agrego ejemplo MF

octave/FEMTrusS.m

@@ -17,7 +17,8 @@ clear all, close all
 % Applied loads and fixed degrees of freedom (supports)
 %%
 
-FMTrusSInput_ej1UT2
+%FMTrusSInput_ej1UT2
+FMTrusSInput_ej1Examen202112
 
 %% 2- Previous calculations and stiffness matrix assembly
 % Assembles the global stiffness matrix KG and computes the matrix for each element.

octave/FMTrusS.m

@@ -9,7 +9,8 @@ addpath( [ pwd '/sources'] );
 %% 1- Input data
 % Input parameters for geometry and material definition of all the trusses.
 % Applied loads and fixed degrees of freedom (supports) are also set here.
-FMTrusSInput_ej1UT2
+#FMTrusSInput_ej1UT2
+FMTrusSInput_ej1Examen202112
 
 %% 2- Pre-process
 % Computation and storage of length, angle, E and A of all truss elements.

octave/sources/FMTrusSInput_ej1Examen202112.m

+
+% section properties: vector with the cross-section areas
+As = 2e-4 ;
+
+% material properties: vector with young moduli values
+Es = [ 200e9 ] ;
+
+NodsCoord = [ ...
+ 0 1 ;
+ 1/sqrt(3) 0 ;
+ 1/sqrt(3)+1 1 ;
+ 1 0 ] ;
+
+% inode jnode material section
+ElemConec = [ ...
+ 1 2 1 1 ;
+ 1 4 1 1 ; ...
+ 2 3 1 1 ; ...
+ 2 4 1 1 ; ...
+ 4 3 1 1   ...
+ ] ;
+
+fixeddofs = [ 1 2 5 6 ] ;
+
+NodalLoads = [ 2 0 -10e3 ; ...
+               4 0 -10e3 ];
+
+# Deformed scale factor
+scalefactor = 1e3;
+
+# row vector with the dofs related to supports which are replaced by virtual forces
+virtualforcessupports = [ ] ;
+
+# row vector with the truss elements which are replaced by virtual forces
+virtualforceselements = [ 4 ] ;
+
+# degree of freedom whose displacement must be determined (leave empty if none)
+unkndispdof = 4 ;
+% -----------------------------

octave/sources/FMTrusSPreprocess.m

 % --- compute lengths and inclination of undeformed elements ---
 Lengths   =  sqrt ( sum( (  NodsCoord( ElemConec(:,2),:) - ...
-                            NodsCoord( ElemConec(:,1),:) ).^2 , 2 ) ) ;
+                            NodsCoord( ElemConec(:,1),:) ).^2 , 2 ) )
 
 Angles = atan2( ( NodsCoord( ElemConec(:,2),2) - NodsCoord( ElemConec(:,1),2) ) , ...
-                ( NodsCoord( ElemConec(:,2),1) - NodsCoord( ElemConec(:,1),1) ) ) ;
+                ( NodsCoord( ElemConec(:,2),1) - NodsCoord( ElemConec(:,1),1) ) ) 
 
 Areas   = As( ElemConec(:,4) ) ;
 Youngs  = Es( ElemConec(:,3) ) ;
@@ -24,16 +24,16 @@ nforceunknowns = nfixeddofs + nelems ;
 # assembles the vector of virtual force states, first the fixed dofs and after the truss elements normal forces.
 if length(virtualforcessupports)>0
   virtualforces  = [ find( fixeddofs == virtualforcessupports) ...
-  virtualforceselements+nfixeddofs ] ;  
+  virtualforceselements+nfixeddofs ] ;
 else
-  virtualforces  = [ virtualforceselements+nfixeddofs ] ;  
+  virtualforces  = [ virtualforceselements+nfixeddofs ] ;
 end
 
 # row vector with the indexes of the dofs of the supports left in the isostatic structure
 isostaticsupports = 1:nfixeddofs ;
 
 if length(virtualforcessupports)>0
-  # deletes the entries corresponding to the supports which are replaced by virtual forces 
+  # deletes the entries corresponding to the supports which are replaced by virtual forces
   isostaticsupports( find( fixeddofs == virtualforcessupports) ) = [] ;
 end
 
@@ -60,14 +60,14 @@ for i=1:nelems
   l   = Lengths(i) ;
   ang = Angles(i);
 
-  nodi = ElemConec(i,1);  
-  nodj = ElemConec(i,2);  
+  nodi = ElemConec(i,1);
+  nodj = ElemConec(i,2);
 
   elemdofs = nodes2dofs ( [ nodi nodj ]' ,2) ;
 
   ca = cos(ang); sa = sin(ang);
   auxproj = [ -ca; -sa; ca; sa] ;
-  
+
   Meq( elemdofs , i+nfixeddofs ) = - auxproj ;
 end
 

octave/sources/FMTrusSProcess.m

@@ -12,11 +12,11 @@ for j=1:hiperdegree
 end
 
 ForceIndepTerm
-x = Meqred \ ForceIndepTerm 
+x = Meqred \ ForceIndepTerm
 
 supportreactions = zeros(nfixeddofs, hiperdegree+1) ;
 
-supportreactions( isostaticsupports , : ) = x( 1:length(isostaticsupports) ,:) 
+supportreactions( isostaticsupports , : ) = x( 1:length(isostaticsupports) ,:)
 if length(virtualforcessupports)>0
   aux = find( fixeddofs == virtualforcessupports) ;
   for j=1:hiperdegree
@@ -29,8 +29,8 @@ supportreactions
 
 Ns = zeros(nelems,hiperdegree+1) ;
 
-%~ Ns(  isostaticforceselem-length(isostaticsupports) , : ) = x( isostaticforceselem, : ) ; 
-Ns(  isostaticforceselem- nfixeddofs , : ) = x( (length(isostaticsupports)+1):end, : ) ; 
+%~ Ns(  isostaticforceselem-length(isostaticsupports) , : ) = x( isostaticforceselem, : ) ;
+Ns(  isostaticforceselem- nfixeddofs , : ) = x( (length(isostaticsupports)+1):end, : ) ;
 if length( virtualforceselements ) > 0
   for i=1:length(virtualforceselements)
     Ns(virtualforceselements,i+1) = 1 ;
@@ -43,6 +43,7 @@ Ns
 Kf = zeros( hiperdegree, hiperdegree) ;
 Ff = zeros( hiperdegree,           1) ;
 
+hiperdegree
 for i=1:hiperdegree
   for j = 1:hiperdegree
     Kf(i,j) = sum( Ns(:,1+i).*Ns(:,1+j) ./ ( Youngs .* Areas ) .* Lengths ) ;
@@ -51,11 +52,14 @@ for i=1:hiperdegree
   Ff(i) = - sum( Ns(:,1) .* Ns(:,1+i) ./ ( Youngs .* Areas ) .* Lengths ) ;
 end
 
-X = Kf \ Ff 
+Kf
+Ff
+
+X = Kf \ Ff
 
 
 ResultReactions = supportreactions * [ 1; X]
-ResultNormalForces = Ns * [ 1 ; X ] 
+ResultNormalForces = Ns * [ 1 ; X ]
 
 Rext = zeros( 2*nnodes,1) ;
 Rext(fixeddofs) = ResultReactions ;