MODULUS OF ELASTICITY:
- The ratio of the stress applied to a body to the strain that results in the body in response to it. The modulus of elasticity of a material is a measure of its stiffness and for most materials remains constant over a range of stress.
- The slope of the straight line portion of a stress-strain diagram. Tangent modulus of elasticity is the slope of the stress-strain diagram at any point. Secant modulus of elasticity is stress divided by strainat any given value of stress or strain. It also is called stress-strain ratio.
- Tangent and secant modulus of elasticity are equal, up to the proportional limit of a material.
- Depending on the type of loading represented by the stress-strain diagram, modulus of elasticity may be reported as: compressive modulus of elasticity (or modulus of elasticity in compression); flexural modulus of elasticity (or modulus of elasticity in flexure); shear modulus of elasticity (or modulus of elasticity in shear); tensile modulus of elasticity (or modulus of elasticity in tension); or torsional modulus of elasticity (or modulus of elasticity in torsion).
- Shear modulus is almost always equal to torsional modulus and both are called modulus of rigidity. Moduli of elasticity in tension and compression are approximately equal and are known as Young's modulus.
- Modulus of rigidity is related to Young's modulus by the equation E = 2G(r 1)
- where E is Young's modulus (psi), G is modulus of rigidity (psi) and r is Poisson's ratio.
- Modulus of elasticity also is called elastic modulus and coefficient of elasticity.