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7/27/2019 Engineering Failure Analysis
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Engineering Failure Analysis
Amena JalilJunior EngineerNational Centre for NDT (NCNDT)
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Engineering Products and Their
Performance
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Main stages in the history of an engineering product
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Engineering Products and Their Performance Contd
Engineering design is essentially a decision making
process .
(i) geometry and dimensions of different parts, (ii)
types of materials used in manufacturing and their
specifications, (iii) fabrication and assembling
techniques, and (iv) service conditions.
Design is initiated after establishing the market needfor a new product or improving the performance of
an existing product.
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Engineering Products and Their Performance Contd
Following this stage, the design is materialized into a
commercial product by the manufacturer.
Finally, the product is put into service to meet its
functional requirements specifying the procedures of
start-up and shut down as well as the maintenance
procedure and its schedule.
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Failure of Engineering Products When an engineering product ceases to perform one
or more of its functions well before its expected
service life, it is said to fail.
Failures can cause loss of lives, unscheduled shut
downs of plants, increasing maintenance and repair
costs as well as very costly litigation and damages .
Weakest link in the chain.
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Definition and Objective of Failure
Analysis Investigations
To determine the cause of failure of a certain
product.
Findings are documented in a report. Results of failure analysis investigations can be
extremely useful to designer s of the same or
similar products.
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Definition and Objective of Failure Analysis
Investigations Contd
Manufacturers can also use the results of failure
analysis investigations for marketing purposes to
promote a new product with better performance
capabilities.
Furthermore, by identifying the deficiencies of
certain structural materials through failure analysisinvestigations, it is possible to develop new materials
or improve the properties of existing materials.
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Typical Defects
Material imperfections, defects generated
during service, and defects introduced as a
result of faulty design practice. Defects can be found within the original
material supply or can be introduced during
the manufacturing process.
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Failure Analysis Procedure
Dependent upon the particular case.
1. What is the mode of failure?
2. What is the most probable cause of failure?
3. How can failure be prevented in the future?
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Failure Analysis Procedure Contd
Any effective failure analysis investigation
must involve three main stages:
(i) clear definition of the problem(ii) complete search of the literature
(iii) development of an experimental program
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Definition Of The Problem
Analyst meets with concerned personnel such as
process engineers, maintenance engineers, etc. to
discuss the problem.
Ask questions..
Inspection of failure site.
Photographic documentation of the failed
component.
Depth of information obtained, site inspection, as
well as the skill and judgment of the analyst.
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Failure analysis of PSV springs of 17-4PH
stainless steel
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Methodology
Chemical analysis
Examination of the fractures.
Microstructural examination
Hardness measurements.
Observation of the cracking surfaces in the scanning electron
microscope .
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