Talk:Strain (materials science)
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The last section on engineering uses epsilon instead of varepsilon. Is there any reason for the inconsistency? If not, I would prefer varepsilon Berland 16:03, 18 January 2007 (UTC)
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[edit] Earthquake
Hello, How would I calculate the force on an object created by a 6.0 earthquake. (The forced movement)
- I'd look at Richter magnitude scale. You can't say how much force or stress an object sees without a particular problem statement. It's like asking how hot a 100W lightbulb is—it just isn't a meaningful question. —Ben FrantzDale 14:43, 15 February 2007 (UTC)
- The magnitude of an earthquake is only an indication of the energy released at point of rupture. At the site you are concerned with, the force on an objects mass due to the earthquake will be a function of the earthquake strong motion (acceleration time history) at the site (F = m*a). This requires either a strong motion record that was recorded at the site during the earthquake, or if it is an estimate of a possible future event from a particular fault source, in which case you know (or estimate from historical records) the magnitude and distance, and with an attenuation relationship (describes the reduction in energy as the wave travels through the earth from fault to your site), you can determine the bedrock ground motion at your site. You then consider how the ground motion is amplified (or perhaps dampened) by the soil layers on your site (this is called site response analysis). The resulting accelerations at different modes of oscillation (frequency or period) can then be used to estimate the acceleration in the earthquake that will excite your particular object. This depends on the natural frequency of the object you are considering. If, say a tall building, high frequency waves will not have much effect, but low frequency (long period) motion will cause the building to sway about its natural frequency. This is the acceleration from an earthquake that you are most concerned with as a designer.GeoEng 07:51, 6 April 2007 (UTC)
[edit] Rewrite
Hi. I think there is an error in this article. (today: 5/11/05) It's written: 'If Strain is greater than 1, the body has been lengthened; if it is smaller than 1, it has been compressed.' In fact it is: if strain > 0, the body has been lengthened and if strain < 0... according to the definition of the strain written in this same article! Am I right?
- Thanks; I've rewritten parts of the article. Please review it and let me know what you think. Tom Harrison (talk) 04:52, 6 November 2005 (UTC)
I just did loads of stuff to this article. I would say its fairly clean, not quite featured article standard, but clean enough to remove the cleanup notice. I took out a couple of bits about earthquakes, I thought that was a bit too detailed (do we really want to know about tectonic folding in a strain article?), and changed the Small values of strain section to Engineering strain vs. true strain. I'm not done with this article yet. --Nathan 07:22, 2 December 2005 (UTC)
[edit] To do
- Torsional strain
- Strain hardening -- & strain softening behaviour! GeoEng 07:53, 6 April 2007 (UTC)
- Necking and poisson's ratio
- Engineering strain vs. True strain
- done. I'll get working on the rest soon. --Nathan 07:22, 2 December 2005 (UTC)
- Mohrs Circle of Strain (yes it can be applied to strain as well!) GeoEng 07:53, 6 April 2007 (UTC)
Tom Harrison (talk) 14:25, 6 November 2005 (UTC)
- Lagrangian strain (non linear component)Katanada (talk) 17:27, 23 January 2008 (UTC)
- Eulerian strain Katanada (talk) 17:27, 23 January 2008 (UTC)
- Deformation gradient tensor --Katanada (talk) 17:30, 23 January 2008 (UTC)
[edit] Strain & deformation
Hi everyone! I've got a question concerning the terms "strain" and "deformation". The article says strain characterizes deformation, while, e.g., Britannica makes no difference between these words. It says "...deformation, or strain,...". So which is correct? Are there any authorities supporting the view expressed in the article? Viktor 12:02, 15 February 2007 (UTC)
- Strain is a technical term with a precise technical dfinition, so in general Britannica may be right, but in technical discussion strain means something particular whereas "deformation" isn't well-defined (as far as I know). —Ben FrantzDale 14:43, 15 February 2007 (UTC)
- Deformation is the accumulation of strains. I would consider units of deformation to be mm, m, etc., whereas strain is normalised over the dimension being considered. GeoEng 07:59, 6 April 2007 (UTC)
Hi, i'm trying to find the strain in an aliminium pipe, how do i find the change in length, so that i can find the strain? Nathan —Preceding unsigned comment added by 141.241.129.75 (talk) 18:02, 20 October 2007 (UTC)
[edit] Merging St. Venant's Compatibility equations article
The St. Venant's compatibility equations article should be merge into the strain article as the former can be seen as a subtopic of strains. Comments? Sanpaz (talk) 16:06, 12 February 2008 (UTC)
