For a bronze alloy, the stress at which plastic deformation begins is 294 MPa and the modulus of elasticity is 121 GPa. (a) What is the maximum load that can be applied to a specimen having a cross-sectional area of 327 mm2 without plastic deformation? (b) If the original specimen length is 129 mm, what is the maximum length to which it may be stretched without causing plastic deformation?

a) load in Newton is 96,138 b) 129.314mm

Explanation:

Stress = force / area (cross sectional area of the bronze)

Force (load) = 294*10^6*327*10^-6 = 96138N

b) modulus e = stress / strain

Strain = stress / e = (294*10^6) / (121*10^ 9) = 2.34 * 10^ - 3

Strain = change in length / original length = DL / 129

Change in length DL = 129 * 2.34*10^ - 3 = 0.31347

Maximum length = change in length + original length = 129.314mm