To understand the bending stress in an arbitrary loaded beam, consider a small element cut from the beam as shown in the diagram at the left. The beam type or actual loads does not effect the derivation of bending strain equation. Recall, the basic definition of normal strain is.implifying and rearranging gives, This equation gives the bending normal stress, and is also commonly called the flexure formula. The y term is the distance from the neutral axis (up is positive). The I term is the moment of inertia about the neutral axis.
John Paul Jones was a hero of the colonial navy during the American Revolution. He defeated a British ship in one of the most famous sea battles in history. (1747-92). The first great American naval hero was Captain John Paul Jones.
John Paul went to sea when he was 12, and his youth was adventure-filled. He was chief mate on a slave ship in 1766 but, disgusted with the work, soon quit. In 1769 he obtained command of the John, a merchantman that he captained until 1770.