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Historical failures

  1. Dec 29, 2005 #1
    what are in the history the big disasters that have taken due to material failure...like i some somewhere there was an huge ship which can carry 20 planes but it was passing/standing in a very cold water,,so that it breaked exactly in the middle....
     
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  3. Dec 30, 2005 #2

    Astronuc

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    heman, you may be thinking of the Liberty ships during War War II (1940-1945), which were made with welded steel construction rather than riveted plate construction. The welded steel was more brittle in cold water of the North Atlantic, and combined with design issues, e.g. doorways in the metal structure, which had sharp corners, and stress concentrations lead to overloads and failure.
    http://www.key-to-steel.com/Articles/Art136.htm
    http://www-g.eng.cam.ac.uk/125/noflash/1925-1950/tipper.html

    See also - http://www.twi.co.uk/j32k/protected/band_13/oilgas_caseup31.html
    See also this for some industrial case studies - http://www.tech.plym.ac.uk/sme/Interactive_Resources/tutorials/FailureAnalysis/index1.html

    Good site about corrosion - http://www.corrosion-doctors.org/Forms/FormType.htm

    Gas turbine failure - http://www.swri.edu/4org/d18/mechflu/planteng/gasturb/failure.htm

    There was also problems with DeHavilland's Comet aircraft resulting in fatigue failures - http://en.wikipedia.org/wiki/De_Havilland_Comet

    I'll try to see if I can dig up more.
     
  4. Dec 30, 2005 #3

    PerennialII

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    Another example of brittle failures are bridge related ones, this site has a collection of them:
    http://filebox.vt.edu/users/aschaeff/silver/silver.html
    'we' redid the Point Pleasant analysis using 'modern' methods just last year as a demonstration case of how accurately we could predict the event of failure (cleavage initiation from interacting SCC cracks), assess material properties and so forth. Proved to be an interesting case & the analysis of course was dead-on.
     
  5. Dec 30, 2005 #4
  6. Dec 30, 2005 #5
    From school two stick in my mind:

    -Tacoma narrows bridge (harmonic resonance)
    -Some big friggin cantelevered mall in Japan (forget the name) But the mech eng was stressed for time and screwed some numbers up. The cantelever snapped and it collapsed killing a lot of people on one of the first days open. edit: I think Im thinking of the Hyatt from above and getting confused with:

    http://blogs.nationalgeographic.com/channel/blog/2005/09/explorer_collapse.html

    guess it didnt stick that well after all
     
    Last edited: Dec 30, 2005
  7. Dec 30, 2005 #6

    Astronuc

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    The bridge and building failures were structural/design failures, related to improper design, rather than material failures. Both facets are important to the engineer.

    A material of a given composition and manufacturing route will have a certain set of intrinsic material properties, e.g. yield strength, ductility, fracture toughness, etc., and those properties will have a certain dependence on environmental variables.

    In addition, the structure or product in which those materials are used will have a certain geometry, and often a complex geometry. Furthermore, the structure and product will be exposed to variable loads in a variable environment, and the material(s) will be subjected to time varying loads under different environments.

    It is incumbent upon the responsible engineer to know, understand and appreciate all of these factors, and to choose a material that will serve up to and beyond the intended design life and under all potential combinations of service conditions and environment. Failure to do so can and will result in catastrophic failure with potentially significant economic loss, and more significantly, injury and/or loss of life.
     
    Last edited: Dec 30, 2005
  8. Dec 31, 2005 #7
    Those are design failures but they are also material failures. I think a design failure independent of material would be where an unstable structure collapses. Yielding or fracture is not necessary, the structure collapses from a lack of stability (boundary conditions).
     
  9. Dec 31, 2005 #8

    russ_watters

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    The Space Shuttle Challenger - O-rings that got brittle at low temperature.
     
  10. Dec 31, 2005 #9

    brewnog

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    I was going to suggest the Markham Colliery disaster, which I seem to recall was reported to have been due to material imperfections, but I think Lord Astronuc has a point, - had these things (bridges, ships, lifts, o-rings) been designed completely properly, taking into account all possible parameters, then the engineers would have taken steps to account for all eventualities.

    Obviously I'm not pointing fingers, and engineers are (mostly) only human, but what is the definition of a 'material failure'? It might be prudent to limit this to cases where the materials used, for whatever reason, did not meet the design criteria (in terms of metallurgical composition, grain structure, that kind of thing) rather than design of the structure/product itself.

