Add scripts and inp files.

This commit is contained in:
James Grogan 2024-05-13 20:50:21 +01:00
parent ad937f2602
commit e19f869a1e
390 changed files with 6580687 additions and 10 deletions

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function [] = 2DSimp()
% MATLAB based 2-D XFEM Solver
% J. Grogan (2012)
clear all
% Define Mesh
NumX=3;
NumY=3;
delX=1.;
delY=1.;
for j=1:NumY+1
for i=1:NumX+1
index=i+(NumX+1)*(j-1);
Node(index,1)=single((i-1.))*delX;
Node(index,2)=single((j-1.))*delY;
end
end
numNodes=(NumX+1)*(NumY+1);
for j=1:NumY
for i=1:NumX
index=i+NumX*(j-1);
Element(index,1)=i+(NumX+1)*(j-1);
Element(index,2)=i+(NumX+1)*(j-1)+1;
Element(index,3)=i+(NumX+1)*(j);
Element(index,4)=i+(NumX+1)*(j)+1;
end
end
numElem=(NumX)*(NumY);
% dofs per node
ndof=1;
% Define Section Properties
rho=1.;
% initial interface position
dpos=0.25;
% Initial temperatures
Tnew=zeros(numNodes,1);
Bound=zeros(numNodes,1);
stored(1)=dpos;
for e=1:numElem
for n=1:4
crdn=Node(Element(e,n),1);
if crdn<=dpos
Tnew(Element(e,n))=1.;
Bound(Element(e,n))=1.;
end
end
end
% Define Time Step
dtime=0.05;
tsteps=20;
time=0.;
% Loop through time steps
for ts=1:tsteps
K=zeros(numNodes*ndof,numNodes*ndof);
M=zeros(numNodes*ndof,numNodes*ndof);
% Loop Through Elements
for e=1:numElem
Ke=zeros(4*ndof);
Me=zeros(4*ndof);
for icrd=1:4;
crdnx(icrd)=Node(Element(e,icrd),1);
crdny(icrd)=Node(Element(e,icrd),2);
end
% regular element - fix extra dofs
gpos=1/sqrt(3.);
gx(1)=-gpos;
gx(2)=gpos;
gx(3)=gpos;
gx(4)=-gpos;
hx(1)=-gpos;
hx(2)=-gpos;
hx(3)=-gpos;
hx(4)=gpos;
% Loop Through Int Points
for i=1:4;
g=gx(i);
h=hx(i);
phi(1)=0.25*(1.-g)*(1.-h);
phi(2)=0.25*(1.+g)*(1.-h);
phi(3)=0.25*(1.+g)*(1.+h);
phi(4)=0.25*(1.-g)*(1.+h);
cond=1.;
spec=1.;
phig(1)=0.25*-(1.-h);
phig(2)=0.25*(1.-h);
phig(3)=0.25*(1.+h);
phig(4)=0.25*-(1.+h);
phih(1)=0.25*-(1.-g);
phih(2)=0.25*-(1.+g);
phih(3)=0.25*(1.+g);
phih(4)=0.25*(1.-g);
rjac=zeros(2,2);
for iter=1:4
rjac(1,1)=rjac(1,1)+phig(iter)*crdnx(iter);
rjac(1,2)=rjac(1,2)+phig(iter)*crdny(iter);
rjac(2,1)=rjac(2,1)+phih(iter)*crdnx(iter);
rjac(2,2)=rjac(2,2)+phih(iter)*crdny(iter);
end
djac=rjac(1,1)*rjac(2,2)-rjac(1,2)*rjac(2,1);
rjaci(1,1)= rjac(2,2)/djac;
rjaci(2,2)= rjac(1,1)/djac;
rjaci(1,2)=-rjac(1,2)/djac;
rjaci(2,1)=-rjac(2,1)/djac ;
for iter=1:4
phix(iter)=rjaci(1,1)*phig(iter)+rjaci(1,2)*phih(iter);
phiy(iter)=rjaci(2,1)*phig(iter)+rjaci(2,2)*phih(iter);
end
we=djac;
Ke=Ke+we*cond*(phix'*phix+phiy'*phiy);
Me=Me+(we*rho*spec*phi'*phi)/dtime;
end
% Add penalty term and get temp gradient on interface
% Assemble Global Matrices
gnum(1)=Element(e,1);
gnum(2)=Element(e,2);
gnum(3)=Element(e,3);
gnum(4)=Element(e,4);
for i=1:4;
for j=1:4;
K(gnum(j),gnum(i))=K(gnum(j),gnum(i))+Ke(j,i);
M(gnum(j),gnum(i))=M(gnum(j),gnum(i))+Me(j,i);
end
end
end
%Remove inactive DOFs(Reduce Matrices)
RHS=M*Tnew;
A=K+M;
Sub=A*Bound;
iindex=0;
for i=1:ndof*numNodes;
if Bound(i)==0.;
iindex=iindex+1;
RHSred(iindex)=RHS(i)-Sub(i);
jindex=0;
for j=1:ndof*numNodes;
if Bound(j)==0.;
jindex=jindex+1;
Ared(iindex,jindex)=A(i,j);
end
end
end
end
%Solve
StiffI=Ared^-1;
Tnewr=(Ared^-1)*RHSred';
iindex=0;
for i=1:ndof*numNodes;
if Bound(i)==0.;
iindex=iindex+1;
Tnew(i)=Tnewr(iindex);
end
end
Tnew
end
stored'

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*Heading
** Job name: Job-1 Model name: Model-1
** Generated by: Abaqus/CAE 6.12-1
*Preprint, echo=NO, model=NO, history=NO, contact=NO
**
** PARTS
**
*Part, name=Part-1
*Node
1, 0., 0., 0.
2, 0.2, 0., 0.
3, 0.4, 0., 0.
4, 0.6, 0., 0.
5, 0.8, 0., 0.
6, 1., 0., 0.
7, 1.2, 0., 0.
8, 1.4, 0., 0.
9, 1.6, 0., 0.
10, 1.8, 0., 0.
11, 2., 0., 0.
*USER ELEMENT,NODES=2,TYPE=U8008,PROP=1,COORDINATES=1,VAR=2,unsymm
11,12
*Element, type=U8008,ELSET=UEL
1, 1, 2
2, 2, 3
3, 3, 4
4, 4, 5
5, 5, 6
6, 6, 7
7, 7, 8
8, 8, 9
9, 9, 10
10, 10, 11
*UEL Property, Elset=UEL
1.
*End Part
**
**
** ASSEMBLY
**
*Assembly, name=Assembly
**
*Instance, name=Part-1-1, part=Part-1
*End Instance
**
*Nset, nset=_PickedSet16, internal, instance=Part-1-1
1,
*Nset, nset=_PickedSet17, internal, instance=Part-1-1
2,
*Nset, nset=Set-6, instance=Part-1-1
1,
*End Assembly
**
** MATERIALS
**
*Material, name=Material-1
*Conductivity
1.,
*Density
1.,
*Specific Heat
1.,
** ----------------------------------------------------------------
**
** Name: Predefined Field-1 Type: Temperature
*Initial Conditions, type=TEMPERATURE
_PickedSet16, 1.,0.
** Name: Predefined Field-2 Type: Temperature
*Initial Conditions, type=TEMPERATURE
_PickedSet17, 0.,0.
** STEP: Step-1
**
*Step, name=Step-1
*Heat Transfer, end=PERIOD, deltmx=100.
0.1, 1.6, 1e-09, 0.1,
**
** BOUNDARY CONDITIONS
**
** Name: BC-1 Type: Temperature
*Boundary
Set-6, 11, 11, 1.
