If the ujoint axial play or flex effort exceed the specifications in the electronic service manual esm, or if a. The rotational motion of the gear box main shaft is transferred to the differential unit for rotating the drive wheels mainly torsional load acts on the propeller shaft, hence it is. Often, there is part of the keel below the propeller that protects the propeller and supports the bottom of the rudder. Shaft deflection, runout, vibration, and axial motion. A design procedure for minimizing propellerinduced vibration in. The division of the propeller shaft into a few sections enables the basic number of transformation to brought down keeping vibration issue from happening, when the general length of the pole expanded. Lowfrequency vibration of a submarine is one key factor restricting its stealth performance. The excitation forces of the rotating propellershaft system, such as the residual unbalance of the propeller, the misalignment of the shafts and the fluidinduced forces acting on the propeller, will be amplified in the process of transmission from the propeller to the hull, because of the elasticity. And like a guitar string, when things are in tune everything is. Us6837345b1 vibration damper for a tubular drive shaft. In the second group of simulations, the structural vibration problems induced by propeller excitation are addressed through a comprehensive analysis for a tanker. Zhang and cao24,25 used the fem to investigate the longitudinal and transverse vibrations of a shaft hull structure excited by har.
Kriso technology for ship propulsion efficiency improvement and propeller noise reduction duration. Aquadrive systems reduce noise by transferring the load of the propeller to the hull so that the engine can sit on soft vibrationabsorbing mounts. When powerplant vibration is encountered, it is sometimes difficult to determine whether it is the result of engine vibration or propeller vibration. The effect of the shaft diameter and torsional stiffness. The whirling of the drive shaft which is a resonance vibration occurs when the rotational speed is equal to the fundamental natural bending frequency, which is. Shaft axial vibration velocity at different shaft speeds. A general logical methodology is utilized to research free vibration of nonuniform timoshenko pillars with various discongruities and limit conditions. Driveshaft vibrations solved stepbystep so i think i finally have this figured out. Driveline vibration is a matter of harmonics, meaning materials vibrating at certain frequencies, like a guitar string. Analysis of propeller shaft transverse vibrations sciencedirect. Propeller drive systems and torsional vibration written by donald p.
Vibration and propeller design considerations for a jumbo. The drive shaft must also be capable of rotating at the very fast speed required by the vehicle. Propeller not corrected fitted properly onto shaft. Design and optimization of automobile propeller shaft with. The propeller shaft ujoint journaljournal bearings is the source of noise andor vibration on an applied vehicle. In most cases, the cause of the vibration can be determined by observing the propeller hub, dome, or spinner while the engine is running within a 1,200 to 1,500rpm range, and determining whether. Note all measurements must be taken from the passenger side of vehicle facing the driver side. The first, code c1 6, is concerned with 1 vibration of the ship girder excited by the propulsion system at shaft frequency, harmon ics of the propellerblade.
Have the propeller lapped to the shaft to fit the taper correctly. Three types of elements suitable for every application. In analysis of propeller shaft transverse vibrations 257 the early 1950s, two wellknown approximate methods for determining critical propeller shaft speeds were developed. Refer to figure 7 below to ensure that the angles measured have. Coupled vibration characteristics of a submarine propeller. The submarine propulsion shafting system consists of propeller, stern shaft, intermediate shaft, journal bearing, thrust bearing, and flexible coupling, as shown in. Reduces engine noise and drivetrain vibration unlike any other on the market. Request pdf vibration analysis of propeller shaft with crack crack occurs frequently in rotating machinery due to manufacturing flaws or fatigue.
Materials are the highest quality available in the industry, and all machining meets or exceeds abyc standards. On vessels with two power trains, however, the propeller shaft never. Detection of cracks in shafts via analysis of vibrations. The article discusses a key problem of ship propulsion system vibration diagnostics, which concerns assessing this part of mechanical energy transmitted from the main engine to the ship propeller which is dissipated due to propeller shaft vibration. Shaft deflection, runout, vibration, and axial motion chapter d4 page 4 contact kalsi engineering search this handbook bearing internal and mounting clearances influence shaft runout side loads cause the shaft to articulate within mounting clearances, resulting in lateral shaft deflection at.
Vibratory shaft forces are caused by the fluctuating load on the propeller blades due to the spatial variation in the wake field. Propeller equipment type vbs ods 8s50mcc engine, renk tunnel gear, vbs1680 propeller ods shaft mounted odbox for direct driven propellers without reduction gearboxes the oil distribution box must be located in the shaft line. Propeller shaft vibration and sounds your online mechanic. Propeller equipment type vbs odf 6l4860b engine, reduction gear, vbs80 propeller fig. Propeller shaft runout 39 calculating the propeller shaft frequency 40 driveline operating angles 42 propeller shaft operating angle 43 measuring operating angles 44 transmission yoke measurement 45 propeller shaft measurement 46 pinion flange measurement 47 48 enginespeed vibration 48 engine frequency formula 49 first and secondorder engine. How to diagnose and fix inboard shaft vibration boating.
