Hi,
i had some trouble finding a solution for this. i am looking for a
numerical approximation to a couple of partial differential equations.
s xx = ( s xx)o - ò (txy/y).dx
s yy = ( s yy)o - ò (txy/x).dy
instead of integrating them numerically, i am looking for numerical
approximations to the above equations namely,
s xx = ( s xx)o - å (Dtxy/Dy). Dx
s yy = ( s yy)o - å (Dtxy/Dx). Dy
ideal solution would include the different ways(methods) available to
solve the equations, pros and cons of those methods and if possible some simple
code(simple solution) to solve the equations using any numerical
method.
the symbols look different from what i typed in a word document. can
attach a word document if you want me to.
shall try to type the equations in words
first set of equations:
sigmaxx = sigmaxx(at point o) - integral(dow towxy /dowy)dx
sigmayy = sigmayy(at point o) - integral(dow towxy/dowx)dy
second set
sigmaxx = sigmaxx(at point o) - sum(delta towxy /deltay)deltax
sigmayy = sigmayy(at point o) - sum(delta towxy/deltax)dy
would appreciate if someone could provide me with an answer
Thank you!! |
Clarification of Question by
ebooks-ga
on
13 Sep 2005 14:14 PDT
i mistyped "instead of integrating them numerically" for "instead of
integrating them analytically"
please make a note of this.
|
Clarification of Question by
ebooks-ga
on
15 Sep 2005 20:30 PDT
guys!!!!
any kind help on "shear difference method" for the separation of
principal stresses using photoelasticity will be appreciated. i badly
need some help on this topic.
Thanks!
|
Request for Question Clarification by
hedgie-ga
on
17 Sep 2005 07:38 PDT
Hi ebooks
You cannot really attach a *.doc file. GA does not support attachments.
The way it is done (if needed) is to upload a file (preferably a *.ps or *.jpg)
to some server you have access to, or a free public server which allows uploads
(suggestions are available if you need that).
It may be a good idea to do that: I am looking at your PDE and
it is not clear at all.
Or, you may give URL of some page where this or such eq. is written properly.
I recon you have function s(x,y) of two variables (also called sigma ??)
by s xx you mean second derivative -or s/xx (if / means subscript) ?
but what is o ? a point (x,y) ??
Is is a PDE or integro-differential equation?
Not clear what you expect either.
Someone can direct to a program which can do numerical solution
(once we figure out which eq. you have)
but you would have to do the solution
yourselef - would that be OK?
This is just that you know you are not being ignored.
I am not volunteering to answer (at this time).
Hedgie
|
Clarification of Question by
ebooks-ga
on
17 Sep 2005 20:55 PDT
Hi,
thank you for your reply. could you please let me know where i can
upload the *.jpg files i have? those files have got my
questions/equations elaborated and specific.
Thanks!!
|
Clarification of Question by
ebooks-ga
on
17 Sep 2005 21:14 PDT
Hi,
i have uploaded a couple of .pdf files. the files have the equations
to be solved. they are basically the equilibrium equations.
basically, the value of "sum of principal stresses" is known on the
boundaries of a rectangular grid. Aim is to find the "sum of principal
stresses" at the interior points of the plate. the value of shear
stress is known at every interior point.
the method used is "shear difference method"
please look at the pdfs for better understanding. i have written down
the equations, the value of the shear stress and some notes on how to
go about.
the links to the documents:
http://rapidshare.de/files/5230783/Document.pdf.html
http://rapidshare.de/files/5230789/Document2.pdf.html
Thank you!!
|
Clarification of Question by
ebooks-ga
on
17 Sep 2005 21:29 PDT
Hi,
incase you want to look at these equations. putting in simple terms, i
am trying to solve the second set equations numerically where
the rhs value of "sigmaxx at o"(boundary points) is known and the
value of shear stress "towxy" is known at every grid point of a
rectangle. i need to find sigmaxx at every other(interior) points of
the rectangle.
the link: http://rapidshare.de/files/5231109/equations.doc.html
Thank you!!
|
Request for Question Clarification by
hedgie-ga
on
18 Sep 2005 00:30 PDT
Yes ebooks
That's a bit more clear.
I myself do not have time to look into this right now.
I hope some other researcher will pick this up .
Hedgie
|
Clarification of Question by
ebooks-ga
on
18 Sep 2005 10:50 PDT
would appreciate if you can spend a couple of hours sometime today. i
know you are busy, but considering my request, could you please spare
some time for me? any work on the equations would be appreciated.
Thanks!!
|
Request for Question Clarification by
hedgie-ga
on
18 Sep 2005 14:36 PDT
ebooks
I am sorry. I did suggest a way which people use to communicate
drawings etc, here at GA - but I have not actually 'picked up' the question.
Previous note was telling you that, as well as telling other researchers
(we have few which can help you with this) that question is available,
that I am not working on it.
There are several reasons, main being that I really will be be very busy
for the whole next week. To make question more attractive (to other researchers)
you may present it better, (I did look - and it is still hard to read and get)
and also answer the querry 'what you expect to get'?:
Pointer to a program or actual solution?
You are offering to buy less then 5 hours of researcher's time.
The person who will invest her time needs to know that your
expectations are realistic. To actually solve it, with all
clarification it looks like it may take, solution could take quite a
bit longer.
Hedgie
|
