MEC3203 Course Name: MATERIALS TECHNOLOGY
This assignment carries 30% of the total assessment for this course
Assessment No: 2 Internal X
External X
Examiner: MAINUL ISLAM Moderator: STEVEN GOH
Due Date: 30 May 2019
Marking Guide
Part A: Failure Analysis – Assessment Criteria [150 marks (including Part C)]
1. Demonstrate a sound knowledge base in the relevant topic;
2. Demonstrate the ability to delineate the problem in the case study;
3. Demonstrate the ability to analyse (and critique) the potential failure modes, and propose the likely cause of failure and a strong justification/argument to back the assertion;
4. Demonstrate the ability to propose rectification or prevention strategies;
5. Demonstrate the ability to professionally present your report (including in-text citation and referencing).
Part B: Materials Selection – Assessment Criteria [150 marks (including Part C)]
1. Demonstrate a sound knowledge base in material selection methodology;
2. Demonstrate the ability to delineate the engineering requirements of the materials;
3. Demonstrate the ability to systematically apply material selection methods;
4. Demonstrate the ability to propose the best material(s), and a strong justification/argument to back the recommendation(s);
5. Demonstrate the ability to professionally present your report (including in-text citation and referencing).
NOTE: It is inadequate to provide an answer like ‘very hard steel’. Be specific in your material selection, and always support it with evidence (such as figures or material selection charts from materials handbook). You can find most of the information resources from the textbook, USQ Library Online or relevant library databases such as ASM Online. Use Harvard referencing style; refer to USQ Library website for details. Limit the number of pages of your report submission to approx. 30 pages excluding appendix.
MEC3203 MATERIALS TECHNOLOGY ASSIGNMENT 2, S1 2019 2
Part C: Oral Interview – Assessment Criteria [% of the Part A and Part B]
1. Demonstrate a sound knowledge in relevant materials topics and the case study;
2. Explain the approaches and relevant findings in failure analysis and materials selection.
NOTE: Scheduled 15mins “face-to-face” interviews will be scheduled with individual students after submission of report to validate and confirm the learning outcomes. Zoom video-conferencing will be used for external students to facilitate the interview. Failure to participate in the interview could result in deducting at least 10% marks.
CASE STUDY
Ensure to download all elements of the case study on the crash of de Havilland Comet BOAC Flight 781 and its relevant reports. The case study will be used as a basis for your scenario.
Aviation Safety Network – Database
ASN Aircraft accident de Havilland DH-106 Comet 1 G-ALYP Elba, 10 January 1954 https://aviation-safety.net/database/record.php?id=19540110-1
Date: Sunday 10 January 1954
Comet G-ALYP left Rome-Ciampino Airport (CIA) at 10:31 on a flight to London. After taking off the aircraft was in touch with Ciampino control tower by radio telephone and from time to time reported its position. These reports indicated that the flight was proceeding according to the B.O.A.C. flight plan and the last of them, which was received at 10:50, said that the aircraft was over the Orbetello Beacon. The captain of another B.O.A.C. aircraft, Argonaut G-ALHJ, gave evidence of communications which passed between him and G-ALYP. The last such message received by the Argonaut began – George How Jig from George Yoke Peter did you get my – and then broke off. At that time, approximately 10:51, the aircraft was probably approaching a height of 27,000 feet. The Comet descended and crashed into the sea off the Island of Elba.
Initial examination and reconstruction of the wreckage of G-ALYP revealed several signs of inflight break-up. Shreds of cabin carpet were found trapped in the remains of the Comet’s tail section; the imprint of a coin was found on a fuselage panel from the rear of the aircraft; and Smears and scoring on the rear fuselage were tested and found to be consistent to the paint applied to the passenger seats of the Comet.
When most of the wreckage was recovered, investigators found that fractures started on the roof, a window then smashed into the back elevators, the back fuselage then tore away, the outer wing structure fell, then the outer wing tips and finally the cockpit broke away and fuel from the wings set the debris on fire.
To find out what caused the first failure, BOAC donated G-ALYU for testing. The airframe was put in a huge water tank, the tank was filled, and water was pumped into the plane to simulate flight conditions. After the equivalent of only 3,000 flights investigators at the Royal Aircraft Establishment (RAE) were able to conclude that the crash had been due to failure of the pressure cabin at the forward ADF window in the roof. This ‘window’ was in fact one of two apertures for the aerials of an electronic navigation system in which opaque fibreglass panels took the place of the window ‘glass.’ The failure was a result of metal fatigue caused by the repeated pressurization and de-pressurization of the aircraft cabin.
