Talk:Bending

A couple of comments:

• The stress maxima are opposite but not allways equal (non-symmetrical sections)
• I don't understand the last sentence: "Because of this area with no stress and the adjacent areas with low stress, bending is not a particularly efficient..." From my point of view that is simply the reason to use I-profiles, truss girders, etc.

--Nk 15:26, 9 Dec 2004 (UTC)

Nk,

• The phrasing in question did indeed assume a symmetric section. I changed it to make it more universally relevant.
• I'm not entirely fond of the current phrasing, but I haven't yet come up with a better way to address the inefficiency of bending (as compared to tension, which uniformly and almost fully--some would say optimally--uses the material at its disposal). As a stop-gap, I mentioned the rationale behind the use of wide-flange beams and truss girders.

--Spindustrious 20:58, 9 Dec 2004 (UTC)

It may be worth mentioning the beams produced by cutting the web of an RSJ in a toothed pattern, offseting and re welding along the neutral axis, leaving (usually) hexagonal gaps down the centre of the web. These show rather graphically how little the web contributes to the strength of the beam, and emphasising the lack of stress along the welded join where the "teeth" are rejoined. I'll look for a good picture.

Shoka

MOst useless article ever.

Categorizing Bending

I maintain that Continuum Mechanics is the best category for this article in light of the recommendations in Wikipedia:Categorization:

• Since the article only peripherally addresses specific subjects within engineering, any such categorization fails this test: "If you go to the article from the category, will it be obvious why it's there? Is the category subject prominently discussed in the article?"
• "An article should not be in both a category and its subcategory."
• "An article will often be in several categories. Restraint should be used, however — categories become less effective the more there are on a given article."

Many fields in engineering (including mechanical and structural engineering) draw from the fundamentals of continuum and fluid mechanics. I think it's a stretch to say that mechanical or structural engineering isn't, in this case, a subcategory of continuum mechanics. Given this doubt, it's appropriate to use restraint as called for in the style manual.

--Spindustrious 15:26, 13 Mar 2005 (UTC)

I do agree that this article isn't appropriate for the Mechanical engineering category, however the rationale is tenuous. The Mechanical and Structural engineering categories are currently not subcategories of Continuum Mechanics, nor am I sure they should be. If so, should they be added as subcategories? Or, perhaps a category for Engineering mechanics should be created instead, that seems more appropriate to me; also Engineering mechanics is currently a stub which could use some expansion anyway. Comments? Commander 16:09, Mar 13, 2005 (UTC)

I too am more comfortable with the category of Engineering Mechanics, but the more I think about it, the less confident I am of the distinction between Continuum and Engineering Mechanics. The preferred term here seems to be the former as evidenced by the strong article and amply populated category... More opinions please! --Spindustrious 16:54, 13 Mar 2005 (UTC)

To me, Continuum Mechanics seems for the most part a pure science field, whereas Engineering Mechanics is more closely related to engineering disciplines. Maybe it's because I had to take Engineering Mechanics as a part of an EE curriculum (the curriculum of most engineering fields require at least a class in statics, whereas mechanical engineers and some others have to take more classes on dynamics). I therefore think that both categories (Continuum Mechanics and Engineering Mechanics) would be appropriate. Commander 17:27, Mar 13, 2005 (UTC)

I agree and that's what I did for the Bulgarian translation - a new Engineering mechanics category. In de: they also have a nice de:Kategorie:Technische Mechanik. --Nk 10:08, 26 Mar 2005 (UTC)

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Figure 2 indicates shear stress in the top figure and no shear stress in the bottom figure. It has to be in both or neither, correct? I believe it should be in neither. Rtdrury 03:53, 5 December 2005 (UTC)

I think the shear stress has been left out of the bottom figure because it is constant throughout the cross-section. It's also hard to show shear stress and normal stress in the same diagram without confusing people. Bending moment is the integral of the shear force, so it is important although it isn't discussed in the article yet. Toiyabe 19:24, 5 December 2005 (UTC)

While Toiyabe's interpretation is spot on, I've amended Figure 2's caption to make it clear that the shear stress has intentionally been left out of the diagram. --Spindustrious 01:57, 7 December 2005 (UTC)