Talk:Specific strength

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Diamond[edit]

There are a few other common (recognizable at least) materials in this list so I was wondering if diamond could go in this list. Anyone know where it would go? Loonybin0 20:00, 19 October 2011 (UTC) — Preceding unsigned comment added by Loonybin0 (talkcontribs)

Data table[edit]

The data table is available at the numsum spreadsheet n°18451 and is editable by the user "wikipedia" which have the password "wikipedia". --Marc Lacoste 20:33, 17 April 2006 (UTC)


EDIT: NOTE

This should be stated as a Strength to Mass ratio.... as Weight and Mass are 2 different things, the units are not a strength to weight. —Preceding unsigned comment added by 209.195.64.15 (talk) 17:45, 30 July 2009 (UTC)

Table error[edit]

The density column has the data in kg/ m^3. I believe that it should be g/cm^3

the tensile strength refrence lists them in g/cm^3

Joe912 20:34, 14 February 2007 (UTC)

Orientation of breaking length[edit]

Because the table is about tensile, as opposed to compressive or bending strength, can it be assumed that breaking length implies a vertical column of material, simply supported from above, rather than from below or cantilevered? The article is not clear on this. — Swpbτ c 16:55, 19 December 2008 (UTC)

Yes. A vertical column of material, hanging straight down from some support and not touching anything else. Please edit the article to make this more WP:OBVIOUS. --68.0.124.33 (talk) 18:40, 31 December 2008 (UTC)

suggest merge[edit]

I would like to have detailed information on "the specific strength of ropes made from nanotubes" in one place. Otherwise the 3 or more places that describe this are likely to diverge and give conflicting information. And so I suggest moving information on that topic out of Space_elevator_safety#Cable_strength and Space_elevator#Cable into a subsection of specific strength, leaving behind a short summary and a link to that subsection. (Forgive me for using the "merge" template, when I don't really want to merge entire articles together; I just want to move some snippets of information from one article to another). Would "nanotube rope" be an appropriate heading for that subsection? --68.0.124.33 (talk) 18:40, 31 December 2008 (UTC)

Seems to be a bad idea to me. This article probably needs to have a few examples of uses and potential uses of high/low specific strength materials.- (User) Wolfkeeper (Talk) 18:57, 31 December 2008 (UTC)
I agree that this "specific strength" article needs a few examples of uses and potential uses of high/low specific strength materials. I also think that other articles should reference this article (perhaps with a short summary), rather than explain every detail again in each of those articles. Putting all the details about "the specific strength of ropes made from nanotubes" in one place seems to be encouraged by the Wikipedia:Content forking guideline. --68.0.124.33 (talk) 17:20, 3 January 2009 (UTC)

Specific velocity[edit]

This seems like a lot of nonsense to me. The units are not adding up. The fundamental purpose of Specific Strength is to get an understanding of a material's efficiency in terms of strength to weight ratio.

Taking the fundamental units, we see the following:

Strength, (Newtons per Square Meter) divided by Density (Kg per cubic meter) Newtons are composed of the fundamental units Kg times acceleration, therefore (Kg*m per seconds^2)

That leaves [(Kg*m/s^2)/m^2] /[kg/m^3]

This simplifies to 1/(m*sec^2)

I Do Not see where this velocity stuff has *any* validity and it merely confuses the fundamental idea. —Preceding unsigned comment added by 65.113.126.62 (talk) 17:30, 10 February 2009 (UTC)

You have got your math wrong, lets take it in steps:
[(kg*m/s^2)/m^2] /[kg/m^3] = [kg/s^2/m]/[kg/m^3] = [kg/s^2/m]*[m^3/kg] = [1/s^2/m]*m^3 = m^3/m/s^2 = m^2/s^2 = (m/s)^2
The unit of specific strength is velocity squared so the concept of specific velocity is correct.
It is a very powerful concept that the maximum speed of a construction for example the speed of a spinning cylinder is independent of scale and depends on the material and geometry only.
I am going to reinsert some of the text you deleted.

