DEMO_febio_0019_vessel_pressure_inflate

Below is a demonstration for:

Building geometry for a cylindrical vessel with tetrahedral elements
Defining the boundary conditions
Coding the febio structure
Running the model
Importing and visualizing the displacement results

Keywords
Plot settings
Control parameters
Creating model boundary polygons
Creating model boundary surfaces
Tetrahedral meshing of vessel
Defining the boundary conditions
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 3.0
febio, FEBio
vessel, cylinder
prescribed pressure
tetrahedral elements, tet4
tube, cylindrical
static, solid
hyperelastic, Ogden
displacement logfile
stress logfile

clear; close all; clc;

Plot settings

fontSize=20;
faceAlpha1=0.8;
markerSize=40;
markerSize2=20;
lineWidth=3;

Control parameters

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

% 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

%Specifying geometry parameters
pointSpacing=1;
radiusOuter1=10;
radiusInner1=9;
radiusOuter2=9;
radiusInner2=7;
vesselLength=60;

%Load
appliedPressure=5e-3;

%Material parameter set
c1=0.03; %Shear-modulus-like parameter
m1=2; %Material parameter setting degree of non-linearity
k_factor=1e2; %Bulk modulus factor
k=c1*k_factor; %Bulk modulus

% FEA control settings
numTimeSteps=10; %Number of time steps desired
max_refs=25; %Max reforms
max_ups=0; %Set to zero to use full-Newton iterations
opt_iter=12; %Optimum number of iterations
max_retries=10; %Maximum number of retires
dtmin=(1/numTimeSteps)/100; %Minimum time step size
dtmax=1/numTimeSteps; %Maximum time step size

Creating model boundary polygons

nRad=round((2*pi*mean([radiusOuter1 radiusOuter2]))/pointSpacing); %Number of radial steps

t=linspace(0,2*pi,nRad)'; %Angles
t=t(1:end-1); %take away last which equals start
v1_Outer=[-(vesselLength/2)*ones(size(t)) radiusOuter1*sin(t) radiusOuter1*cos(t)]; %Circular coordinates

t=linspace(0,2*pi,nRad)'; %Angles
t=t(1:end-1); %take away last which equals start
v2_Outer=[(vesselLength/2)*ones(size(t)) radiusOuter2*sin(t) radiusOuter2*cos(t)]; %Circular coordinates

nRad=round((2*pi*mean([radiusInner1 radiusInner2]))/pointSpacing); %Number of radial steps

t=linspace(0,2*pi,nRad)'; %Angles
t=t(1:end-1); %take away last which equals start
v1_Inner=[-(vesselLength/2)*ones(size(t)) radiusInner1*sin(t) radiusInner1*cos(t)]; %Circular coordinates

t=linspace(0,2*pi,nRad)'; %Angles
t=t(1:end-1); %take away last which equals start
v2_Inner=[(vesselLength/2)*ones(size(t)) radiusInner2*sin(t) radiusInner2*cos(t)]; %Circular coordinates

Plotting model boundary polygons

cFigure;
hold on;
title('Model boundary polygons','FontSize',fontSize);
plotV(v1_Outer,'r.-')
plotV(v1_Inner,'g.-')
plotV(v2_Outer,'b.-')
plotV(v2_Inner,'y.-')
axisGeom(gca,fontSize);

drawnow;

Creating model boundary surfaces

% controlStructLoft.numSteps=17;
controlStructLoft.closeLoopOpt=1;
controlStructLoft.patchType='tri';

%Meshing outer surface
[F1,V1]=polyLoftLinear(v1_Outer,v2_Outer,controlStructLoft);
F1=fliplr(F1); %Invert orientation

%Meshing inner surface
[F2,V2]=polyLoftLinear(v1_Inner,v2_Inner,controlStructLoft);

%Meshing left
[F3,V3]=regionTriMesh3D({v1_Outer,v1_Inner},pointSpacing,0,'linear');
F3=fliplr(F3); %Invert orientation

%Meshing right
[F4,V4]=regionTriMesh3D({v2_Outer,v2_Inner},pointSpacing,0,'linear');

%Merging surface sets
[Fv,Vv,Cv]=joinElementSets({F1,F2,F3,F4},{V1,V2,V3,V4});
[Fv,Vv]=mergeVertices(Fv,Vv);
Fv=fliplr(Fv);

Plotting model boundary surfaces

cFigure;
hold on;
title('Model boundary surfaces','FontSize',fontSize);

gpatch(Fv,Vv,Cv);
% patchNormPlot(Fv,Vv);

icolorbar;
colormap(gjet(4));

