Plane Stress and Plane Strain MCQ with answer and solution

Concept

Independent stress components in plane stress

Formula

NONE

Step-by-step solution

1. In plane stress, stress components in the direction perpendicular to the plane are assumed to be zero. 2. The state of stress at a point in the plane is characterized by distinct normal and shear components. Answer: B

Explanation

Plane stress refers to a condition where all stress components out of a specific plane are zero. In a 2D plane stress state, the active stress components are two normal stresses and one shear stress. Since shear stresses on perpendicular faces are equal by symmetry, there are exactly three independent components, making option B correct.

Why the other options are wrong

A) Two stress components are insufficient to fully describe a 2D state of stress. D) Plane stress requires fewer than five independent stress components.

Shortcut

Plane stress has 3 independent components: σ_x, σ_y, and τ_xy.

Common mistake

Counting both shear stresses (τxy and τyx) as independent components and selecting option C (4) instead of 3.