Modulus of rigidity (1 Viewer)

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what is modulus of rigidity and shear modulus? What do they define?
 
There are three moduli of rigidity:
1. Young's Modulus
2.Bulk Modulus
3.Shear Modulus

Modulus is generally defined as Stress/Strain

1.Young's Modulus is generally used for solid materials( In problems, for wires..)

[itex]Y= \frac{Longitudinal Stress}{Longitudinal Strain}[/itex]

2. Bulk Modulus is generally used for Liquids and Gases

[itex]B= \frac{Volumetric Stress}{Volumetric Strain}[/itex]

3. Shear Modulus is used where tangential stress is applied and the object bends or tangentially bends making some angle with vertical.

I assume you know what stress and strain is.
 

Pyrrhus

Homework Helper
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Rigidity is the required force to produce a unit incrementum of length.

In prismatic beams, the product of EA is known as axial rigidity.

[tex] \delta = \frac{PL}{EA} [/tex]

where [itex] \delta [/itex] is the change in length, P is the force applied at the centroid, L is the original length, E is the modulus of elasticity (assuming the material is at the elastic-linear region) and A is the cross sectional area. Of course this is for Homogenous materials.

In general the rigidity will be a measure of a structural member "opposing the change in length", with rigidity it's often used flexibility, which is inverse to the rigidity.
 

Pyrrhus

Homework Helper
2,153
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Maybe you are refering to the modulus of elasticity in shear stress, also know as modulus of rigidity.

According to Hooke's Law in shear (elastic-linear region)

[tex] \tau = G \gamma [/tex]

where [itex] \tau [/itex] is the shear stress, G is the modulus of rigidity or elasticity in shear and [itex] \gamma [/itex] is the angle of distorsion or the unit deformation.

The rigidity here is about measuring the structural element resistance to the "change of its shape".
 
Last edited:
what does the product of rigidity modulus and moment of inertia of a beam mean??
 
can some one please tell me the derivation of modulus of rigidity or shear modulus i stuck
i need to finish with this equation:

G=E/2(1+U) please help out if you can

thanks
 

FredGarvin

Science Advisor
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Last edited by a moderator:

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