User talk:Janek Kozicki

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Atomic orbitals table
As you suggested, I started working on converting your monolithic Image:orbitals_table.png into a table of smaller atomic-orbital images. Check out Atomic orbital/orbitals table. Definitely nicer in my opinion. Not sure if it should go further and have a separate image for each m. DMacks 01:48, 6 April 2007 (UTC)


 * wow, looks great, thanks :) Janek Kozicki 06:16, 6 April 2007 (UTC)

How to draw Figure 5.
Hi Janek Kozicki,

Thank you for writing this artical. I am interested in drawing the Figure 5. Would you please tell me how to do?

Thanks!

Jinsong


 * Hi, which article, which figure? Janek Kozicki (talk) 16:23, 17 May 2008 (UTC)

Bresler-Pister yield criterion
The yield surface that you have plotted looks a bit strange. Please look at the Bresler Pister yield criterion page for pointers on equations for more reasonable looking surfaces. Bbanerje (talk) 00:55, 19 May 2008 (UTC)
 * yeah, I totally agree. Problem is that I need this equation expressed in principal stresses s1,s2,s3. The C++ code to calculate it was following:

void viewer::generateScalarField {	using namespace std; for(int i=0;i<sizeX;i++) for(int j=0;j<sizeY;j++) for(int k=0;k<sizeZ;k++) {				// calculate s1,s2,s3 from the position in 3D array scalarField // the origin of the coordinate system is in the center (sizeXYZ * 0.5) // and the 3D array scalarField represents a cube from -1.0 to 1.0

double s1 = (double)i/(double)sizeX*2.0-1.0; double s2 = (double)j/(double)sizeY*2.0-1.0; double s3 = (double)k/(double)sizeZ*2.0-1.0;

// Bresler-Pister double c0=0.2; double c1=0.07; double c2=0.07; scalarField[i][j][k] = (1.0/sqrt(6.0)) * sqrt( pow(s1-s2,2)+pow(s2-s3,2)+pow(s3-s1,2) ) - c0 - c1*(s1+s2+s3) - c2*pow(s1+s2+s3,2); } }
 * the surface which I'm plotting is where values in the 3D array  are ZERO. I've picked the values c0,c1,c2 in a way so that they show this surface in a best way (to see it whole instead of a part). As you see, the equation which I used is the one written here. All other surfaces were plotted in the same way (using the principal stresses equation). This could mean that this equation is incorrect, or I made a typo when I writing it into C++ code above (do you see a typo there?). Equations in Bresler Pister yield criterion need some transformations to express them in principal stresses, and I simply don't have time to transform them.
 * Concluding, if you (or anybody) can make the transofrmations and give that equation expressed in principal stresses I can plot the surface. For the time being please feel free to delete that part, or put another template there informing that it's very likely that it contains a mistake. Janek Kozicki


 * Just for the record, plotting other surfaces involved only changing that single line

scalarField[i][j][k] = ....
 * And here is the C++ code I used for each surface:

// Tresca Guest scalarField[i][j][k] = std::max(abs(s1-s2),std::max(abs(s2-s3),abs(s3-s1)))-0.2; /********************/ // Huber Mises Hencky scalarField[i][j][k] = pow(s1-s2,2)+pow(s2-s3,2)+pow(s3-s1,2)-0.2; /********************/ // Mohr-Coulomb double Rc = 0.8; double Rr = 0.5; double m=Rc/Rr; double K=(m-1.0)/(m+1.0); double c=Rc/(m+1.0); scalarField[i][j][k] = std::max(abs( (s1-s2)/2.0)-c+K*(s1+s2)/2.0 ,				std::max(abs( (s2-s3)/2.0)-c+K*(s2+s3)/2.0 , abs( (s3-s1)/2.0)-c+K*(s3+s1)/2.0 )); /********************/ // Drucker-Prager double Rc = 0.8; double Rr = 0.5; double m=Rc/Rr; double K = 2.0*Rc/(sqrt(3.0)*(m+1)); double alpha = (m-1.0)/(sqrt(3.0)*(m+1)); scalarField[i][j][k] = alpha*(s1+s2+s3) + sqrt((pow(s1-s2,2)+pow(s2-s3,2)+pow(s3-s1,2))/6.0)-K;
 * Thanks for your work on Yield surface article! Janek Kozicki (talk) 19:43, 19 May 2008 (UTC)
 * Hi Janek, I've added expressions for $$c_0, c_1, c_2$$ in the Bresler-Pister part of Yield surface. The shape of the yield surface depends strongly on these parameters and a non-convex yield surface is not very reasoanble (though some would disagree).  Could you plug in some reasonable numbers for $$\sigma_c, \sigma_t, \sigma_b$$  to calculate c0, c1, c2 (instead of using 0.2, 0.07, 0.07) and see what shapes you get for the yield surface?  You should get an envelope that is convex.  I'm working on the Willam-Warnke criterion and will add in some details in the next few days. Bbanerje (talk) 04:21, 21 May 2008 (UTC)
 * Thanks, it looks much better now, that's the code I used:

