structural & thermal analysis of aluminum & carbon piston

International Journal of Recent Innovation and Trends in Mechanical Engineering, Vol. (1), issue (1),

2019.

36

STRUCTURAL & THERMAL ANALYSIS OF ALUMINUM &

CARBON PISTON

Hitesh Kumar

Email: [email protected]

Professor, Deptt.of Mechanical Engg.

Technocrats Institutes of Technology, Bhopal, INDIA.

ABSTRACT: Now a day with increase in the levels of technology, the efforts required to produce any kind of work has been

constantly decreasing. The efforts which are required to achieve desired output can be decreased effectively and

economically by the implementation of improved designs. Piston which is one of the most vital component of an

engine and is in contact with the working substance, it requires to be designed in such a way that maximum amount

of energy released by the working substance is translated into useful work and also work in harmony with remaining

components of an engine, so that the losses induced in the process are minimized and efficiency is improved. In this

thesis work we will be discussing about the carbon pistons for use in IC engines. Carbon being a non-metallic

substance has advantages over its metallic counterparts. In this research work we will discuss about the idea behind

the use of carbon pistons and will also put lights on various properties and benefits of carbon pistons.

KEYWORDS: Finite Element Analysis, Simulation, IC Engine

1) INTRODUCTION

Piston is that part of IC engine which reciprocates within the cylinder. The basic function of piston is

to gather the impulse generated inside the cylinder due to expansion of gases and to transmit it to the

crankshaft via piston rod/connecting rod.. It is made gas-tight with the use of piston rings. Piston also

absorbs side thrust resulting due to the obliquity of conrod. Another important function of piston is to

remove a large amount of heat energy produced in a working cycle.

2) LITERATURE REVIEW

1) In the research paper presented by G Gopal et.al.[1] titled “Analysis of Piston, Connecting rod

and primarily emphasized on the study of piston,conrod and crankshaft assembly. The motive of

this research paper was to select the most appropriate material based on stress and thermal

analysis. Enhanced stresses and lower displacement when Al 2618 Piston, Titanium Conrod and

High alloy steel Crankshaft are used. Heat Transfer Rate is more when Al 6061Piston &Conrod

and EN508 Crankshaft are used. Stress values are lower in case of Set 2 of materials i.e. Al 2168

Piston, Titanium Conrod and High Alloy Steel Crankshft.

2) Another research work presented by MuhammetCerit et.al [4] titled, “Temperature and Thermal

Stress analysis of a ceramic coated aluminium alloy piston used in a diesel engine” focused on to

analyze thermal stress distribution and temperature distribution in a zirconia coated aluminium

piston. Magnesia stabilized zirconia (MgZrO3) is used as a Thermal Barrier Coating which is

sprayed on the piston crowm to enhance the engine performance..ANSYS is used as a FEA tool

to analyse temperature and thermal stresses induced in the piston.Max. Temperature on the piston

head centre increased by 32.7%, 55.8%, 72.5%, 84.8% for coating thickness of 0.4mm, 0.8mm,

1.2mm, 1.6m respectively.


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3) In this study by WilfriedWunderlich et.al [3] titled, “Thermal Cyclic Fatigue Analysis of

ThreeAluminium Piston Alloys” the main objective was to analyze three Al-Si alloys namely

SC100, ACA8, A4032 and compare them with aluminium A2618-T6 to predict their thermal

fatigue behavior. Metals are extruded in the form of bars with a length of 1m and starin meter

6M52 was fixed with each specimen and the results were recorded on NEC personal computer.

Aluminium alloy A2618 performed better with higher yield stress and better elongation to failure

as compared to other alloys.

3) METHODOLOGY

1) Specifications of Engine:

Table 1 Engine Specifications

S.No. Parameter Value

1. Displacement 99.7CC

2. Max. Power 5.516Kw

3. Bore 51mm

4. Stroke 48.8mm

5. Compression Ratio 9.15:1

2) Specifications of Piston:

Table 2 Piston Specifications

S.No. Parameter Value

1. Thickness Of Piston Head(tH) 5.268mm

2. Radial Width(t1) 1.81mm

3. Axial Thickness(t2) 1.267mm

4. Width Of Top Land(b1) 5.268mm

5. Width Of Ring Land(b2) 0.95mm

6. Thickness Of Piston Barrel At Top

End(t3)

8.24mm

7. Thickness Of Piston Barrel At Open

End(t4)

2.06mm

8. Length Of Skirt(Ls) 30.6mm

9. Length Of Piston Pin(l1) 22.95mm

10. Piston Pin Diameter(dp) 14.28mm


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3) Material Selection:

Indian Standards & Norms has specified grades of aluminum which are recommended formanufacturing

of piston to accomplish this work Aluminum Alloy 4658 as per IS7793-1975 [5] and Carbon FU4270 is

used.

