Engineering revision notes

Material properties

Strength: 

There are different types of strength depending upon the type of force being applied.

• Tensile strength is how well the material resists against a pulling force: 
  • 2 different values for tensile strength are oftem given. Yield strength is the amount of stress needed to permanently deform the material and the ultimate tensile strength (UTS) is the stress at which the material finally breaks.
• Compressive strength is how well the material resists a squeezing force.
• Torsional strength is how well the material resists a twisting force.

Most materials have good strength against all of the different forces. Other materials may have good strength in one type but not in another.

Ductility:

• Ductile materials are stretched by applying a tensile force (for example, thermoplastic polymers).
• Non-ductile materials will break rather than stretch when a tensile force is applied.
• One way to measure ductility is the ratio…