What are the failure theories?

Theories of failure

• Maximum principal stress theory (Rankine’s theory)
• Maximum shear stress theory (Coulomb, Tresca and Guest’s theory)
• Distortion energy theory (Huber von Mises and Hencky’s theory)
• Maximum strain theory (St. Venant’s theory)
• Maximum total strain energy theory (Haigh’s theory)

What is Beltrami theory?

Maximum Strain Energy Theory (Beltrami or Haigh’s Theory): This theory is based on the assumption that strains are recoverable up to the elastic limit. The energy absorbed by the material at failure up to this point is a single-valued function independent of the stress system causing it.

What is Rankine theory of failure?

Rankine’s Theory assumes that failure will occur when the maximum principal stress at any point reaches a value equal to the tensile stress in a simple tension specimen at failure. This theory is also called the Maximum Stress Theory.

Which is the best theory of failure?

There is no such thing as the best failure theory. The use of different failure criterion would would be appropriate for different materials. For example, the maximum principal stress/strain theory would be appropriate for brittle materials like cast iron or glass.

Which theory of failure is most accurate?

The maximum shear stress theory gives the most accurate results amongst all the failure theories.

What is Tresca failure?

Maximum Shear Stress theory or Tresca theory of failure relates to the maximum shear stress of ductile materials. Von Mises stress theory represents the maximum distortion energy of a ductile material. This theory is considered to be more conservative. Considered less conservative when compared with Tresca theory.

Why do we use Von Mises?

von-Mises stress is widely used because it is suitable for the situation where the material is ductile and the failure mode corresponds to a normal stress. And this situation is a common one in engineering applications.

What is the significance of von Mises stress in structural analysis?

Von Mises stress is a value used to determine if a given material will yield or fracture. The von Mises yield criterion states that if the von Mises stress of a material under load is equal or greater than the yield limit of the same material under simple tension then the material will yield.

What is Rankine theory of earth pressure?

1 Rankine’s Earth Pressure Theory The Rankine’s theory assumes that there is no wall friction , the ground and failure surfaces are straight planes, and that the resultant force acts parallel to the backfill slope. In case of retaining structures, the earth retained may be filled up earth or natural soil.

Why is theory of failure important?

Theories of failure are those theories which help us to determine the safe dimensions of a machine component when it is subjected to combined stresses due to various loads acting on it during its functionality.

What is Tresca’s Theory of failure?

This failure criterion is developed by the French mechanical engineer, Henri Tresca and based on his name maximum shear stress theory is also known as the Tresca theory of failure. Due to the enormous contribution in the field of plasticity, Henry Tresca is popular as the father of the field of plasticity.

What is the difference between Tresca and von Mises theory?

Maximum Shear Stress theory or Tresca theory of failure relates to the maximum shear stress of ductile materials. Von Mises stress theory represents the maximum distortion energy of a ductile material. This theory is considered to be more conservative. Considered less conservative when compared with Tresca theory.

What is the difference between Tresca Theory and maximum shear stress theory?

To establish failure criteria of material, all failure theories compare a specific parameter with the same parameter for the uniaxial tension test. The maximum shear stress theory is no exception and the parameter for comparison in Tresca theory is maximum shear stress.

What is Tresca behavior in 3-D?

The Tresca behavior in 3-D is an artifact of describing the maximum shear stresses in the three principal coordinate planes. This ignores the effects that occur at smaller scales in polycrystalline aggregates, and the averaging necessary to reach macroscopic behavior.