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library("iemisc") import::from(ramify, mat) vo <- mat("0, 0; 600, 0; 630, 580; 1200, 650; 1200, 920; 900, 920; 900, 845; 0, 845") vo vi <- mat("0, 300; 300, 300; 300, 695; 0, 695") vi # The following will plot both the original and the final (transformed plot) SP <- secprop(outer = vo, inner = vi, original_plot = 1, final_plot = 1) SP
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```{octave eval = FALSE} % % Copyright (C) 2008 Colin Caprani - www.colincaprani.com % % This program is free software: you can redistribute it and/or modify % it under the terms of the GNU General Public License as published by % the Free Software Foundation, either version 3 of the License, or % (at your option) any later version. % % This program is distributed in the hope that it will be useful, % but WITHOUT ANY WARRANTY; without even the implied warranty of % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the % GNU General Public License for more details. % % You should have received a copy of the GNU General Public License % along with this program. If not, see http://www.gnu.org/licenses/.
function SP = secprop(outer,inner,plotflag) % Section Properties Calculator % outer is a matrix of outer coordinates (x,y) % inner is a matrix of coordinates for a void % SP is a vector of A,I,yt and yb properties of the section
[nOC n] = size(outer); [nIC n] = size(inner); outer(nOC+1,:) = outer(1,:); inner(nIC+1,:) = inner(1,:); propsOC = zeros(1,3); propsIC = propsOC; propsOC = algor(outer); if(nIC > 2); propsIC = algor(inner); end; A = propsOC(1) - propsIC(1); I = propsOC(2) - propsIC(2); ybar = propsOC(3) - propsIC(3); ybar = ybar/A; I = I-A*ybar^2; A = 2*A; I = 2*I; yt = max(outer(:,2)) - ybar; yb = ybar; SP = [A,I,yt,yb]; SP = SP'; if plotflag == 1 outer(nOC+1:2*nOC-1,1) = -outer(nOC:-1:2,1); outer(nOC+1:2*nOC-1,2) = outer(nOC:-1:2,2); inner(nIC+1:2*nIC-1,1) = -inner(nIC:-1:2,1); inner(nIC+1:2*nIC-1,2) = inner(nIC:-1:2,2); h = fill(outer(:,1),outer(:,2),'r'); hold on; fill(inner(:,1),inner(:,2),'w'); axis equal; s1 = sprintf('Area = %d mm2 | Height to N-A = %3.1f mm',A,round(ybar*10)/10); s2 = sprintf('Second Moment of Area = %d mm4',I); s3 = sprintf('Elastic Moduli, t = %d mm3; b = %d mm3',I/yt,I/yb); annotation1 = annotation('textbox',[0.15 0.12 0.4 0.14], {s1,s2,s3});
% annotation1 line modified by Irucka Embry to avoid the error message associated with % set: unknown hggroup property FitHeightToText end end
function props = algor(vc) A = 0; ybar = 0; I = 0; x = vc(:,1); y = vc(:,2); n = length(x); for i = 1:(n-1) A = A + 0.5(x(i)-x(i+1))(y(i)+y(i+1)); ybar = ybar + (1/6)(x(i)-x(i+1))(y(i)^2 + y(i)y(i+1) + y(i+1)^2); I = I + (1/12)(x(i)-x(i+1))(y(i)^3 + y(i)^2y(i+1)+y(i)*y(i+1)^2 + y(i+1)^3); end props = [A,I,ybar]; end
% check against GNU Octave
vo = [0, 0; 600, 0; 630, 580; 1200, 650; 1200, 920; 900, 920; 900, 845; 0, 845]; vi = [0, 300; 300, 300; 300, 695; 0, 695]; SP = secprop(vo, vi, 1)
print("file.png")
% Results warning: annotation: couldn't parse PROP/VAL pairs, skipp warning: called from annotation at line 218 column 7 secprop at line 36 column 21
SP =
1.1175e+06 8.6279e+10 4.1937e+02 5.0063e+02
\bigskip \bigskip ```r linguisticsdown::include_graphics2("secprop_gnu-octave_figure.png")
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Colin Caprani, "Section Properties Calculator", https://www.colincaprani.com/programming/matlab/.
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