Design and Analysis of I.C. Engine Piston and Piston-Ring on Composite Material using Creo and Ansys Software PDF

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Journal of Engineering and Science Vol. 01, Special Issue 01, July 2016 DESIGN AND ANALYSIS OF I.C. ENGINE PISTON AND PISTON-RING ON COMPOSITE MATERIAL USING CREO AND ANSYS SOFTWARE K. Sathish Kumar UG Student, Department of Mechanical Engineering, United Institute of Technology, Coimbatore 641020. ...

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Design and Analysis of I.C. Engine Piston and Piston-Ring on Composite Material using Creo and Ansys So ware Sathish Kumar Journal of Engineering and Science

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Journal of Engineering and Science

Vol. 01, Special Issue 01, July 2016

DESIGN AND ANALYSIS OF I.C. ENGINE PISTON AND PISTON-RING ON COMPOSITE MATERIAL USING CREO AND ANSYS SOFTWARE K. Sathish Kumar

UG Student, Department of Mechanical Engineering, United Institute of Technology, Coimbatore 641020. Email: [email protected] Abstract - In this Paper the stress distribution is evaluated on the four stroke engine piston by using FEA. The finite element analysis is performed by using FEA software. The couple field analysis is carried out to calculate stresses and deflection due to thermal loads and gas pressure. These stresses will be calculated for two different materials. The results are compared for all the two materials and the best one is proposed. The materials used in this project are aluminium alloy, and SiC reinforced ZrB2 composite material. In this project the natural frequency and Vibration mode of the piston and rings were also obtained and its vibration characteristics are analyzed. With using computer aided design (CAD), CREO software the structural model of a piston will be developed. Furthermore, the finite element analysis performed with using software ANSYS. SiC reinforced ZrB2 : Silicon carbide reinforced Zirconium diboride is a ceramic matrix composite (CMC) material is also used. Keywords - Stress distribution, Four stroke engine piston, Finite element analysis, Aluminium alloy and SiC, Natural frequency, Vibration mode, Computer aided design (CAD), Ceramic matrix composite (CMC) material, Ansys.

I.

INTRODUCTION

Automobile components are in great demand these days because of increased use of automobiles. The increased demand is due to improved performance and reduced cost of these components. R&D and testing engineers should develop critical components in shortest possible time to minimize launch time for new products. This necessitates understanding of new technologies and quick absorption in the development of new products. A piston is a component of reciprocating IC-engines. It is the moving component that is contained by a cylinder and is made gastight by piston rings. In an engine, its purpose is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and/or connecting rod. As an important part in an engine, piston endures the cyclic gas pressure and the inertial forces at work, and this working condition may cause the fatigue damage of piston, such as piston side wear, piston head/crown cracks and so on. The investigations indicate that the greatest stress appears on the upper end of the piston and stress concentration is one of the mainly reason for fatigue failure. This paper describes the stress distribution on piston of internal combustion engine by using FEA. The FEA is performed by CAD and CAE software. The main objectives are to investigate and analyze the thermal stress and mechanical stress distribution of piston at the real engine condition during combustion process. The paper describes the FEA technique to predict the higher stress and critical region on the component. With using CREO 2.0 software the structural model of a piston will be developed. Using ANSYS V14.5 software, simulation and stress analysis is performed. II.

LITERATURE REVIEW

An optimized piston which is lighter and stronger is coated with zirconium for bio-fuel. In this paper[1], the coated piston undergone a Von misses test by using ANSYS for load applied on the top. Analysis of the stress distribution was done on various parts of the coated piston for finding the stresses due to the gas pressure and

