Question

In the generalised Hook’s law equation, εX=C11σx+ C12 (σY+σZ), the constant C11 is __________

(a) E

(b) 1/E

(c) 0

(d) μ

I got this question in an international level competition.

Origin of the question is Generalised Hooke’s Law topic in division Elements of Elasticity of Geotechnical Engineering I

Answer 1

The correct choice is (b) 1/E

The best explanation: Let us consider the case of uniaxial stress,

σY=σZ=0

∴ εX=C11σx

∴ C11= εX/σx=1/E.