165 lines
4.7 KiB
Text
165 lines
4.7 KiB
Text
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c Subroutine UEL
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c Calculates element mass and stiffness matrices and residual flux
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c vector for Abaqus NR Solver.
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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,
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2 kinc,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 gpx(4),gwei(4),phi(4),phix(4),phic(4),gm(4),gm2(4,4)
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dimension theta(2)
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real dpos, npos(6), ndof(6)
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common dpos,npos,ndof
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c
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c level set calculation
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c store nodal positions and temperatures
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dpos1=0.6
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c material property definition
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rho = 1.
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spec = 1.
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c penalty term
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beta=100.
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c initialization (nrhs=1)
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do k1=1,ndofel
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rhs(k1,nrhs)=0.
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do k2=1,ndofel
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amatrx(k2,k1)=0.
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enddo
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enddo
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if (lflags(3).eq.4) return
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c transient analysis
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if (lflags(1).eq.33) then
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c determine node level set params
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crdn1=coords(1,1)
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crdn2=coords(1,2)
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theta(1)=abs(crdn1-dpos1)*sign(1.,crdn1-dpos1)
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theta(2)=abs(crdn2-dpos1)*sign(1.,crdn2-dpos1)
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enr=2
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elen=abs(crdn2-crdn1)
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ajacob=elen/2.
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if (sign(1.,theta(1))/=sign(1.,theta(2)))then
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c enriched element
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enr=4
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point=(dpos1-crdn1)/ajacob-1.
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rlen1=abs(-point-1.)
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rlen2=abs(1.-point)
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rmid1=-1.+rlen1/2.
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rmid2=1.-rlen2/2.
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c Get int point locations and weights
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gpx(1)=-(rlen1/2.)/sqrt(3.)+rmid1
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gpx(2)=(rlen1/2.)/sqrt(3.)+rmid1
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gpx(3)=-(rlen2/2.)/sqrt(3.)+rmid2
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gpx(4)=(rlen2/2.)/sqrt(3.)+rmid2
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gwei(1)=(rlen1/2.)
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gwei(2)=(rlen1/2.)
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gwei(3)=(rlen2/2.)
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gwei(4)=(rlen2/2.)
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else
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c regular element
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gpx(1)=-1./sqrt(3.)
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gpx(2)=1./sqrt(3.)
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gwei(1)=1.
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gwei(2)=1.
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endif
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c assemble amatrx and rhs
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do k=1,enr
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c loop through gauss pts: i
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c=gpx(k)
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c get ip level set value: Oi
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c get shape functions and derivatives
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c Ni
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phi(1)=(1.-c)/2.
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phi(3)=(1.+c)/2.
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term=theta(1)*phi(1)+theta(2)*phi(3)
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c if (term<0.)then
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c cond=0.
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c spec=0.1
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c else
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cond=1.
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spec=1.
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c endif
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c if(enr==4)then
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phi(2)=phi(1)*(abs(term)-abs(theta(1)))
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phi(4)=phi(3)*(abs(term)-abs(theta(2)))
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c else
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c phi(2)=0.
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c phi(4)=0.
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c endif
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c dNdci
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phic(1)=-0.5
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phic(3)=0.5
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dterm=sign(1.,term)*(phic(1)*theta(1)+phic(3)*theta(2))
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c if(enr==4)then
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phic(2)=phic(1)*(abs(term)-abs(theta(1)))
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1 +phi(1)*dterm
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phic(4)=phic(3)*(abs(term)-abs(theta(2)))
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1 +phi(3)*dterm
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c else
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c phic(2)=0.
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c phic(4)=0.
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c endif
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c dNdxi
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phix(1)=phic(1)*(1./ajacob)
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phix(2)=phic(2)*(1./ajacob)
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phix(3)=phic(3)*(1./ajacob)
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phix(4)=phic(4)*(1./ajacob)
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c interpolate temperatures Tbar to int point: i
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dtdx=u(1)*phix(1)+u(2)*phix(2)
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1 +u(3)*phix(3)+u(4)*phix(4)
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t=u(1)*phi(1)+u(2)*phi(2)
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1 +u(3)*phi(3)+u(4)*phi(4)
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told=(u(1)-du(1,nrhs))*phi(1)+(u(2)-du(2,nrhs))*phi(2)+
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1 (u(3)-du(3,nrhs))*phi(3)+(u(4)-du(4,nrhs))*phi(4)
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c other housekeeping
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dtdt=(t-told)/dtime
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we=gwei(k)*ajacob
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c Assemble Element Stiffness Matrix and Add to Global
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do ki=1,4
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c loop over nodes
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rhs(ki,nrhs)=rhs(ki,nrhs)-we*(phi(ki)*rho*spec*dtdt
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1 + cond*(phix(ki)*dtdx))
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do kj=1,4
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amatrx(ki,kj)=amatrx(ki,kj)+we*(phi(ki)*phi(kj)
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1 *rho*spec/dtime+cond*(phix(ki)*phix(kj)))
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end do
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end do
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enddo
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end if
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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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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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return
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end
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