# Why do we have two different Elastic Modulus in Tension and Torsion?

I was trying to get a value for elastic modulus for 316L stainless steel material from internet, and I saw a brochure online which was giving two different values for elastic modulus, one in tension and one in torsion. I was confused why this is the case?

• Can you provide the link to the online brochure?
– r13
Jun 24 at 12:59
• There are many elastic moduli: Young's (axial), shear (torsion), bulk (volumetric), biaxial, plane-strain, P-wave, complex... Jun 25 at 3:04

Probably the value for the torsion related modulus for 316L should be close to 79[GPa], compared to 200-210 [GPa] for tension.

The shear modulus for isotropic materials can be analytically calculated as

$$G = \frac{E}{2\cdot(1+\nu)}$$

where:

• G is the shear modulus
• E is the tensile modulus
• $$\nu$$ is the Poisson's ratio.

You can see a derivation in the following link (University of Auckland)