ME 212 Lecture Notes - Lecture 8: Flexural Strength, Neutral Axis, Pure Bending
Document Summary
Forces and couples acting on the beam cause bending (flexural stresses) and shearing stresses on any cross section of the beam and deflection perpendicular to the longitudinal axis of the beam. If couples are applied to the ends of the beam and no forces act on it, the bending is said to be pure bending. If forces produce the bending, the bending is called ordinary bending. Stresses caused by the bending moment are known as flexural or bending stresses. Consider a beam to be loaded as shown. Consider a fiber at a distance y from the neutral axis, because of the beam"s curvature, as the effect of bending moment, the fiber is stretched by an amount of cd. Since the curvature of the beam is very small, bcd and oba are considered as similar triangles. By hooke"s law, (cid:304) = (cid:305) / e, then which means that the stress is proportional to the distance y from the neutral axis.
