Strength of Materials

8.1 INTRODUCTION

When a beam is subjected to some type of loading, the beam deflects from its original position. The amount by which a beam deflects depends upon its support conditions, cross section of the beam and the bending moment.

Strength and stiffness are the two main design criteria for a beam. As per the strength criterion the beam should be strong enough to resist the bending stresses and shear stresses. According to stiffness criterion, the beam should be stiff enough to resist the deflection beyond a permissible limit.

When a load is placed on a beam, the beam deflects or sags as shown in Figure 8.1.

 

 

Fig. 8.1 Beam under load. ...