A 10 m long mild steel rail section is fixed at 300 K temperature. If temperature increases by 60 K, find stress in rail section if ends are not yielded. Coefficient of thermal expansion is 12×10^-6/K.

Question

Quizplus · Accepted Answer

The stress in the rail section due to thermal expansion can be calculated using the formula: $\sigma = E \alpha \Delta T$, where $E$ is the modulus of elasticity of mild steel (approximately $210 \times 10^3$ N/mm$^2$), $\alpha$ is the coefficient of thermal expansion ($12 \times 10^{-6}$ /K), and $\Delta T$ is the change in temperature (60 K). Substituting the given values, $\sigma = 210 \times 10^3 \times 12 \times 10^{-6} \times 60 = 151.2$ N/mm$^2$. However, since none of the provided options exactly matches this calculation, the closest option, which is 144 N/mm$^2$, is considered correct due to possible rounding or simplification in the question's formulation.

A 10 M Long Mild Steel Rail Section Is Fixed