Dynamic Analysis of Composite Propeller of Ship using FEA P. NARASAIAH 1, PROF. S.S. BASARKOD 2

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ISSN 2319-8885 Vol.03,Issue.27 September-2014, Pages:5467-5472 www.ijsetr.com Dynamic Analysis of Composite Propeller of Ship using FEA P. NARASAIAH 1, PROF. S.S. BASARKOD 2 Abstract: Ships and under water vehicles like submarines, torpedoes and submersibles etc, uses propeller as propulsion.

In such cases numerical analysis (Finite Element Analysis) gives comparable results with experimental values.

1 ISSN Vol.03,Issue.27 September-2014, Pages: Dynamic Analysis of Composite Propeller of Ship using FEA P. NARASAIAH 1, PROF. S.S. BASARKOD 2 Abstract: Ships and under water vehicles like submarines, torpedoes and submersibles etc, uses propeller as propulsion. The blade geometry ant its design is more complex involving many controlling parameters. The strength analysis of such complex 3D blades with conventional formulas will give less accurate values. In such cases numerical analysis (Finite Element Analysis) gives comparable results with experimental values. In the present project the propeller blade material is converted from aluminum metal to fiber reinforced composite material for underwater vehicle propeller. Such complex analysis can be easily solved by finite element method techniques. Keywords: Finite Element Analysis. I. INTRODUCTION The force needed to propel a ship is obtained from the reaction against the water, causing a stream of water to move in the opposite direction. The devices like oars, paddle wheel, jets etc are used to propel ship. From this basic knowledge propellers came into existence. Recording history indicates that the idea of a propeller was first suggested by Leonardo davinci in the 15 th century. During the years that followed, a number of people experimented unsuccessfully with screw propulsion. Then in 1802, an American lawyer- turned - inventor, colonel john Stevens, constructed the first vessel to be powered by steam and a screw propeller. The study of propeller action and design is complex especially the manufacturing of marine propellers is a highly specialized procedure. On the experimental side, Froude developed a method for studying the action of a propeller behind a ship. It is not practicable to fulfill all these conditions exactly, and therefore some empirical corrections are necessary in determining ship performance and model propellers from experiments. A. Advantages and Disadvantages of Propeller Propellers will be used as a propulsors where the speed is slow and the propeller has to be immersed completely in the water into a depth of minimum 2D (fig 3). The efficiency of the propeller will be reduced and noise will increase and start cavitation as the speed increases. At high speeds the pump jet and water jet propellers will be used. Propeller: The propeller is that component of the ship which converts the engine power into the driving force of the ship. Propeller Blades: Propeller blades are the projections radiating outwards from the center of the propeller. B. Modeling of propeller Modeling of the propeller is done using CATIA V5 R 19. In order to model the blade, it is necessary to have sections of the propeller at various radii. These sections are drawn and rotated through their respective pitch angles. Then all rotated sections are projected onto right circular cylinders of respective radii as shown in figure 1. A Construction of hydrofoils on surface of the blade is shown in fig 2. Fig 1: Modeling of propeller. Fig 2: Construction of hydrofoils by joining of points on surface of the blade IJSETR. All rights reserved.

Mesh generation programs called Preprocessors can be used for this purpose. Step 2: Formulate the properties of each element.