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thermal variations. Vonmisses stress is increased by 16% and deflection is increased after optimization. But all the parameters are well with in design consideration. Design, Analysis and optimization of piston [2] which is stronger, lighter with minimum cost and with less time. Since the design and weight of the piston influence the engine performance. Analysis of the stress distribution in the various parts of the piston to know the stresses due to the gas pressure and thermal variations using with Ansys. With the definite-element analysis software, a three-dimensional definite-element analysis [3] has been carried out to the gasoline engine piston. Considering the thermal boundary condition, the stress and the deformation distribution conditions of the piston under the coupling effect of the thermal load and explosion pressure have been calculated, thus providing reference for design improvement. Results show that, the main cause of the piston safety, the piston deformation and the great stress is the temperature, so itis feasible to further decrease the piston temperature with structure optimization. This paper [4] involves simulation of a 2-stroke 6S35ME marine diesel engine piston to determine its temperature field, thermal, mechanical and coupled thermal-mechanical stress. The distribution and magnitudes of the afore-mentioned strength parameters are useful in design, failure analysis and optimization of the engine piston. The piston model was developed in solid-works and imported into ANSYS for preprocessing, loading and post processing. Material model chosen was 10-node tetrahedral thermal solid 87. The simulation parameters used in this paper were piston material, combustion pressure, inertial effects and temperature. This work [5] describes the stress distribution of the piston by using finite element method (FEM). FEM is performed by using computer aided engineering (CAE) software. The main objective of this project is to investigate and analyze the stress distribution of piston at the actual engine condition during combustion process.. The report describes the mesh optimization by using FEM technique to predict the higher stress and critical region on the component. The impact of crown thickness, thickness ofbarrel and piston top land height on stress distribution and total deformation is monitored during the study[6] of actual four stroke engine piston. The entire optimization is carried out based on statistical analysisFEA analysis is carried out using ANSYS for optimum geometry.This paper describes the stress distribution and thermal stresses of three different aluminum alloys piston by using finite element method (FEM). The parameters used for the simulation are operating gas pressure, temperature and material properties of piston. The specifications used for the study of these pistons belong to four stroke single cylinder engine of Bajaj Kawasaki motorcycle.

Fig. 1 : Labeled Image of a Piston

III.

PISTON MATERIALS AND MANUFACTURING PROCESS

Following materials are used for I.C. Engines pistons: Cast iron, Cast Aluminium, cast steel and forged aluminium. The material used for piston is mainly aluminium alloy. Aluminium pistons can be either cast of forged. In early years cast iron was almost universal material for pistons because it posses excellent wearing qualities, coefficient of expansion and genera suitability in manufacture. But due to reduction of weight in reciprocating parts, the use of aluminium for piston was essential. To obtain equal strength a greater thickness of metal is necessary. But

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some of the advantages of the light metal is lost. Aluminium is inferior to cast iron in strength and wearing qualities, and its greater coefficient of expansion necessities greater clearance in the cylinder to avoid the risk of seizure. The heat conductivity of aluminium is about thrice that of cast iron this combined with the greater thickness necessary for strength, enables and aluminium alloy piston to run at much lower temperature than a cast iron as a result carbonized oil doesn t form on the underside of the piston, and the crank case therefore keeps cleaner. This cool running property of aluminium is now recognized as being quite as valuable as its lightness. Indeed; piston are sometimes made thicker than necessary for strength in order to give improved cooling. IV. PROBLEM DEFINITION AND METHODOLOGY In this paper the stress distribution is evaluated on the four stroke engine piston by using FEA. The finite element analysis is performed by using FEA software. The couple field analysis is carried out to calculate stresses and deflection due to thermal loads and gas pressure. The materials used in this project are aluminium alloy and SiC reinforced ZrB2 composite material. In this project the natural frequency and Vibration mode of the piston were also obtained and its vibration characteristics are analyzed. With using computer aided design (CAD), UNI-GRAPHICS software the structural model of a piston will be developed. Furthermore, the finite element analysis performed with using software ANSYS. The methodology used for doing the analysis is as follows:  Develop a 3D model from the available 2D drawings of the Piston.   