Another worrying fact was that the supports around the windows were only riveted not glued, as the original specifications for the aircraft had called for. The problem was exacerbated by the punch rivet construction technique employed. Unlike drill riveting, the imperfect nature of the hole created by punch riveting may cause the start of fatigue cracks around the rivet.
The Comet’s pressure cabin had been designed to a safety factor comfortably in excess of that required by British Civil Airworthiness Requirements (2.5x P as opposed to the requirement of 1.33x P and an ultimate load of 2x P, P being the cabin ‘Proof’ pressure) and the accident caused a revision in the estimates of the safe loading strength requirements of airliner pressure cabins.
Probable Cause:
PROBABLE CAUSE: -We have formed the opinion that the accident at Elba was caused by structural failure of the pressure cabin, brought about by fatigue. We reach this opinion for the following reasons: –
(i) The low fatigue resistance of the cabin has been demonstrated by the test described in Part 3, and the test result is interpretable as meaning that there was, at the age of the Elba aeroplanes a definite risk of fatigue failure occurring.
(ii) The cabin was the first part of the aeroplane to fail in the Elba accident.
(iii) The wreckage indicates that the failure in the cabin was of the same basic type as that produced in the fatigue test.
(iv) This explanation seems to us to be consistent with all the circumstantial evidence.
(v) The only other defects found in the aeroplane were not concerned at Elba, as demonstrated by the wreckage. –
Part A FAILURE ANALYSIS
Scenario for the -Failure Analysis- part of this assignment is in the form of a client brief in reviewing similar failures documented in the past to provide some insights into the current failure investigation into structural failure of the pressure cabin:
1) Outline a brief background on the failure, operations, and its operating environment;
2) Provide an analysis of the potential causes of failure based on an extensive review of literature;
3) Review and critique any “failure report” found; comment specifically on whether the methodology is suitable and adequate based on your extensive review of literature; 3) Comment on whether additional information or additional investigation is required (e.g. sample testing); and
4) Recommend suitable solutions or rectification to the problem (based on certain assumptions).
Part B MATERIALS SELECTION
“The de Havilland Comet I entered service in 1952, and became the first commercial airliner to be powered by jet engines. It was introduced as the flagship aircraft on the routes of the British Overseas Airways Corporation, and was hailed as a triumph of British engineering. However there were a number of accidents involving this aircraft, culminating, in 1954, in the loss of two aircraft in similar circumstances. These were Comet G-ALYP near Elba, and Comet G-ALYY near Naples. A Court of Inquiry was convened, and the task of discovering the cause of these accidents was given to the Royal Aircraft Establishment at Farnborough. The investigation explored a number of avenues, and finally gave structural failure of the pressure cabin brought about by fatigue as the cause of the accidents.” (P. A. Withey, in Failure Analysis Case Studies II, 2001).
Far from the conclusion came out of investigations conducted by various parties and also out of your own report as part of Part A Failure Analysis, you are now required to derive recommendation(s) in your report on selecting suitable materials to avoid such failures (some assumptions may be required).
Scenario for the -Materials Selection- part of this assignment is in the form of a client brief:
1) Provide an outline and analysis of the performance requirements;
2) Evaluate and select an appropriate materials selection method;
3) Systematically justify your selection of materials for the component(s);
4) Comment on whether additional information or additional investigation is required;
5) Recommend suitable materials for the pressure cabin (based on certain assumptions).
Some background information to provide context for the problem:
· https://en.wikipedia.org/wiki/De_Havilland_Comet
· https://en.wikipedia.org/wiki/BOAC Flight 781
· https://www.youtube.com/watch?v=_BZnn5OYcBc
· https://www.youtube.com/watch?v=o8DTrLN8uMA
· https://www.sciencedirect.com/topics/engineering/de-havilland-comets
· https://www.baaa-acro.com/sites/default/files/import/uploads/2017/04/G-ALYP.pdf
· https://www.thisdayinaviation.com/tag/flight-781/
· http://calleam.com/WTPF/?p=3578
· http://www.bbc.com/future/story/20170404-the-british-airliner-that-changed-the-world
· https://www.news.com.au/travel/travel-advice/flights/the-tragedies-that-changed-the-shape-of-plane-windows-forever/news-story/bc723a15ce58a97d839483bfd0e7ce4a
The aim is to learn consolidate and apply their knowledge gained in a real world case study requiring failure analysis and materials selection, and further complemented by a need to investigate deeper into the relevant sources. The key focus will be strong reasoning and justification supported by sound evidence/assumptions for both failure analysis and material selection tasks. Use the marking rubric provided.
