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Shear modulus
Intermediate
Resistance to shearing.
G = shear stress/shear strainG = shear stress/shear strain, resistance to sideways deformation. Liquids have zero shear modulus.
Steel G ≈ 80 GPa.
Gases and liquids can't support static shear.
In more detail
The shear modulus G = shear stress/shear strain describes how much a material resists sideways deformation. Shear modulus is typically smaller than Young's modulus.
Real-world uses
- Engineers use shear modulus to design shafts and bolts.
- Seismic wave speeds depend on the shear modulus of rocks.
- Seismologists use the shear modulus to describe how rock resists sideways movement, which affects the speed of S waves.
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Frequently asked questions
What is shear stress?
A force applied parallel to a surface, causing layers to slide over each other.
Do liquids have shear modulus?
Ideal liquids do not resist shear permanently, so their shear modulus is zero.
Can a fluid have a shear modulus?
No. A fluid cannot sustain a static shear stress, so the shear modulus is zero for liquids and gases.
Related topics in Fluids & Elasticity
Hooke's law for solids · Young's modulus · Bulk modulus · Stress–strain curve · Poisson's ratio · Elastic potential energy density