Unformatted text preview: 35 = 21 mm Ans.
Let the piston pin be made of heat treated alloy steel for which the bending stress ( σ b )may be
taken as 140 MPa. Now let us check the induced bending stress in the pin.
We know that maximum bending moment at the centre of the pin, 39 275 × 100
= 491 × 10 3 N-mm
We also know that maximum bending moment (M),
M= (d0 )4 − (di )4 π (35)4 − (21) 4 σb = σb = 3664 σb
d0 3 / 3664 = 134 N/mm2 or MPa
σ b = 491 × 10
Since the induced bending stress in the pin is less than the permissible value of 140 MPa (i.e.
140 N/mm2), therefore, the dimensions for the pin as calculated above (i.e. d0 = 35 mm and di = 21 mm)
491 × 103 = π
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This note was uploaded on 09/30/2012 for the course MECHANICAL 403 taught by Professor A.thirumoorthy during the Spring '11 term at Anna University Chennai - Regional Office, Coimbatore.
- Spring '11