202 lines
5.5 KiB
Text
202 lines
5.5 KiB
Text
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c 2D XFEM Corrosion Element
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subroutine uel(rhs,amatrx,svars,energy,ndofel,nrhs,nsvars,props,
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1 nprops,coords,mcrd,nnode,u,du,v,a,jtype,time,dtime,kstep,kinc,
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2 jelem,params,ndload,jdltyp,adlmag,predef,npredf,lflags,
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3 mlvarx,ddlmag,mdload,pnewdt,jprops,njprop,period)
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c
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include 'aba_param.inc'
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c
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dimension rhs(mlvarx,*),amatrx(ndofel,ndofel),svars(nsvars),
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1 energy(8),props(*),coords(mcrd,nnode),
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2 u(ndofel),du(mlvarx,*),v(ndofel),a(ndofel),time(2),
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3 params(3),jdltyp(mdload,*),adlmag(mdload,*),
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4 ddlmag(mdload,*),predef(2,npredf,nnode),lflags(*),jprops(*)
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c
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dimension phig(8),phih(8),phi(8),phix(8),phiy(8)
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dimension crdnx(4),crdny(4),w(8),dndg(4),dndh(4)
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dimension theta(4),rjac(2,2),rjaci(2,2)
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c
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parameter(zero=0.d0,one=1.d0)
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c material property definition
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thick = 1.
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rho = 1.
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beta=40.
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vel=0.0
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dpos=0.25+vel*time(2)
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c initialization (nrhs=1)
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do k1=1,ndofel
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rhs(k1,nrhs)=zero
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do k2=1,ndofel
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amatrx(k2,k1)=zero
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enddo
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enddo
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if (lflags(1).eq.33) then
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do icrd=1,4
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crdnx(icrd)=coords(1,icrd)
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crdny(icrd)=coords(2,icrd)
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theta(icrd)=abs(crdnx(icrd)-dpos)*
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1 sign(1.,crdnx(icrd)-dpos)
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enddo
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if sign(1.,theta(1))/=sign(1.,theta(2))then
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c Enriched
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ienr=8
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elen=abs(crdnx(2)-crdnx(1))
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frac=abs(dpos-crdnx(1))/elen
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rlen1=2.*frac
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rlen2=2.*(1.-frac)
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rmid1=-1+rlen1/2.
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rmid2=1-rlen2/2.
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gx(1)=rmid1-(rlen1/2.)/sqrt(3.)
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gx(2)=rmid1+(rlen1/2.)/sqrt(3.)
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gx(3)=rmid1+(rlen1/2.)/sqrt(3.)
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gx(4)=rmid1-(rlen1/2.)/sqrt(3.)
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gx(5)=rmid2-(rlen2/2.)/sqrt(3.)
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gx(6)=rmid2+(rlen2/2.)/sqrt(3.)
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gx(7)=rmid2+(rlen2/2.)/sqrt(3.)
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gx(8)=rmid2-(rlen2/2.)/sqrt(3.)
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gpos=1/sqrt(3.)
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hx(1)=-gpos
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hx(2)=-gpos
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hx(3)=+gpos
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hx(4)=+gpos
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hx(5)=-gpos
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hx(6)=-gpos
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hx(7)=+gpos
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hx(8)=+gpos
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do iw=1,4
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w(iw)=frac/2.;
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w(iw+4)=(1.-frac)/2.;
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enddo
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else
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c Normal Shp Funs
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ienr=4
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gpos=1./sqrt(3.)
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gx(1)=-gpos
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gx(2)=gpos
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gx(3)=gpos
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gx(4)=-gpos
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hx(1)=-gpos
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hx(2)=-gpos
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hx(3)=gpos
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hx(4)=gpos
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do iw=1,4
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w(iw)=1.
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enddo
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endif
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c assemble amatrx and rhs
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do k=1,ienr
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c loop through gauss pts
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g=gx(k)
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h=hx(k)
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phi(1)=0.25*(1.-g)*(1.-h)
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phi(3)=0.25*(1.+g)*(1.-h)
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phi(5)=0.25*(1.+g)*(1.+h)
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phi(7)=0.25*(1.-g)*(1.+h)
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riLS=theta(1)*phi(1)+theta(2)*phi(3)+
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1 theta(3)*phi(5)+theta(4)*phi(7)
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if (riLS<0.)then
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cond=0.
