#### Elastic Properties of Solids

The elastic properties of a solid body describe the manner in which a configuration of forces applied to the body leads to a deformation.

In earlier mechanics we were concerned with the effects on the state of motion of a body caused by the forces upon it. Now we are concerned with the effects of force on the shape of the body itself. A solid body under load experiences a deformation. A deformation is considered elastic if, when the load is removed, the object returns to its original shape.

Elasticity appears fairly regularly on the MCAT, and the basics of this discipline, which is often neglected in lecture course, are pretty easy to master. On the exam, you may be expected to distinguish the three common types of deformation, elongation, shearing and compression, and their corresponding moduli, for example, or you may be asked to distinguish an elastic from a non-elastic deformation.

WikiPremed Resources

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Elasticity Cards
Chapter from the Wisebridge Learning System for Physics

Elasticity Concepts
Concept chapter for Elasticity in PDF format

Elasticity Practice Items
Problem set for Elasticity in PDF format

Elastic Properties of Solids Images
Image gallery for study with links to larger teaching JPEGs for classroom presentation

Question Drill for Elasticity
Conceptual Vocabulary Self-Test

Basic Terms Crossword Puzzle

Basic Puzzle Solution

Learning Goals

Proficiency

Master basic problem solving using Young's modulus, shear modulus and bulk modulus.

Recognize and understand the meaning of the yield point and the breaking point.

Define elastic hysteresis and damping.

Suggested Assignments

Study the basic terminology for elasticity using the question server. Complete the fundamental terms crossword puzzle. Here is the solution to the puzzle.

Study the physics cards for elasticity.

Study the elasticity chapter. Perform the practice items. Here is the answer key for the problem set.

Take a review tour of the elasticity web resources.

Conceptual Vocabulary for Elasticity

Elasticity
Elasticity is a branch of physics which studies the properties of materials which deforms under stress, but then return to their original shape when the stress is removed.
Stress
Stress is a measure of force per unit area within a body. It is a body's internal distribution of force per area that reacts to external applied loads.
Strain
Strain is the geometrical expression of deformation caused by the action of stress on a physical body.
Shear strain
Shear strain is a strain that acts parallel to the face of a material that it is acting on.
Shear modulus
Shear modulus is defined as the ratio of shear stress to the shear strain.
Shear stress
Shear stress is a stress state where the stress is parallel or tangential to a face of the material.
Hooke's law
Hooke's law of elasticity is an approximation that states that the amount by which a material body is deformed is linearly related to the force causing the deformation.
Normal stress
Normal stress is stress that acts perpendicular to the face of the material, a compression or a tension.
Elastic modulus
The slope of its stress-strain curve in the elastic deformation region, the elastic modulus describes an object's tendency to be deformed elastically under load.
Tensile stress
Tensile stress, or tension, is the stress state leading to expansion.
Bulk modulus
The bulk modulus of a substance essentially measures the substance's resistance to uniform compression.
Deformation
Often described in terms of strain, deformation is a change in shape due to an applied force.
Normal strain
Normal strains produce dilations without a shape-change as such.
Young's modulus
Young's modulus is a measure of the stiffness of a given material, also known as the tensile modulus.
Stiffness
Stiffness is the resistance of an elastic body to deflection or deformation by an applied force.
Yield
The yield point of a material is the stress at which a material begins to plastically deform.
Rigid body
A rigid body is an idealization of a solid body of finite size in which deformation is neglected.
Plasticity
Plasticity is a property of a material to undergo a non-reversible change of shape in response to an applied force.
Fracture toughness
Fracture toughness is a property which describes the ability of a material containing a crack to resist fracture.
Stress-strain curve
A stress-strain curve is a graph derived from measuring load versus extension for a sample of a material.
Hysteresis
Hysteresis is a property of systems that do not instantly react to the forces applied to them, but react slowly, or do not return completely to their original state.
Ductility
Ductility is the mechanical property of being capable of sustaining large plastic deformations due to tensile stress without fracture.
Toughness
Toughness is the resistance to fracture of a material when stressed, defined as the amount of energy that a material can absorb before rupturing.
Viscoelasticity
Viscoelasticity, also known as anelasticity, describes materials that exhibit both viscous and elastic characteristics when undergoing plastic deformation.
Rheology
Rheology is the study of the deformation and flow of matter under the influence of an applied stress.
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