ABAQUS Fortran基于提供的代码 P53，完善 8 节点单元程序，并增加对应力结果的处理。

 1.改写输入数据格式，使之能适应任意几何（可利用节点坐标输 入节点，利用单元-节点关系输入单元）； 2. 计算节点应力，给出并实现至少一种应力处理方案，提供处理 前后的应力结果（可用表格和云图表示），可与其它软件对比； 3.提交总结报告（包括方法/方案描述、带详细注释的代码、程序框图、算例描述、结果比较分析等）、可编译源代码、可执行文件、 数据文件、结果文件

 program p53       

!-----------------------------------------------------------------------------

!      program 5.3 plane strain of an elastic solid using uniform

!      8-node quadrilateral elements numbered in the x direction

!-----------------------------------------------------------------------------

 use new_library   ;  use geometry_lib   ;   implicit none

 integer::nels,nxe,neq,nband,nn,nr,nip,nodof=2,nod=8,nst=3,ndof,loaded_nodes,&

          i,k,iel,ndim=2

 real::aa,bb,e,v,det ;  character(len=15) :: element = 'quadrilateral'        

!--------------------------- dynamic arrays-----------------------------------

 real    ,allocatable :: kb(:,:),loads(:),points(:,:),dee(:,:),coord(:,:),    &

                         jac(:,:), der(:,:),deriv(:,:),weights(:),            & 

                         bee(:,:),km(:,:),eld(:),sigma(:),g_coord(:,:)

 integer, allocatable :: nf(:,:), g(:) , num(:)  , g_num(:,:) , g_g(:,:)       

!--------------------------input and initialisation----------------------------

  open (10,file='p53.dat',status=    'old',action='read')

  open (11,file='p53.res',status='replace',action='write')                      

  read (10,*) nels,nxe,nn,nip,aa,bb,e,v      ;    ndof=nod*nodof 

  allocate ( nf(nodof,nn), points(nip,ndim),g(ndof), g_coord(ndim,nn),        &

            dee(nst,nst),coord(nod,ndim),jac(ndim,ndim),weights(nip),         &

            der(ndim,nod), deriv(ndim,nod), bee(nst,ndof), km(ndof,ndof),     &

            eld(ndof),sigma(nst),num(nod),g_num(nod,nels),g_g(ndof,nels))       

  nf=1; read(10,*) nr ;if(nr>0)read(10,*)(k,nf(:,k),i=1,nr)

  call formnf(nf);neq=maxval(nf)        ;  nband = 0              

  call deemat (dee,e,v); call sample(element,points,weights)

!----------------loop the elements to find bandwidth and neq-------------------

  elements_1: do iel = 1 , nels

              call geometry_8qx(iel,nxe,aa,bb,coord,num); g_num(:,iel) = num

              call num_to_g(num,nf,g); g_coord(:,num)=transpose(coord)

              g_g(:,iel)=g  ;  if(nband<bandwidth(g))nband=bandwidth(g)

  end do elements_1

    write(11,'(a)') "Global coordinates "

    do k=1,nn;write(11,'(a,i5,a,2e12.4)')"Node",k,"       ",g_coord(:,k);end do

    write(11,'(a)') "Global node numbers "

    do k = 1 , nels; write(11,'(a,i5,a,8i5)')                                  &

                              "Element ",k,"        ",g_num(:,k); end do  

    write(11,'(2(a,i5))')                                                      &

             "There are ",neq ,"  equations and the half-bandwidth is", nband

             allocate(kb(neq,nband+1),loads(0:neq)); kb=.0        

!--------------- element stiffness integration and assembly--------------------

 elements_2: do iel = 1 , nels

             num = g_num(: , iel);  g = g_g( : , iel)

             coord = transpose(g_coord(:,num)) ; km=0.0   

          gauss_pts_1: do i = 1 , nip

               call shape_der (der,points,i) ; jac = matmul(der,coord) 

   det = determinant(jac);  call invert(jac)

               deriv = matmul(jac,der) ; call beemat (bee,deriv) 

             km = km + matmul(matmul(transpose(bee),dee),bee) *det* weights(i)

          end do gauss_pts_1   

   call formkb (kb,km,g)

 end do elements_2                                                             

 loads=.0; read(10,*)loaded_nodes,(k,loads(nf(:,k)),i=1,loaded_nodes) 

!----------------------------equation solution--------------------------------

    call cholin(kb) ;call chobac(kb,loads) 

    write(11,'(a)') "The nodal displacements are :"

    write(11,'(a)') "Node         Displacement"

    do k=1,nn; write(11,'(i5,a,2e12.4)') k,"   ",loads(nf(:,k)); end do

!------------------------recover stresses at centroids ------------------------

   i = 1 ; points = .0

        write(11,'(a)') "The centroidal stresses are :"

 elements_3:do iel = 1 , nels

         write(11,'(a,i5)') "Element No.  ",iel 

    num = g_num(: , iel); g = g_g(: , iel)

    coord = transpose(g_coord(:,num)); eld=loads(g)

       call shape_der (der,points,i); jac= matmul(der,coord)

       call invert(jac) ;    deriv= matmul(jac,der)

       call beemat(bee,deriv) ;  sigma = matmul (dee,matmul(bee,eld)) 

       write(11,'(a,i5)') "Point  ",i   ;  write(11,'(3e12.4)') sigma

 end do elements_3

end program p53