DEMO_febio_0021_bone_three_point_bending

Below is a demonstration for:

Building geometry for a bone
Defining the boundary conditions
Coding the febio structure
Running the model
Importing and visualizing the displacement results

Keywords
Plot settings
Control parameters
Get bone geometry
Remesh using geomgram
Create and position cylinder geometry
Mesh using tetgen
Visualize interior point
Define material regions in bone
Visualizing solid mesh
Joining node sets
Define boundary conditions
Define bone contact surfaces
Defining the FEBio input structure
Quick viewing of the FEBio input file structure
Exporting the FEBio input file
Running the FEBio analysis
Import FEBio results

Keywords

febio_spec version 4.0
febio, FEBio
indentation
contact, sliding, sticky, friction
rigid body constraints
tetrahedral elements, tet4
triangular elements, tri3
three point bending
static, solid
hyperelastic, Ogden
displacement logfile
stress logfile

clear; close all; clc;

Plot settings

fontSize=15;
faceAlpha1=0.8;
faceAlpha2=0.3;
markerSize=40;
lineWidth=3;

Control parameters

% Path names
defaultFolder = fileparts(fileparts(mfilename('fullpath')));
savePath=fullfile(defaultFolder,'data','temp');
pathNameSTL=fullfile(defaultFolder,'data','STL');

% Defining file names
febioFebFileNamePart='tempModel';
febioFebFileName=fullfile(savePath,[febioFebFileNamePart,'.feb']); %FEB file name
febioLogFileName=[febioFebFileNamePart,'.txt']; %FEBio log file name
febioLogFileName_disp=[febioFebFileNamePart,'_disp_out.txt']; %Log file name for exporting displacement
febioLogFileName_force=[febioFebFileNamePart,'_force_out.txt']; %Log file name for exporting force
febioLogFileName_stress=[febioFebFileNamePart,'_stress_out.txt']; %Log file name for exporting stress

%Geometric parameters
corticalThickness=3; %Thickness used for cortical material definition
volumeFactor=10; %Factor to scale desired volume for interior elements w.r.t. boundary elements
pointSpacing=5;

%Material parameter set
D_density=1e-9; %Density for all materials

E_youngs1=17000; %Youngs modulus
nu1=0.25; %Poissons ratio

% Cancellous bone
E_youngs2=1500; %Youngs modulus
nu2=0.25; %Poissons ratio

% FEA control settings
analysisType='STATIC';
numTimeSteps=20; %Number of time steps desired
max_refs=25; %Max reforms
max_ups=0; %Set to zero to use full-Newton iterations
opt_iter=15; %Optimum number of iterations
max_retries=6; %Maximum number of retires
dtmin=(1/numTimeSteps)/100; %Minimum time step size
dtmax=1/numTimeSteps; %Maximum time step size
min_residual=1e-10;
symmetric_stiffness=0;

runMode='external';% 'internal' or 'external'

%Contact parameters
contactInitialOffset=0.1;
contactPenalty=1000;
laugon=0;
minaug=1;
maxaug=10;

%Boundary conditions specification
bcFix=0;

%Loading parameters
zDisp=-20-2*contactInitialOffset;

Get bone geometry

%Load basic model
[F_bone,V_bone]=graphicsModels(5);
V_bone=V_bone*1000; %Scale to mm

%Reorient
V_mean=mean(V_bone,1);
V_bone=V_bone-V_mean(ones(size(V_bone,1),1),:); %Center around origin
[R]=pointSetPrincipalDir(V_bone); %Get rotation matrix
V_bone=V_bone*R; %Rotate

Remesh using geomgram

optionStruct.pointSpacing=pointSpacing;
optionStruct.disp_on=0;
[F_bone,V_bone]=ggremesh(F_bone,V_bone,optionStruct);

Create and position cylinder geometry

pointSpacingBeams=pointSpacing/2;

inputStruct.cylRadius=10;
inputStruct.numRadial=round((2*pi*inputStruct.cylRadius)./pointSpacingBeams);
inputStruct.cylHeight=max(V_bone(:,2))-min(V_bone(:,2));
nh=round(inputStruct.cylHeight./pointSpacingBeams);
nh=nh+double(iseven(nh));
inputStruct.numHeight=nh;
inputStruct.meshType='quad';
inputStruct.closeOpt=0;

