Types of fractures -At a glance with few case studies

TYPES OF FRACTURES

1. BME18007-ENGG
METALLURGY
GOOGLE MEET -5

2. CONTENTS PREVIEW
• TYPES OF FRACTURE
•DUCTILE FRACTURE
•BRITTLE FRACTURE
•DBT
•FATIGUE FRACTURE
•CREEP FRACTURE

3. Failure Vs Fracture
•Failure can be defined, in general, as an event that does not accomplish its
intended purpose.
• Failure of a material component is the loss of ability to function normally.
•Components of a system can fail one of many ways, for example excessive
deformation, fracture, corrosion, burning-out, degradation of specific properties
(thermal, electrical, or magnetic), etc.
• Failure of components, especially, structural members and machine elements can
lead to heavy loss of lives, wealth and even may jeopardize the society!
•. Causes for failure include: improper materials selection, improper processing,
inadequate design, misuse of a component, and improper maintenance.
• It’s the engineer’s responsibility to anticipate and prepare for possible failure;
and in the event of failure, to assess its cause and then take preventive measures.

4. Fracture
•Fracture is a form of failure, and is defined as the separation or
fragmentation of a solid body into two or more parts under the action
of stress.
•The process of fracture can be considered to be made up of two
components:
1.crack initiation followed by
2.crack propagation.

5. Fractures are classified w.r.t. several
characteristics
•Ductile fracture
•Brittle fracture
•Ductile Brittle Transition (DBT)
•Fatigue fracture
•Creep fracture

10. DBT …Catastrophes
•Ductile to brittle transition is about how small changes in ambient
temperature can make a big difference in terms of mechanical
performance.
•Cold shortness was a big problem for a long time in sword making. It
means that things get brittle when it's cold.
•Back in the World War II era, there were some ships called the LIBERTY
SHIPS which were a British design, but manufactured largely in the United
States. But in the process, when these ships were sent into very cold North
Atlantic waters, some failed. Some literally split in half. They fractured
catastrophically.
•Due to ….DBT/COLD SHORTNESS

13. REASONS FOR ENGINEERING DISASTERS
•A disaster is referred as Engineering disaster ,when the failure is
caused by an Engineering failure.
•Design flaws
•Material failure
•Insuffient knowledge
•Different underestimations
•Even carelessnessness