0
4.3kviews
Choose and write the correct option:

A mild steel bar is in three parts, each 200mm long as shown in fig. The diameters of the parts are indicated on the diagram. The bar is subjected to axial pull of (P) N. If E=2×105 MPa and the elongations in the three parts AB,BC, and CD are Δ1,Δ2,and Δ3 respectively, then the ratio of the greatest elongation to the least elongation will be :

i) 9

ii) 4

iii) 3

iv) 2

Composite Bar

1 Answer
1
404views

enter image description here

For equilibrium, along axial axis,

Fx=0

a) Portion AB

Elongation is given by,

Δ1=PlABAABEAB

Δ1=P200π42022105=3.183106P

b)Portion BC

Elongation is Δ2=PlBCABCEBC

Δ2=P200π41022105=1.273105P

c)Portion CD:

Elongation is Δ3=P200π43022105=1.414106P

The ratio of greatest elongation to the least elongation is Δ2Δ3

=1.273105P1.414106P

= 9

Please log in to add an answer.