% Derive patch data for a cylinder
[Fc,Vc,Cc]=patchcylinder(inputStruct);
R=euler2DCM([0.5*pi 0 0]);
Vc=Vc*R;
Vc1=Vc;
Vc2=Vc;
Vc2(:,1)=Vc2(:,1)-60;
Vc3=Vc;
Vc3(:,1)=Vc3(:,1)+60;

logicSelect=min(Vc1(:,1))<V_bone(:,1) & max(Vc1(:,1))>V_bone(:,1);
zOffset=max(V_bone(logicSelect,3));
Vc1(:,3)=Vc1(:,3)-min(Vc1(:,3))+zOffset+contactInitialOffset;

logicSelect=min(Vc2(:,1))<V_bone(:,1) & max(Vc2(:,1))>V_bone(:,1);
zOffset=min(V_bone(logicSelect,3));
Vc2(:,3)=Vc2(:,3)-max(Vc2(:,3))+zOffset-contactInitialOffset;

logicSelect=min(Vc3(:,1))<V_bone(:,1) & max(Vc3(:,1))>V_bone(:,1);
zOffset=min(V_bone(logicSelect,3));
Vc3(:,3)=Vc3(:,3)-max(Vc3(:,3))+zOffset-contactInitialOffset;

Plotting surface geometry

cFigure;
hold on;
gpatch(F_bone,V_bone,'kw','k',1);
gpatch(Fc,Vc1,'gw','g',1);
gpatch(Fc,Vc2,'rw','r',1);
gpatch(Fc,Vc3,'bw','b',1);

axisGeom;
camlight headlight;
drawnow

Mesh using tetgen

%Find interior point
V_inner_bone=getInnerPoint(F_bone,V_bone);

Visualize interior point

cFigure; hold on;
gpatch(F_bone,V_bone,'w','none',0.5);
plotV(V_inner_bone,'r.','MarkerSize',25)
axisGeom; camlight headlight;
drawnow;

Regional mesh volume parameter

tetVolume=tetVolMeanEst(F_bone,V_bone); %Volume for regular tets

tetGenStruct.stringOpt='-pq1.2AaY';
tetGenStruct.Faces=F_bone;
tetGenStruct.Nodes=V_bone;
tetGenStruct.holePoints=[];
tetGenStruct.faceBoundaryMarker=ones(size(F_bone,1),1); %Face boundary markers
tetGenStruct.regionPoints=V_inner_bone; %region points
tetGenStruct.regionA=tetVolume*volumeFactor;

[meshOutput]=runTetGen(tetGenStruct); %Run tetGen

% Access elements, nodes, and boundary faces
E=meshOutput.elements;
V=meshOutput.nodes;
Fb=meshOutput.facesBoundary;
Cb=meshOutput.boundaryMarker;
CE=meshOutput.elementMaterialID;

 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
--- TETGEN Tetrahedral meshing --- 20-Apr-2023 10:43:58
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
--- Writing SMESH file --- 20-Apr-2023 10:43:58
----> Adding node field
----> Adding facet field
----> Adding holes specification
----> Adding region specification
--- Done --- 20-Apr-2023 10:43:58
--- Running TetGen to mesh input boundary--- 20-Apr-2023 10:43:58
Opening /mnt/data/MATLAB/GIBBON/data/temp/temp.smesh.
Delaunizing vertices...
Delaunay seconds:  0.016974
Creating surface mesh ...
Surface mesh seconds:  0.004776
Recovering boundaries...
Boundary recovery seconds:  0.009703
Removing exterior tetrahedra ...
Spreading region attributes.
Exterior tets removal seconds:  0.005588
Recovering Delaunayness...
Delaunay recovery seconds:  0.004794
Refining mesh...
Refinement seconds:  0.056087
Smoothing vertices...
Mesh smoothing seconds:  0.068169
Improving mesh...
Mesh improvement seconds:  0.003806

Writing /mnt/data/MATLAB/GIBBON/data/temp/temp.1.node.
Writing /mnt/data/MATLAB/GIBBON/data/temp/temp.1.ele.
Writing /mnt/data/MATLAB/GIBBON/data/temp/temp.1.face.
Writing /mnt/data/MATLAB/GIBBON/data/temp/temp.1.edge.

Output seconds:  0.045191
Total running seconds:  0.215371

Statistics:

  Input points: 3386
  Input facets: 6768
  Input segments: 10152
  Input holes: 0
  Input regions: 1

  Mesh points: 4762
  Mesh tetrahedra: 17889
  Mesh faces: 39162
  Mesh faces on exterior boundary: 6768
  Mesh faces on input facets: 6768
  Mesh edges on input segments: 10152
  Steiner points inside domain: 1376

--- Done --- 20-Apr-2023 10:43:58
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
--- Importing TetGen files --- 20-Apr-2023 10:43:58
--- Done --- 20-Apr-2023 10:43:58

Define material regions in bone

indBoundary=unique(Fb(Cb==1,:));
DE=minDist(V,V(indBoundary,:));
logicCorticalNodes=DE<=corticalThickness;
logicCorticalElements=any(logicCorticalNodes(E),2);
logicCancellousElements=~logicCorticalElements;

