Topic 1: Introduction and Historical failures Fracture of solid bodies ▪ From macroscopic point of view , a simple fracture is the separation of a body into two or more pieces in response to the applied stresses ▪ At the most basic level the fracture is a process of breaking interatomic bonds in the solids Why is it so important ▪ In many cases it occurs without priori warning ▪ It occurs much below the design stresses ▪ Great loss of human lives and structure itself ▪ Great loss of capital investments Historical disasters due to fracture of components ▪ Liberty ships ▪ Comet aircrafts ▪ Boston Molasses Tank Failure ▪ Aloha Airlines Fuselage Failure Topic 1: Liberty ships Typical size of cargo ships Fracture of Liberty ships Liberty Ships ▪ Supplies were vital to the United States in order to sustain the battle against the Germans. A very successful bombing operation by Germany on the ships had inflicted significant damage. ▪ Basically cargo ships – US during WWII ▪ 18 shipyards built 2708 ships between 1941-1945 ▪ Mass production technique: Welding is extensively used instead of riveting. ▪ Produced many ships very fast. Some even took only 63 hours!!!!!! ▪ Nearly 200 ships out of 2710 broke in half without giving any warning ▪ They failed in cold weather and rough seas ▪ Loss of life and capital investments Fracture of Comet aircrafts Comet aircraft failures ▪ UK based de Havilland aircraft company is first to built commercial passenger aircrafts ▪ First manufactured in 1952 in UK was the first twin-jet-engine passenger aircraft to fly 40,000 ft with pressurized cabins ▪ First Comet passenger plane took off on 02 May, 1952 ▪ First one year no problem ▪ Many orders came throughout the globe ▪ After a year three aircrafts blown in the air with loss of life. ▪ First two were not related to fracture but the third one is due to brittle fracture. S.No Date Location Cause 1 26 Oct 52 Rome Aircraft 2 03 Mar 53 Karachi Aircraft 3 02 May 53 Calcutta Aircraft 4 25 June 53 Senegal Pilot 5 10 Jan 54 Italy Aircraft 6 08 Apr 54 Italy Aircraft