**
** OUTPUT REQUESTS
**
*Restart, write, frequency=0
**
** FIELD OUTPUT: F-Output-1
**
*Output, field, variable=PRESELECT
*Output, history, frequency=0
*End Step

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function [] = FESolve()
% MATLAB based FE Solver
% J. Grogan (2012)
clear all
% Define Geometry
len=1.;
% Define Section Properties
rho=1.;
spec=1.;
cond=1.;
% Generate Mesh
numElem=10;
ndCoords=linspace(0,len,numElem+1);
numNodes=size(ndCoords,2);
indx=1:numElem;
elemNodes(:,1)=indx;
elemNodes(:,2)=indx+1;
% Initialize Conditions
Tnew=zeros(numNodes,1);
Tnew(1)=1.;
% Define Time Step
dtime=.1;
tsteps=10;
time=0.;
% Loop through time steps
for ts=1:tsteps;
time=time+dtime;
K=zeros(numNodes,numNodes);
M=zeros(numNodes,numNodes);
% Loop Through Elements
for e=1:numElem;
Ke=zeros(2);
Me=zeros(2);
gpx(1)=-1./sqrt(3.);
gpx(2)=1./sqrt(3.);
ajacob=abs(ndCoords(elemNodes(e,2))-ndCoords(elemNodes(e,1)))/2.;
% Loop Through Int Points
for i=1:2;
c=gpx(i);
phi(1)=(1.-c)/2.;
phi(2)=(1.+c)/2.;
phic(1)=-0.5;
phic(2)=0.5;
phix(1)=phic(1)/ajacob;
phix(2)=phic(2)/ajacob;
we=ajacob;
Ke=Ke+we*cond*phix'*phix;
Me=Me+(we*rho*spec*phi'*phi)/dtime;
end
% Assemble Global Matrices
K(elemNodes(e,1),elemNodes(e,1))=K(elemNodes(e,1),elemNodes(e,1))+Ke(1,1);
K(elemNodes(e,1),elemNodes(e,2))=K(elemNodes(e,1),elemNodes(e,2))+Ke(1,2);
K(elemNodes(e,2),elemNodes(e,1))=K(elemNodes(e,2),elemNodes(e,1))+Ke(2,1);
K(elemNodes(e,2),elemNodes(e,2))=K(elemNodes(e,2),elemNodes(e,2))+Ke(2,2);
M(elemNodes(e,1),elemNodes(e,1))=M(elemNodes(e,1),elemNodes(e,1))+Me(1,1);
M(elemNodes(e,1),elemNodes(e,2))=M(elemNodes(e,1),elemNodes(e,2))+Me(1,2);
M(elemNodes(e,2),elemNodes(e,1))=M(elemNodes(e,2),elemNodes(e,1))+Me(2,1);
M(elemNodes(e,2),elemNodes(e,2))=M(elemNodes(e,2),elemNodes(e,2))+Me(2,2);
end
%Apply Boundary Conditions (Reduce Matrices)
T1=1;
RHS=M*Tnew;
for i=1:numNodes-1;
for j=1:numNodes-1;
Kred(i,j)=K(i+1,j+1);
Mred(i,j)=M(i+1,j+1);
end
Subr(i)=(K(i+1,1)+M(i+1,1))*T1;
RHSr(i)=RHS(i+1);
end
%Solve
StiffI=(Mred+Kred)^-1;
Tnewr=StiffI*(RHSr'-Subr');
for i=1:numNodes-1;
Tnew(i+1)=Tnewr(i);
end
Tnew(1)=1.;
Tnew
end

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function [] = FESolveSimp()
% MATLAB based 1-D XFEM Solver
% J. Grogan (2012)
clear all
% Define Geometry
len=10.;
% Define Section Properties
rho=1.;
% Generate Mesh
numElem=10;
charlen=len/numElem;
ndCoords=linspace(0,len,numElem+1);
numNodes=size(ndCoords,2);
indx=1:numElem;
elemNodes(:,1)=indx;
elemNodes(:,2)=indx+1;
% dofs per node
ndof=1;
% Initial temperatures
Tnew=zeros(numNodes,1);
Bound=zeros(numNodes,1);
Tnew(1)=1.;
Bound(1)=1.;
% Define Time Step
dtime=0.01;
tsteps=10;
time=0.;
% Loop through time steps
for ts=1:tsteps
K=zeros(numNodes,numNodes);
M=zeros(numNodes,numNodes);
% Loop Through Elements
for e=1:numElem
Ke=zeros(2*ndof);
Me=zeros(2*ndof);
crdn1=ndCoords(elemNodes(e,1));
crdn2=ndCoords(elemNodes(e,2));
elen=abs(crdn2-crdn1);
ajacob=elen/2.;
gpx(1)=-1/sqrt(3.);
gpx(2)=1/sqrt(3.);
w(1)=1.;
w(2)=1.;
% Loop Through Int Points
for i=1:2;
c=gpx(i);
phi(1)=(1.-c)/2.;
phi(2)=(1.+c)/2.;
cond=1.;
spec=1.;
phic(1)=-0.5;
phic(2)=0.5;
phix(1)=phic(1)/ajacob;
phix(2)=phic(2)/ajacob;
we=ajacob*w(i);
Ke=Ke+we*cond*phix'*phix;
Me=Me+(we*rho*spec*phi'*phi)/dtime;
end
% Assemble Global Matrices
gnum=elemNodes(e,1);
for i=1:2;
for j=1:2;
K(gnum+j-1,gnum+i-1)=K(gnum+j-1,gnum+i-1)+Ke(j,i);
M(gnum+j-1,gnum+i-1)=M(gnum+j-1,gnum+i-1)+Me(j,i);
end
end
end
%Remove NON-ENHANCED DOFs(Reduce Matrices)
iindex=0.;
A=K+M;
Sub=A*Bound;
RHS=M*Tnew-Sub;
% Apply Boundary Conditions
for i=1:numNodes;
if Bound(i)==0.;
iindex=iindex+1;
RHSR(iindex)=RHS(i);
jindex=0;
for j=1:numNodes;
if Bound(j)==0.;
jindex=jindex+1;
AR(iindex,jindex)=A(i,j);
end
end
end
end
%Solve
Tnewr=(AR^-1)*RHSR';
% Restore Matrices
iindex=0;
for i=1:numNodes;
if Bound(i)==0.;
iindex=iindex+1;
Tnew(i)=Tnewr(iindex);
end
end
Tnew
end

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function [] = FESolveX()
% MATLAB based 1-D XFEM Solver
% J. Grogan (2012)
clear all
% Define Geometry
len=10.;
% Define Section Properties
rho=1.;
% Generate Mesh
numElem=40;
charlen=len/numElem;
ndCoords=linspace(0,len,numElem+1);
numNodes=size(ndCoords,2);
indx=1:numElem;
elemNodes(:,1)=indx;
elemNodes(:,2)=indx+1;
% dofs per node
ndof=2;
% initial interface position
dpos=4.6;
% Initial temperatures
Tnew=zeros(numNodes*2,1);
%storage
stored(1)=dpos;
for e=1:numElem
crdn1=ndCoords(elemNodes(e,1));
if crdn1<=dpos
Tnew(2*elemNodes(e,1)-1)=1.;
end
end
% Define Time Step
dtime=0.1;
tsteps=10;
time=0.;
% penalty term
beta=200.;
% Loop through time steps
for ts=1:tsteps
% Get interface velocity
d(1)=dpos+charlen;
d(2)=dpos+3*charlen/4;
d(3)=dpos+charlen/4;
d(4)=dpos;
for e=1:numElem
crdn1=ndCoords(elemNodes(e,1));
crdn2=ndCoords(elemNodes(e,2));
for j=1:4
if d(j)>=crdn1 & d(j)<crdn2
elen=abs(crdn2-crdn1);
ajacob=elen/2.;
point=(d(j)-crdn1)/ajacob-1.;
theta(1)=abs(crdn1-dpos)*sign(crdn1-dpos);
theta(2)=abs(crdn2-dpos)*sign(crdn2-dpos);
tmp1a=Tnew(elemNodes(e,1)*2-1);
tmp1b=Tnew(elemNodes(e,1)*2);
tmp2a=Tnew(elemNodes(e,2)*2-1);
tmp2b=Tnew(elemNodes(e,2)*2);
xi=point;
gm(1)=(1.-xi)/2.;
gm(3)=(1.+xi)/2.;
term=theta(1)*gm(1)+theta(2)*gm(3);
gm(2)=gm(1)*(abs(term)-abs(theta(1)));
gm(4)=gm(3)*(abs(term)-abs(theta(2)));
t(j)=gm(1)*tmp1a+gm(2)*tmp1b+gm(3)*tmp2a+gm(4)*tmp2b;
end
end
end
vel=1.*(0.5/charlen)*(2*t(1)+t(2)-t(3)-2*t(4));
vel=0.;
% Update interface position
dpos=dpos+vel*dtime;
