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 (talk • contribs)

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)[reply]


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)[reply]

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)[reply]



Why would you mix CGS units (g/cm^3) with SI units? The SI unit for specific strength uses Pa m^3/kg. This is what is stated in the article.


There is no good reason to use g/cm^3 for density.PhillipKeane (talk) 04:45, 18 March 2019 (UTC)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]
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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

Agreed. I'll see if I can move it out to the space elevator article. Wizard191 (talk) 14:51, 19 November 2009 (UTC)[reply]
The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.
Ummm.. a discussion that lasted 10 hours and had two participants is closed???- Wolfkeeper 20:06, 19 November 2009 (UTC)[reply]
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)[reply]

Nothing about basalt fiber[edit]

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

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 (talk • contribs) 12:37, 26 November 2012 (UTC)[reply]

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)[reply]

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)[reply]

Another column for the chart[edit]

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

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

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)[reply]

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)[reply]

Data in tables is not accurate[edit]

It seems to me that the data in the tables is not accurate. Tensile strength for many materials can vary significantly based on manufacturing processes, but there is no detail of material types here.

Tensile strengths should use nominal values from a published table from an educational source. Not from a table that's in a company's product brochure of a new material they are trying to sell.

Just at first glance it appears that Aluminum, Stainless steel, and Titanium are wrong, which calls into question everything else on the table if those are so far off. The information on the other wikipedia pages that these link to doesn't even agree with this table. — Preceding unsigned comment added by 207.45.130.10 (talk) 19:51, 13 May 2015 (UTC)[reply]

I second that. I shall add "Dubious" to the article. The tensile strengths given for Aluminum alloy and Titanium seem to be in the right ball-park, however the tensile strength for steel seems WAY high. 2000 MPa is about 2.5 - 5 times higher than any other source I could find. It also doesn't make sense from an economic standpoint. Strength to weight ratio is critical to aerospace engineering, so why would advanced rockets be made of Aluminum alloy and Titanium if steel is cheaper and has a higher strength to weight ratio? [1] [2] [3] Fauble2000 (talk) 15:03, 20 August 2015 (UTC)[reply]

References

  1. ^ http://www.steelconstruction.info/Steel_material_properties#cite_note-BSEN1993-1-4-5
  2. ^ http://www.ezlok.com/TechnicalInfo/MPStainlessSteel.html
  3. ^ http://www.engineeringtoolbox.com/young-modulus-d_417.html

Table error[edit]

It appears that the line Titanium contains a calculation error. The breaking length should be ~7.7km based on the other values. An easy way to see this is that Titanium is listed as having a longer breaking length than the Titanium alloy (Best C), even though it has >3X worse specific strength. — Preceding unsigned comment added by 2601:184:4880:F3E7:B1B1:5799:35D3:4622 (talk) 02:07, 24 April 2017 (UTC)[reply]

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First Sentence and Paragraph are Unclear[edit]

The first sentence begins: "The specific strength is a material's tre|m]]...". The first paragraph seems to have gotten mangled in the edit of 29 Dec 2017; the article never does clearly state what the specific strength is. Since I am not an expert, I will not attempt to correct the article. 73.242.220.29 (talk) 15:24, 19 February 2018 (UTC)[reply]

Yup, well spotted. Many thanks, fixed.GliderMaven (talk) 17:37, 19 February 2018 (UTC)[reply]

yuri unit??[edit]

This made up supposed unit is not even mentioned on the Space elevator page let alone anywhere else. 2001:480:91:FF00:0:0:0:16 (talk) 20:32, 9 April 2019 (UTC)[reply]

The link in to referenced article is broken. Can the author of this section or provider of that link update it? — Preceding unsigned comment added by Isecscribe (talk • contribs) 13:53, 11 December 2020 (UTC)[reply]

Hair[edit]

Could we add human hair to the table of examples? It's probably the material most cited in media descriptions of tensile strength of fibers. -ProhibitOnions (T) 10:12, 24 June 2020 (UTC)[reply]

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