Question

Rankine's theory of failure is applicable for which of the following type of materials?

• A. Brittle
• B. Ductile
• C. Elastic
• D. Plastic

Hint:

Use Rankine’s theory for brittle materials — it focuses on maximum normal stress causing sudden fracture without yielding.

Answer 1

The Correct Option is A

Rankine's theory, also known as the maximum normal stress theory, states that failure occurs when the maximum principal stress in a material reaches the ultimate tensile stress.
This theory is most applicable for brittle materials, which fail primarily due to normal stress and exhibit very little plastic deformation.
Brittle materials, such as cast iron and ceramics, tend to fracture suddenly without significant yielding, which makes maximum stress a good criterion for failure prediction.
- Ductile materials are better evaluated using theories like von Mises or Tresca, which consider shear stress.
- Elastic and plastic are behavior descriptors, not material types directly applicable for Rankine’s assumption.