Representative Probiems

$7\mathrm{.}5-11$ A $100$ mm cube of conerete $(E=31$GPa, $v=0\mathrm{.}2)$ is compressed in biaxial stress by means of a framework that is loaded as shown in the figure.

Assuming that each load $F$ equals $110$ kN $,$ determine the change $AV$ in the volume of the cube and the strain energy $U$ stored in the cube.

PROBLEM $7\mathrm{.}5-11$