Question

If w is the displacement in z-direction, the linear strain component in is defined by __________

(a) \(ε_Z=\frac{∂w}{∂z}\)

(b) \(ε_Z=\frac{∂z}{∂w}\)

(c) \(ε_Z=\frac{dz}{dw}\)

(d) εZ=z+w

The question was posed to me during an internship interview.

This intriguing question comes from Strain Components and Compatibility Equations in section Elements of Elasticity of Geotechnical Engineering I

Answer 1

Correct answer is (a) \(ε_Z=\frac{∂w}{∂z}\)

For explanation: The strain is the ratio of change in dimension of an object to its original dimension. Therefore, the linear strain component in is defined by,

 \(ε_Z=\frac{∂w}{∂z}\). Where, w is the displacement in z-direction.