    I don't think this has anything to do with unstable structure collapse, yielding, fracture, or boundary conditions. I subscribe to the idea that if something stops being fit for purpose, it has failed.
     
  11. Dec 31, 2005 #10
    Design codes are constantly evolving from such failures, looking at how the material fails is key to revising the equations that engineers use. Recent building and bridge failures from earthquakes have resulted in tremendous code revisions, without looking at how the material failed, there would be no progress in the design process other than to throw more material at it without thought.
     
  12. Jan 1, 2006 #11

    PerennialII

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    .... think drawing the line between design/material is somewhat difficult. Cases belonging directly to either are slam dunks (in terms of placing the 'blame'), but often (or even usually) failures result from neglect of 'something', like a certain failure mechanism of a material arising in conditions which we're 'something' other than thought of or unknown (which doesn't imply neglect in design or an inapropriate design itself, design methods don't usually reflect state-of-the-art knowledge of material behavior (for one)) - and the division doesn't quite work then.
     
  13. Jan 1, 2006 #12

    I think the Titanic was constructed with riveted plates, but it also had the same problem with low tempetures.
     
  14. Jan 2, 2006 #13

    russ_watters

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    The word "failure" is the engineering term for any time something breaks, but you can certainly distinguish between different types - sometimes the failure is an actual mistake and sometimes it is caused by not anticipating a certain situation. And sometimes it is a material that is thought to behave in one way, but doesn't. Ie, the brittle failures of the Challenger and the liberty ships were something that should have been anticipated (the Challenger actually was), but weren't. The behavior of materials in earthquakes wasn't understood until relatively recently, and some of those failures were not anticipated. The Tacoma Narrows bridge failure was way outside of what engineers planned for at the time.

    The only time it is ever possible for an engineer (or engineer's client) to go to jail over an engineering issue is if a situation should have been anticipated, but wasn't - or if it was, but was ignored. Ie, a club owner in Philly went to jail because the club was located on a pier and collapsed (killing several people) due to the resonance of dancing - just days after engineers inspected it and told the owner it was in danger of collapsing.
     
    Last edited: Jan 2, 2006
  15. Jan 2, 2006 #14

    Astronuc

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    The Titanic was constructed with the standard carbon steel (for marine construction) of the time, and that steel tended to have higher levels of sulfur and phosphorus, and insufficient Mn to mitigate the effects of sulfur. As a result, the steel was much more brittle at lower temperatures.

    The Titanic was not designed for 'hitting an iceberg' at speed, or with a glancing blow as is what apparently happened.

    Material was a factor, but the ship also encountered an abnormal operational situation for which it was not designed.


    As Russ indicated, the Challenger situation should have been anticipated.

    The Liberty ship problem occurred before the application of rigourous fracture mechanics was imposed. That was a material problem (low ductility or embrittlement at low temperatures, which could be encountered during service), as well as a design (stress concentrations) and manufacturing quality (poor welds and residual stress) in some cases.


    The Verrazano Narrows bridge occurred before proper structural testing became part of the design process. It was an example of flow induced vibration (fluid structure interaction, vortex shedding) and was unanticipated at the time it was designed.
     
  16. Jan 2, 2006 #15

    russ_watters

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    Well really, the Challenger situation was anticipated by engineers who were then coerced into giving approval for launch. Now that's a prime engineering ethics case study.
    I didn't realize that - that's surprising.
     
  17. Jan 2, 2006 #16
    De Haviland Comet, the first Jet Airliner was a disaster waiting to happen. And it happened quite a lot. It took a long time before the reason was clear. It was metal fatique, the repetition of forces imposed on the structure eventually caused it to collapse. For the Comet it seemed to be the window sils due to the recurring stress of the pressure differential between the cabin and the outside. After all it was the first large pressured cabin in an aircraft.

    But the lessons were taken and fatique stress is one of the most important design items for aircraft nowadays.
     
  18. Jan 2, 2006 #17

    Astronuc

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    http://www.nrl.navy.mil/content.php?P=FRACTUREMECH
    and it wasn't until the 1950's that fracture mechanics research took off.

    Some history - http://www.vbt.bme.hu/phdsymp/2ndphd/proceedings/ceriolo.pdf

    Fracture mechanics - http://www.key-to-steel.com/articles/art45.htm
    It is important to realize that Griffith's work was applied to brittle materials, but steel was not necessarily considered brittle. See also - http://nvl.nist.gov/pub/nistpubs/sp958-lide/html/181-183.html

    And -
    from Wikipedia
     
    Last edited: Jan 2, 2006
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