Table 4 FU4270 Properties

S.No. Alloy Physical Properties

Casting Hardness(HB) Tensile

Strength(N/mm2)

Co-eff. Of Thermal

Exp.

1. 2285 90-130 225-275 23-24

2. 4658 90-140 195-245 20.5-21.5

3. 4928-A 90-125 175-215 18.5-19.5

4. 4928-B 90-125 165-205 17-18

4) MODELING:

Modeling generally refers to a process in design which employs mathematical representation of

model for 3D Surface of a model.CATIA V5 R20 [6] is used for modeling in this research work. After

studying the literature review it can be concluded that a comparative study can be done on piston using

different materials and analyze the effects on pistons due to change in material. After modeling of piston

is completed in CATIA V5 , the model is imported in ANSYS for further analysis. The following steps

are taken thereafter;

a) Generation of computer model.

b) Assigning material properties to model.

c) Applying boundary conditions.

S.No. Properties Fu4270

1. Bulk Density g/cm3

1.8

2. Young’s Modulus Gpa 13

3. Bending Strength Mpa 80-100

4. Compressive Strength Mpa 150

5. Coeff. Of Thermal Exp. 10-6

K-1

5

6. Thermal Conductivity W/mK 40


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d) Applying Load.

e) Generation of mesh.

f) Introducing Equivalent Stress and Total Deformation.

g) Solving the inputs for results.

Fig. 2 Piston Modeling

Fig. 3 Piston 3D Model

5. FINITE ELEMENT ANALYSIS:

The finite element analysis is anumerical method for solving problems of engineering. It is traditionally a

branchof Solid Mechanics. Most common areas of interest are Heat Transfer, Structural Analysis, and

Mass Transport. For the designed Pistons it is a must to compare the performance of both pistons and for


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this purpose ANSYS 14.5 [7] is used as FEA tool. ANSYS 14.5 is software used for solving a number of

mathematical problems. The Process of Analysis is divided in following steps;

a) Pre-Processing

b) Solver

c) Post-Processing

5.1 APPLYING BOUNDARY CONDITIONS:

Fig. 4 Boundary Conditions (Support)

Fig. 5 Boundary Conditions (Displacement)


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Frictionless support is provided on both sides of piston pin for Boundary Conditions.Boundary

Conditions for providing displacement, yellow part of the piston is selected and it inconstantly zero in X

& Y axes. The piston is allowed to move freely along Z axis.

5.2 APPLYING LOAD:

Fig. 6 Load Application

A load of 1.16Mpa is applied on piston head in downward direction.

5.3 MESHING:

5.4

Fig. 7 Meshing


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For meshing of piston mesh module in ANSYS 14.5 was used. The meshing element which is used here

is a Triangular Element.

Meshing Element - Triangular Element

Element Size - 1mm

Total Nodes - 127012 Nodes

Total Element - 72404

6 RESULTS

6.1 STATIC ANALYSIS FOR EQUIVALENT STRESS:

On applying boundary conditions and solving equivalent stress (for maximum values) for aluminum alloy

piston is 80.643 Mpa and Minimum value is 0.0219 Mpa.

Fig. 8 Equivalent Sresses (Al Alloy)

On applying boundary conditions and solving for equivalent stress (for maximum values) for FU4270

piston is 82.325 Mpa and Minimum value is 0.0158 Mpa.


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Fig. 9 Equivalent Sresses (FU4270)

6.2 TOTAL DEFORMATION:

On applying boundary conditions and solving totaldeformation (for maximum values) for aluminum alloy

piston is 0.00906 mm and Minimum value is 0.0 mm.

Fig. 10 Total Deformation (Al Alloy)

On applying boundary conditions and solving total deformation ( for maximum values) for FU4270

piston is 0.0501 mm and Minimum value is 0.0 mm.


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Fig. 11 Total Deformation (FU4270)

6.3 THERMAL ANALYSIS FOR MAX. & MI. TEMPERATURE:

On applying boundary conditions and solving for Max. & Min. Temperature for Aluminum piston is

280ºC and 129.71ºC.

Fig. 12 Max & Min. Temp (Al Alloy)On applying boundary conditions and solving for Max. & Min.

Temperature for Aluminum piston is 280ºC and 127.81ºC.


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Fig. 13 Max. & Min. Temp. (FU4270)

6.4 THERMAL ANALYSIS FOR TOTAL HEAT FLUX:

On applying boundary conditions and solving Total Heat Flux for Aluminum piston is 72.729W/ mm2 and

4.3996W/ mm2.

Fig. 14 Total Heat Flux (Al alloy)


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On applying boundary conditions and solving Total Heat Flux for Fu-4270 piston is 17.072W/ mm2 and

1.9203W/ mm2.

