Mechanical Properties of Materials – Tensile, Compressive, Shear, Torsional and Yield Strength Defined

Topics Covered

Background

Tensile Strength

Compressive Strength

Shear Strength

Torsional Strength

Yield Strength

Background

Stress is defined as the force per unit area. Thus, the formula for calculating stress is:

Where σ denotes stress, F is load and A is the cross sectional area. The most commonly used units for stress are the SI units, or Pascals (or N/m2), although other units like psi (pounds per square inch) are sometimes used.

Forces may be applied in different directions such as:

         Tensile or stretching

         Compressive or squashing/crushing

         Shear or tearing/cutting

         Torsional or twisting

This gives rise to numerous corresponding types of stresses and hence measure/quoted strengths. While data sheets often quote values for strength (e.g compressive strength), these values are purely uniaxial, and it should be noted that in real life several different stresses may be acting.

Tensile Strength

The tensile strength is defined as the maximum tensile load a body can withstand before failure divided by its cross sectional area. This property is also sometimes referred to Ultimate Tensile Stress or UTS.

AZoM - Metals, ceramics, polymers and composites - tensile stresses

Typically, ceramics perform poorly in tension, while metals are quite good. Fibres such as glass, Kevlar and carbon fibre are often added polymeric materials in the direction of the tensile force to reinforce or improve their tensile strength.

Compressive Strength

Compressive strength is defined as the maximum compressive load a body can bear prior to failure, divided by its cross sectional area.

AZoM - Metals, ceramics, polymers and composites - compressive stresses

Ceramics typically have good tensile strengths and are used under compression e.g. concrete.

Shear Strength

Shear strength is the maximum shear load a body can withstand before failure occurs divided by its cross sectional area.

AZoM - Metals, ceramics, polymers and composites - shear stresses

This property is relevant to adhesives and fasteners as well as in operations like the guillotining of sheet metals.

Torsional Strength

Torsional strength is the maximum amount of torsional stress a body can withstand before it fails, divided by its cross sectional area.

AZoM - Metals, ceramics, polymers and composites - torsional stresses

This property is relevant for components such as shafts.

Yield Strength

Yield strength is defined as the stress at which a material changes from elastic deformation to plastic deformation. Once the this point, known as the yield point is exceeded, the materials will no longer return to its original dimensions after the removal of the stress.

 

Source: AZoM.com

 

Date Added: May 19, 2006 | Updated: Jun 11, 2013
Comments
  1. Ashok Huprikar Ashok Huprikar India says:

    What is shear strength of phosphor bronze gun metal and cast iron?

  2. manoj kumar manoj kumar India says:

    What is shear strength of high carbon steels ?

  3. t parmar t parmar India says:

    what is shear stength of EN47

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