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spec=0.01
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else
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cond=1.
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spec=1.
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endif
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do iter=1,4
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phi(2*iter)=phi(2*iter-1)*
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1 (abs(riLS)-abs(theta(iter)))
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enddo
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phig(1)=0.25*-(1.-h)
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phig(3)=0.25*(1.-h)
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phig(5)=0.25*(1.+h)
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phig(7)=0.25*-(1.+h)
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phih(1)=0.25*-(1.-g)
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phih(3)=0.25*-(1.+g)
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phih(5)=0.25*(1.+g)
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phih(7)=0.25*(1.-g)
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diLSg=sign(1.,iLS)*(phig(1)*theta(1)+phig(3)*
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1 theta(2)+phig(5)*theta(3)+phig(7)*theta(4))
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diLSh=sign(1.,iLS)*(phih(1)*theta(1)+phih(3)*
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1 theta(2)+phih(5)*theta(3)+phih(7)*theta(4))
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do iter=1,4
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phig(2*iter)=phig(2*iter-1)*(abs(iLS)-
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1 abs(theta(iter)))+phi(2*iter-1)*diLSg
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phih(2*iter)=phih(2*iter-1)*(abs(iLS)-
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1 abs(theta(iter)))+phi(2*iter-1)*diLSh
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enddo
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rjac=0.
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do iter=1,4
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rjac(1,1)=rjac(1,1)+phig(2*iter-1)*crdnx(iter)
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rjac(1,2)=rjac(1,2)+phig(2*iter-1)*crdny(iter)
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rjac(2,1)=rjac(2,1)+phih(2*iter-1)*crdnx(iter)
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rjac(2,2)=rjac(2,2)+phih(2*iter-1)*crdny(iter)
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enddo
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djac=rjac(1,1)*rjac(2,2)-rjac(1,2)*rjac(2,1)
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rjaci(1,1)= rjac(2,2)/djac
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rjaci(2,2)= rjac(1,1)/djac
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rjaci(1,2)=-rjac(1,2)/djac
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rjaci(2,1)=-rjac(2,1)/djac
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do iter=1,8
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phix(iter)=rjaci(1,1)*phig(iter)+rjaci(1,2)*phih(iter)
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phiy(iter)=rjaci(2,1)*phig(iter)+rjaci(2,2)*phih(iter)
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enddo
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dtdx=zero
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dtdy=zero
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t =zero
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told=zero
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do i=1,8
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dtdx=u(i)*phix(i)+dtdx
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dtdy=u(i)*phiy(i)+dtdy
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t=u(i)*phi(i)+t
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told=(u(i)-du(i,nrhs))*phi(i)+told
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end do
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dtdt=(t-told)/dtime
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we=w(k)*djac
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do ki=1,8
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c loop over nodes
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rhs(ki,nrhs) = rhs(ki,nrhs) -
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1 we*(phi(ki)*rho*spec*dtdt +
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2 cond*(phix(ki)*dtdx + phiy(ki)*dtdy))
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do kj=1,8
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amatrx(ki,kj)= amatrx(ki,kj) +
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1 we*(phi(ki)*phi(kj)*rho*spec/dtime +
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1 cond*(phix(ki)*phix(kj)+phiy(ki)*phiy(kj)))
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end do
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end do
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enddo
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c if interface is in the element a penalty term is needed
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if(enr==4)then
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xi=point
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gm(1)=(1.-xi)/2.
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gm(3)=(1.+xi)/2.
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term=theta(1)*gm(1)+theta(2)*gm(3)
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gm(2)=gm(1)*(abs(term)-abs(theta(1)))
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gm(4)=gm(3)*(abs(term)-abs(theta(2)))
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term2=gm(1)*u(1)+gm(2)*u(2)+gm(3)*u(3)+gm(4)*u(4)
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diff=abs(term2-1.)
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c add penalty flux/force: BGtc
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targetT=1.
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do i=1,4
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rhs(i,nrhs)=rhs(i,nrhs)+beta*gm(i)*diff
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enddo
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c find GtG
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gm2=0.
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do i=1,4
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do j=1,4
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gm2(i,j)=gm(i)*gm(j)
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enddo
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enddo
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c add penalty stiffness
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do i=1,4
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do j=1,4
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amatrx(i,j)=amatrx(i,j)+beta*gm2(i,j)
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enddo
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enddo
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endif
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end if
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return
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end
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