Gr8xoz (talk) 14:28, 27 March 2010 (UTC)

OR. UNCITED. BUNK. With prejudice, I removed that mystical made-up muddled fantasy. I'm shocked that it sat there for over three years without someone other than 65.113.126.62 suggesting the emperor had no clothes. Shame on you all!  :-) Anyone can do dimensional analysis. Showing (above) that the dimensions match is not the point. Units are frequently the same for things that are very different. Finding the same units does clue us in to possible relatedness, but it's not a signal to ferret-out (at the cost of all reason) a relation when it's not there. The same units doesn't make two things related. For example: torque and energy are both in force-length but are not the same thing at all. 108.7.15.10 (talk) 19:16, 31 December 2013 (UTC)

Material about space elevators not appropriate here[edit]

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.
Done. Wizard191 (talk) 19:11, 19 November 2009 (UTC)

There is no reason for this article to have a section on space elevators. There are lots of applications for materials with very high specific strength. Space elevators are a particularly interesting one, but this article is about a straightforward concept and needs to focus on that concept. It is like having a section on nuclear fusion in the article on "pressure" because fusion requires high pressure. Mark Foskey (talk) 04:37, 19 November 2009 (UTC)

Agreed. I'll see if I can move it out to the space elevator article. Wizard191 (talk) 14:51, 19 November 2009 (UTC)

The above discussion is closed. Please do not modify it. Subsequent comments should be made in a new section.


Ummm.. a discussion that lasted 10 hours and had two participants is closed???- Wolfkeeper 20:06, 19 November 2009 (UTC)
Most of these engineering articles don't get too much discussion action so if two or three participants agree on a certain direction I usually take it upon myself to implement it (unless another user volunteers to). If you are in disagreement I'm more than willing to discuss it more; it just seemed like a pretty logical and straightforward request. Wizard191 (talk) 20:27, 19 November 2009 (UTC)

Nothing about basalt fiber[edit]

The article hasn't nothing about basalt fiber.Agre22 (talk) 00:26, 23 November 2009 (UTC)agre22

Graphene composite useful to rank?[edit]

http://www.nature.com/ncomms/journal/v3/n1/full/ncomms1661.html

This graphene composite is interesting, although the standout property is toughness it ranks up there with titanium in specific strength. Up to 600 Mpa tensile strength for a ~2 gram sample.

I'd say it was worth adding to the list. — Preceding unsigned comment added by Louis.barson (talkcontribs) 12:37, 26 November 2012 (UTC)

The 600 MPa tensile strength is for 50% by weight of each of reduced graphene oxide fiber and single walled nanotubes. The fiber should be identified with all of the elements of the table filled in. It seems like a good addition to the table. Do you need help with the mechanics of the edit? - Fartherred (talk) 23:34, 26 November 2012 (UTC)

MYuri[edit]

The formula, given in the article is wrong. Formulas 1 Yuri = 1 (m/s)2 and 1 MYuri = 1 N/kg/m contradict each other. Indeed, 1 N/kg/m= (m/s2)/m=1/s2. So the last one should be 1 Yuri = N /(kg/m). Hence I'm removing the incorrect one and adding the correct one. Vikasatkin (talk) 03:24, 22 January 2013 (UTC)

Another column for the chart[edit]

Can we add a column "Pounds per cubic foot"?--Wyn.junior (talk) 11:39, 5 April 2014 (UTC)

Let's just stick to SI units, please. Hqb (talk) 07:07, 7 April 2014 (UTC)

Shouldn't this be rewritten?[edit]

(kN·m/kg)
Shouldn't this be this?
[kN·(m/kg)]
--Wyn.junior (talk) 14:32, 7 April 2014 (UTC)

No, why? "a·b/c" is perfectly unambiguous, and doesn't need extra parentheses, whether as "(a·b)/c" or as "a·(b/c)". (On the other hand, "a/b/c" would not be a valid unit formula according to the SI rules.) Hqb (talk) 15:31, 7 April 2014 (UTC)