E1=E(logicCorticalElements,:);
E2=E(logicCancellousElements,:);
E=[E1;E2];
elementMaterialID=[ones(size(E1,1),1);2*ones(size(E2,1),1);];
meshOutput.elements=E;
meshOutput.elementMaterialID=elementMaterialID;

Visualizing solid mesh

hFig=cFigure; hold on;
optionStruct.hFig=hFig;
meshView(meshOutput,optionStruct);
axisGeom;
drawnow;

Joining node sets

Fc1=Fc+size(V,1);
Fc2=Fc+size(V,1)+size(Vc1,1);
Fc3=Fc+size(V,1)+size(Vc1,1)+size(Vc2,1);
V=[V;Vc1;Vc2;Vc3];

Define boundary conditions

if bcFix==1

    %Supported nodes
    indb=unique(Fb(:));
    logicLeft=V(indb,1)<-200;
    bcSupportList=indb(logicLeft);

Visualize BC's

    hf=cFigure;
    title('Boundary conditions model','FontSize',fontSize);
    xlabel('X','FontSize',fontSize); ylabel('Y','FontSize',fontSize); zlabel('Z','FontSize',fontSize);
    hold on;

    gpatch(Fb,V,'kw','none',faceAlpha2);
    hp1(1)=plotV(V(bcSupportList,:),'k.','MarkerSize',markerSize);

    legend(hp1,{'BC support'});

    axisGeom(gca,fontSize);
    camlight headlight;
    drawnow;

end

Define bone contact surfaces

N=patchNormal(fliplr(Fb),V);
nz=[0 0 -1];
d=dot(N,nz(ones(size(N,1),1),:),2);

contactAdd=pointSpacing;

VF=patchCentre(Fb,V);
logicSecondary1=VF(:,1)>(min(Vc1(:,1))-contactAdd) & VF(:,1)<(max(Vc1(:,1))+contactAdd) & d<0;
logicSecondary2=VF(:,1)>(min(Vc2(:,1))-contactAdd) & VF(:,1)<(max(Vc2(:,1))+contactAdd) & d>0;
logicSecondary3=VF(:,1)>(min(Vc3(:,1))-contactAdd) & VF(:,1)<(max(Vc3(:,1))+contactAdd) & d>0;

F_prim1=fliplr(Fb(logicSecondary1,:));
F_prim2=fliplr(Fb(logicSecondary2,:));
F_prim3=fliplr(Fb(logicSecondary3,:));

Visualize

cFigure; hold on;

gpatch(Fb,V,'w','none',0.5);

hp2(1)=gpatch(F_prim1,V,'r','k',1);
patchNormPlot(F_prim1,V);

hp2(2)=gpatch(F_prim2,V,'g','k',1);
patchNormPlot(F_prim2,V);

hp2(3)=gpatch(F_prim3,V,'b','k',1);
patchNormPlot(F_prim3,V);

hp2(4)=gpatch(Fc1,V,'c','k',1);
patchNormPlot(Fc1,V);

hp2(5)=gpatch(Fc2,V,'y','k',1);
patchNormPlot(Fc2,V);

hp2(6)=gpatch(Fc3,V,'m','k',1);
patchNormPlot(Fc3,V);

legend(hp2,{'primary 1','primary 2','primary 3','secondary 1','secondary 2','secondary 3'});

axisGeom;
camlight headlight;
drawnow;

Defining the FEBio input structure

See also febioStructTemplate and febioStruct2xml and the FEBio user manual.

%Get a template with default settings
[febio_spec]=febioStructTemplate;

%febio_spec version
febio_spec.ATTR.version='4.0';

%Module section
febio_spec.Module.ATTR.type='solid';

%Control section
febio_spec.Control.analysis='STATIC';
febio_spec.Control.time_steps=numTimeSteps;
febio_spec.Control.step_size=1/numTimeSteps;
febio_spec.Control.solver.max_refs=max_refs;
febio_spec.Control.solver.qn_method.max_ups=max_ups;
febio_spec.Control.solver.symmetric_stiffness=symmetric_stiffness;
febio_spec.Control.time_stepper.dtmin=dtmin;
febio_spec.Control.time_stepper.dtmax=dtmax;
febio_spec.Control.time_stepper.max_retries=max_retries;
febio_spec.Control.time_stepper.opt_iter=opt_iter;

