Question

Consider the following statement for a beam based on theory of bending:
1. Strain developed in any fibre is directly proportional to the distance of fibre from neutral surface.
2. For flexural loading and linearly elastic action the neutral axis passes through the centroid of cross-section.
3. The assumption of the plane cross-section remaining plane will not hold good during inelastic action.
4. Instances in which the neutral axis does not pass through the centroid of a cross-section include a homogenous symmetrical beam (with respect to axis) and subjected to inelastic action.

Which of these statements are correct ?

• A. 1, 2, 3 and 4
• B. 1, 2 and 4
• C. 3 and 4
• D. 1 and 2

Answer 1

The correct option is B 1, 2 and 4

The strain distribution is linear or strain is proportional to the distance of fibre from neutral surface. The assumption of plane sections remaining plane sections remaining plane holds good during inelastic or plastic analysis also. For plastic action the neutral axis not pass through centroid and is located at a point where area is equally divided into two halves.