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

6. Ductile to brittle Transition

8. 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.

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

10. Bhopal gas tragedy

11. 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 .

14. 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

15. 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).