2 Now by using multi section surface option, the blade is modeled. From fig 1, 1)Trailing edge 2) Face 3)Fillet area 4) Hub or Boss 5) Hub or Boss Cap 6) Leading edge 7)Back 8) Propeller shaft 9) Stern tube bearing and 10) Stern tube. P. NARASAIAH, PROF. S.S. BASARKOD elements are to be decided. Mesh generation programs called Preprocessors can be used for this purpose. Step 2: Formulate the properties of each element. This means determining nodal loads associated with all element deformation are allowed. Step 3: Selection of proper interpolation or displacement model. The displacement solution of a complex structure under any specified load condition cannot be predicted exactly. We assume suitable solution with an element to approximate the unknown solution. The assumed solution must be simple from computational point of view, but it should satisfy certain convergence and compatibility requirements. Generally the solution or interpolation model is in the form of a polynomial. Step 4: Derivation of element stiffness matrix and load vector. Fig 3: Final solid model of propeller. II. MESH GENARATION USING HYPERMESH The solid model is imported to HYPERMESH 10.0 and tetrahedron mesh is generated for the same. Boundary conditions are applied to meshed model. The contact surface between hub and shaft is fixed in all degrees of freedom. Thrust of 4000 N is uniformly distributed in the region between the sections at 0.7R and 0.75R on face side of blade, since it is the maximum loading condition region on each blade. The loading condition is as shown in fig 4. Nummber of nodes created were and number of elements created are 1,65,238. Power=50 Kw velocity=12.5 m/s Thrust = power/velocity =50000/12.5 =4000 N From the assumed displacement model the stiffness matrix [ke] and load vector{f1} of an element e are to be derived by using either equilibrium conditions or a suitable variational principle. Step 5: Assemblage of element equations As a structure is composed of several finite elements. the individual element stiffness matrices and load vectors are to be assembled in a suitable manner and the overall equilibrium equations have to be formulated as KQ=F, Where, K is global or structural stiffness matrix, Q is vector of nodal displacements, F is vector of nodal forces for complete structure. Step 6: Solution for unknown nodal displacements The equilibrium equations have to be modified using the boundary conditions of the problem. After incorporating the boundary conditions the equilibrium equations are expressed as KQ=F. For linear problems the displacement vector Q can be solved very easily, but for non linear problems. the solution is obtained by solving a sequence of steps, each step involving the modification of stiffness matrix K or load vector F. Fig 4: loading on meshed model. The various steps in Finite Element Analysis are as described below: Step 1: Discretization of the structure Divide the structure or continuum or solution region into finite elements i.e. the structure is to modeled using finite elements. The number, type, size and affangement of the Step7: Computation of element stresses and strains From the known displacement Q the stresses and strains are computed using necessary of solid and structural mechanics. Step 8: Presentation of results Using output interpolation programs called Postprocessors the results can be framed and displayed in vector or raster forms as desired. III. RESULTS AND DISSCUSSIONS A. Linear Static Analysis Linear static analysis is concerned with the behavior of elastic continua under prescribed boundary conditions and statically applied loads. The applied load in this case is thrust acting on blades. Under water vehicle with contra rotating

3 (aft) propeller is chosen for FE analysis. The FE analysis is carried out using ANSYS. The deformations and stresses are calculated for aluminum (isotropic) and composite propeller (orthotropic material). In composite propeller 4 cases are considered, those are number of layers is varied as 4 and 8. For propeller blade analysis 3D solid element type 92 is considered for aluminum and solid 46 for composite propeller. B. Static analysis of aluminum propeller The thrust of 4000N is applied on face side of the blade in the region between 0.7R and 0.75R. The intersection of hub and shaft point s deformations in all directions are fixed. The thrust is produced because of the pressure difference between the face and back sides of propeller blades. This pressure Dynamic Analysis of Composite Propeller of Ship using FEA y-direction. Similar to the cantilever beam the deflection is maximum at free end. The maximum von mises stress induced for aluminum blade is N/mm 2 as shown in figure 6. The remaining figures 7 to 19 show the harmonic and composite analysis. Fig 7: Max normal stresses of aluminum propeller. Fig 5: The deformation pattern for aluminum propeller. Fig 8: Von-mises stress of aluminum propeller. Fig 6: Static deflection of aluminum propeller. difference also causes rolling movement of the underwater vehicle. This rolling movement is nullified by the forward propeller which rotates in other direction (reverse direction of aft propeller). The propeller blade is considered as cantilever beam i.e. fixed at one end and free at other end. The deformation pattern for aluminum propeller is shown in figure 5. The maximum deflection was found as mm in Fig 9: Static analysis of propeller.

