Question

Which of the following assumptions is correct for plastic design?

(a) material obeys Hooke’s law before the stress reaches fy

(b) yield stress and modulus of elasticity does not have same value in compression and tension

(c) material is homogenous and isotropic in both elastic and plastic states.

(d) material is not sufficiently ductile to permit large rotations

The question was posed to me in examination.

My question comes from General Requirements for Plastic Design and Plastic Hinge topic in chapter Plastic and Local Buckling Behaviour of Steel of Design of Steel Structures

Answer 1

Right answer is (c) material is homogenous and isotropic in both elastic and plastic states.

The best explanation: The material obeys Hooke’s law till the stress reaches fy. The yield stress and modulus of elasticity have the same value in compression and tension. The material is homogeneous and isotropic in both elastic and plastic states. The material is assumed to be sufficiently ductile to permit large rotations of section to take place.