stored(ts+1)=dpos;
K=zeros(numNodes*ndof,numNodes*ndof);
M=zeros(numNodes*ndof,numNodes*ndof);
pforce=zeros(numNodes*ndof,1);
% Loop Through Elements
for e=1:numElem
Ke=zeros(2*ndof);
Me=zeros(2*ndof);
crdn1=ndCoords(elemNodes(e,1));
crdn2=ndCoords(elemNodes(e,2));
theta(1)=abs(crdn1-dpos)*sign(crdn1-dpos);
theta(2)=abs(crdn2-dpos)*sign(crdn2-dpos);
enr=2;
elen=abs(crdn2-crdn1);
ajacob=elen/2.;
if sign(theta(1))~=sign(theta(2))
% enriched element
enr=4;
% get interface position on element
point=(dpos-crdn1)/ajacob-1.;
% devide element for sub integration
len1=abs(-point-1.);
len2=abs(1.-point);
mid1=-1+len1/2.;
mid2=1-len2/2.;
gpx(1)=-(len1/2.)/sqrt(3.)+mid1;
gpx(2)=(len1/2.)/sqrt(3.)+mid1;
gpx(3)=-(len2/2.)/sqrt(3.)+mid2;
gpx(4)=(len2/2.)/sqrt(3.)+mid2;
w(1)=(len1/2.);
w(2)=(len1/2.);
w(3)=(len2/2.);
w(4)=(len2/2.);
fdofs(1)=2*elemNodes(e,1);
fdofs(2)=2*elemNodes(e,2);
else
% regular element - fix extra dofs
gpx(1)=-1/sqrt(3.);
gpx(2)=1/sqrt(3.);
w(1)=1.;
w(2)=1.;
end
% Loop Through Int Points
for i=1:enr;
c=gpx(i);
phi(1)=(1.-c)/2.;
phi(3)=(1.+c)/2.;
term=theta(1)*phi(1)+theta(2)*phi(3);
if term<0
cond=0.;
spec=0.01;
else
cond=1.;
spec=1.;
end
phi(2)=phi(1)*(abs(term)-abs(theta(1)));
phi(4)=phi(3)*(abs(term)-abs(theta(2)));
phic(1)=-0.5;
phic(3)=0.5;
dterm=sign(term)*(phic(1)*theta(1)+phic(3)*theta(2));
phic(2)=phic(1)*(abs(term)-abs(theta(1)))+phi(1)*dterm;
phic(4)=phic(3)*(abs(term)-abs(theta(2)))+phi(3)*dterm;
phix(1)=phic(1)/ajacob;
phix(2)=phic(2)/ajacob;
phix(3)=phic(3)/ajacob;
phix(4)=phic(4)/ajacob;
we=ajacob*w(i);
Ke=Ke+we*cond*phix'*phix;
Me=Me+(we*rho*spec*phi'*phi)/dtime;
end
% Add penalty term and get temp gradient on interface
if enr==4;
xi=point;
gm(1)=(1.-xi)/2.;
gm(3)=(1.+xi)/2.;
term=theta(1)*gm(1)+theta(2)*gm(3);
gm(2)=gm(1)*(abs(term)-abs(theta(1)));
gm(4)=gm(3)*(abs(term)-abs(theta(2)));
tpos=gm(1)*Tnew(1)+gm(2)*Tnew(2)+gm(3)*Tnew(3)+gm(4)*Tnew(4);
pen=beta*(gm'*gm);
pfL=beta*1*gm';
Ke=Ke+pen;
else
pen=zeros(4);
pfL=zeros(4,1);
end
% Assemble Global Matrices
gnum=2.*elemNodes(e,1)-1.;
for i=1:4;
for j=1:4;
K(gnum+j-1,gnum+i-1)=K(gnum+j-1,gnum+i-1)+Ke(j,i);
M(gnum+j-1,gnum+i-1)=M(gnum+j-1,gnum+i-1)+Me(j,i);
end
pforce(gnum+i-1)=pforce(gnum+i-1)+pfL(i);
end
end
%Remove inactive DOFs(Reduce Matrices)
T1=1;
RHS=M*Tnew;
iindex=0;
for i=1:ndof*numNodes;
check=1;
if i==fdofs(1)|i==fdofs(2)
check=0;
elseif mod(i,2)~=0 & i~=1
check=0;
end
if check==0
jindex=0;
iindex=iindex+1;
for j=1:ndof*numNodes;
check=1;
if j==fdofs(1)|j==fdofs(2)
check=0;
elseif mod(j,2)~=0 & j~=1
check=0;
end
if check==0
jindex=jindex+1;
Kred(iindex,jindex)=K(i,j);
Mred(iindex,jindex)=M(i,j);
end
end
Subr(iindex)=(K(i,1)+M(i,1))*T1;
RHSr(iindex)=RHS(i);
pforcer(iindex)=pforce(i);
end
end
%Solve
StiffI=(Mred+Kred)^-1;
Tnewr=StiffI*(RHSr'-Subr'+pforcer');
iindex=0.;
for i=1:ndof*numNodes;
check=1;
if i==fdofs(1)|i==fdofs(2)
check=0;
elseif mod(i,2)~=0 & i~=1
check=0;
end
if check==0
iindex=iindex+1;
Tnew(i)=Tnewr(iindex);
else
Tnew(i)=0.;
end
end
Tnew(1)=1.;
Tnew
end
stored'

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function [] = FESolveX2D()
% MATLAB based 2-D XFEM Solver
% J. Grogan (2012)
clear all
% Define Mesh
NumX=4;
NumY=1;
delX=1.;
delY=1.;
for j=1:NumY+1
for i=1:NumX+1
index=i+(NumX+1)*(j-1);
Node(index,1)=single((i-1.))*delX;
Node(index,2)=single((j-1.))*delY;
end
end
numNodes=(NumX+1)*(NumY+1);
for j=1:NumY
for i=1:NumX
index=i+NumX*(j-1);
Element(index,1)=i+(NumX+1)*(j-1);
Element(index,2)=i+(NumX+1)*(j-1)+1;
Element(index,3)=i+(NumX+1)*(j)+1;
Element(index,4)=i+(NumX+1)*(j);
end
end
numElem=(NumX)*(NumY);
% dofs per node
ndof=2;
% Define Section Properties
rho=1.;
% initial interface position
dpos=0.1;
% Initial temperatures
Tnew=zeros(numNodes*2,1);
Bound=zeros(numNodes*2,1);
stored(1)=dpos;
for e=1:numElem
for n=1:4
crdn=Node(Element(e,n),1);
if crdn<=dpos
Tnew(2*Element(e,n)-1)=1.;
Bound(2*Element(e,n)-1)=1.;
end
end
end
% Define Time Step
dtime=0.1;
tsteps=10;
time=0.;
% penalty term
beta=80.;
% Loop through time steps
for ts=1:tsteps
% Get interface velocity
d(1)=dpos+delX;
d(2)=dpos+3*delX/4;
d(3)=dpos+delX/4;
d(4)=dpos;
for e=1:numElem
crdn1=Node(Element(e,1),1);
crdn2=Node(Element(e,2),1);
for j=1:4
if d(j)>=crdn1 & d(j)<crdn2
elen=abs(crdn2-crdn1);
ajacob=elen/2.;
point=(d(j)-crdn1)/ajacob-1.;
theta(1)=abs(crdn1-dpos)*sign(crdn1-dpos);
theta(2)=abs(crdn2-dpos)*sign(crdn2-dpos);
tmp1a=Tnew(Element(e,1)*2-1);
tmp1b=Tnew(Element(e,1)*2);
tmp2a=Tnew(Element(e,2)*2-1);
tmp2b=Tnew(Element(e,2)*2);
xi=point;
gm(1)=(1.-xi)/2.;
gm(3)=(1.+xi)/2.;
term=theta(1)*gm(1)+theta(2)*gm(3);
gm(2)=gm(1)*(abs(term)-abs(theta(1)));
gm(4)=gm(3)*(abs(term)-abs(theta(2)));
t(j)=gm(1)*tmp1a+gm(2)*tmp1b+gm(3)*tmp2a+gm(4)*tmp2b;
end
end
end
% vel=-0.1*(0.5/delX)*(2*t(1)+t(2)-t(3)-2*t(4))
vel=0.0;
% Update interface position
dpos=dpos+vel*dtime;
stored(ts+1)=dpos;
K=zeros(numNodes*ndof,numNodes*ndof);
M=zeros(numNodes*ndof,numNodes*ndof);
pforce=zeros(numNodes*ndof,1);
% Loop Through Elements
for e=1:numElem
Ke=zeros(4*ndof);
Me=zeros(4*ndof);
for icrd=1:4;
crdnx(icrd)=Node(Element(e,icrd),1);
crdny(icrd)=Node(Element(e,icrd),2);
theta(icrd)=abs(crdnx(icrd)-dpos)*sign(crdnx(icrd)-dpos);
end
if sign(theta(1))~=sign(theta(2))
% enriched element
enr=8;
% get interface position on element
elen=abs(crdnx(2)-crdnx(1));
frac=abs(dpos-crdnx(1))/elen;
len1=2.*frac;
len2=2.*(1.-frac);
% devide element for sub integration
mid1=-1+len1/2.;
mid2=1-len2/2.;
gx(1)=mid1-(len1/2.)/sqrt(3.);