%Material section
materialName1='Material1';
febio_spec.Material.material{1}.ATTR.name=materialName1;
febio_spec.Material.material{1}.ATTR.type='neo-Hookean';
febio_spec.Material.material{1}.ATTR.id=1;
febio_spec.Material.material{1}.E=E_youngs1;
febio_spec.Material.material{1}.v=nu1;
febio_spec.Material.material{1}.density=D_density;

materialName2='Material2';
febio_spec.Material.material{2}.ATTR.name=materialName2;
febio_spec.Material.material{2}.ATTR.type='neo-Hookean';
febio_spec.Material.material{2}.ATTR.id=2;
febio_spec.Material.material{2}.E=E_youngs2;
febio_spec.Material.material{2}.v=nu2;
febio_spec.Material.material{2}.density=D_density;

materialName3='Material3';
febio_spec.Material.material{3}.ATTR.name=materialName3;
febio_spec.Material.material{3}.ATTR.type='rigid body';
febio_spec.Material.material{3}.ATTR.id=3;
febio_spec.Material.material{3}.density=D_density;
febio_spec.Material.material{3}.center_of_mass=mean(Vc1,1);

materialName4='Material4';
febio_spec.Material.material{4}.ATTR.name=materialName4;
febio_spec.Material.material{4}.ATTR.type='rigid body';
febio_spec.Material.material{4}.ATTR.id=4;
febio_spec.Material.material{4}.density=D_density;
febio_spec.Material.material{4}.center_of_mass=mean(Vc2,1);

materialName5='Material5';
febio_spec.Material.material{5}.ATTR.name=materialName5;
febio_spec.Material.material{5}.ATTR.type='rigid body';
febio_spec.Material.material{5}.ATTR.id=5;
febio_spec.Material.material{5}.density=D_density;
febio_spec.Material.material{5}.center_of_mass=mean(Vc3,1);

%Mesh section
% -> Nodes
febio_spec.Mesh.Nodes{1}.ATTR.name='nodeSet_all'; %The node set name
febio_spec.Mesh.Nodes{1}.node.ATTR.id=(1:size(V,1))'; %The node id's
febio_spec.Mesh.Nodes{1}.node.VAL=V; %The nodel coordinates

% -> Elements
partName1='CorticalBone';
febio_spec.Mesh.Elements{1}.ATTR.name=partName1; %Name of this part
febio_spec.Mesh.Elements{1}.ATTR.type='tet4'; %Element type of this set
febio_spec.Mesh.Elements{1}.ATTR.mat=1; %material index for this set
febio_spec.Mesh.Elements{1}.elem.ATTR.id=(1:1:size(E1,1))'; %Element id's
febio_spec.Mesh.Elements{1}.elem.VAL=E1;

partName2='CancellousBone';
febio_spec.Mesh.Elements{2}.ATTR.name=partName2; %Name of this part
febio_spec.Mesh.Elements{2}.ATTR.type='tet4'; %Element type of this set
febio_spec.Mesh.Elements{2}.ATTR.mat=2; %material index for this set
febio_spec.Mesh.Elements{2}.elem.ATTR.id=size(E1,1)+(1:1:size(E2,1))'; %Element id's
febio_spec.Mesh.Elements{2}.elem.VAL=E2;

partName3='Part3';
febio_spec.Mesh.Elements{3}.ATTR.name=partName3; %Name of this part
febio_spec.Mesh.Elements{3}.ATTR.type='quad4'; %Element type of this set
febio_spec.Mesh.Elements{3}.ATTR.mat=3; %material index for this set
febio_spec.Mesh.Elements{3}.elem.ATTR.id=size(E1,1)+size(E2,1)+(1:1:size(Fc1,1))'; %Element id's
febio_spec.Mesh.Elements{3}.elem.VAL=Fc1;

partName4='Part4';
febio_spec.Mesh.Elements{4}.ATTR.name=partName4; %Name of this part
febio_spec.Mesh.Elements{4}.ATTR.type='quad4'; %Element type of this set
febio_spec.Mesh.Elements{4}.ATTR.mat=4; %material index for this set
febio_spec.Mesh.Elements{4}.elem.ATTR.id=size(E1,1)+size(E2,1)+size(Fc1,1)+(1:1:size(Fc2,1))'; %Element id's
febio_spec.Mesh.Elements{4}.elem.VAL=Fc2;

partName5='Part5';
febio_spec.Mesh.Elements{5}.ATTR.name=partName5; %Name of this part
febio_spec.Mesh.Elements{5}.ATTR.type='quad4'; %Element type of this set
febio_spec.Mesh.Elements{5}.ATTR.mat=5; %material index for this set
febio_spec.Mesh.Elements{5}.elem.ATTR.id=size(E1,1)+size(E2,1)+size(Fc1,1)+size(Fc2,1)+(1:1:size(Fc3,1))'; %Element id's
febio_spec.Mesh.Elements{5}.elem.VAL=Fc3;

