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Format: Format Kindle
This is a good forensic and historical evaluation of some factors that may have played a key role in the Titanic's sinking. The role of metallurgy, quality control, construction techniques and poor design assumptions is highlighted, with painstaking efforts to replicate the material and workmanship prevalent at the time of the doomed ship's fabrication. Naturally, any engineer can quibble with the authors' details and conclusions, but overall I think they have it right. Connections are typically what fail first in any structure, and the rivets used to waterseal the big boat were subject to considerable variation in quality. The toughness issue which earler investigators had pinpointed as the cause of the hull rupture is debunked, but not entirely, in my opinion as a materials engineer. Unquestionably the material would be deemed poor in toughness by the ubiquitous Charpy test, but the key question for the authors is, was it tough enough to resist fracture while the riveted seams parted anyway? At the end of that cold tragic day, it mattered not a whit whether the flooding holes in the ship's side were caused by cracked metal or torn seams. The primary lesson for engineers is that your structure is only as good as its weakest link and your assumptions had better make sure that link is tested to the max. A good little book that may require the reader to know a smidgen about steel.
4 internautes sur 6 ont trouvé ce commentaire utile
W. D ONEIL
- Publié sur Amazon.com
It is really hard to know how many stars to give this. When it is good, it is very, very good indeed, but when it is bad....
Foecke is a prominent materials scientist who was called upon to participate in the forensic examination of the Titanic remains but fell out with the leadership over research and publication issues. Hooper McCarty did a PhD dissertation (JHU, 2003) in materials science entitled "Analysis of the Rivets from the RMS Titanic Using Experimental and Theoretical Techniques." Together they have done about all the work that has ever been done on the analysis of the wrought iron and steel rivet material from the wreck. If you want to understand the materials issues in these rivets, they are the authorities.
Unfortunately they are not quite so authoritative on the implications. One useful additional piece is provided by Richard Woytowich, "Riveted Hull Joint Design in RMS Titanic and Other Pre-World War I Ships," Marine Technology 40, No. 2 (Apr 2003): 82-92 (whose timing unfortunately that they could not make use of Woytowich's work, and vice-versa). Woytowich is a professor of mechanical/marine engineering and knows much more than Hooper McCarty and Foecke show any evidence of about how ships were put together, and is better able to show clearly what the implications of rivet problems were.
Unfortunately, the work of Woytowich never got integrated with that of Hooper McCarty and Foecke. If you don't have a fairly good engineering background (and access to Woytowich's paper) it might be tricky to fill in the gaps.
The amount of wrought iron rivet material recovered from the wreck site is small. On the other hand Hooper McCarty and Foecke were analyzing it on micrometer scales, so that they could learn a great deal from a little bit of material and could not possibly have analyzed very much of it. It would be better to have a bigger sample, but what they do have is highly revealing. What it shows under their examination, beyond any question, is that there was at least some very bad wrought iron used for rivets in TITANIC.
They are also basically correct in thinking that it would not take very many weak rivets in way of the iceberg impact points to cause a seam to let go over a considerable length -- Woytowich leaves no doubt about that. With the seam under load, failure of a few rivets would transfer inordinate load to the adjacent rivets, which may very well let go even if they are not particularly weak. The reason for this is made clearer by Woytowich, who shows that joint efficiency was low as designed, even assuming full-strength rivets.
Where Hooper McCarty and Foecke fall down in all this to an extent is in having a wrong picture of the rivets in the shell plating below the waterline at the bow. They seem to imagine that these had formed snap heads and were inserted from outboard, with the riveters setting the points up in snap form from inboard. In fact, in TITANIC the iron rivets had formed pan heads which were inboard and the riveters beat the points down flush into the countersink in the outboard plate, chipping them as need be to make them flush. (This is quite different to how the hydraulically-set rivets were treated, which may have confused them). However, this does not appear to do anything to invalidate their picture of the seam letting go, rather than soft ice somehow cutting through tough steel.
The authors do quite thoroughly demolish the idea that the mild steel material of the shell plating was lacking in toughness in any meaningful sense. It was quite good quality steel for the day and perfectly adequate to the use.
They also go into a number of other issues, with some hits and some misses.
Unfortunately, the writing of the book is pedestrian and the organization is atrocious. And they have compressed a relatively small amount of meat (because they do not go into all the details of the analysis) into an extended book, which feels fairly puffy as a result.
If you want more technical meat without all the other stuff you may do better reading Jennifer J. Hooper et al., "Metallurgical Analysis of Wrought Iron From the RMS Titanic," Marine Technology 40, No. 2 (Apr 2003): 73-81, or (pretty much equivalently) J. J. Hooper et al., "The Metallurgical Analysis of Wrought Iron From the RMS Titanic," Measurement Science and Technology 14, No. 9 (Sep 2003): 1556-63.