gx(2)=mid1+(len1/2.)/sqrt(3.);
gx(3)=mid1+(len1/2.)/sqrt(3.);
gx(4)=mid1-(len1/2.)/sqrt(3.);
gx(5)=mid2-(len2/2.)/sqrt(3.);
gx(6)=mid2+(len2/2.)/sqrt(3.);
gx(7)=mid2+(len2/2.)/sqrt(3.);
gx(8)=mid2-(len2/2.)/sqrt(3.);
gpos=1/sqrt(3.);
hx(1)=-gpos;
hx(2)=-gpos;
hx(3)=+gpos;
hx(4)=+gpos;
hx(5)=-gpos;
hx(6)=-gpos;
hx(7)=+gpos;
hx(8)=+gpos;
for iw=1:4
w(iw)=frac/2.;
w(iw+4)=(1.-frac)/2.;
end
else
% regular element - fix extra dofs
enr=4;
gpos=1/sqrt(3.);
gx(1)=-gpos;
gx(2)=gpos;
gx(3)=gpos;
gx(4)=-gpos;
hx(1)=-gpos;
hx(2)=-gpos;
hx(3)=gpos;
hx(4)=gpos;
for iw=1:4
w(iw)=1.;
end
end
% Loop Through Int Points
for i=1:enr;
g=gx(i);
h=hx(i);
phi(1)=0.25*(1.-g)*(1.-h);
phi(3)=0.25*(1.+g)*(1.-h);
phi(5)=0.25*(1.+g)*(1.+h);
phi(7)=0.25*(1.-g)*(1.+h);
iLS=theta(1)*phi(1)+theta(2)*phi(3)+theta(3)*phi(5)+theta(4)*phi(7);
if iLS<0.
cond=0.;
spec=0.01;
else
cond=1.;
spec=1.;
end
for iter=1:4
phi(2*iter)=phi(2*iter-1)*(abs(iLS)-abs(theta(iter)));
end
phig(1)=0.25*-(1.-h);
phig(3)=0.25*(1.-h);
phig(5)=0.25*(1.+h);
phig(7)=0.25*-(1.+h);
phih(1)=0.25*-(1.-g);
phih(3)=0.25*-(1.+g);
phih(5)=0.25*(1.+g);
phih(7)=0.25*(1.-g);
diLSg=sign(iLS)*(phig(1)*theta(1)+phig(3)*theta(2)+phig(5)*theta(3)+phig(7)*theta(4));
diLSh=sign(iLS)*(phih(1)*theta(1)+phih(3)*theta(2)+phih(5)*theta(3)+phih(7)*theta(4));
for iter=1:4
phig(2*iter)=phig(2*iter-1)*(abs(iLS)-abs(theta(iter)))+phi(2*iter-1)*diLSg;
phih(2*iter)=phih(2*iter-1)*(abs(iLS)-abs(theta(iter)))+phi(2*iter-1)*diLSh;
end
rjac=zeros(2,2);
for iter=1:4
rjac(1,1)=rjac(1,1)+phig(2*iter-1)*crdnx(iter);
rjac(1,2)=rjac(1,2)+phig(2*iter-1)*crdny(iter);
rjac(2,1)=rjac(2,1)+phih(2*iter-1)*crdnx(iter);
rjac(2,2)=rjac(2,2)+phih(2*iter-1)*crdny(iter);
end
djac=rjac(1,1)*rjac(2,2)-rjac(1,2)*rjac(2,1);
rjaci(1,1)= rjac(2,2)/djac;
rjaci(2,2)= rjac(1,1)/djac;
rjaci(1,2)=-rjac(1,2)/djac;
rjaci(2,1)=-rjac(2,1)/djac ;
for iter=1:8
phix(iter)=rjaci(1,1)*phig(iter)+rjaci(1,2)*phih(iter);
phiy(iter)=rjaci(2,1)*phig(iter)+rjaci(2,2)*phih(iter);
end
we=w(i)*djac;
Ke=Ke+we*cond*(phix'*phix+phiy'*phiy);
Me=Me+(we*rho*spec*phi'*phi)/dtime;
end
% Add penalty term and get temp gradient on interface
if enr==8;
xi=2.*frac-1;
yi=0.;
gm(1)=0.25*(1.-xi)*(1.-yi);
gm(3)=0.25*(1.+xi)*(1.-yi);
gm(5)=0.25*(1.+xi)*(1.+yi);
gm(7)=0.25*(1.-xi)*(1.+yi);
gm(2)=gm(1)*(-abs(theta(1)));
gm(4)=gm(3)*(-abs(theta(2)));
gm(6)=gm(5)*(-abs(theta(3)));
gm(8)=gm(7)*(-abs(theta(4)));
pen=beta*(gm'*gm);
pfL=beta*1.*gm';
Ke=Ke+pen;
else
pen=zeros(8);
pfL=zeros(8,1);
end
% Assemble Global Matrices
gnum(1)=2*Element(e,1)-1;
gnum(2)=2*Element(e,2)-1;
gnum(3)=2*Element(e,3)-1;
gnum(4)=2*Element(e,4)-1;
for i=1:4;
for j=1:4;
K(gnum(j),gnum(i))=K(gnum(j),gnum(i))+Ke(2*j-1,2*i-1);
K(gnum(j)+1,gnum(i)+1)=K(gnum(j)+1,gnum(i)+1)+Ke(2*j,2*i);
M(gnum(j),gnum(i))=M(gnum(j),gnum(i))+Me(2*j-1,2*i-1);
M(gnum(j)+1,gnum(i)+1)=M(gnum(j)+1,gnum(i)+1)+Me(2*j,2*i);
end
end
for i=1:4;
pforce(gnum(i))=pforce(gnum(i))+pfL(2*i-1);
pforce(gnum(i)+1)=pforce(gnum(i)+1)+pfL(2*i);
end
end
%Remove inactive DOFs(Reduce Matrices)
RHS=M*Tnew;
A=K+M;
Sub=A*Bound;
iindex=0;
for i=1:ndof*numNodes;
if Bound(i)==0.;
iindex=iindex+1;
RHSred(iindex)=RHS(i)-Sub(i)+pforce(i);
jindex=0;
for j=1:ndof*numNodes;
if Bound(j)==0.;
jindex=jindex+1;
Ared(iindex,jindex)=A(i,j);
end
end
end
end
%Solve
StiffI=Ared^-1;
Tnewr=(Ared^-1)*RHSred';
iindex=0;
for i=1:ndof*numNodes;
if Bound(i)==0.;
iindex=iindex+1;
Tnew(i)=Tnewr(iindex);
end
end
Tnew
end
stored';

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function [] = FESolveX2DLS()
% MATLAB based 2-D XFEM Solver
% J. Grogan (2012)
clear all
% Define Mesh
NumX=3;
NumY=1;
delX=1.;
delY=1.;
for j=1:NumY+1
for i=1:NumX+1
index=i+(NumX+1)*(j-1);
Node(index,1)=single((i-1.))*delX;
Node(index,2)=single((j-1.))*delY;
end
end
numNodes=(NumX+1)*(NumY+1);
for j=1:NumY
for i=1:NumX
index=i+NumX*(j-1);
Element(index,1)=i+(NumX+1)*(j-1);
Element(index,2)=i+(NumX+1)*(j-1)+1;
Element(index,3)=i+(NumX+1)*(j)+1;
Element(index,4)=i+(NumX+1)*(j);
end
end
numElem=(NumX)*(NumY);
% dofs per node
ndof=2;
% Define Section Properties
rho=1.;
% initial interface position
dpos=0.1;
% Initial temperatures
Tnew=zeros(numNodes*2,1);
Bound=zeros(numNodes*2,1);
stored(1)=dpos;
for e=1:numElem
for n=1:4
crdn=Node(Element(e,n),1);
if crdn<=dpos
Tnew(2*Element(e,n)-1)=1.;
Bound(2*Element(e,n)-1)=1.;
end
end
end
% Define Time Step
dtime=0.1;
tsteps=20;
time=0.;
% penalty term
beta=80.;
% Loop through time steps
for ts=1:tsteps
% Get interface velocity
d(1)=dpos+delX;
d(2)=dpos+3*delX/4;
d(3)=dpos+delX/4;
d(4)=dpos;
for e=1:numElem
crdn1=Node(Element(e,1),1);
crdn2=Node(Element(e,2),1);
for j=1:4
if d(j)>=crdn1 & d(j)<crdn2
elen=abs(crdn2-crdn1);
ajacob=elen/2.;
point=(d(j)-crdn1)/ajacob-1.;
theta(1)=abs(crdn1-dpos)*sign(crdn1-dpos);
theta(2)=abs(crdn2-dpos)*sign(crdn2-dpos);
tmp1a=Tnew(Element(e,1)*2-1);
tmp1b=Tnew(Element(e,1)*2);
tmp2a=Tnew(Element(e,2)*2-1);
tmp2b=Tnew(Element(e,2)*2);
xi=point;
gm(1)=(1.-xi)/2.;
gm(3)=(1.+xi)/2.;
term=theta(1)*gm(1)+theta(2)*gm(3);
gm(2)=gm(1)*(abs(term)-abs(theta(1)));
gm(4)=gm(3)*(abs(term)-abs(theta(2)));
t(j)=gm(1)*tmp1a+gm(2)*tmp1b+gm(3)*tmp2a+gm(4)*tmp2b;
end
end
end
% vel=-0.1*(0.5/delX)*(2*t(1)+t(2)-t(3)-2*t(4))
vel=0.0;
% Update interface position
dpos=dpos+vel*dtime;
stored(ts+1)=dpos;
K=zeros(numNodes*ndof,numNodes*ndof);
M=zeros(numNodes*ndof,numNodes*ndof);
pforce=zeros(numNodes*ndof,1);
% Loop Through Elements
for e=1:numElem
Ke=zeros(4*ndof);
Me=zeros(4*ndof);