%MeshDomains section
febio_spec.MeshDomains.SolidDomain{1}.ATTR.name=partName1;
febio_spec.MeshDomains.SolidDomain{1}.ATTR.mat=materialName1;

febio_spec.MeshDomains.SolidDomain{2}.ATTR.name=partName2;
febio_spec.MeshDomains.SolidDomain{2}.ATTR.mat=materialName2;

febio_spec.MeshDomains.ShellDomain{1}.ATTR.name=partName3;
febio_spec.MeshDomains.ShellDomain{1}.ATTR.mat=materialName3;

febio_spec.MeshDomains.ShellDomain{2}.ATTR.name=partName4;
febio_spec.MeshDomains.ShellDomain{2}.ATTR.mat=materialName4;

febio_spec.MeshDomains.ShellDomain{3}.ATTR.name=partName5;
febio_spec.MeshDomains.ShellDomain{3}.ATTR.mat=materialName5;

% -> NodeSets
if bcFix==1
    nodeSetName1='bcSupportList';
    febio_spec.Mesh.NodeSet{1}.ATTR.name=nodeSetName1;
    febio_spec.Mesh.NodeSet{1}.VAL=mrow(bcSupportList);
end

% -> Surfaces
surfaceNameSec1='contact_secondary1';
febio_spec.Mesh.Surface{1}.ATTR.name=surfaceNameSec1;
febio_spec.Mesh.Surface{1}.quad4.ATTR.id=(1:1:size(Fc1,1))';
febio_spec.Mesh.Surface{1}.quad4.VAL=Fc1;

surfaceNameSec2='contact_secondary2';
febio_spec.Mesh.Surface{2}.ATTR.name=surfaceNameSec2;
febio_spec.Mesh.Surface{2}.quad4.ATTR.id=(1:1:size(Fc2,1))';
febio_spec.Mesh.Surface{2}.quad4.VAL=Fc2;

surfaceNameSec3='contact_secondary3';
febio_spec.Mesh.Surface{3}.ATTR.name=surfaceNameSec3;
febio_spec.Mesh.Surface{3}.quad4.ATTR.id=(1:1:size(Fc3,1))';
febio_spec.Mesh.Surface{3}.quad4.VAL=Fc3;

surfaceNamePrim1='contact_primary1';
febio_spec.Mesh.Surface{4}.ATTR.name=surfaceNamePrim1;
febio_spec.Mesh.Surface{4}.tri3.ATTR.id=(1:1:size(F_prim1,1))';
febio_spec.Mesh.Surface{4}.tri3.VAL=F_prim1;

surfaceNamePrim2='contact_primary2';
febio_spec.Mesh.Surface{5}.ATTR.name=surfaceNamePrim2;
febio_spec.Mesh.Surface{5}.tri3.ATTR.id=(1:1:size(F_prim2,1))';
febio_spec.Mesh.Surface{5}.tri3.VAL=F_prim2;

surfaceNamePrim3='contact_primary3';
febio_spec.Mesh.Surface{6}.ATTR.name=surfaceNamePrim3;
febio_spec.Mesh.Surface{6}.tri3.ATTR.id=(1:1:size(F_prim3,1))';
febio_spec.Mesh.Surface{6}.tri3.VAL=F_prim3;

% -> Surface pairs
febio_spec.Mesh.SurfacePair{1}.ATTR.name='Contact1';
febio_spec.Mesh.SurfacePair{1}.primary=surfaceNamePrim1;
febio_spec.Mesh.SurfacePair{1}.secondary=surfaceNameSec1;

febio_spec.Mesh.SurfacePair{2}.ATTR.name='Contact2';
febio_spec.Mesh.SurfacePair{2}.primary=surfaceNamePrim2;
febio_spec.Mesh.SurfacePair{2}.secondary=surfaceNameSec2;

febio_spec.Mesh.SurfacePair{3}.ATTR.name='Contact3';
febio_spec.Mesh.SurfacePair{3}.primary=surfaceNamePrim3;
febio_spec.Mesh.SurfacePair{3}.secondary=surfaceNameSec3;

%Boundary condition section
% -> Fix boundary conditions
if bcFix==1
    febio_spec.Boundary.bc{1}.ATTR.name='zero_displacement_xyz';
    febio_spec.Boundary.bc{1}.ATTR.type='zero displacement';
    febio_spec.Boundary.bc{1}.ATTR.node_set=nodeSetName1;
    febio_spec.Boundary.bc{1}.x_dof=1;
    febio_spec.Boundary.bc{1}.y_dof=1;
    febio_spec.Boundary.bc{1}.z_dof=1;
end