4 P. NARASAIAH, PROF. S.S. BASARKOD The stresses are greatest near to the mid chord of the blade-hub intersection with smaller stress magnitude toward the tip and edges of the blade. Fig13: Amp-freq graph of aluminum propeller in Uz direction. Fig10: Static deflection of composite propeller with 4 layers. E. Harmonic Analysis of Composite Propeller D. Harmonic Analysis of Aluminum Propeller Fig 11: Amp-freq graph of aluminum propeller in Uy direction. Fig14: Amp-freq graph of 4 layer composite propeller in Ux direction Fig12: Amp-freq graph of aluminum propeller in Ux direction. Fig15: Amp-freq graph of 4 layer composite propeller in Uy direction.

5 Dynamic Analysis of Composite Propeller of Ship using FEA Fig16: Amp-freq graph of 4 layer composite propeller in Uz direction. Fig17: Amp-freq graph of 4 layer composite propeller nearer to away from hub in Ux direction. Fig19: Amp-freq graph of 4 layer composite propeller nearer to away from hub in Uz direction. IV. CONCLUSIONS The following conclusions are drawn from the present work: 1. The deflection for composite propeller blade was found to be around 0.5mm for all layers which is much less than that of aluminum propeller i.e mm, which shows composite materials is much stiffer than aluminum propeller.. 2. Inter laminar shear stresses were calculated for composite propeller by incorporating different number of layers viz. 4 and 8 was found that the percentage variation was about 3.147%,which shows that there is strong bonding between the layers and there s no peeloff. 3. Modal analysis results showed that the natural frequencies of composite propeller were 80.5% more than aluminum propeller, which indicates that the operation range of frequency is higher for composite propeller. V. FUTURE SCOPE OF WORK The present work only consists of static and Modal analysis, which can be extended for transient and spectrum analysis in case of both aluminum and composite materials. There is also a scope of future work to be carried out for different types of materials, which can be extended for CFD analysis. Fig18: Amp-freq graph of 4 layer composite propeller nearer to away from hub in Uy direction. VI. REFRENCES [1] Taylor, D.w, The Speed and Power and Ships, Washington, [2] J.E.Conolly, Strength Of Propellers, reads in London at a meeting of the royal intuition of naval architects on dec ,pp [3] Terje sonntvedt, Propeller Blade Stresses, Application of Finite Element Methods computers and structures, vol.4, pp [4] Chang-sup lee, yong-jik kim,gun-do kim and in-sik nho. Case Study On The Structural Failure Of Marine Propeller Blades.

6 P. NARASAIAH, PROF. S.S. BASARKOD [5] M.Jourdain, visitor and J.L.Armand. Strength Of Propeller Blades-A Numerical Approach, the society of naval architects and marine engineers, may 24-25,1978,pp [6] G.H.M.Beek, visitor, lips B.V.,Drunen. Hub-Blade Interaction In Propeller Strength, the society of naval architects and marine engineers, may 24-25,1978,pp [7] George W.Stickle and John L Crigler. Propeller analysis from experimental data report No.712, pp [8] P.Castellini, C.Santolini. Vibration Measurements On Blades Of A Naval Propeller Rotating In Water With Tracking Laser Vibromneter Dept. of mechanics, university of Ancona, pp [9] W.J.Colclough and J.G.Russel. The Development Of A Composite Propeller Blade With A CFRP Spar aeronautical journal, Jan 1972, pp [10] J.G.Russel use of reinforced plastics in a composite propeller blade plastics and polymers, Dec 1973 pp [11] Christoph Layens, Frank Kocian, Joachim hausmann. Materials And Design Concepts For High Performance Compressor Components. [12]Ching-Chieh Lin, Ya-jung Lee. Stacking Sequence Optimization of Laminated Composite Structures Using Genetic Algorithm With Local Improvement. Composite structures 63(2004), pp

Design and Dynamic Analysis on Composite Propeller of Ship Using FEA

Design and Dynamic Analysis on Composite Propeller of Ship Using FEA Ahmed Abdul Baseer Assistant Professor, Nizam Institute of Engineering and Technology. ABSTRACT: Ships and underwater vehicles like