Talk:Corotational Truss Element

I removed the reference to the doRayleigh flag. That does not seem to be implemented in the source code.

corotTruss appears to implement Rayleigh damping by default. Truss does not. Someone should verify these findings.

I used the following (MATLAB) script for verification:

clear all; clc %% Damp = 1; Corot = 1;

fout = fopen('Tester\Driver.tcl','w');

fprintf(fout,'wipe\n'); fprintf(fout,'model BasicBuilder -ndm 2 -ndf 3\n'); fprintf(fout,'file mkdir Data/\n');

fprintf(fout,'node 1 0.0 0.0\n'); fprintf(fout,'node 2 1.0 0.0\n'); fprintf(fout,'node 3 2.0 0.0\n'); fprintf(fout,'node 4 3.0 0.0\n'); fprintf(fout,'fix 1 1 1 1 \n'); fprintf(fout,'fix 2 0 1 1\n'); fprintf(fout,'fix 3 0 1 1\n'); fprintf(fout,'fix 4 0 1 1\n'); fprintf(fout,'mass 2 1.0 0.0 0.0\n'); fprintf(fout,'mass 3 1.0 0.0 0.0\n'); fprintf(fout,'mass 4 1.0 0.0 0.0\n');

fprintf(fout,'uniaxialMaterial Elastic 1 100.0\n');

if Corot

   fprintf(fout,'element corotTruss 1 1 2 1.0 1\n');
   fprintf(fout,'element corotTruss 2 2 3 1.0 1\n');
   fprintf(fout,'element corotTruss 3 3 4 1.0 1\n');

else

   fprintf(fout,'element Truss 1 1 2 1.0 1 -doRayleigh 1 \n');
   fprintf(fout,'element Truss 2 2 3 1.0 1 -doRayleigh 1 \n');
   fprintf(fout,'element Truss 3 3 4 1.0 1 -doRayleigh 1 \n');

end

if Damp

   fprintf(fout,'region 1 -ele 1 2 3 -rayleigh 0.0 0.1 0.0 0.0\n');

end

fprintf(fout,'timeSeries Rectangular 1 0.0 1.0 -factor 1.0e-4\n'); fprintf(fout,'pattern UniformExcitation 1 1 -accel 1\n');

fprintf(fout,'recorder Node -file Data/TestD.txt -time -nodeRange 1 4 -dof 1 disp\n'); fprintf(fout,'recorder Element -file Data/TestF.txt -time -eleRange 1 3 localForce\n');

fprintf(fout,'constraints Penalty 1.0e8 1.0e8\n'); fprintf(fout,'numberer RCM\n'); fprintf(fout,'system ProfileSPD\n'); fprintf(fout,'test EnergyIncr 1.0e-5 30 1\n'); fprintf(fout,'algorithm NewtonLineSearch\n');

fprintf(fout,'analysis Transient\n'); fprintf(fout,'integrator Newmark 0.5 0.25\n'); fprintf(fout,'analyze 500 0.02\n');

%% tic; cd('Tester'); !OpenSees_2_2_2 Driver.tcl toc cd ..

%% Read results raw = dlmread('Tester\Data\TestD.txt',' '); time = raw(:,1); x = raw(:,2:end);

raw = dlmread('Tester\Data\TestD.txt',' '); N = raw(:,2:end);

%% Plot figure(1); %clf; plot(time,x(:,end),'LineWidth',2); hold all