Hydrostatic volume strain from Young's modulus and Poisson's ratio
= Hydrostatic volume strain from Young's modulus and Poisson's ratio
{title2=$\Delta V/V=-3(1-2\nu)p/E$}
For an isotropic linearly elastic solid, equal compressive principal <stresses> $-p$ produce three equal normal <strains> $-(1-2\nu)p/E$. Adding them gives the displayed <volume> <strain>, or <bulk modulus> $K=E/[3(1-2\nu)]$. It is a small-strain relation using the <pressure> change, not an arbitrary absolute <pressure> reference.