for icrd=1:4;
crdnx(icrd)=Node(Element(e,icrd),1);
crdny(icrd)=Node(Element(e,icrd),2);
theta(icrd)=abs(crdnx(icrd)-dpos)*sign(crdnx(icrd)-dpos);
end
if sign(theta(1))~=sign(theta(2))
% enriched element
enr=8;
% get interface position on element
elen=abs(crdnx(2)-crdnx(1));
frac=abs(dpos-crdnx(1))/elen;
len1=2.*frac;
len2=2.*(1.-frac);
% devide element for sub integration
mid1=-1+len1/2.;
mid2=1-len2/2.;
gx(1)=mid1-(len1/2.)/sqrt(3.);
gx(2)=mid1+(len1/2.)/sqrt(3.);
gx(3)=mid1+(len1/2.)/sqrt(3.);
gx(4)=mid1-(len1/2.)/sqrt(3.);
gx(5)=mid2-(len2/2.)/sqrt(3.);
gx(6)=mid2+(len2/2.)/sqrt(3.);
gx(7)=mid2+(len2/2.)/sqrt(3.);
gx(8)=mid2-(len2/2.)/sqrt(3.);
gpos=1/sqrt(3.);
hx(1)=-gpos;
hx(2)=-gpos;
hx(3)=+gpos;
hx(4)=+gpos;
hx(5)=-gpos;
hx(6)=-gpos;
hx(7)=+gpos;
hx(8)=+gpos;
for iw=1:4
w(iw)=frac/2.;
w(iw+4)=(1.-frac)/2.;
end
else
% regular element - fix extra dofs
enr=4;
gpos=1/sqrt(3.);
gx(1)=-gpos;
gx(2)=gpos;
gx(3)=gpos;
gx(4)=-gpos;
hx(1)=-gpos;
hx(2)=-gpos;
hx(3)=gpos;
hx(4)=gpos;
for iw=1:4
w(iw)=1.;
end
end
% Loop Through Int Points
for i=1:enr;
g=gx(i);
h=hx(i);
phi(1)=0.25*(1.-g)*(1.-h);
phi(3)=0.25*(1.+g)*(1.-h);
phi(5)=0.25*(1.+g)*(1.+h);
phi(7)=0.25*(1.-g)*(1.+h);
iLS=theta(1)*phi(1)+theta(2)*phi(3)+theta(3)*phi(5)+theta(4)*phi(7);
if iLS<0.
cond=0.;
spec=0.01;
else
cond=1.;
spec=1.;
end
for iter=1:4
phi(2*iter)=phi(2*iter-1)*(abs(iLS)-abs(theta(iter)));
end
phig(1)=0.25*-(1.-h);
phig(3)=0.25*(1.-h);
phig(5)=0.25*(1.+h);
phig(7)=0.25*-(1.+h);
phih(1)=0.25*-(1.-g);
phih(3)=0.25*-(1.+g);
phih(5)=0.25*(1.+g);
phih(7)=0.25*(1.-g);
diLSg=sign(iLS)*(phig(1)*theta(1)+phig(3)*theta(2)+phig(5)*theta(3)+phig(7)*theta(4));
diLSh=sign(iLS)*(phih(1)*theta(1)+phih(3)*theta(2)+phih(5)*theta(3)+phih(7)*theta(4));
for iter=1:4
phig(2*iter)=phig(2*iter-1)*(abs(iLS)-abs(theta(iter)))+phi(2*iter-1)*diLSg;
phih(2*iter)=phih(2*iter-1)*(abs(iLS)-abs(theta(iter)))+phi(2*iter-1)*diLSh;
end
rjac=zeros(2,2);
for iter=1:4
rjac(1,1)=rjac(1,1)+phig(2*iter-1)*crdnx(iter);
rjac(1,2)=rjac(1,2)+phig(2*iter-1)*crdny(iter);
rjac(2,1)=rjac(2,1)+phih(2*iter-1)*crdnx(iter);
rjac(2,2)=rjac(2,2)+phih(2*iter-1)*crdny(iter);
end
djac=rjac(1,1)*rjac(2,2)-rjac(1,2)*rjac(2,1);
rjaci(1,1)= rjac(2,2)/djac;
rjaci(2,2)= rjac(1,1)/djac;
rjaci(1,2)=-rjac(1,2)/djac;
rjaci(2,1)=-rjac(2,1)/djac ;
for iter=1:8
phix(iter)=rjaci(1,1)*phig(iter)+rjaci(1,2)*phih(iter);
phiy(iter)=rjaci(2,1)*phig(iter)+rjaci(2,2)*phih(iter);
end
we=w(i)*djac;
Ke=Ke+we*cond*(phix'*phix+phiy'*phiy);
Me=Me+(we*rho*spec*phi'*phi)/dtime;
end
% Add penalty term and get temp gradient on interface
if enr==8;
xi=2.*frac-1;
yi=0.;
gm(1)=0.25*(1.-xi)*(1.-yi);
gm(3)=0.25*(1.+xi)*(1.-yi);
gm(5)=0.25*(1.+xi)*(1.+yi);
gm(7)=0.25*(1.-xi)*(1.+yi);
gm(2)=gm(1)*(-abs(theta(1)));
gm(4)=gm(3)*(-abs(theta(2)));
gm(6)=gm(5)*(-abs(theta(3)));
gm(8)=gm(7)*(-abs(theta(4)));
pen=beta*(gm'*gm);
pfL=beta*1.*gm';
Ke=Ke+pen;
else
pen=zeros(8);
pfL=zeros(8,1);
end
% Assemble Global Matrices
gnum(1)=2*Element(e,1)-1;
gnum(2)=2*Element(e,2)-1;
gnum(3)=2*Element(e,3)-1;
gnum(4)=2*Element(e,4)-1;
for i=1:4;
for j=1:4;
K(gnum(j),gnum(i))=K(gnum(j),gnum(i))+Ke(2*j-1,2*i-1);
K(gnum(j)+1,gnum(i)+1)=K(gnum(j)+1,gnum(i)+1)+Ke(2*j,2*i);
M(gnum(j),gnum(i))=M(gnum(j),gnum(i))+Me(2*j-1,2*i-1);
M(gnum(j)+1,gnum(i)+1)=M(gnum(j)+1,gnum(i)+1)+Me(2*j,2*i);
end
end
for i=1:4;
pforce(gnum(i))=pforce(gnum(i))+pfL(2*i-1);
pforce(gnum(i)+1)=pforce(gnum(i)+1)+pfL(2*i);
end
end
%Remove inactive DOFs(Reduce Matrices)
RHS=M*Tnew;
A=K+M;
Sub=A*Bound;
iindex=0;
for i=1:ndof*numNodes;
if Bound(i)==0.;
iindex=iindex+1;
RHSred(iindex)=RHS(i)-Sub(i)+pforce(i);
jindex=0;
for j=1:ndof*numNodes;
if Bound(j)==0.;
jindex=jindex+1;
Ared(iindex,jindex)=A(i,j);
end
end
end
end
%Solve
StiffI=Ared^-1;
Tnewr=(Ared^-1)*RHSred';
iindex=0;
for i=1:ndof*numNodes;
if Bound(i)==0.;
iindex=iindex+1;
Tnew(i)=Tnewr(iindex);
end
end
Tnew
end
stored'

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function [] = FESolveXT()
% MATLAB based 1-D XFEM Solver
% J. Grogan (2012)
clear all
% Define Geometry
len=10.;
% Define Section Properties
rho=1.;
% Generate Mesh
numElem=10;
charlen=len/numElem;
ndCoords=linspace(0,len,numElem+1);
numNodes=size(ndCoords,2);
indx=1:numElem;
elemNodes(:,1)=indx;
elemNodes(:,2)=indx+1;
% dofs per node
ndof=2;
% initial interface position
dpos=4.6;
% Initial temperatures
Tnew=zeros(numNodes*2,1);
Bound=zeros(numNodes*2,1);
%storage
stored(1)=dpos;
for e=1:numElem
for n=1:2
crdn1=ndCoords(elemNodes(e,n));
if crdn1<=dpos
Tnew(2*elemNodes(e,n)-1)=1.;
Bound(2*elemNodes(e,n)-1)=1.;
end
end
end
% Define Time Step
dtime=0.01;
tsteps=10;
time=0.;
% penalty term
beta=50.;
% Loop through time steps
for ts=1:tsteps
% Get interface velocity
d(1)=dpos+charlen;
d(2)=dpos+3*charlen/4;
d(3)=dpos+charlen/4;
d(4)=dpos;
for e=1:numElem
crdn1=ndCoords(elemNodes(e,1));
crdn2=ndCoords(elemNodes(e,2));
for j=1:4
if d(j)>=crdn1 & d(j)<crdn2
elen=abs(crdn2-crdn1);
ajacob=elen/2.;
point=(d(j)-crdn1)/ajacob-1.;
theta(1)=abs(crdn1-dpos)*sign(crdn1-dpos);
theta(2)=abs(crdn2-dpos)*sign(crdn2-dpos);
tmp1a=Tnew(elemNodes(e,1)*2-1);
tmp1b=Tnew(elemNodes(e,1)*2);
tmp2a=Tnew(elemNodes(e,2)*2-1);
tmp2b=Tnew(elemNodes(e,2)*2);
xi=point;
gm(1)=(1.-xi)/2.;
gm(3)=(1.+xi)/2.;
term=theta(1)*gm(1)+theta(2)*gm(3);
gm(2)=gm(1)*(abs(term)-abs(theta(1)));
gm(4)=gm(3)*(abs(term)-abs(theta(2)));
t(j)=gm(1)*tmp1a+gm(2)*tmp1b+gm(3)*tmp2a+gm(4)*tmp2b;
end
end
end
vel=1.*(0.5/charlen)*(2*t(1)+t(2)-t(3)-2*t(4));
vel=0.
