Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

RE: STRESS AND FORCE

[Subject Prev][Subject Next][Thread Prev][Thread Next]
-----Original Message-----
From: Christopher Wright [mailto:chrisw(--nospam--at)skypoint.com] 
Sent: Friday, November 14, 2008 11:06 AM
To: seaint(--nospam--at)seaint.org
Subject: Re: STRESS AND FORCE


On Nov 14, 2008, at 12:46 PM, Acharya, Suresh wrote:

> Question arises which stress you want to use a indicator? Principal 
> stresses, Von Mises stress, or stresses based on several other 
> hypothesis?

Not to beat this topic to death, but that question was answered in sophomore
strength of materials--the chapter on failure theories. von Mises or maximum
shear for ductile materials, maximum principle stress for materials like
cast iron or for crack propagation. Every criterion depending on plastic
flow has to be related to yield stress.





===============================
Thanks for reminder!

Back to the stress vs. force discussion, the strength of materials (?) book
by Byars, Snyder and Plants in the failure theory section or similar chapter
(which I read about a decade ago), discusses why forces are better than
stresses to define factor of safety or failure in real world structures.
Some of the reasons being the effort to correlate the triaxial stress state
in a structural element to the material strengths that are measured in
uniaxial tests; other modes of failure (such as instability/shape) being
more critical; brittle or ductile classification of materials being
subjective and that often depending on temperature and other environmental
conditions, etc. 

-Suresh Acharya, S.E.  
===============================






Christopher Wright P.E. |"They couldn't hit an elephant at
chrisw(--nospam--at)skypoint.com   | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania
1864)
http://www.skypoint.com/members/chrisw/



******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* 
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: http://www.seaint.org 
******* ****** ****** ****** ******* ****** ****** ******** 


******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* 
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: http://www.seaint.org 
******* ****** ****** ****** ******* ****** ****** ********