Task
Assignment Brief
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 approximately 30 pages excluding appendix.
Introduction
The National Transportation Safety Board (NTSB) is an independent United States federal government agency charged with determining the probable cause of transportation accidents, promoting transportation safety, and assisting victims of transportation accidents and their families. On July 11, 2012 at 2:03 a.m., eastern standard time, an eastbound Norfolk Southern Railway Company (NS) train derailed 17 cars within the city limits of Columbus, OH at a curve in the track. No train crewmembers sustained injuries. However, two citizens in the area sustained minor burn injuries.
Approximately 100 people were evacuated from an area of 1 mile surrounding the derailment. The train consisted of 2 locomotives, 97 loaded cars, and 1 empty car. The 3rd through the 19th cars derailed. Of the cars that derailed, three (positions 12 through 14) containing denatured ethanol breached, released product, and caught fire.
The derailment and ensuing fire destroyed both main tracks of the line. The railroad estimated the damage at over $1.2 million (Zakar and Mueller, 2016). During the on-scene investigation, multiple fractured rail segments were transported from the derailment site to a separate location within the Ohio State Fairgrounds for preliminary examination. Thirty-five rail pieces were recovered from the derailment area, several of which were attached to each other by joint bars. Of the pieces recovered, 24 of the exposed fracture faces exhibited transverse detail fractures, progressive fractures that originate at or near the surface of the rail head.
Three of these rail fragments were transported to the NTSB Materials Laboratory in Washington, DC for additional examination. Fractured rail has been studied extensively, with many fractures due to contact fatigue from rolling wheels of passing trains (Thompson et al., 1993, Grigorovich et al., 2006). Besides the primary loading on the rail, secondary loading from thermal and residual stresses (Ravaee and Hassani, 2007), as well as environmental changes such as temperature, strongly as environmental changes such as temperature, strongly influence the likelihood of track failures (Edel, 1988).
Wheel-rail contact is only one of a variety of loading conditions requiring complicated long-term studies to determine appropriate life and inspection limits of rail under service (Orringer et al., 1988). The rail industry has classified rail defects and failures with nomenclature unique to the business (Zakar and Mueller, 2016). Progressive fractures initiating at or near the rail surface, called detail fractures in North America, are denoted by the orientation relative to the rail rolling direction.
Transverse detail fractures can initiate due to rolling contact fatigue failure modes such as shelling (a longitudinal separation of the rail head near the wheel running surface) and head checking (transverse cracking on the gage corner from excessive surface cold working). These failure modes are typical when shear stresses at the wheel- rail contact region exceed the limits for the rail steel. Detail fractures also initiate at internal defects in the rail from manufacturing flaws (Tov and Vyaz'mina, 1976). Understanding and detecting these and other failure mechanisms is important in preventing catastrophic derailments due to rail failure.
Part A: Failure Analysis
"Failure Analysis" is part of this assignment. In the form of a client brief, review similar failures documented in the past; provide insights into the current failure investigation into train derailment caused by fractured rail.
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 the literature.
3)Comment on whether additional information or additional investigation is required (E.g.: Sample testing).
4)Recommend suitable solutions or rectification to the problem (based on certain assumptions).
Part B: Materials Selection
"The National Transportation Safety Board (NSTB) determined the probable cause of this accident was a broken rail that exhibited evidence of rolling contact fatigue. While no recommendations were developed specifically from this accident, the NTSB did reiterate previous safety recommendations~etc.
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. Even though NSTB not decided recommendations, you are now required to derive recommendation(s) in your report on selecting suitable materials to avoid such failures (some assumptions may be required).
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 additional information or additional investigation required.
5)Recommend suitable materials and treatments needed for the rail (based on certain assumptions).
Notes:
•This is a major assignment for Materials Technology and is used as a skill application exercise and consolidation of studies done in the course.
•The purpose is for students to consolidate and apply their knowledge gained; and apply critical thinking and have a deeper appreciation of materials in a real-world case study.
•This assignment is an open-ended explorative and lateral thinking exercise but must exhibit a systematic and engineering approach to failure analysis and materials selection.
•There are no single correct answers or right format for the journal. It is encouraged for students to develop their own methodology based on literature.
•The report(s) needs to address the criteria adequately to demonstrate their knowledge and thought process. Any proposed failures/materials selection must be supported by strong reasoning and justification based on sound evidence; if no evidence is provided, then assumptions/limitations must be stated with further work (e.g. investigation or testing) proposed.
•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.