     

The 3D model is created using CREO 2.0 software The 3D model is converted into parasolid and imported into ANSYS to do couple field analysis. The thermal analysis is performed on the piston model with the heat of (160°C-200°C) for Aluminum alloy material. Temperature distribution is plotted from the thermal analysis for Aluminum alloy material. Structural analysis is performed by applying temperature distribution from the thermal analysis as body loads and working pressure of 3.3Mpa to find the stress distribution due to thermal and structural loads for Aluminum alloy material. Plot deflections and stresses for the piston from the above analysis. The above analysis is repeated for SiC reinforced ZrB2 composite material. Perform modal analysis for all the 2 materials. Compare the results for all the 2 materials.

V. MODELING AND ANALYSIS PISTON DESIGN The piston is designed according to the procedure and specification which are given in machine design and data hand books. The dimensions are calculated in terms of SI Units. The pressure applied on piston head, temperatures of various areas of the piston, heat flow, stresses, strains, length, diameter of piston and hole, thicknesses, etc., parameters are taken into consideration . A.

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

DESIGN CONSIDERATIONS FOR A PISTON

In designing a piston for an engine, the following points should be taken into consideration: It should have enormous strength to withstand the high pressure. It should have minimum weight to withstand the inertia forces. It should form effective oil sealing in the cylinder.

It should provide sufficient bearing area to prevent undue wear. It should have high speed reciprocation without noise.

It should be of sufficient rigid construction to withstand thermal and mechanical distortions. It should have sufficient support for the piston pin.

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ASSUMPTIONS MADE It is very difficult to exactly model the piston, in which there are still researches are going on to find out transient thermo elastic behavior of piston during combustion process. There is always a need of some assumptions to model any complex geometry. These assumptions are made, keeping in mind the difficulties involved in the theoretical calculation and the importance of the parameters that are taken and those which are ignored. In modeling we always ignore the things that are of less importance and have little impact on the analysis. The assumptions are always made depending upon the details and accuracy required in modeling. 1. The assumptions which are made while modeling the process are given below:B.

2. The piston material is considered as homogeneous and isotropic. 3. Inertia and body force effects are negligible during the analysis. 4. The piston is stress free before the application of analysis.

5. The analysis is based on pure thermal loading and thus only stress level due to the above said is done the analysis does not determine the life of the piston. 6. Only ambient air-cooling is taken into account and no forced Convection is taken.

7. The thermal conductivity of the material used for the analysis is uniform throughout.

8. The specific heat of the material used is constant throughout and does not change with temperature. C. THE PISTON MODEL The following are the sequence of steps in which the piston is modeled.  Drawing a half portion of piston. 

Exiting the sketcher .



Creating a hole .



Developing the model .

VI. PROPERTIES OF MATERIALS The materials chosen for this work are Aluminum alloy and Silicon carbide reinforced Zirconium diboride for an internal combustion engine piston. The mechanical properties of alloy and Silicon carbide reinforced Zirconium diboride are listed in the following table 1 S.No 1 2 3 4 5 6 7 8

Name of the property

Density Coefficient of Thermal Expansion Youngs Modulus Poissons Ratio Ultimate Strength Specfic Heat Thermal Conductivity Yield Strength

Aluminium Alloy

2770 kg/m3 1 e -06 K-1 71e3 mpa 0.33 310 mpa 0.13 J/Kgk 174 W/mk 280 mpa

SiC reinforced ZrB2

2060 kg/m3 5.9 e-06 K-1 4.86e5 mpa 0.11 1070 mpa 500 J/kgk 93.7 W/mk 930 mpa

Table 1 Material Properties

a.

