Question

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

(a) E

(b) 1/E

(c) –μ/E

(d) μ

I have been asked this question during an interview for a job.

I need to ask this question from Generalised Hooke’s Law in section Elements of Elasticity of Geotechnical Engineering I

Answer 1

Right choice is (c) –μ/E

To explain: Let us consider the case of uniaxial stress,

σY=σZ=0

∴ εX=C11σx

∴ C11= εX/σx=1/E and let, εY= εZ= C12σx

C12σx=E εX

∴ C12=(1/E)*( εY/ εX)

∴ C12=–μ/E.