THERMAL STRESS & STRAIN ENERGY

The length, Young’s modulus and coefficient of thermal expansion of bar P are twice that of bar Q. what will be the ration of stress developed in bar P to that in bar Q if the temperature of both bars is increased by the same amount?

• 2

• 8

• 16

• 4

What is the strain energy stored in a body due to gradually applied load?

• (σ^2/2E)V

• (σ/2E)V^2

• (σ^2/2E)V^2

A steel rod of length L and diameter D, fixed at both ends, is uniformly heated to a temperature rise of δT. The Youngs modulus is E and the coefficient of linear expansion is unity. The thermal stress in the rod is (a)  

Calculate the Strain energy stored in a body of stress 0.0366 N/mm^2. The cross sectional area is 60 m^2and length of body is 1 m. Take E = 2×105 N/mm^2.

• 0.2009 N.mm

• 0.0416 N.mm

• 0.0987 N.mm

• 0.1316 N.mm

The strain energy in a body due to suddenly applied load compared to when it is applied to gradually applied load

• same

• twice

• four times

• half

(a)   is the maximum stress induced in a bar 2500 mm², when a load of 2000 kN is applied suddenly.

Modulus of resilience is the ratio of ______

• minimum strain energy and unit volume

• maximum stress energy and unit volume

• proof resilience and unit volume

• resilience and unit area

The ability of a material to absorb energy when elastically deformed and to return it when unloaded is called __________

• Elasticity

• Resilience

• Plasticity

• Strain resistance

The maximum strain energy stored at elastic limit is __________

• Resilience

• Proof resilience

• Elasticity

• Malleability

Force of 100 kN is applied on 900 mm long rod of 20 mm diameter and is simultaneously heated at 70^o C. What is the total elongation of the rod? (Assume coefficient of thermal expansion = 10 x 10^{–6 o}C, Young's modulus = 150 Gpa)

• 2.54 mm

• 2.00 mm

• 1.27 mm

• 0.63 mm