Question

An alloy to be used for a spring application must have a modulus resilience of at least 0.79 x 106 J/m3 (0.79 x 106 Pa). What must be its minimum yield strength (in MPa)? Assume that the modulus of elasticity for this alloy is 102 GPa

Using Ur=Sig^2/2E, I am getting 401.447E6 Mpa but apparently thats wrong.

Answer 1

4.13 MPa

Step-by-step explanation:

Given

Modulus of elasticity = E = 102 GPa

E = 102 * 10^9

Modulus resilience U = 0.79 * 106Pa

Modulus of Resilience U = y²/2E --- Make y the subject of formula

y² = 2EU

y = √(2EU)

y = √(2 * 102 * 10^9 * 0.79 * 106)

y = √1.708296E13

y = 4133153.759540044

y = 4.13E6

y = 4.13MPa