double sc=0.5; double st=0.2; double sb=0.4;

double c1= ( (st-sc) / (sqrt(3)*(st+sc)) ) *( (4*sb*sb-sb*(sc+st)+sc*st) / (4*sb*sb+2*sb*(st-sc)-sc*st) ); double c2= ( 1/(sqrt(3)*(st+sc)) ) *( (sb*(3*st-sc)-2*sc*st)/( 4*sb*sb+2*sb*(st-sc)-sc*st ) ); double c0=sc/sqrt(3)+c1*sc-c2*sc*sc; scalarField[i][j][k] = (1.0/sqrt(6.0)) * sqrt( pow(s1-s2,2)+pow(s2-s3,2)+pow(s3-s1,2) ) - c0 - c1*(s1+s2+s3) - c2*pow(s1+s2+s3,2.0);
 * Janek Kozicki (talk) 08:46, 21 May 2008 (UTC)
 * Hi, I've added instructions on how to create the Willam-Warnke surface in the yield surface discussion page at Talk:Yield_surface. Thanks for your surface plots. Bbanerje (talk) 03:02, 25 May 2008 (UTC)
 * Hi, you did a great deal of work. Thanks a lot. Have a look there for unexpected results. Janek Kozicki (talk) 19:03, 25 May 2008 (UTC)
 * There's an updated version for you to play with at Talk:Yield_surface. Let's see how that goes. Bbanerje (talk) 01:00, 26 May 2008 (UTC)

Update on Willam-Warnke
There was a mistake in the expression for rt in the original version. If should be

r_t = \sqrt{\tfrac{6}{5}}~\cfrac{\sigma_b\sigma_t}{\sigma_c(2\sigma_b+\sigma_t)} $$ Note the + sign in the denominator on the right hand side. That, and a careful calculation of $$\theta$$ should fix the problem with the yield surface. Bbanerje (talk) 00:04, 28 May 2008 (UTC)

Notification of automated file description generation
Your upload of File:Bresler Pister Surface 2D.png or contribution to its description is noted, and thanks (even if belatedly) for your contribution. In order to help make better use of the media, an attempt has been made by an automated process to identify and add certain information to the media's description page.

This notification is placed on your talk page because a bot has identified you either as the uploader of the file, or as a contributor to its metadata. It would be appreciated if you could carefully review the information the bot added. To opt out of these notifications, please follow the instructions here. Thanks! Message delivered by Theo's Little Bot (opt-out) 14:09, 21 February 2014 (UTC)


 * Another one of your uploads, File:Bresler Pister Yield Surface 3D.png, has also had some information automatically added. If you get a moment, please review the bot's contributions there as well. Thanks! Message delivered by Theo's Little Bot (opt-out) 14:10, 22 February 2014 (UTC)

how to draw the pictures you uploaded？
Hi Janek Kozicki ！you upload so many pictures ，awesome！ I wonder how to plot the pictures ？what graphic softwares can do this ？ — Preceding unsigned comment added by 202.113.11.209 (talk) 03:28, 8 July 2015 (UTC)

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Nomination of Displacement field (mechanics) for deletion
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