%Rigid section
% ->Rigid body fix boundary conditions
febio_spec.Rigid.rigid_bc{1}.ATTR.name='RotFix_1';
febio_spec.Rigid.rigid_bc{1}.ATTR.type='rigid_fixed';
febio_spec.Rigid.rigid_bc{1}.rb=3;
febio_spec.Rigid.rigid_bc{1}.Rx_dof=1;
febio_spec.Rigid.rigid_bc{1}.Ry_dof=1;
%febio_spec.Rigid.rigid_bc{1}.Rz_dof=1;
febio_spec.Rigid.rigid_bc{1}.Ru_dof=1;
febio_spec.Rigid.rigid_bc{1}.Rv_dof=1;
febio_spec.Rigid.rigid_bc{1}.Rw_dof=1;

febio_spec.Rigid.rigid_bc{2}.ATTR.name='RotFix_2';
febio_spec.Rigid.rigid_bc{2}.ATTR.type='rigid_fixed';
febio_spec.Rigid.rigid_bc{2}.rb=4;
febio_spec.Rigid.rigid_bc{2}.Rx_dof=1;
febio_spec.Rigid.rigid_bc{2}.Ry_dof=1;
febio_spec.Rigid.rigid_bc{2}.Rz_dof=1;
febio_spec.Rigid.rigid_bc{2}.Ru_dof=1;
febio_spec.Rigid.rigid_bc{2}.Rv_dof=1;
febio_spec.Rigid.rigid_bc{2}.Rw_dof=1;

febio_spec.Rigid.rigid_bc{3}.ATTR.name='RotFix_3';
febio_spec.Rigid.rigid_bc{3}.ATTR.type='rigid_fixed';
febio_spec.Rigid.rigid_bc{3}.rb=5;
febio_spec.Rigid.rigid_bc{3}.Rx_dof=1;
febio_spec.Rigid.rigid_bc{3}.Ry_dof=1;
febio_spec.Rigid.rigid_bc{3}.Rz_dof=1;
febio_spec.Rigid.rigid_bc{3}.Ru_dof=1;
febio_spec.Rigid.rigid_bc{3}.Rv_dof=1;
febio_spec.Rigid.rigid_bc{3}.Rw_dof=1;

% ->Rigid body prescribe boundary conditions
febio_spec.Rigid.rigid_bc{4}.ATTR.name='RigidPrescribe';
febio_spec.Rigid.rigid_bc{4}.ATTR.type='rigid_displacement';
febio_spec.Rigid.rigid_bc{4}.rb=3;
febio_spec.Rigid.rigid_bc{4}.dof='z';
febio_spec.Rigid.rigid_bc{4}.value.ATTR.lc=1;
febio_spec.Rigid.rigid_bc{4}.value.VAL=zDisp;
febio_spec.Rigid.rigid_bc{4}.relative=0;

%Contact section
for qc=1:1:3
    febio_spec.Contact.contact{qc}.ATTR.surface_pair=febio_spec.Mesh.SurfacePair{qc}.ATTR.name;
    febio_spec.Contact.contact{qc}.ATTR.type='sticky';
    febio_spec.Contact.contact{qc}.penalty=contactPenalty;
    febio_spec.Contact.contact{qc}.laugon=laugon;
    febio_spec.Contact.contact{qc}.tolerance=0.2;
    febio_spec.Contact.contact{qc}.minaug=minaug;
    febio_spec.Contact.contact{qc}.maxaug=maxaug;
    febio_spec.Contact.contact{qc}.snap_tol=0.01;
    febio_spec.Contact.contact{qc}.max_traction=0;
    febio_spec.Contact.contact{qc}.search_tolerance=0.01;
end

%LoadData section
% -> load_controller
febio_spec.LoadData.load_controller{1}.ATTR.name='LC_1';
febio_spec.LoadData.load_controller{1}.ATTR.id=1;
febio_spec.LoadData.load_controller{1}.ATTR.type='loadcurve';
febio_spec.LoadData.load_controller{1}.interpolate='LINEAR';
%febio_spec.LoadData.load_controller{1}.extend='CONSTANT';
febio_spec.LoadData.load_controller{1}.points.pt.VAL=[0 0; 1 1];

%Output section
% -> log file
febio_spec.Output.logfile.ATTR.file=febioLogFileName;
febio_spec.Output.logfile.node_data{1}.ATTR.file=febioLogFileName_disp;
febio_spec.Output.logfile.node_data{1}.ATTR.data='ux;uy;uz';
febio_spec.Output.logfile.node_data{1}.ATTR.delim=',';

febio_spec.Output.logfile.rigid_body_data{1}.ATTR.file=febioLogFileName_force;
febio_spec.Output.logfile.rigid_body_data{1}.ATTR.data='Fx;Fy;Fz';
febio_spec.Output.logfile.rigid_body_data{1}.ATTR.delim=',';
febio_spec.Output.logfile.rigid_body_data{1}.VAL=3;

febio_spec.Output.logfile.element_data{1}.ATTR.file=febioLogFileName_stress;
febio_spec.Output.logfile.element_data{1}.ATTR.data='s1';
febio_spec.Output.logfile.element_data{1}.ATTR.delim=',';

