Experiments are conducted to validate the applicability of the proposed model through the comparison with numerical calculation, over a range of rotational speeds. The impact factors including eccentricity of cross section, damping coefficient and length-diameter ratio are discussed by comparing the Poincare surface of section. And the influence on the transient accelerations of the coupled vibrations are investigated in detail. The optimized design for marine propeller shaft is thus realized based on the adjustment of the unbalance quantity and structural dimension.

ВЛИЯНИЕ НЕОДНОРОДНОСТИ РАСПРЕДЕЛЕНИЯ КОЭФФИЦИЕНТА ЖЕСТКОСТИ ДЕЙДВУДНЫХ ПОДШИПНИКОВ НА СОБСТВЕННУЮ ЧАСТОТУ ПОПЕРЕЧНЫХ КОЛЕБАНИЙ ВАЛОПРОВОДА СУДНА

One of the most significant factors affecting the natural frequency of transverse vibrations of shaft-slide bearing systems is the stiffness coefficient of the slide bearing. The need to consider the influence of heterogeneity of stiffness coefficient of the bearing on its natural frequency is caused by the fact that when the bearing is worn, the modulus of longitudinal elasticity of the material changes, and since the bearing wears unevenly, the non-uniform distribution of the stiffness coefficient occurs. The problem of determining the natural frequency of transverse vibrations of a ship propeller shaft based on the foundation with a variable stiffness coefficient along the length has been studied. The differential equation of the propeller shaft vibrations written taking into account the stiffness coefficient variable along the shaft length is considered. It has been noted that, in the general case, this equation is a fourth-order partial differential equation and cannot be integrated in quadratures for an arbitrary stiffness distribution function along the shaft length. A numerical-analytical method for determining the natural frequency of a system based on approximation of the stiffness distribution function by a piecewise-linear function is proposed. The method is applied to calculate the natural frequencies of the pipeline section taking into account the functions describing the change in the stiffness coefficient. The proposed method allows to consider the section of the shafting enclosed in the stern bearing, subject to the non-uniform distribution of the stiffness coefficient of the bearing, and is the basis for improving the accuracy of finding the true natural frequency of transverse vibrations of the shafting.

АВТОМАТИЗАЦИЯ МЕТОДИКИ РАСЧЕТА СОБСТВЕННОЙ ЧАСТОТЫ ПОПЕРЕЧНЫХ КОЛЕБАНИЙ ГРЕБНОГО ВАЛА

Improving the designing quality of engineering systems and accuracy of their calculations is the basis for increasing the technical and economic indicators of modern engineering. Using automated calculations during the design phase raises labour productivity and product quality. There have been discussed the stages of software implementation of engineering calculations of the natural frequency of transverse vibrations of the ship propeller shafts. The problem of determining the first natural frequency of transverse vibrations of the shaft depending on the method of its fixing has been solved. A computational scheme has been build, which presents a uniform cross-section beam based on a point elastic support with a concentrated mass at its end. Differential equations for oscillations have been derived; the method of finding the natural frequencies has been described. For proper calculating natural frequency there has been developed a sequence and its software implementation in Maple environment with application of computer algebra package. The effect of the method of fixing on natural frequency of shaft transverse vibrations has been estimated. The problem of finding natural frequency of transverse vibrations on the extended elastic stern shaft bearing has been considered. The algorithm presented in the paper serves as a basis for formalizing and automating the stage of calculating transverse vibrations and is also applicable for calculating the natural frequencies of various elements, including the shaft and the sliding bearing.

Parametric Stability Analysis of Active Magnetic Bearing Supported Rotor System With a Novel Control Law Subject to Periodic Base Motion

Active magnetic bearings (AMBs) are being continuously explored for industrial applications mainly because of their friction-free operation. However, if a rotor-shaft-AMB system is used in applications such as turbo engine of an aircraft or in the propeller shaft of a ship, it would be subject to parametric excitation because of the moving base of the system. Parametric excitation is known to cause instability in systems. This paper addresses the issue of such flexible rotor-AMB system and performs the parametric stability analysis. A novel control law based on the constitutive relationship of a viscoelastic material called the four-element control law is developed. Because of the presence of periodic base motion terms in the system state matrix, the system can be classified as a linear periodic system. Thus, the stability analysis is carried out using Floquet–Liapunov theory on stability of periodic system, for which an approximate state transition matrix is first found and stability of the system is then decided based on the absolute value of eigenvalue. Three different base motions (roll, pitch, and yaw) were considered for evaluating the performance of the proposed control law. Simulation results reveal that the proposed control law has better stability characteristics than the proportional-integral-derivative (PID) control law.

Aerodynamic Characteristic of Deflected Slipstream Aimed at Vertical Takeoff and Landing

The deflected slipstream is one kind of vertical takeoff and landing technology with lightweight lift machinery. Thus, the influence of different parameters on the aerodynamic characteristics of a multi-element wing under propeller slipstream is experimentally studied. The parameters concerned here include horizontal distance between propeller and wing, flap deflection angles, and inclination angle between propeller shaft and wing main chord direction. In addition, Gurney flaps are also used to further improve the aerodynamic performance. It is indicated that the horizontal distance between propeller and wing has little influence. The efficiency of first flap deflection in redirecting propeller slipstream is greater than that of the second flap deflection. The maximum turning angle can reach 44 deg, and the magnitude of resultant force can reach 78% of propeller thrust when the first flap deflects 50 deg and the second flap 40 deg for the cases when the inclination angle is equal to 0 deg. The turning angle can increase to 56 deg when the inclination angle is equal to 18 deg, which is beneficial to vertical takeoff and landing. With the addition of Gurney flaps, the turning angle can be further enhanced, though the resultant force is reduced. These findings can provide valuable reference for the implementation of vertical takeoff and landing based on deflected slipstream.

A novel approach for failure mode and effect analysis in propeller shaft manufacturing industry using fuzzy analytic hierarchy process and GRA VIKOR

A novel approach for failure mode and effect analysis in propeller shaft manufacturing industry using fuzzy analytic hierarchy process and GRA VIKOR