7: Calculations

There are a number of material properties that are commonly derived from a tensile test curve. Click on the properties below to see how they are calculated.

Yield Stress
Proof Stress
Ultimate Tensile Strength
Young's Modulus
Total Strain to Fracture
Plastic Strain to Fracture
Fracture Energy


 

 

Modulus of Elasticity (Young’s Modulus)

The Modulus is a measure of stiffness, so the modulus of a material is very important in applications where the amount of distortion should be small: e.g. for cantilever beams or crankshaft deflection between bearings

Yield Strength

This is the most important strength value for design. In most applications it is necessary to stay within the elastic region, so that no permanent deformation due to the load occurs. It is very important for springs, pressure vessels etc.

Ductility

This is important for materials in fabrication. High ductility means that they can be shaped easily without breaking in the process. Designers also often want a minimum level of ductility so that if the stress that is applied to the component is too high the material will deform before it breaks.