# Bodies in Equilibrium, elasticity and fracture

1. Jun 6, 2004

### pupatel

can anyone help me with this please....?????

How much pressure is needed to compress the volume of a steel block by 0.14 percent?

2. Jun 6, 2004

### Gokul43201

Staff Emeritus
I'm not sure what units you are used to but I'll use SI here :

The bulk modulus of steel is about
$$G=160 * 10^9 N/m^2 = dP/(dV/V)$$
$$=>dP = G(dV/V)$$
$$=160*10^9*0.0014$$
$$=224 * 10^6 N/m^2$$
$$= 224 MPa$$

Of course, this change in volume exists only so long as the pressure is applied, and the steel springs back once the pressure is removed. However, in a very small number of low carbon steels, at about 220 MPa, you reach the yield stress and the steel will begin to plastically deform. Once this starts, the volume change becomes permanent.

Last edited: Jun 6, 2004