A. Applying Temperatures, Convections and Loads The piston is divided into the areas defined by a series of grooves for sealing rings. The boundary conditions for mechanical simulation were defined as the pressure acting on the entire piston head surface (maximum pressure in the engine cylinder). It is necessary to load certain data on material that refer to both its mechanical and thermal

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properties to do the coupled Thermo-mechanical calculations .The temperature load is applied on different areas and pressure applied on piston head. The regions like piston head and piston ring regions are applied with large amount of heat (160°C-200°C). The convection values on the piston wall ranges from 232W/mK to 1570W/mK. The working pressure is 3.3Mpa. VII. STRUCTURAL ANALYSIS STRUCTURAL BOUNDARY CONDITIONS Structural analysis is performed on the piston by applying temperature distribution from the thermal analysis as body loads using Ansys. Also a pressure of 3.3Mpa on the piston head. As we are coupling thermal analysis with structural analysis, this analysis is called couple field analysis.

A.

FOR PISTON

VIII.

RESULTS AND DISCUSSION

The results obtained from applying aluminium material for piston are,

Fig 2 : Boundary condition applied for piston

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Fig 3 : Total Deformation of aluminium piston

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Fig 4: Directional Deformation of aluminium piston

Fig 5 : Von

Misses strain of aluminium piston

The results obtained from applying Silicon carbide reinforced Zirconium diboride material for piston are,

Fig 6 : Total Deformation of SiC reinforced ZrB2 piston

Fig 8 : Von

Fig 7: Directional Deformation of SiC reinforced ZrB2 piston

Misses strain of SiC reinforced ZrB2 piston

Fig 9 : Thermal Boundary condition applied for piston

The Thermal results obtained from applying aluminium material for piston are,

Fig 10 : Total Heat flex of aluminium piston

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Fig 11 : Directional Heat flex of aluminium piston

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Fig 12 : Total Heat flex of SiC reinforced ZrB2 piston

Fig 13 : Directional Heat flex of SiC reinforced ZrB2 piston

COMPARISON OF RESULT ON STATIC ANALYSIS IN PISTON Static Analysis

Thermal Analysis

piston

Total Deformation

Directional deformation ( Y axis )

Von Misses strain

Aluminium

0.079441 mm

0.0017008 mm

0.00083123

SiC reinforced ZrB2

0.057721 mm

0.0012238 mm

0.000062824

Total Heat Flex

Directional Heat Flex ( Y Axis )

Aluminium

3.6615e-12 W/mm2

3.6163e-12 W/mm2

1.3177e-12 W/mm2

1.2956e-12 W/mm2

SiC reinforced ZrB2

Table 2 : Static analysis of piston

B.

piston

Table 3 : Thermal analysis of piston

FOR PISTON RING

The results obtained from applying aluminium & SiC reinforced ZrB2 material for piston ring are,

Fig 14 : Total Deformation of aluminium piston Ring

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Fig 15 : Total Deformation of SiC reinforced ZrB2 piston Ring

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Fig 16: Directional Deformation of aluminium piston Ring

Fig 18 : Von Misses strain of aluminium piston Ring

Fig 20 : Boundary condition applied for piston Ring

Fig 17: Directional Deformation of SiC reinforced ZrB2 piston Ring

Fig 19 : Von

Misses strain of SiC reinforced ZrB2 piston Ring

Fig 21 : Thermal Boundary condition applied for piston Ring

The Thermal results obtained from applying aluminium & SiC reinforced ZrB2 material for piston Ring are,

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Journal of Engineering and Science

Vol. 01, Special Issue 01, July 2016

Fig 22 : Total Heat flex of aluminium piston Ring

Fig 23 : Total Heat flex of SiC reinforced ZrB2 piston Ring

COMPARISON OF RESULT ON STATIC ANALYSIS IN PISTON RING Static Analysis

Thermal Analysis

Piston Rings

Total Deformation

Directional deformation ( Y axis )

Aluminium

7581.4 mm

258.91 mm

0.0341

SiC reinforced ZrB2

5610.2 mm

195.26 mm

0.025228

Von Misses strain

Total Heat Flex

Directional Heat Flex ( Y Axis )

Aluminium

0.43793 W/mm2

0.43793 W/mm2

0.39757 W/mm2

0.39757 W/mm2

SiC reinforced ZrB2

Table 4 : Static analysis of piston Ring

C.