Talk:Yield (engineering)

Missing Definition?

Is the meaning of the greek letter 'nu' given anywhere in the isotropic yield criteria? — Preceding unsigned comment added by Jdc2179 (talk • contribs) 17:19, 7 June 2013 (UTC)

Suggestion

Add a link to the "von Mises stress" page

Suggestion

Do you think it would be a good idea to insert a strain-stress graph? Fractografie 09:16, 12 August 2006 (UTC)

Absolutely! SietskeEN 19:29, 12 August 2006 (UTC)

Suggestion

I have recently been working on an article about ultimate failure in materials. Because this is the end result of an overyielded material I was wondering what the best way to incorporate my site within this one was. I was thinking about adding a small section within this article, or just using a sentence or two to embed my site within this one. —Preceding unsigned comment added by Engl315ISU (talk • contribs) 05:15, 14 April 2008 (UTC)

Suggest merging Elastic limit into this article

The two seem one and the same to me. If there's a good reason why that page shouldn't be merged with this, can someone please make the difference between them clear? 217.42.242.45 22:14, 3 May 2007 (UTC)

They're not quite the same -- "elastic limit" has a more precise definition than "yield stress" does. However, you might merge and redirect both elastic limit and proportional limit here, as long as the differences are clearly specified. 75.46.140.40 02:18, 12 May 2007 (UTC)

To follow that up, here is an online source for the definitions. Any merge should probably include an expansion of the "definition" section of this (yield) article. 75.46.140.40 13:59, 12 May 2007 (UTC)

I suggest this doesn't happen as many people studying A level Physics use this page often when learning about Young's Modulus and the deformation of solids.—Preceding unsigned comment added by 82.163.35.83 (talk • contribs) 12:03, May 31, 2007

Merging 2 articles: Yield (engineering) and yield surface

I see this topic of Yield (engineering) being the main article, and yield surface being part of the yield criterion subsection, where the yield surface is presented for each of the different yield criteria (e.g. Tresca, Von Mises, Drucker, etc)

The development of each of this Yield Criteria can be its own article, or they can just be included within the Yield (engineering) article.

Comments?

Sanpaz 15:50, 30 August 2007 (UTC)

That sounds good to me. I think the two articles above can be merged in too since they are just definitions—that will be easy so I'll go do that now. -- Basar (talk · contribs) 01:11, 2 September 2007 (UTC)

I'm a tiny wikipedia contributor, I've written that article only because I needed this information and I couldn't (to my surprise) find it in wikipedia. If you wanted my opinion, then unfortunately I have no opinion about this. The "see also" at the bottom was good for me. A separate article means shorter URL if someone wants just 'yield surface'. Will the search box work if someone typed "yield surface" in it? You can move it if you really want to. On the other hand - wouldn't this article "outgrow" the Yield (engineering) article? You know, yield surface is a big topic, and I've written only a tiny part about it. For example there are several other representations of each surface (the formulas, I mean), if someone really did the homework well, this article could get 3 times bigger. Janek Kozicki 20:09, 11 October 2007 (UTC)

I find these two articles of sufficient length and depth that to not include both as they are is a disservice to wikipedia. If either article was not as indepth then the case should be made that one should be merged with the other. As it stands significant cuts would have to be made to each article in order for it to be conform to existing wikipedia standards if they were merged. Since neither article has had any talk on the subject of merging these two articles in the last three months I am going to take down the merge article tag and declare these two articles remain unmerged. Zippedpinhead (talk) 18:23, 13 December 2007 (UTC)

The length of the article is not a reason for not merging. Merging has to do more with the fact that Yield surface is not a topic by itself. It forms part of the overall topic of Yield and Yield Criteria. I see the whole structure of various related articles as: Plasticity (physics) being the starting point. Yield (engineering) as a sub-article. In the later the topics of yield criterion, yield curve, yield surface, flow rule, associated and non-associated flow rule, etc, would be addressed. Then from this article links to other Yield Criteria articles (Von Mises, Tresca, Drucker-Prager, Mohr-Coulomb, etc) can be placed. In each of this articles I see the specific Yield surface, yield curve, etc, for each criteria, being addressed. I have not done this for lack of time, but if somebody is up to it, go ahead. Sanpaz (talk) 21:52, 13 December 2007 (UTC)

As a large number of yield loci formulations exist, I think the modular structure proposed above would be well suited for future articles in that area. mastic 11:22, 3 September 2007 (UTC) —Preceding unsigned comment added by Mutrux (talk • contribs)

Civil engineering ?

Yield surfaces are used in other areas of engineering as well, for example in sheet metal forming simulations. Wouldn't it make sense to put the articles in a broader category?

mastic 11:30, 3 September 2007 (UTC)—Preceding unsigned comment added by Mutrux (talk • contribs)

Yes, if you are referring to the WikiProject, just ignore that as it does not represent the articles classification, just which organized groups are helping the article. Organized groups may not exist for other relevant fields. The article's actual categorization is seen on the bottom of the article where it is currently in materials science and solid mechanics. Civil engineering links into solid mechanics, but I don't know about other areas of engineering such as mechanical or industrial. I think they should link in if they don't. -- Basar (talk · contribs) 15:35, 3 September 2007 (UTC)

Fikret Mert Veral

I think this may be the name of the person who added the info about the material "Steel, API 5L X65" to the original table in the tensile strength article. Searching Google, I can't find any non-(wikipedia or copy and paste job) page that returns both API 5L X65 and Fikret Mert Veral. I propose removing it from the table. Khakiandmauve (talk) 18:21, 26 June 2009 (UTC)