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

Tetrahedral meshing of vessel

faceBoundaryMarker=Cv;
[V_regions]=getInnerPoint(Fv,Vv);
[regionA]=tetVolMeanEst(Fv,Vv); %Volume for regular tets
stringOpt='-pq1.2AaY';

inputStruct.stringOpt=stringOpt;
inputStruct.Faces=Fv;
inputStruct.Nodes=Vv;
inputStruct.holePoints=[];
inputStruct.faceBoundaryMarker=faceBoundaryMarker; %Face boundary markers
inputStruct.regionPoints=V_regions; %region points
inputStruct.regionA=regionA;
inputStruct.minRegionMarker=2; %Minimum region marker

% Mesh model using tetrahedral elements using tetGen
[meshOutput]=runTetGen(inputStruct); %Run tetGen

 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
--- TETGEN Tetrahedral meshing --- 11-Dec-2020 12:22:35
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
--- Writing SMESH file --- 11-Dec-2020 12:22:35
----> Adding node field
----> Adding facet field
----> Adding holes specification
----> Adding region specification
--- Done --- 11-Dec-2020 12:22:35
--- Running TetGen to mesh input boundary--- 11-Dec-2020 12:22:35
Opening /mnt/data/MATLAB/GIBBON/data/temp/temp.smesh.
Delaunizing vertices...
Delaunay seconds:  0.474423
Creating surface mesh ...
Surface mesh seconds:  0.013527
Recovering boundaries...
Boundary recovery seconds:  0.039334
Removing exterior tetrahedra ...
Spreading region attributes.
Exterior tets removal seconds:  0.01613
Recovering Delaunayness...
Delaunay recovery seconds:  0.012089
Refining mesh...
Refinement seconds:  0.111095
Optimizing mesh...
Optimization seconds:  0.00742

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:  0.125806
Total running seconds:  0.800328

Statistics:

  Input points: 6565
  Input facets: 13130
  Input segments: 19695
  Input holes: 0
  Input regions: 1

  Mesh points: 9848
  Mesh tetrahedra: 40525
  Mesh faces: 87615
  Mesh faces on exterior boundary: 13130
  Mesh faces on input facets: 13130
  Mesh edges on input segments: 19695
  Steiner points inside domain: 3283

--- Done --- 11-Dec-2020 12:22:36
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
--- Importing TetGen files --- 11-Dec-2020 12:22:36
--- Done --- 11-Dec-2020 12:22:36

Access model element and patch data

Fb=meshOutput.facesBoundary;
Cb=meshOutput.boundaryMarker;
V=meshOutput.nodes;
CE=meshOutput.elementMaterialID;
E=meshOutput.elements;

Visualizing mesh using meshView, see also anim8

meshView(meshOutput,[]);

Defining the boundary conditions

The visualization of the model boundary shows colors for each side of the cube. These labels can be used to define boundary conditions.

%Define supported node set
bcSupportList=unique(Fb(ismember(Cb,[3 4]),:)); %Node set part of selected face

F_pressure=fliplr(Fb(Cb==2,:));

Visualizing boundary conditions. Markers plotted on the semi-transparent model denote the nodes in the various boundary condition lists.

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

gpatch(Fb,V,'kw','k',0.5);

hl(1)=plotV(V(bcSupportList,:),'k.','MarkerSize',markerSize);
hl(2)=gpatch(F_pressure,V,'rw','r',0.5);

legend(hl,{'BC support','Pressure surface'});

axisGeom(gca,fontSize);
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='3.0';

%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.max_ups=max_ups;
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='Ogden';
febio_spec.Material.material{1}.ATTR.id=1;
febio_spec.Material.material{1}.c1=c1;
febio_spec.Material.material{1}.m1=m1;
febio_spec.Material.material{1}.c2=c1;
febio_spec.Material.material{1}.m2=-m1;
febio_spec.Material.material{1}.k=k;

%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='Part1';
febio_spec.Mesh.Elements{1}.ATTR.name=partName1; %Name of this part
febio_spec.Mesh.Elements{1}.ATTR.type='tet4'; %Element type
febio_spec.Mesh.Elements{1}.elem.ATTR.id=(1:1:size(E,1))'; %Element id's
febio_spec.Mesh.Elements{1}.elem.VAL=E; %The element matrix

% -> Surfaces
surfaceName1='LoadedSurface';
febio_spec.Mesh.Surface{1}.ATTR.name=surfaceName1;
febio_spec.Mesh.Surface{1}.tri3.ATTR.id=(1:1:size(F_pressure,1))';
febio_spec.Mesh.Surface{1}.tri3.VAL=F_pressure;

% -> NodeSets
nodeSetName1='bcSupportList';
febio_spec.Mesh.NodeSet{1}.ATTR.name=nodeSetName1;
febio_spec.Mesh.NodeSet{1}.node.ATTR.id=bcSupportList(:);

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

%Boundary condition section
% -> Fix boundary conditions
febio_spec.Boundary.bc{1}.ATTR.type='fix';
febio_spec.Boundary.bc{1}.ATTR.node_set=nodeSetName1;
febio_spec.Boundary.bc{1}.dofs='x,y,z';