Quick viewing of the FEBio input file structure

The febView function can be used to view the xml structure in a MATLAB figure window.

febView(febio_spec); %Viewing the febio file

Exporting the FEBio input file

Exporting the febio_spec structure to an FEBio input file is done using the febioStruct2xml function.

febioStruct2xml(febio_spec,febioFebFileName); %Exporting to file and domNode
%system(['gedit ',febioFebFileName,' &']);

Running the FEBio analysis

To run the analysis defined by the created FEBio input file the runMonitorFEBio function is used. The input for this function is a structure defining job settings e.g. the FEBio input file name. The optional output runFlag informs the user if the analysis was run succesfully.

febioAnalysis.run_filename=febioFebFileName; %The input file name
febioAnalysis.run_logname=febioLogFileName; %The name for the log file
febioAnalysis.disp_on=1; %Display information on the command window
febioAnalysis.runMode=runMode;
febioAnalysis.maxLogCheckTime=10; %Max log file checking time

[runFlag]=runMonitorFEBio(febioAnalysis);%START FEBio NOW!!!!!!!!

 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-------->    RUNNING/MONITORING FEBIO JOB    <-------- 20-Apr-2023 10:44:05
FEBio path: /home/kevin/FEBioStudio2/bin/febio4
# Attempt removal of existing log files                20-Apr-2023 10:44:05
 * Removal succesful                                   20-Apr-2023 10:44:05
# Attempt removal of existing .xplt files              20-Apr-2023 10:44:05
 * Removal succesful                                   20-Apr-2023 10:44:05
# Starting FEBio...                                    20-Apr-2023 10:44:05
  Max. total analysis time is: Inf s
 * Waiting for log file creation                       20-Apr-2023 10:44:05
   Max. wait time: 10 s
 * Log file found.                                     20-Apr-2023 10:44:06
# Parsing log file...                                  20-Apr-2023 10:44:06
    number of iterations   : 4                         20-Apr-2023 10:44:06
    number of reformations : 4                         20-Apr-2023 10:44:06
------- converged at time : 0.05                       20-Apr-2023 10:44:06
    number of iterations   : 7                         20-Apr-2023 10:44:07
    number of reformations : 7                         20-Apr-2023 10:44:08
------- converged at time : 0.1                        20-Apr-2023 10:44:08
    number of iterations   : 3                         20-Apr-2023 10:44:08
    number of reformations : 3                         20-Apr-2023 10:44:08
------- converged at time : 0.15                       20-Apr-2023 10:44:08
    number of iterations   : 3                         20-Apr-2023 10:44:09
    number of reformations : 3                         20-Apr-2023 10:44:09
------- converged at time : 0.2                        20-Apr-2023 10:44:09
    number of iterations   : 4                         20-Apr-2023 10:44:09
    number of reformations : 4                         20-Apr-2023 10:44:09
------- converged at time : 0.25                       20-Apr-2023 10:44:09
    number of iterations   : 3                         20-Apr-2023 10:44:10
    number of reformations : 3                         20-Apr-2023 10:44:10
------- converged at time : 0.3                        20-Apr-2023 10:44:10
    number of iterations   : 3                         20-Apr-2023 10:44:11
    number of reformations : 3                         20-Apr-2023 10:44:11
------- converged at time : 0.35                       20-Apr-2023 10:44:11
    number of iterations   : 3                         20-Apr-2023 10:44:11
    number of reformations : 3                         20-Apr-2023 10:44:11
------- converged at time : 0.4                        20-Apr-2023 10:44:11
    number of iterations   : 4                         20-Apr-2023 10:44:12
    number of reformations : 4                         20-Apr-2023 10:44:12
------- converged at time : 0.45                       20-Apr-2023 10:44:12
    number of iterations   : 4                         20-Apr-2023 10:44:13
    number of reformations : 4                         20-Apr-2023 10:44:13
------- converged at time : 0.5                        20-Apr-2023 10:44:13
    number of iterations   : 4                         20-Apr-2023 10:44:13
    number of reformations : 4                         20-Apr-2023 10:44:13
------- converged at time : 0.55                       20-Apr-2023 10:44:13
    number of iterations   : 3                         20-Apr-2023 10:44:14
    number of reformations : 3                         20-Apr-2023 10:44:14
------- converged at time : 0.6                        20-Apr-2023 10:44:14
    number of iterations   : 4                         20-Apr-2023 10:44:15
    number of reformations : 4                         20-Apr-2023 10:44:15
------- converged at time : 0.65                       20-Apr-2023 10:44:15
    number of iterations   : 4                         20-Apr-2023 10:44:15
    number of reformations : 4                         20-Apr-2023 10:44:15
------- converged at time : 0.7                        20-Apr-2023 10:44:15
    number of iterations   : 4                         20-Apr-2023 10:44:16
    number of reformations : 4                         20-Apr-2023 10:44:16
------- converged at time : 0.75                       20-Apr-2023 10:44:16
    number of iterations   : 3                         20-Apr-2023 10:44:17
    number of reformations : 3                         20-Apr-2023 10:44:17
------- converged at time : 0.8                        20-Apr-2023 10:44:17
    number of iterations   : 4                         20-Apr-2023 10:44:17
    number of reformations : 4                         20-Apr-2023 10:44:17
------- converged at time : 0.85                       20-Apr-2023 10:44:17
    number of iterations   : 4                         20-Apr-2023 10:44:18
    number of reformations : 4                         20-Apr-2023 10:44:18
------- converged at time : 0.9                        20-Apr-2023 10:44:18
    number of iterations   : 3                         20-Apr-2023 10:44:19
    number of reformations : 3                         20-Apr-2023 10:44:19
------- converged at time : 0.95                       20-Apr-2023 10:44:19
    number of iterations   : 4                         20-Apr-2023 10:44:19
    number of reformations : 4                         20-Apr-2023 10:44:19
------- converged at time : 1                          20-Apr-2023 10:44:19
 Elapsed time : 0:00:14                                20-Apr-2023 10:44:20
 N O R M A L   T E R M I N A T I O N
# Done                                                 20-Apr-2023 10:44:20
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