Vibration and propeller design considerations for a jumbo mark ii class washington state ferry by wylie moreshead, p. Boat propeller problems vibration, cavitation, tip. The propeller shaft exchanges motor torque to the back pivot through at least one widespread joints. And like a guitar string, when things are in tune everything is fine, but when things are out of tune, they really suck. Torsional vibration analysis of a long propeller shaft. A vibration damper for a tubular propeller shaft in the drive train of a motor vehicle having a mass body mounted concentrically, in the propeller shaft or in a sleeve attached in the propeller shaft, by way of at least one rubber spring element. Klein4 1,2,3pearlstone center for aeronautical engineering studies and laboratory for mechanical health monitoring, department of mechanical engineering, bengurion university of the negev, p. The hull surface forces mainly originate from transient cavitation on the propeller blades. Propeller excitation of longitudinal vibration characteristics of. Drive shaft construction can be made of steel, aluminum, or composite material hollow shaft may have cardboard liner to reduce noise has a yoke welded to each end universal joints are used at each end may have balance weights attached. From the wright brothers on, many have designed, built or converted. On rearwheel drive vehicles, driveshafts sometimes called propeller shafts can cause vibration due to improper balance, poor companion flange alignment or excessive driveline angle.
A method to assess transverse vibration energy of ship. Metal andor flexible rubber stop elements that limit the vibration travel of the mass body at least in the radial direction are arranged between the. If the propeller shaft and differential companion flange do not fit together properly, centering is altered and the balance is lost. Vibration fracture analysis and optimization design of. If the bend exceeds the standard dimension or the propeller shaft indicates cracks over the tubing or on yoke weld seams, replace the propeller shaft. Typical vibration torque variation in a propeller shaft of a conventional, lowspeed diesel engine propulsion plant. When the natural frequency of the propeller shaft is close to the excitation frequency of the engine, it will cause resonanceof the drive shaft gao, 2016, thus. What i did this morning was mark the old position, tapos baklas propeller shaft, then i mounted it 180 degrees the other way.
Diagnose by evaluating the ujoint with the propeller shaft removed. A simple, practical and sufficiently accurate method for finding the natural frequencies of a propeller shaft assembly is described. The results of the analysis are evaluated on basis of the specifications of lloyds register of shipping. Excellent vibration isolation, fail safe design, can hold 30 20,000 pounds per mount. Propeller induced structural vibration through the thrust. Vibration analysis of propeller shaft with crack request pdf. More about propeller shaft the propeller shaft is used as a driving shaft to joint the output shaft of the gear box with the differential unit in the rear axle. The report presents a torsional vibration analysis of a ships propeller shaft system driven by an electric motor. Since the driveshaft turns three or more times faster than a vehicles wheels, typical driveshaft vibration is always faster at higher frequency than wheel. Propeller shaft function, types, components and requirement. Torsional vibration involves the whole shaft system of the propulsion plant, embracing engine crankshaft, intermediate shafts and propeller shaft, as well as engine running gear, flywheel, propeller and where appropriate reduction gearing, flexible couplings, clutches and pto drives. Joint angle the propeller shaft joint has some angle due to the structure of a vehicle, so when a propeller shaft rotates, a vibrating force is generated.
One of the most common cause of driveline vibration are worn ujoints or slip splines, outofbalance components, yokes out of phase or misaligned angles, approaching critical speed range, and yoke ears that are not concentric with the. You know you never hit bottom, but suddenly hatch hinges clatter while underway, and a tingle starts in your feet and travels all the way through your spine. On singleengine vessels, the propeller shaft generally emerges from the hull through the keel. I noticed a significant reduction in my 80kph vibration problem. The drives shaft must also operate through constantly changing the angles between the transmission, the differential and the axels. Ask captain chris how to determine what is causing a vibration on your boat. Vibration in a driveshaft can be caused by many conditions. Computer techniques for use in ship hull vibration. The drive shaft also called propeller shaft or prop shaft is a component of the drive train in a vehicle, with the purpose of delivering torque from the transmission to the differential, which then transmits this torque to the wheels in. Further, a comparison has been made with similar results using a diesel direct propulsion system. Concentrating at the blade passing frequency, we were able to obtain the propeller dynamic. In case of two or multi stage propeller shaft length of the rear propeller shaft change in length. Drive shaft vibrations solved stepbystep tacoma world. Whiling speeds of the shaft are determined at various conditions as well as the effect of the shaft torsional stiffness and shaft diameter are presented and discussed.
Analyzing vibration in automotive drive shaft and its reduction. Propeller cavitation causes vibration, noise and serious damage to your propeller. Propellerinduced hull vibration analytical methods. Hello everyone, id like to set a mechanical simulation of a rotating 540rpm propeller shaft of a ship.
There are several ways of predicting forces and induced pressure field from propellers. Figure 4 turbine engine and propeller shaft modeling example 35. Learn how to track down inboard engine vibrations so they dont rattle your soul. Shaft and bearing vibration monitoring is specified in the iso7919 and iso10816 norms respectively and is applicable to any rotating machines such as hydro turbines, gas turbines, steam turbines, pumps, fans, cooling fan towers. Pdf coupled vibration characteristics of a submarine. Pdf propeller induced structural vibration through the thrust bearing. Does the vibration increase or decrease at certain speeds. The propeller shaft can be mounted onto the diff in two ways. Studies of ship bending vibration 7 showed that the dynamic characteristics of the propellershaft system strongly influenced the response of the ship to propeller excitation. At about 1960, procedures were being developed for predicting, by calculation from wake data and the geometry of propellers and hull, the propeller generated excitation at. In traditional engine installations, the engine must be very precisely aligned to the propeller shaft. Design and analysis of drive shaft for heavy duty truck. The abs guidance notes on ship vibration have been developed.
1167 1244 6 475 704 180 1261 89 208 834 26 1312 1251 954 1057 929 1407 1384 1442 456 1180 840 622 1292 665 771 1399 1542 114 846 709 1059 740 468 265 912 714 839 238 360 1228 1186