%Loads section
% -> Surface load
febio_spec.Loads.surface_load{1}.ATTR.type='pressure';
febio_spec.Loads.surface_load{1}.ATTR.surface=surfaceName1;
febio_spec.Loads.surface_load{1}.pressure.ATTR.lc=1;
febio_spec.Loads.surface_load{1}.pressure.VAL=appliedPressure;
febio_spec.Loads.surface_load{1}.symmetric_stiffness=1;

%LoadData section
% -> load_controller
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}.points.point.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.node_data{1}.VAL=1:size(V,1);

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 febView(febio_spec)

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

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.disp_log_on=1; %Display convergence information in the command window
febioAnalysis.runMode='external';%'internal';
febioAnalysis.t_check=0.25; %Time for checking log file (dont set too small)
febioAnalysis.maxtpi=1e99; %Max analysis time
febioAnalysis.maxLogCheckTime=10; %Max log file checking time

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

 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-------->    RUNNING/MONITORING FEBIO JOB    <-------- 11-Dec-2020 12:22:41
FEBio path: /home/kevin/FEBioStudio/bin/febio3
# Attempt removal of existing log files                11-Dec-2020 12:22:41
 * Removal succesful                                   11-Dec-2020 12:22:41
# Attempt removal of existing .xplt files              11-Dec-2020 12:22:41
 * Removal succesful                                   11-Dec-2020 12:22:41
# Starting FEBio...                                    11-Dec-2020 12:22:41
  Max. total analysis time is: 1e+99 s
 * Waiting for log file creation                       11-Dec-2020 12:22:41
   Max. wait time: 10 s
 * Log file found.                                     11-Dec-2020 12:22:41
# Parsing log file...                                  11-Dec-2020 12:22:41
    number of iterations   : 4                         11-Dec-2020 12:22:43
    number of reformations : 4                         11-Dec-2020 12:22:43
------- converged at time : 0.1                        11-Dec-2020 12:22:43
    number of iterations   : 4                         11-Dec-2020 12:22:44
    number of reformations : 4                         11-Dec-2020 12:22:44
------- converged at time : 0.2                        11-Dec-2020 12:22:44
    number of iterations   : 4                         11-Dec-2020 12:22:46
    number of reformations : 4                         11-Dec-2020 12:22:46
------- converged at time : 0.3                        11-Dec-2020 12:22:46
    number of iterations   : 4                         11-Dec-2020 12:22:48
    number of reformations : 4                         11-Dec-2020 12:22:48
------- converged at time : 0.4                        11-Dec-2020 12:22:48
    number of iterations   : 4                         11-Dec-2020 12:22:49
    number of reformations : 4                         11-Dec-2020 12:22:49
------- converged at time : 0.5                        11-Dec-2020 12:22:49
    number of iterations   : 5                         11-Dec-2020 12:22:51
    number of reformations : 5                         11-Dec-2020 12:22:51
------- converged at time : 0.6                        11-Dec-2020 12:22:51
    number of iterations   : 5                         11-Dec-2020 12:22:54
    number of reformations : 5                         11-Dec-2020 12:22:54
------- converged at time : 0.7                        11-Dec-2020 12:22:54
    number of iterations   : 7                         11-Dec-2020 12:22:57
    number of reformations : 7                         11-Dec-2020 12:22:57
------- converged at time : 0.8                        11-Dec-2020 12:22:57
    number of iterations   : 8                         11-Dec-2020 12:23:00
    number of reformations : 8                         11-Dec-2020 12:23:00
------- converged at time : 0.9                        11-Dec-2020 12:23:00
    number of iterations   : 6                         11-Dec-2020 12:23:03
    number of reformations : 6                         11-Dec-2020 12:23:03
------- converged at time : 1                          11-Dec-2020 12:23:03
 Elapsed time : 0:00:22                                11-Dec-2020 12:23:03
 N O R M A L   T E R M I N A T I O N
# Done                                                 11-Dec-2020 12:23:03
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

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),1,1);

    %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)]);

Plotting the simulated results using anim8 to visualize and animate deformations

    DN_magnitude=sqrt(sum(N_disp_mat(:,:,end).^2,2)); %Current displacement magnitude

    % Create basic view and store graphics handle to initiate animation
    hf=cFigure; %Open figure
    gtitle([febioFebFileNamePart,': Press play to animate']);
    title('Displacement magnitude [mm]','Interpreter','Latex')
    hp=gpatch(Fb,V_DEF(:,:,end),DN_magnitude,'k',1); %Add graphics object to animate
    hp.Marker='.';
    hp.MarkerSize=markerSize2;
    hp.FaceColor='interp';

    axisGeom(gca,fontSize);
    colormap(gjet(250)); colorbar;
    caxis([0 max(DN_magnitude)]);
    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
        DN_magnitude=sqrt(sum(N_disp_mat(:,:,qt).^2,2)); %Current displacement magnitude

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

end

GIBBON www.gibboncode.org

Kevin Mattheus Moerman, [email protected]

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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.

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