Fig. 15 Total Heat Flux (FU4270)

6.5 COMPARISON OF ALUMINUM & CARBON PISTON:

a).Equivalent Stresses:

The figure is a graphical representation of Von-Mises Stress for both the piston materials i.e. Aluminium

(Gr-4658) and Carbon (Fu-4270).

Fig 16. Total Deformation:

80.642 82.325

0

10

20

30

40

50

60

70

80

90

100

ALUMINIUM CARBON

Equivalent Stress (in Mpa)


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Fig 17. Total Deformation

The above figure is a graphical representation of Total Deformation for both the piston materials i.e.

Aluminum (Gr-4658) and Carbon (Fu-4270).

b) Piston weight:

Fig 18. Piston Weight

The above figure is a graphical representation of Piston Weight for both the piston materials i.e.

Aluminium (Gr-4658) and Carbon (Fu-4270).

0.00906

0.0501

0

0.1

0.2

0.3

0.4

0.5

ALUMINIUM CARBON

TOTAL DEFORMATION(in mm)

93.77

60.93

0

10

20

30

40

50

60

70

80

90

100

ALUMINIUM CARBON

Piston Weight (in gms)


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c) Max. & Min. Temperatures:

Fig 19. Max. & Min. Temp.

The figure is a graphical representation of Max. & Min. Temperature for both the piston materials i.e.

Aluminium (Gr-4658) and Carbon (Fu-4270).

d) Total Heat Flux:

Fig 5 .Total Heat Flux

129.71 127.81

280 280

0

50

100

150

200

250

300

350

400

450

Aluminium Carbon

Max. Temperature

Min. Temperature

72.729

17.072 0

10

20

30

40

50

60

70

80

Aluminium Carbon

Total Heat Flux


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The above figure is a graphical representation of Total Heat Flux for both the piston materials i.e.

Aluminum (Gr-4658) and Carbon (Fu-4270). Above graphs provides the outcome for Von-Mises

(Equivalent Stresses), Total deformation and Total Weight for both aluminum & carbon piston in which

these properties were considered as key element in the performance of an IC Engine. After

comprehensive analysis of piston design, Equivalent stresses, Total Deformation, and Total Weight for

Aluminum (Gr4658) Piston are, 80.643Mpa, 0.00906mm and 93.77gms respectively and for Carbon

(FU4270) Piston it is 82.325Mpa, 0.0501 and 60.96gms respectively, which indicates that carbon piston

has significantly lower weight than aluminum piston which will result in better performance of an IC

Engine.

7. CONCLUSION

As seen in the results, under identical loading conditions stresses and deformation in both aluminium&

carbon pistons are found with minor differences in both factors, but a substantial difference is found in the

weight of piston. Total weight of the carbon(FU4270) piston is approximately 35.02% lower as compared

to the aluminium(Gr4658) piston. This significant weight reduction will result in reduced inertial forces

thus allowing the use of lighter components. Also this reduction in weight will result in reduced

vibrations in an IC Engine. At maximum load, total deformation of carbon (FU4270) piston is marginally

higher as compared to aluminium piston. After analyzing the results it can be concluded that Carbon can

be used as a material for piston manufacturing due to its weight reduction and inherent properties over the

conventional materials. In other word we can say that on introducing the new suitable materials for

manufacturing pistons, it can give better results and performances with maintained cost and therefore

improvement in reliability, efficiency of engine and performance after changing the material of piston

will be the expected outcome of this research work.

REFERENCES

[1] G Gopala , Dr L Suresh Kumarb , K VijayaBahskar Reddy , M Uma MaheshwaraRaod, G Srinivasulu “Analysis of Piston,

Connecting rod and Crank shaft assembly”, ScienceDirect Materials Today: Proceedings 4 (2017) 7810–7819.

[2] EkremBuyukkaya, “Thermal analysis of functionally graded coating AlSi alloy and steel pistons”, ScienceDirect Surface &

Coatings Technology 202 (2008) 3856–3865 11 February 2008.

[3] WilfriedWunderlich, Morihito Hayashi, “Thermal Cyclic Fatigue Analysis of Three Aluminum Piston Alloys”, International

Journal of Material and Mechanical Engineering, 2012, 1: 57-60.

[4]MuhammetCerit, Mehmet Coban, “Temperature and thermal stress analyses of a ceramic-coated aluminum alloy piston used

in a diesel engine”,International Journal of Thermal Sciences Volume 77, March 2014, Pages 11-18.

[5] IS 7793: 1975 ALUMINIUM ALLOYS FOR IC ENGINE PISTONS

[6] Tickoo, S., 2010. CATIA V5R20 for Designers.CADCIM technologies.

[7] Moaveni, S., 2011. Finite element analysis theory and application with ANSYS, 3/e. Pearson Education India.

structural & thermal analysis of aluminum & carbon piston

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