% Update interface position
dpos=dpos+vel*dtime;
stored(ts+1)=dpos;
K=zeros(numNodes*ndof,numNodes*ndof);
M=zeros(numNodes*ndof,numNodes*ndof);
pforce=zeros(numNodes*ndof,1);
% Loop Through Elements
for e=1:numElem
Ke=zeros(2*ndof);
Me=zeros(2*ndof);
crdn1=ndCoords(elemNodes(e,1));
crdn2=ndCoords(elemNodes(e,2));
theta(1)=abs(crdn1-dpos)*sign(crdn1-dpos);
theta(2)=abs(crdn2-dpos)*sign(crdn2-dpos);
enr=2;
elen=abs(crdn2-crdn1);
ajacob=elen/2.;
if sign(theta(1))~=sign(theta(2))
% enriched element
enr=4;
% get interface position on element
point=(dpos-crdn1)/ajacob-1.;
% devide element for sub integration
len1=abs(-point-1.);
len2=abs(1.-point);
mid1=-1+len1/2.;
mid2=1-len2/2.;
gpx(1)=-(len1/2.)/sqrt(3.)+mid1;
gpx(2)=(len1/2.)/sqrt(3.)+mid1;
gpx(3)=-(len2/2.)/sqrt(3.)+mid2;
gpx(4)=(len2/2.)/sqrt(3.)+mid2;
w(1)=(len1/2.);
w(2)=(len1/2.);
w(3)=(len2/2.);
w(4)=(len2/2.);
else
% regular element - fix extra dofs
gpx(1)=-1/sqrt(3.);
gpx(2)=1/sqrt(3.);
w(1)=1.;
w(2)=1.;
end
% Loop Through Int Points
for i=1:enr;
c=gpx(i);
phi(1)=(1.-c)/2.;
phi(3)=(1.+c)/2.;
term=theta(1)*phi(1)+theta(2)*phi(3);
if term<0
cond=0.;
spec=0.01;
else
cond=1.;
spec=1.;
end
phi(2)=phi(1)*(abs(term)-abs(theta(1)));
phi(4)=phi(3)*(abs(term)-abs(theta(2)));
phic(1)=-0.5;
phic(3)=0.5;
dterm=sign(term)*(phic(1)*theta(1)+phic(3)*theta(2));
phic(2)=phic(1)*(abs(term)-abs(theta(1)))+phi(1)*dterm;
phic(4)=phic(3)*(abs(term)-abs(theta(2)))+phi(3)*dterm;
phix(1)=phic(1)/ajacob;
phix(2)=phic(2)/ajacob;
phix(3)=phic(3)/ajacob;
phix(4)=phic(4)/ajacob;
we=ajacob*w(i);
Ke=Ke+we*cond*phix'*phix;
Me=Me+(we*rho*spec*phi'*phi)/dtime;
end
% Add penalty term and get temp gradient on interface
if enr==4;
xi=point;
gm(1)=(1.-xi)/2.;
gm(3)=(1.+xi)/2.;
term=theta(1)*gm(1)+theta(2)*gm(3);
gm(2)=gm(1)*(abs(term)-abs(theta(1)));
gm(4)=gm(3)*(abs(term)-abs(theta(2)));
tpos=gm(1)*Tnew(1)+gm(2)*Tnew(2)+gm(3)*Tnew(3)+gm(4)*Tnew(4);
pen=beta*(gm'*gm);
pfL=beta*1*gm';
Ke=Ke+pen;
else
pen=zeros(4);
pfL=zeros(4,1);
end
% Assemble Global Matrices
gnum=2.*elemNodes(e,1)-1.;
for i=1:4;
for j=1:4;
K(gnum+j-1,gnum+i-1)=K(gnum+j-1,gnum+i-1)+Ke(j,i);
M(gnum+j-1,gnum+i-1)=M(gnum+j-1,gnum+i-1)+Me(j,i);
end
pforce(gnum+i-1)=pforce(gnum+i-1)+pfL(i);
end
end
%Remove inactive DOFs(Reduce Matrices)
RHS=M*Tnew;
A=K+M;
Sub=A*Bound;
iindex=0;
for i=1:ndof*numNodes;
if Bound(i)==0.;
iindex=iindex+1;
RHSred(iindex)=RHS(i)-Sub(i)+pforce(i);
jindex=0;
for j=1:ndof*numNodes;
if Bound(j)==0.;
jindex=jindex+1;
Ared(iindex,jindex)=A(i,j);
end
end
end
end
%Solve
Tnewr=(Ared^-1)*RHSred';
iindex=0;
for i=1:ndof*numNodes;
if Bound(i)==0.;
iindex=iindex+1;
Tnew(i)=Tnewr(iindex);
end
end
Tnew
end
stored'

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function [] = FESolveXT2()
% MATLAB based 1-D XFEM Solver
% J. Grogan (2012)
clear all
% Define Geometry
len=1.;
% Define Section Properties
rho=1.;
% Generate Mesh
numElem=16;
charlen=len/numElem;
ndCoords=linspace(0,len,numElem+1);
numNodes=size(ndCoords,2);
indx=1:numElem;
elemNodes(:,1)=indx;
elemNodes(:,2)=indx+1;
% dofs per node
ndof=2;
% initial interface position
dpos=0.4;
% Initial temperatures
Tnew=zeros(numNodes*2,1);
Bound=zeros(numNodes*2,1);
%storage
stored(1)=dpos;
for e=1:numElem
for n=1:2
crdn1=ndCoords(elemNodes(e,n));
if crdn1<=dpos
Tnew(2*elemNodes(e,n)-1)=1.;
end
end
end
Bound(1)=1.;
% Define Time Step
dtime=0.001;
tsteps=100;
time=0.;
% penalty term
beta=100.;
% Loop through time steps
for ts=1:tsteps
eNodes=zeros(2*numNodes,1);
% Get interface velocity
d(1)=dpos+charlen;
d(2)=dpos+3*charlen/4;
d(3)=dpos+charlen/4;
d(4)=dpos;
for e=1:numElem
crdn1=ndCoords(elemNodes(e,1));
crdn2=ndCoords(elemNodes(e,2));
for j=1:4
if d(j)>=crdn1 && d(j)<crdn2
elen=abs(crdn2-crdn1);
ajacob=elen/2.;
point=(d(j)-crdn1)/ajacob-1.;
theta(1)=abs(crdn1-dpos)*sign(crdn1-dpos);
theta(2)=abs(crdn2-dpos)*sign(crdn2-dpos);
tmp1a=Tnew(elemNodes(e,1)*2-1);
tmp1b=Tnew(elemNodes(e,1)*2);
tmp2a=Tnew(elemNodes(e,2)*2-1);
tmp2b=Tnew(elemNodes(e,2)*2);
xi=point;
gm(1)=(1.-xi)/2.;
gm(3)=(1.+xi)/2.;
term=theta(1)*gm(1)+theta(2)*gm(3);
gm(2)=gm(1)*(abs(term)-abs(theta(1)));
gm(4)=gm(3)*(abs(term)-abs(theta(2)));
t(j)=gm(1)*tmp1a+gm(2)*tmp1b+gm(3)*tmp2a+gm(4)*tmp2b;
end
end
end
vel=0.5*(0.5/charlen)*(2*t(1)+t(2)-t(3)-2*t(4));
% Update interface position
dpos=dpos+vel*dtime;
stored(ts+1)=dpos;
K=zeros(numNodes*ndof,numNodes*ndof);
M=zeros(numNodes*ndof,numNodes*ndof);
pforce=zeros(numNodes*ndof,1);
% Loop Through Elements
for e=1:numElem
Ke=zeros(2*ndof);
Me=zeros(2*ndof);
crdn1=ndCoords(elemNodes(e,1));
crdn2=ndCoords(elemNodes(e,2));
theta(1)=abs(crdn1-dpos)*sign(crdn1-dpos);
theta(2)=abs(crdn2-dpos)*sign(crdn2-dpos);
enr=2;
elen=abs(crdn2-crdn1);
ajacob=elen/2.;
if sign(theta(1))~=sign(theta(2))
% enriched element
eNodes(2*elemNodes(e,1))=1;
eNodes(2*elemNodes(e,2))=1;
enr=4;
% get interface position on element
point=(dpos-crdn1)/ajacob-1.;
% devide element for sub integration
len1=abs(-point-1.);
len2=abs(1.-point);
mid1=-1+len1/2.;
mid2=1-len2/2.;
gpx(1)=-(len1/2.)/sqrt(3.)+mid1;
gpx(2)=(len1/2.)/sqrt(3.)+mid1;
gpx(3)=-(len2/2.)/sqrt(3.)+mid2;
gpx(4)=(len2/2.)/sqrt(3.)+mid2;
w(1)=(len1/2.);
w(2)=(len1/2.);
w(3)=(len2/2.);
w(4)=(len2/2.);
else
% regular element - fix extra dofs
gpx(1)=-1/sqrt(3.);
gpx(2)=1/sqrt(3.);
w(1)=1.;
w(2)=1.;
end
% Loop Through Int Points
for i=1:enr;
c=gpx(i);
phi(1)=(1.-c)/2.;
phi(3)=(1.+c)/2.;
term=theta(1)*phi(1)+theta(2)*phi(3);
% if term<0
% cond=0.00;
% spec=0.001;
% else
cond=1.;
spec=1.;
% end
if enr==4
phi(2)=phi(1)*(abs(term)-abs(theta(1)));
phi(4)=phi(3)*(abs(term)-abs(theta(2)));
else
phi(2)=0.0;
phi(4)=0.0;
end
phic(1)=-0.5;
phic(3)=0.5;
dterm=sign(term)*(phic(1)*theta(1)+phic(3)*theta(2));
if enr==4
phic(2)=phic(1)*(abs(term)-abs(theta(1)))+phi(1)*dterm;
phic(4)=phic(3)*(abs(term)-abs(theta(2)))+phi(3)*dterm;
else
phic(2)=0.0;
phic(4)=0.0;
end
phix(1)=phic(1)/ajacob;
phix(2)=phic(2)/ajacob;
phix(3)=phic(3)/ajacob;
phix(4)=phic(4)/ajacob;
we=ajacob*w(i);
Ke=Ke+we*cond*phix'*phix;
Me=Me+(we*rho*spec*phi'*phi)/dtime;
end
if enr==5;
Ke(1,2)=0.;
Me(1,2)=0.;
Ke(2,1)=0.;
Me(2,1)=0.;
Ke(1,4)=0.;
Me(1,4)=0.;
Ke(4,1)=0.;
Me(4,1)=0.;
Ke(3,2)=0.;
Me(3,2)=0.;
Ke(2,3)=0.;
Me(2,3)=0.;
Ke(4,3)=0.;
Me(4,3)=0.;
Ke(3,4)=0.;
Me(3,4)=0.;
end
% Add penalty term and get temp gradient on interface
if enr==4;
xi=point;
gm(1)=(1.-xi)/2.;
gm(3)=(1.+xi)/2.;
term=theta(1)*gm(1)+theta(2)*gm(3);
gm(2)=gm(1)*(abs(term)-abs(theta(1)));
gm(4)=gm(3)*(abs(term)-abs(theta(2)));
pen=beta*(gm'*gm);
pfL=beta*1*gm';
Ke=Ke+pen;
else
pen=zeros(4);
pfL=zeros(4,1);
end
Ke;
Me;
% Assemble Global Matrices
gnum=2.*elemNodes(e,1)-1.;
for i=1:4;
for j=1:4;
K(gnum+j-1,gnum+i-1)=K(gnum+j-1,gnum+i-1)+Ke(j,i);
M(gnum+j-1,gnum+i-1)=M(gnum+j-1,gnum+i-1)+Me(j,i);
end
pforce(gnum+i-1)=pforce(gnum+i-1)+pfL(i);
end
end
%Remove NON-ENHANCED DOFs(Reduce Matrices)
iindex=0.;
for i=1:ndof*numNodes;
check=0;
if mod(i,2)==0 && eNodes(i)~=1
check=1;
end
if check==0
iindex=iindex+1;
TR1(iindex)=Tnew(i);
BR1(iindex)=Bound(i);
pforceR1(iindex)=pforce(i);
jindex=0;
for j=1:ndof*numNodes;
check=0;
if mod(j,2)==0 && eNodes(j)~=1
check=1;
end
if check==0
jindex=jindex+1;
MR1(iindex,jindex)=M(i,j);
KR1(iindex,jindex)=K(i,j);
end
end
end
end
AR1=KR1+MR1;
SubR1=AR1*BR1';
RHSR1=MR1*TR1'-SubR1+pforceR1';
% Apply Boundary Conditions
Biindex=0.;
for i=1:iindex;
if BR1(i)==0.;
Biindex=Biindex+1;
RHSR2(Biindex)=RHSR1(i);
jindex=0;
for j=1:iindex;
check=0;
if BR1(j)==0.;
jindex=jindex+1;
AR2(Biindex,jindex)=AR1(i,j);
end
end
end
end
%Solve
Tnewr=(AR2^-1)*RHSR2';
% Restore Matrices
Biindex=0;
for i=1:iindex;
if BR1(i)==0.;
Biindex=Biindex+1;
TR1(i)=Tnewr(Biindex);
end
end
iindex=0;
for i=1:ndof*numNodes;
check=0;
if mod(i,2)==0 && eNodes(i)~=1
check=1;
end
if check==0
iindex=iindex+1;
Tnew(i)=TR1(iindex);
end
end
Tnew
end
stored'

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@ -0,0 +1,128 @@
function [] = GetF()
% set up grid
gd=0.;
numElem=4;
eLen=0.25;
for i=1:numElem+1
ndCrd(i)=gd;
gd=gd+eLen;
end
for i=1:numElem
elemNod(i,1)=i;
elemNod(i,2)=i+1;
end
% Initial level set
dpos=0.1;
for i=1:numElem+1
lSet(i)=sign(ndCrd(i)-dpos)*abs(dpos-ndCrd(i));
end
lSet'
for tstep=1:120
% Velocity BC
F=zeros(numElem+1,1);
for i=1:numElem
if sign(lSet(elemNod(i,1)))~=sign(lSet(elemNod(i,2)))
F(elemNod(i,1))= 0.0005;
F(elemNod(i,2))= 0.0005;
end
end
% Assemble 'Stiffness' Matrices
A=zeros(numElem+1);
for i=1:numElem
pos(1)=-1/sqrt(3);
pos(2)=1/sqrt(3);
AfL=zeros(2);
AfLGLS=zeros(2);
for j=1:2
shp(1)=(1-pos(j))/2.;
shp(2)=(1+pos(j))/2.;
dshp(1)=-0.5;
dshp(2)=0.5;
rset=shp(1)*lSet(elemNod(i,1))+shp(2)*lSet(elemNod(i,2));
dls=dshp(1)*lSet(elemNod(i,1))+dshp(2)*lSet(elemNod(i,2));
AfL=AfL+shp'*sign(rset)*(dls*dshp);
AfLGLS=AfLGLS+(dshp'*dls)*(0.25/abs(dls))*(dls*dshp);
end
for k=1:2;
for j=1:2;
A(elemNod(i,j),elemNod(i,k))=A(elemNod(i,j),elemNod(i,k))+AfL(j,k)+AfLGLS(j,k);
end
end
end
% Apply BCs
RHS=zeros(numElem+1,1);
Sub=A*F;
iindex=0;
for i=1:numElem+1
if F(i)==0.
iindex=iindex+1;
RHSred(iindex)=RHS(i)-Sub(i);
Fred=0.;
jindex=0;
for j=1:numElem+1
if F(j)==0.
jindex=jindex+1;
Ared(iindex,jindex)=A(i,j);
end
end
end
end
% Solve for Fred
Fred=(Ared^-1)*RHSred';
% Get F
iindex=0;
for i=1:numElem+1
if F(i)==0.