Good catch. I've removed it. Wizard191 (talk) 17:30, 27 June 2009 (UTC)

Brittle Materials

Is there a reason the table contains brittle materials such as glass and concrete in an article about yielding (other than that it was copied from the tensile strength article)? I think it's a good idea to remove from the table anything that doesn't have a value for yield.Khakiandmauve (talk) 18:28, 26 June 2009 (UTC)

Agreed. Wizard191 (talk) 17:31, 27 June 2009 (UTC)

Macroscopic samples of most materials tend to "yield" almost as soon at a stress is applied to them. However, for practical reasons, a phenomenological "yield point" is identified from a stress-strain curve for certain materials where it is relatively easy to identify such a point. Though the yield points of concrete, rocks and other "brittle" materials may be difficult to determine under uniaxial loading conditions, these materials can have well defined yield strengths that vary with the applied pressure. Bbanerje (talk) 23:02, 28 June 2009 (UTC)

While you are completely right, and I think that some form of it should be included in the article, I still think that the brittle materials should be removed from the table. Yield stresses are an engineering construct meant to allow us to model scenarios where structural members fail due to yielding. Brittle materials are not designed to be loaded in a yielding manner, because they fail so quickly in that mode, and even if we wanted to model up a brittle material in a yielding situation, I believe the assumptions of the model quickly fail. As such, yield stresses are never determined or used by engineers. For the same reasons yield stresses are not usually used plastics, however they are still developed and published for "rough calculations". Wizard191 (talk) 23:31, 28 June 2009 (UTC)

Macroscopic samples of materials may tend to yield as soon as stress is applied, but that's not what's being represented in the table. The bigger issue to me is, we've got a table in an article about yielding that has both yield and ultimate strength columns, but some entries don't have values for yield. Based on that alone, I think they're detracting from the article. I could even make a case for removing the ultimate stress column entirely, but I think there's some value in comparing yield and ultimate strength. Khakiandmauve (talk) 00:23, 29 June 2009 (UTC)

Removed from the two tables anything that didn't have an entry for yield (including the gold, lead, silver, and zinc from the 2nd table). I hesistated to remove the ultra-high molecular weight polyethelene (UHMWPE) fibers, because of the references which also get deleted, but on checking, the link to the pdf file was broken and the other link doesn't show any information for yield. Also, I would recommend finding references for the properties. Matweb should be convenient for most of these (if primary sources are preferred, they provide those as well); I'd recommend adding the reference to the table caption, like "[1] except as noted", or something similar. Khakiandmauve (talk) 16:04, 1 July 2009 (UTC)

Stress Strain Plot

Shouldn't the vertical axis be σ=PA not σ=P/A as is the case now? Frankenstien (talk) 00:15, 11 May 2010 (UTC)

While "P" is an odd symbol to use for force, it is defined in the picture as the force so σ=P/A is correct. Wizard191 (talk) 00:46, 11 May 2010 (UTC)

Snapback

I was wondering if a body of knowledge exists on what I call paradoxical yield. This is when a stretched object 'snaps back' due to structural changes when stretched past the yield point. For instance clothing stretched by surface tension shrinks when the stress is removed. (Examples are harder to find for bodies surviving compressive yield) 24.184.234.24 (talk) 01:50, 14 April 2011 (UTC)LeucineZipper

Yeah, it's a common effect in bending processes, and the effect is known as spring back. Wizard191 (talk) 02:16, 14 April 2011 (UTC)

Proof Stress?

In the introduction is the following:

"Besides this we have proof stress. It is that point where 0.2% plastic deformation occurs while returning to its original shape"

If this is correct it needs explaining. How can something that has deformed plastically return to its original shape?

I think that in materials with no clearly defined elastic limit, the yield strength is defined as the stress which causes a 0.2% permanent strain. This might be what the remark refers to, but I don't think it is called the "proof stress".

David.Boettcher (talk) 17:49, 12 August 2017 (UTC)

Theoretical shear stress should be higher than the experimental shear stress

In the second table re theoretical limits α-Fe is listed as having a theoretical value of 2.6 GPa, and a measure value of 27.5 GPa. That can't be right, can it? — Preceding unsigned comment added by 155.4.71.143 (talk) 14:15, 11 November 2022 (UTC)

I added a "dubious" template for both α-Fe and Ni. Theoretical shear stress should be higher than the Experimental shear stress. If for some esoteric reason it is not, the text should explain the apparent contradiction (which it currently does not). Annette Maon (talk) 22:38, 5 August 2024 (UTC)

I assume the figure 27.5 is incorrect; being more than tenfold greater than 2.6. I have changed the former to 2.75.

The problem of the experimental value being greater than the theoretical value remains. It is counter-intuitive. Dolphin (t) 07:32, 6 August 2024 (UTC)

It is not just counter intuitive. As far as I can tell it is wrong which means it should not be there at all (especially since we have no sources for it). I may be wrong about this but even if I am, a reasonable reader would be just as confused by it and the text should at least provide an explanation. Annette Maon (talk) 10:57, 6 August 2024 (UTC)

Annette Maon’s action in reverting my edit in order to insert the number “27.5” was grossly inappropriate. We do not behave like that on Wikipedia. Annette knows that the number 27.5 could not be correct, and could be in error by as much as tenfold. Insertion of such an erroneous number, knowing it must be significantly in error, must be considered vandalism by Annette Maon.

If Annette Maon wishes to avoid accusations of being a vandal, and the consequences that might follow, they should revert their most recent edit to this article. Dolphin (t) 12:37, 6 August 2024 (UTC)