Assessment criteria sheet for MEC3203 Assignment 2, S1 2018
Level 1
Level 2 Level 3 Level 4 Level 5
0-4 marks
No attempt or
knowledge
demonstrated
were limited
and/or without
support. 4-8 marks
Knowledge
demonstrated
was either
incorrect or
poorly articulated
and supported. 8-12 marks
Knowledge
demonstrated
was somewhat
correct and
adequately
articulated and
supported. 12-16 marks Knowledge demonstrated was clear, correct, and well articulated and supported. Limited evidence provided. 16-20 marks
Knowledge demonstrated was clear, correct, comprehensive and extremely well articulated and supported; Further evidence included. 20
0-8 marks
No attempt or
limited delineation
of the case study
problem. 8-16 marks
Poor delineation
of the case study
problem. 16-24 marks Delineation was
somewhat
articulated, and
adequately
supported and/or
justified. 24-32 marks Delineation was clear and well
articulated, supported and/or justified. 32-40 marks
Delineation was clear,
comprehensive and extremely well articulated, supported and/or justified. 40
0-8 marks
No attempt or the
analysis (and
critique) was
limited and/or
without support or
justification. 8-16 marks
The analysis (and
critique) was
poorly
articulated,
supported and/or
justified. 16-24 marks
The analysis (and
critique) was
somewhat
articulated,
supported and/or
justified. 24-32 marks The analysis (and critique) was clear and well articulated, supported and/or justified. 32-40 marks
The analysis (and critique)
was clear, comprehensive
and extremely well
articulated, supported
and/or justified. 40
0-8 marks
No attempt or
proposed
strategies were
limited and/or
without support or
justification. 8-16 marks
Proposed
strategies were
poorly
articulated,
supported and/or
justified. 16-24 marks
Proposed
strategies were
somewhat
articulated,
supported and/or
justified. 24-32 marks
Proposed strategies
were clear and well
articulated,
supported and/or
justified. 32-40 marks
Proposed strategies were clear, comprehensive and extremely well articulated, supported and/or justified. 40
0-2 marks
No attempt at in
text citations and
referencing and/or
professional
presentation and
language were
limited. 3-4 marks
Poor
demonstration of
in-text citations
and referencing
and/or
professional
presentation and
language. 4-6 marks
Adequate
demonstration of
in-text citations
and referencing
and/or
professional
presentation and
language. 6-8 marks
Good demonstration
of in-text citations
and referencing
and/or professional
presentation and
language. 8-10 marks
Excellent demonstration of
in-text citations and
referencing and/or
professional presentation
and language. 10
150
Level 1
Level 2 Level 3 Level 4 Level 5
0-4 marks
No attempt or
knowledge
demonstrated were
limited and/or
without support. 4-8 marks
Knowledge
demonstrated
was either
incorrect or
poorly articulated
and supported. 8-12 marks
Knowledge demonstrated was somewhat correct
and adequately articulated and supported. 12-16 marks
Knowledge demonstrated was clear, correct, and well articulated and supported. Limited evidence provided. 16-20 marks
Knowledge demonstrated was clear, correct, comprehensive and extremely well articulated and supported; Further evidence included. 20
0-8 marks
No attempt or limited delineation of the engineering
requirements. 8-16 marks
Poor delineation
of the engineering
requirements. 16-24 marks
Delineation was
somewhat articulated, and adequately supported and/or
justified. 24-32 marks
Delineation was
clear and well
articulated,
supported and/or
justified. 32-40 marks
Delineation was clear,
comprehensive and extremely well articulated, supported and/or justified. 40
0-8 marks
No attempt or application of method(s) was limited and/or
without support or justification. 8-16 marks
Poor application
of method(s)
and/or with some
support or
justification. 16-24 marks Adequate application
of method(s) with
support or justification. 24-32 marks
Good application of
method(s) with
support or
justification. 32-40 marks
Excellent application of method(s) with support or justification. 40
0-8 marks
No attempt or
materials selection proposal was limited and/or
without support or justification. 8-16 marks
The materials
selection proposal
was poorly
articulated,
supported and/or
justified. 16-24 marks
The materials
selection proposal was
somewhat articulated,
supported and/or
justified. 24-32 marks
The materials
selection proposal
was clear and well
articulated,
supported and/or
justified. 32-40 marks
The materials selection
proposal was clear,
comprehensive and
extremely well articulated,
supported and/or justified. 40
0-2 marks
No attempt at in
text citations and
referencing and/or
professional
presentation and
language were
limited. 3-4 marks
Poor
demonstration of
in-text citations
and referencing
and/or
professional
presentation and
language. 4-6 marks
Adequate demonstration of in-text citations and referencing and/or
professional presentation and language. 6-8 marks
Good
demonstration of in
text citations and
referencing and/or
professional
presentation and
language. 8-10 marks
Excellent demonstration of
in-text citations and
referencing and/or
professional presentation
and language. 10
150

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