iindex=iindex+1;
F(i)=Fred(iindex);
end
end
% Update level set
mMat=zeros(numElem+1);
mMatGLS=zeros(numElem+1);
f1=zeros(numElem+1,1);
f2=zeros(numElem+1,1);
f3=zeros(numElem+1,1);
h=0.25;
visc=0.000;
for i=1:numElem
pos(1)=-1/sqrt(3);
pos(2)=1/sqrt(3);
mMatL=zeros(2);
mMatGLSL=zeros(2);
f1L=zeros(2,1);
f2L=zeros(2,1);
f3L=zeros(2,1);
for j=1:2
shp(1)=(1-pos(j))/2.;
shp(2)=(1+pos(j))/2.;
dshp(1)=-0.5;
dshp(2)=0.5;
Floc=shp(1)*F(elemNod(i,1))+shp(2)*F(elemNod(i,2));
rset=shp(1)*lSet(elemNod(i,1))+shp(2)*lSet(elemNod(i,2));
dls=dshp(1)*lSet(elemNod(i,1))+dshp(2)*lSet(elemNod(i,2));
mMatL=mMatL+shp'*shp;
mMatGLSL=mMatGLSL+((dshp'*(dls/abs(dls)))*Floc*(h/abs(Floc)))*shp;
f1L=f1L+shp'*Floc*abs(dls);
f2L=f2L+(dshp'*(dls/abs(dls))*Floc)*(h/abs(Floc))*Floc*abs(dls);
vs=h*((abs(visc+Floc*abs(dls)))/(abs(Floc*dls)+h));
f3L=f3L+vs*dshp'*dls;
end
for k=1:2;
for j=1:2;
mMat(elemNod(i,j),elemNod(i,k))=mMat(elemNod(i,j),elemNod(i,k))+mMatL(j,k);
mMatGLS(elemNod(i,j),elemNod(i,k))=mMatGLS(elemNod(i,j),elemNod(i,k))+mMatGLSL(j,k);
end
f1(elemNod(i,k))=f1(elemNod(i,k))+f1L(k);
f2(elemNod(i,k))=f2(elemNod(i,k))+f2L(k);
f3(elemNod(i,k))=f3(elemNod(i,k))+f3L(k);
end
end
dt=0.01;
lSet=lSet-((((mMat+mMatGLS)^-1)/dt)*(f1+f2+f3))';
lSet'
end

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function [] = S2D()
% MATLAB based 2-D XFEM Solver
% J. Grogan (2012)
clear all
% Define Mesh
NumX=10;
NumY=1;
delX=1.;
delY=1.;
for j=1:NumY+1
for i=1:NumX+1
index=i+(NumX+1)*(j-1);
Node(index,1)=single((i-1.))*delX;
Node(index,2)=single((j-1.))*delY;
end
end
numNodes=(NumX+1)*(NumY+1);
for j=1:NumY
for i=1:NumX
index=i+NumX*(j-1);
Element(index,1)=i+(NumX+1)*(j-1);
Element(index,2)=i+(NumX+1)*(j-1)+1;
Element(index,3)=i+(NumX+1)*(j)+1;
Element(index,4)=i+(NumX+1)*(j);
end
end
numElem=(NumX)*(NumY);
% Define Section Properties
rho=1.;
cond=1.;
spec=1.;
% initial interface position
dpos=0.25;
% Initial temperatures
Tnew=zeros(numNodes,1);
Bound=zeros(numNodes,1);
for e=1:numElem
for n=1:4
crdn=Node(Element(e,n),1);
if crdn<=dpos
Tnew(Element(e,n))=1.;
Bound(Element(e,n))=1.;
end
end
end
% Define Time Step
dtime=0.1;
tsteps=10;
% Loop through time steps
for ts=1:tsteps
K=zeros(numNodes,numNodes);
M=zeros(numNodes,numNodes);
% Loop Through Elements
for e=1:numElem
Ke=zeros(4);
Me=zeros(4);
for icrd=1:4;
crdnx(icrd)=Node(Element(e,icrd),1);
crdny(icrd)=Node(Element(e,icrd),2);
end
gpos=1/sqrt(3.);
gx(1)=-gpos;
gx(2)=gpos;
gx(3)=gpos;
gx(4)=-gpos;
hx(1)=-gpos;
hx(2)=-gpos;
hx(3)=gpos;
hx(4)=gpos;
% Loop Through Int Points
for i=1:4;
g=gx(i);
h=hx(i);
phi(1)=0.25*(1.-g)*(1.-h);
phi(2)=0.25*(1.+g)*(1.-h);
phi(3)=0.25*(1.+g)*(1.+h);
phi(4)=0.25*(1.-g)*(1.+h);
phig(1)=0.25*-(1.-h);
phig(2)=0.25*(1.-h);
phig(3)=0.25*(1.+h);
phig(4)=0.25*-(1.+h);
phih(1)=0.25*-(1.-g);
phih(2)=0.25*-(1.+g);
phih(3)=0.25*(1.+g);
phih(4)=0.25*(1.-g);
rjac=zeros(2,2);
for iter=1:4
rjac(1,1)=rjac(1,1)+phig(iter)*crdnx(iter);
rjac(1,2)=rjac(1,2)+phig(iter)*crdny(iter);
rjac(2,1)=rjac(2,1)+phih(iter)*crdnx(iter);
rjac(2,2)=rjac(2,2)+phih(iter)*crdny(iter);
end
djac=rjac(1,1)*rjac(2,2)-rjac(1,2)*rjac(2,1);
rjaci(1,1)= rjac(2,2)/djac;
rjaci(2,2)= rjac(1,1)/djac;
rjaci(1,2)=-rjac(1,2)/djac;
rjaci(2,1)=-rjac(2,1)/djac ;
for iter=1:4
phix(iter)=rjaci(1,1)*phig(iter)+rjaci(1,2)*phih(iter);
phiy(iter)=rjaci(2,1)*phig(iter)+rjaci(2,2)*phih(iter);
end
we=djac;
Ke=Ke+we*cond*(phix'*phix+phiy'*phiy);
Me=Me+(we*rho*spec*phi'*phi)/dtime;
end
% Assemble Global Matrices
gnum(1)=Element(e,1);
gnum(2)=Element(e,2);
gnum(3)=Element(e,3);
gnum(4)=Element(e,4);
for i=1:4;
for j=1:4;
K(gnum(j),gnum(i))=K(gnum(j),gnum(i))+Ke(j,i);
M(gnum(j),gnum(i))=M(gnum(j),gnum(i))+Me(j,i);
end
end
end
%Remove inactive DOFs(Reduce Matrices)
RHS=M*Tnew;
A=K+M;
Sub=A*Bound;
iindex=0;
for i=1:numNodes;
if Bound(i)==0.;
iindex=iindex+1;
RHSred(iindex)=RHS(i)-Sub(i);
jindex=0;
for j=1:numNodes;
if Bound(j)==0.;
jindex=jindex+1;
Ared(iindex,jindex)=A(i,j);
end
end
end
end
%Solve
Tnewr=(Ared^-1)*RHSred';
iindex=0;
for i=1:numNodes;
if Bound(i)==0.;
iindex=iindex+1;
Tnew(i)=Tnewr(iindex);
end
end
Tnew
end

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function [] = XCOR1D()
% MATLAB based 1-D XFEM Solver
% J. Grogan (2012)
clear all
% Define Geometry
len=1.;
% Define Section Properties
rho=1.;
% Generate Mesh
numElem=4;
charlen=len/numElem;
ndCoords=linspace(0,len,numElem+1);
numNodes=size(ndCoords,2);
indx=1:numElem;
elemNodes(:,1)=indx;
elemNodes(:,2)=indx+1;
% dofs per node
ndof=2;
% initial interface position
dpos=0.6;
% Initial temperatures
Tnew=zeros(numNodes*2,1);
Bound=zeros(numNodes*2,1);
%storage
stored(1)=dpos;
for e=1:numElem
for n=1:2
crdn1=ndCoords(elemNodes(e,n));
if crdn1<=dpos
Tnew(2*elemNodes(e,n)-1)=1.;
end
end
end
Bound(1)=1.;
% Define Time Step
dtime=0.01;
tsteps=10;
time=0.;
% penalty term
beta=100.;
% Loop through time steps
for ts=1:tsteps
eNodes=zeros(2*numNodes,1);
% Get interface velocity
d(1)=dpos+charlen;
d(2)=dpos+3*charlen/4;
d(3)=dpos+charlen/4;
d(4)=dpos;
for e=1:numElem
crdn1=ndCoords(elemNodes(e,1));
crdn2=ndCoords(elemNodes(e,2));
for j=1:4
if d(j)>=crdn1 && d(j)<crdn2
elen=abs(crdn2-crdn1);
ajacob=elen/2.;
point=(d(j)-crdn1)/ajacob-1.;
theta(1)=abs(crdn1-dpos)*sign(crdn1-dpos);
theta(2)=abs(crdn2-dpos)*sign(crdn2-dpos);
tmp1a=Tnew(elemNodes(e,1)*2-1);
tmp1b=Tnew(elemNodes(e,1)*2);
tmp2a=Tnew(elemNodes(e,2)*2-1);
tmp2b=Tnew(elemNodes(e,2)*2);
xi=point;
gm(1)=(1.-xi)/2.;
gm(3)=(1.+xi)/2.;
term=theta(1)*gm(1)+theta(2)*gm(3);
gm(2)=gm(1)*(abs(term)-abs(theta(1)));
gm(4)=gm(3)*(abs(term)-abs(theta(2)));
t(j)=gm(1)*tmp1a+gm(2)*tmp1b+gm(3)*tmp2a+gm(4)*tmp2b;
end
end
end
vel=0.5*(0.5/charlen)*(2*t(1)+t(2)-t(3)-2*t(4));
vel=0.
