Britannica
Sources used in this answer
How do Youngâs modulus, shear modulus, and bulk modulus describe different kinds of elastic response?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
mechanics of solids
Figure 1: The position vector x and the velocity vector v of a material point, the body force fdV acting on an element dV of volume, and the surface force TdS acting on an element dS of surface in a Cartesian coordinate system 1, 2, 3 (see text).
In the study of mechanics of solids, elastic moduli quantify a material's resistance to deformation under specific types of stress. Each modulus represents a specific form of Hookeâs law, describing how a material returns to its original configuration after the removal of an external force.123
- Youngâs modulus: Describes the elastic response to uniaxial tension or compression. It measures a material's ability to withstand changes in length when subjected to a force applied in one direction, such as stretching a metal rod.3
- Shear modulus: Also known as the modulus of rigidity, this constant describes the response to transverse internal forces. It measures the resistance to shearing deformations, where a material is distorted such that its internal layers slide parallel to one another, changing the shape of the material without changing its volume.1
- Bulk modulus: Describes the resistance to changes in volume when a material is subjected to uniform pressure on all surfaces. It is a measure of incompressibility; a higher bulk modulus indicates that a substance is more difficult to compress.2
These moduli are interrelated in isotropic materials through constants such as the Poisson ratio.4