Shear modulus

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Elastic shear modulus.

An important elastic modulus, also known as rigidity or the modulus of rigidity, or the second Lamé parameter. Symbolized as μ or sometimes G.

Definition

The ratio of shear stress to shear strain:

Other expressions

Shear modulus can be expressed in terms of elastic properties:

And it can be expressed in terms of acoustic properties:

from which it follows that

where IS is shear impedance and ρ is density.

Typical values

Usually about 3 × 1010 Pa.

Conversion formulas — edit
The elastic properties of homogeneous isotropic linear elastic materials are uniquely determined by any two moduli. Given any two, the others can thus be calculated. Key reference: Mavko, G, T Mukerji and J Dvorkin (2003), The Rock Physics Handbook, Cambridge University Press.

P-wave velocity
S-wave velocity
Velocity ratio
1st Lamé parameter
Shear modulus
Young's modulus
Bulk modulus
Poisson's ratio
P-wave modulus