Import FEBio results

if runFlag==1 %i.e. a succesful run

Importing nodal displacements from a log file

    dataStruct=importFEBio_logfile(fullfile(savePath,febioLogFileName_disp),0,1);

    %Access data
    N_disp_mat=dataStruct.data; %Displacement
    timeVec=dataStruct.time; %Time

    %Create deformed coordinate set
    V_DEF=N_disp_mat+repmat(V,[1 1 size(N_disp_mat,3)]);

Importing element stress from a log file

    dataStruct=importFEBio_logfile(fullfile(savePath,febioLogFileName_stress),0,1);

    %Access data
    E_stress_mat=dataStruct.data;
    E_stress_mat(isnan(E_stress_mat))=0;

Plotting the simulated results using anim8 to visualize and animate deformations

    [CV]=faceToVertexMeasure(E,V,E_stress_mat(:,:,end));

    % Create basic view and store graphics handle to initiate animation
    hf=cFigure; %Open figure
    gtitle([febioFebFileNamePart,': Press play to animate']);
    title('$\sigma_{1}$ [MPa]','Interpreter','Latex')
    hp=gpatch(Fb,V_DEF(:,:,end),CV,'k',1); %Add graphics object to animate
    hp.FaceColor='interp';
    hp2=gpatch([Fc1;Fc2;Fc3],V,'w','k',0.5);

    axisGeom(gca,fontSize);
    colormap(gjet(250)); colorbar;
    caxis([min(E_stress_mat(:)) max(E_stress_mat(:))]/20);
    axis(axisLim(V_DEF)); %Set axis limits statically
    camlight headlight;

    % Set up animation features
    animStruct.Time=timeVec; %The time vector
    for qt=1:1:size(N_disp_mat,3) %Loop over time increments

        [CV]=faceToVertexMeasure(E,V,E_stress_mat(:,:,qt));

        %Set entries in animation structure
        animStruct.Handles{qt}=[hp hp hp2]; %Handles of objects to animate
        animStruct.Props{qt}={'Vertices','CData','Vertices'}; %Properties of objects to animate
        animStruct.Set{qt}={V_DEF(:,:,qt),CV,V_DEF(:,:,qt)}; %Property values for to set in order to animate
    end
    anim8(hf,animStruct); %Initiate animation feature
    drawnow;

Importing rigidbody force data from a log file

    dataStruct=importFEBio_logfile(fullfile(savePath,febioLogFileName_force),0,1);

    %Access data
    Force_mat=dataStruct.data;

    Fz=squeeze(Force_mat(:,3,:));

Visualize stress-stretch curve

    cFigure; hold on;
    title('Force-displacement curve','FontSize',fontSize);
    xlabel('Displacement [mm]','FontSize',fontSize,'Interpreter','Latex');
    ylabel('$F_z$ [N]','FontSize',fontSize,'Interpreter','Latex');

    plot(timeVec(:).*zDisp,Fz(:),'r-','lineWidth',lineWidth);

    view(2); axis tight;  grid on; axis square; box on;
    set(gca,'FontSize',fontSize);
    drawnow;

end

GIBBON www.gibboncode.org

Kevin Mattheus Moerman, [email protected]

GIBBON footer text

License: https://github.com/gibbonCode/GIBBON/blob/master/LICENSE

GIBBON: The Geometry and Image-based Bioengineering add-On. A toolbox for image segmentation, image-based modeling, meshing, and finite element analysis.

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/.