Material failure

Introduction to mechanical failure,case studies.

1. Material failure Examples Prepared By Er.L.Loganathan , M.E., ( Ph.D ). Assistant professor, Department of Mechanical engineering, Kamaraj college of engineering and technology, Virudhunagar.

2. Titanic Ship failure( 1,500 people Died) Theory 1 Multiple rivet failures upon collision with iceberg failed because of brittle fracture Theory 2 Failure of the steel hull upon collision with iceberg

3. Material used Rivet - wrought iron steel hull - plain carbon

4. Three factors 1. The water temperature was below freezing 2. Titanic was traveling at a high speed on impact with the iceberg 3. hull steel contained high levels of sulphur

5. Ductile to brittle Transition

6. Effect of sulphur The test showed high levels of both oxygen and sulphur , which implies that the steel was semi-kilned low carbon steel, made using the open-hearth process. High oxygen content leads to an increased ductile-to-brittle transition temperature , which was determined as 25 to 35°C for the Titanic steel.

7. Modern steels Most modern steels would need to be chilled below -60°C before they exhibited similar behavior like Titanic

8. Bhopal gas tragedy

9. Bhopal gas tragedy Bhopal gas tragedy, a disaster that happened by a Gas leak is considered as one of the world's worst Industrial catastrophes that occurred on the night of December 2–3, 1984 at the Union carbide India Limited (UCIL) Pesticide plant in Bhopal, Madhya Pradesh, India. The official immediate death toll was 2,259 and the government of Madhya Pradesh has confirmed a total of 3,787 deaths related to the gas release .

10. Methyl Isocyanate (MIC) A leak of  Methyl Isocyanate (MIC)  gas and other chemicals from the plant resulted in the exposure of thousands of people. The toxic substance spread its way in and around the neighborhood located near the plant. That Resulted in a very high death toll Exposure to low levels of methyl isocyanate can cause eye and throat irritation . People exposed to high levels of methyl isocyanate in the air have experienced severe lung and eye damage

11. How Happened? Water entered Tank E610 containing 40 tons of MIC . The resulting in exothermic reaction which increased the temperature inside the tank to over  200 °C(392 °F)  and raised the pressure. About 30 metric tons of methyl isocyanate (MIC) escaped from the tank into the atmosphere, which got added to a weak wind which frequently changed direction, which in turn helped the gas to cover more area in a shorter period of time (about one hour).