Question

Consider the stepped bar made with a linear elastic material and subjected to an axial load of $1kN$ as shown in figure



Segments $1$ and $2$ have cross sectional area of $100m{m}^2$ and $60m{m}^2$, Young's modulus of $2\times {10}^{5}MPa$ and $3\times {10}^{5}MPa$ and length of $400mm$ and $900mm$ respectively. The strain energy in $N-mm$ up to 2 decimal place in the bar due to the axial load is

• A. 35

Answer 1

The correct option is A 35

$U=\sum \frac{P^2{L}_1}{2A_1{E}_1}$

$=\frac{(1000{)}^2\times 400}{2\times 100\times 2\times {10}^5}+\frac{(1000{)}^2\times 900}{2\times 60\times 3\times {10}^5}$

$=10+25=35Nmm$