A copper bar has the desired length when at 35°C. How much stress is required to keep it at this length if the temperature increases to 65°C?
Thermal stress -Y*alpha*deltaT where Y is Young's modulus 11x10^10; alpha is the coefficient of linear expansion 1.7x10^-5 delta T 30 So Stress -11x10^10*1.7x10^-5*30 -5.61x10^7 Pa (The negative sign means compression)
Stress dT*C*E (65 - 35)*C*E where C is the thermal expansion coefficient and E is Young's modulus for copper.
