An ASTM A572 Grade 50 steel bar is attached to a rigid wall at one end and a spring at the other end, with the other end of the spring being attached to a rigid wall, as shown below. The bar is 20 cm long with cross sectional area of 1.2 cm2, and it is initially at 20C. For this steel E=190 GPa, Fy=390 MPa, Poisson's ratio is 0.29, the coefficient of thermal expansion is 13x10-6 1/C, and for the spring k=4x108 N/m.

a) The temperature of the whole bar is raised slowly and uniformly raised from 20C to 720C. Find the stress, the elastic, thermal, plastic, and total strains in the bar, and the force and change in length for the spring. b) The bar is slowly and uniformly cooled back to 20C. Find the stress, the elastic, thermal, plastic, and total strains in the bar, and the force and change in length for the spring. c) An engineer proposes to reduce the distortion in the bar by leaving it connected to the walls just after Part d. Then slowly and uniformly cooling the bar from 20C to 10C, and then raise its temperature slowly and uniformly back to 20C. Find the stress, the elastic, thermal, plastic, and total strains in the bar, and the force and change in length for the spring when the bar is back at 20C. d) To what temperature (in C) would we need to cool the bar in Part c to eliminate the distortion?

Answer rating: 100% (QA)

To solve this problem we can use the principles of thermal stress and strain Well calculate the stre... View the full answer