% Update interface position
dpos=dpos+vel*dtime;
stored(ts+1)=dpos;
K=zeros(numNodes*ndof,numNodes*ndof);
M=zeros(numNodes*ndof,numNodes*ndof);
pforce=zeros(numNodes*ndof,1);
% Loop Through Elements
for e=1:numElem
Ke=zeros(2*ndof);
Me=zeros(2*ndof);
crdn1=ndCoords(elemNodes(e,1));
crdn2=ndCoords(elemNodes(e,2));
theta(1)=abs(crdn1-dpos)*sign(crdn1-dpos);
theta(2)=abs(crdn2-dpos)*sign(crdn2-dpos);
enr=2;
elen=abs(crdn2-crdn1);
ajacob=elen/2.;
if sign(theta(1))~=sign(theta(2))
% enriched element
eNodes(2*elemNodes(e,1))=1;
eNodes(2*elemNodes(e,2))=1;
enr=4;
% get interface position on element
point=(dpos-crdn1)/ajacob-1.;
% devide element for sub integration
len1=abs(-point-1.);
len2=abs(1.-point);
mid1=-1+len1/2.;
mid2=1-len2/2.;
gpx(1)=-(len1/2.)/sqrt(3.)+mid1;
gpx(2)=(len1/2.)/sqrt(3.)+mid1;
gpx(3)=-(len2/2.)/sqrt(3.)+mid2;
gpx(4)=(len2/2.)/sqrt(3.)+mid2;
w(1)=(len1/2.);
w(2)=(len1/2.);
w(3)=(len2/2.);
w(4)=(len2/2.);
else
% regular element - fix extra dofs
gpx(1)=-1/sqrt(3.);
gpx(2)=1/sqrt(3.);
w(1)=1.;
w(2)=1.;
end
% Loop Through Int Points
for i=1:enr;
c=gpx(i);
phi(1)=(1.-c)/2.;
phi(3)=(1.+c)/2.;
term=theta(1)*phi(1)+theta(2)*phi(3);
% if term<0
% cond=0.00;
% spec=0.001;
% else
cond=1.;
spec=1.;
% end
if enr==4
phi(2)=phi(1)*(abs(term)-abs(theta(1)));
phi(4)=phi(3)*(abs(term)-abs(theta(2)));
else
phi(2)=0.0;
phi(4)=0.0;
end
phic(1)=-0.5;
phic(3)=0.5;
dterm=sign(term)*(phic(1)*theta(1)+phic(3)*theta(2));
if enr==4
phic(2)=phic(1)*(abs(term)-abs(theta(1)))+phi(1)*dterm;
phic(4)=phic(3)*(abs(term)-abs(theta(2)))+phi(3)*dterm;
else
phic(2)=0.0;
phic(4)=0.0;
end
phix(1)=phic(1)/ajacob;
phix(2)=phic(2)/ajacob;
phix(3)=phic(3)/ajacob;
phix(4)=phic(4)/ajacob;
we=ajacob*w(i);
Ke=Ke+we*cond*phix'*phix;
Me=Me+(we*rho*spec*phi'*phi)/dtime;
end
if enr==5;
Ke(1,2)=0.;
Me(1,2)=0.;
Ke(2,1)=0.;
Me(2,1)=0.;
Ke(1,4)=0.;
Me(1,4)=0.;
Ke(4,1)=0.;
Me(4,1)=0.;
Ke(3,2)=0.;
Me(3,2)=0.;
Ke(2,3)=0.;
Me(2,3)=0.;
Ke(4,3)=0.;
Me(4,3)=0.;
Ke(3,4)=0.;
Me(3,4)=0.;
end
% Add penalty term and get temp gradient on interface
if enr==4;
xi=point;
gm(1)=(1.-xi)/2.;
gm(3)=(1.+xi)/2.;
term=theta(1)*gm(1)+theta(2)*gm(3);
gm(2)=gm(1)*(abs(term)-abs(theta(1)));
gm(4)=gm(3)*(abs(term)-abs(theta(2)));
pen=beta*(gm'*gm);
pfL=beta*1*gm';
Ke=Ke+pen;
else
pen=zeros(4);
pfL=zeros(4,1);
end
Ke;
Me;
% Assemble Global Matrices
gnum=2.*elemNodes(e,1)-1.;
for i=1:4;
for j=1:4;
K(gnum+j-1,gnum+i-1)=K(gnum+j-1,gnum+i-1)+Ke(j,i);
M(gnum+j-1,gnum+i-1)=M(gnum+j-1,gnum+i-1)+Me(j,i);
end
pforce(gnum+i-1)=pforce(gnum+i-1)+pfL(i);
end
end
%Remove NON-ENHANCED DOFs(Reduce Matrices)
iindex=0.;
for i=1:ndof*numNodes;
check=0;
if mod(i,2)==0 && eNodes(i)~=1
check=1;
end
if check==0
iindex=iindex+1;
TR1(iindex)=Tnew(i);
BR1(iindex)=Bound(i);
pforceR1(iindex)=pforce(i);
jindex=0;
for j=1:ndof*numNodes;
check=0;
if mod(j,2)==0 && eNodes(j)~=1
check=1;
end
if check==0
jindex=jindex+1;
MR1(iindex,jindex)=M(i,j);
KR1(iindex,jindex)=K(i,j);
end
end
end
end
AR1=KR1+MR1;
SubR1=AR1*BR1';
RHSR1=MR1*TR1'-SubR1+pforceR1';
% Apply Boundary Conditions
Biindex=0.;
for i=1:iindex;
if BR1(i)==0.;
Biindex=Biindex+1;
RHSR2(Biindex)=RHSR1(i);
jindex=0;
for j=1:iindex;
check=0;
if BR1(j)==0.;
jindex=jindex+1;
AR2(Biindex,jindex)=AR1(i,j);
end
end
end
end
%Solve
Tnewr=(AR2^-1)*RHSR2';
% Restore Matrices
Biindex=0;
for i=1:iindex;
if BR1(i)==0.;
Biindex=Biindex+1;
TR1(i)=Tnewr(Biindex);
end
end
iindex=0;
for i=1:ndof*numNodes;
check=0;
if mod(i,2)==0 && eNodes(i)~=1
check=1;
end
if check==0
iindex=iindex+1;
Tnew(i)=TR1(iindex);
end
end
Tnew
end
stored';

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@ -0,0 +1,197 @@
function [] = XCOR1Db()
% MATLAB based 1-D XFEM Solver
% J. Grogan (2012)
clear all
% Define Geometry
len=1.;
% Define Section Properties
rho=1.;
% Generate Mesh
numElem=4;
charlen=len/numElem;
ndCoords=linspace(0,len,numElem+1);
numNodes=size(ndCoords,2);
indx=1:numElem;
elemNodes(:,1)=indx;
elemNodes(:,2)=indx+1;
% dofs per node
ndof=2;
% initial interface position
dpos=0.6;
% Initial temperatures
Tnew=zeros(numNodes*2,1);
Bound=zeros(numNodes*2,1);
%storage
stored(1)=dpos;
for e=1:numElem
for n=1:2
crdn1=ndCoords(elemNodes(e,n));
if crdn1<=dpos
Tnew(2*elemNodes(e,n)-1)=1.;
end
end
end
Bound(1)=1.;
% Define Time Step
dtime=0.01;
tsteps=10;
time=0.;
% penalty term
beta=100.;
% Loop through time steps
for ts=1:tsteps
eNodes=zeros(2*numNodes,1);
% Get interface velocity
d(1)=dpos+charlen;
d(2)=dpos+3*charlen/4;
d(3)=dpos+charlen/4;
d(4)=dpos;
for e=1:numElem
crdn1=ndCoords(elemNodes(e,1));
crdn2=ndCoords(elemNodes(e,2));
for j=1:4
if d(j)>=crdn1 && d(j)<crdn2
elen=abs(crdn2-crdn1);
ajacob=elen/2.;
point=(d(j)-crdn1)/ajacob-1.;
theta(1)=abs(crdn1-dpos)*sign(crdn1-dpos);
theta(2)=abs(crdn2-dpos)*sign(crdn2-dpos);
tmp1a=Tnew(elemNodes(e,1)*2-1);
tmp1b=Tnew(elemNodes(e,1)*2);
tmp2a=Tnew(elemNodes(e,2)*2-1);
tmp2b=Tnew(elemNodes(e,2)*2);
xi=point;
gm(1)=(1.-xi)/2.;
gm(3)=(1.+xi)/2.;
term=theta(1)*gm(1)+theta(2)*gm(3);
gm(2)=gm(1)*(abs(term)-abs(theta(1)));
gm(4)=gm(3)*(abs(term)-abs(theta(2)));
t(j)=gm(1)*tmp1a+gm(2)*tmp1b+gm(3)*tmp2a+gm(4)*tmp2b;
end
end
end
vel=0.5*(0.5/charlen)*(2*t(1)+t(2)-t(3)-2*t(4));
vel=0.
% Update interface position
dpos=dpos+vel*dtime;
stored(ts+1)=dpos;
K=zeros(numNodes*ndof,numNodes*ndof);
M=zeros(numNodes*ndof,numNodes*ndof);
pforce=zeros(numNodes*ndof,1);
% Loop Through Elements
for e=1:numElem
Ke=zeros(2*ndof);
Me=zeros(2*ndof);
crdn1=ndCoords(elemNodes(e,1));
crdn2=ndCoords(elemNodes(e,2));
theta(1)=abs(crdn1-dpos)*sign(crdn1-dpos);
theta(2)=abs(crdn2-dpos)*sign(crdn2-dpos);
enr=2;
elen=abs(crdn2-crdn1);
ajacob=elen/2.;
if sign(theta(1))~=sign(theta(2))
% enriched element
eNodes(2*elemNodes(e,1))=1;
eNodes(2*elemNodes(e,2))=1;
enr=4;
% get interface position on element
point=(dpos-crdn1)/ajacob-1.;
% devide element for sub integration
len1=abs(-point-1.);
len2=abs(1.-point);
mid1=-1+len1/2.;
mid2=1-len2/2.;
gpx(1)=-(len1/2.)/sqrt(3.)+mid1;
gpx(2)=(len1/2.)/sqrt(3.)+mid1;
gpx(3)=-(len2/2.)/sqrt(3.)+mid2;
gpx(4)=(len2/2.)/sqrt(3.)+mid2;
w(1)=(len1/2.);
w(2)=(len1/2.);
w(3)=(len2/2.);
w(4)=(len2/2.);
else
% regular element - fix extra dofs
gpx(1)=-1/sqrt(3.);
gpx(2)=1/sqrt(3.);
w(1)=1.;
w(2)=1.;
end
% Loop Through Int Points
for i=1:enr;
c=gpx(i);
phi(1)=(1.-c)/2.;
phi(3)=(1.+c)/2.;
term=theta(1)*phi(1)+theta(2)*phi(3);
cond=1.;
spec=1.;
phi(2)=phi(1)*(abs(term)-abs(theta(1)));
phi(4)=phi(3)*(abs(term)-abs(theta(2)));
phic(1)=-0.5;
phic(3)=0.5;
dterm=sign(term)*(phic(1)*theta(1)+phic(3)*theta(2));
phic(2)=phic(1)*(abs(term)-abs(theta(1)))+phi(1)*dterm;
phic(4)=phic(3)*(abs(term)-abs(theta(2)))+phi(3)*dterm;
phix(1)=phic(1)/ajacob;
phix(2)=phic(2)/ajacob;
phix(3)=phic(3)/ajacob;
phix(4)=phic(4)/ajacob;
we=ajacob*w(i);
Ke=Ke+we*cond*phix'*phix;
Me=Me+(we*rho*spec*phi'*phi)/dtime;
end
% Add penalty term and get temp gradient on interface
if enr==4;
xi=point;
gm(1)=(1.-xi)/2.;
gm(3)=(1.+xi)/2.;
term=theta(1)*gm(1)+theta(2)*gm(3);
gm(2)=gm(1)*(abs(term)-abs(theta(1)));
gm(4)=gm(3)*(abs(term)-abs(theta(2)));
pen=beta*(gm'*gm);
pfL=beta*1*gm';
Ke=Ke+pen;
else
pen=zeros(4);
pfL=zeros(4,1);
end
% Assemble Global Matrices
gnum=2.*elemNodes(e,1)-1.;
for i=1:4;
for j=1:4;
K(gnum+j-1,gnum+i-1)=K(gnum+j-1,gnum+i-1)+Ke(j,i);
M(gnum+j-1,gnum+i-1)=M(gnum+j-1,gnum+i-1)+Me(j,i);
end
pforce(gnum+i-1)=pforce(gnum+i-1)+pfL(i);
end
end
A=K+M;
Sub=A*Bound;
RHS=M*Tnew-Sub+pforce;
% Apply Boundary Conditions
Biindex=0.;
for i=1:ndof*numNodes;
if Bound(i)==0.;
Biindex=Biindex+1;
RHSR(Biindex)=RHS(i);
jindex=0;
for j=1:ndof*numNodes;
if Bound(j)==0.;
jindex=jindex+1;
AR(Biindex,jindex)=A(i,j);
end
end
end
end
%Solve
Tnewr=(AR^-1)*RHSR';
% Restore Matrices
Biindex=0;
for i=1:ndof*numNodes;
if Bound(i)==0.;
Biindex=Biindex+1;
Tnew(i)=Tnewr(Biindex);
end
end
Tnew
end
stored';