Conrod Ppt Nf 2

7/28/2019 Conrod Ppt Nf 2

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Selection Of Material

for

CONNECTING ROD


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The connecting rod does this important taskof converting reciprocating motion of thepiston into rotary motion of the crankshaft. It

consists of an upper section which is joinedto the piston with the help of a gudgeon pinand a lower section which gets attached tothe crank shaft with bolts.


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An Example of a Connecting Rod


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Stresses are induced in a connecting roddue to the axial forces action on it. Theseforces arise from gas pressure and inertiaof piston.

The maximum axial load is compressive (at TDC).

Bending stresses also occur after firing due to acertain angle of inclination of the rod.

Stresses


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After understanding the stresses developed in a

connecting rod, we can enlist the following

material requirements:-

1. High strength in both tension and

compression.


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compression.

2. High fatigue strength.


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compression.

2. High fatigue strength.3. It must retain its its properties at higher

temperatures which can be developed during

engine operation.


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compression.

2. High fatigue strength.3. It must retain its its properties at higher

temperatures which can be developed during

engine operation.

4. High impact strength.


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Based on these requirements, the

following materials can be selected:-

Cast Iron

Medium Carbon Steel ( 45 S 6 )

Aluminum

Titanium


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The following influencing factors have to

be considered:-

1.Cost


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be considered:-

1.Cost

2.Durability


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be considered:-

1.Cost

2.Durability

3.Weight


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be considered:-

1.Cost

2.Durability

3.Weight

4.Ease of Manufacture / Machinability


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be considered:-

1.Cost

2.Durability

3.Weight

4.Ease of Manufacture / Machinability

5.Availability


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0102030405060708090

CastIron Al. M.C.S Ti

Cost


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0102030405060708090

CastIron

Al. M.C.S Ti.

Durability


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0102030405060708090

CastIron

Al. M.C.S Ti.

Weight


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01020304050607080

CastIron Al. M.C.S Ti.

Availability


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01020304050607080

Castiron Al. M.C.S Ti.

E.O.M


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0102030405060708090

C.I Al. M.C.S Ti.

CostDbt.WeightAvail.Mach.


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Result:-

In accordance with these design steps,

Medium Carbon Steel is preferred as a

material for connecting rod. A commonly

used form of MCS is 45 S 6.

Aluminum and titanium can be used for high

performance engines like F1 cars where strength andlight-weight dominate over the cost factor.

Conrod Ppt Nf 2

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