Mechanics of Solids, 2nd Edition

CHAPTER 9

Deflection of Beams

9.1 Introduction

When a beam is loaded its neutral plane is deformed, though its length may not change. It means that this plane is curved. In a plane figure the neutral plane is represented by a straight line. The displacement of the central line of the neutral plane from its original position in the direction of normal at any point is termed as deflection of the beam. Fig. 9.1 illustrates this definition of the deflection. Since there is almost no change in the transverse dimension of the beam cross-section, it may be understood that the top and bottom surfaces of the beam will deform in the same way as the neutral plane and hence for all practical purposes for calculation of deflection of beam the beam may be ...