The maximum principal stress theory for the failure of a material at the elastic limit is known as:
Try it first: pick an option, then read the explanation.
Correct answer: C. Rankine's theory
Asked in SSC JE 24/01/2018 (Morning)
Detailed Explanation
The simplest theory of failure: a material fails when the largest principal stress reaches the yield (or ultimate) stress in simple tension.
Why “Rankine's theory” Is Correct
This is Rankine's theory, which suits brittle materials such as cast iron, concrete and glass.
Why the Other Options Are Wrong
- A. Guest's or Tresca's theory: Guest/Tresca: maximum shear stress.
- B. St. Venant's theory: St. Venant: maximum principal strain.
- D. Haigh's theory: Haigh: total strain energy.
Key Point
Rankine → maximum principal stress (brittle materials); square yield locus.
Key Concepts for Students
- Ignores the other principal stresses.
- Unsafe for ductile materials in pure shear.
- Square yield locus in 2-D.
Practice more: this is question 27 in Principal Stress and Principal Planes MCQs – Part 2. Try the whole set and check every answer instantly.