Strain Energy Problem

Question

A bar of length L and of uniform cross-section area A and second moment of area 1 is subjected to pull P.If the young's modulus of elasticity of the bar material is E,the expression for strain energy stored in the bar will be 1)P2L2/2AE 2)PL2/2EI 3)PL2/AE 4)P2L/AE

(Note:The P2L2 and 2AE in the option is P squared,L squared and 2 times AE respectively)

Answer 1

5) None of the above.

The strain energy stored in the bar will be $$U = \frac{1}{2}P\Delta$$

where $$\Delta = \frac{PL}{AE}$$

or $$U=\frac{P^2L}{2AE}$$

See Strain Energy