When a beam carries transverse loading it bends which can be sagging or hogging. The form of curve to which the beam bends after loading is called elastic curve or deflection curve. Exact value of deflection is required in many designs and also to check the dimensional accuracy of various machine elements. Deflection at any point on the axis of the beam is the distance between its position before loading and after loading. Beam is a flexural member subjected to flexure and shear. But deflection due to shear is small so it is neglected.