变量“n”不能出现在下面的表达式中

Question

我想对岩石力学中的应变和应力变化进行迭代，但遇到错误：

"real::STRAIN (1:N), SIGMA (1:N),DSIGMA (1:N),STRAIN (1:N)=0.0"

和

"real,Dimension(6)::CEL(1:N,1:N)!刚度矩阵"

!program elastic_plastic

implicit none
!define all parameter
integer :: i = 1.0,j,K,M,N,inc
real::STRAIN (1:N), SIGMA (1:N),DSIGMA (1:N),DSTRAIN (1:N)=0.0
real,Dimension(6)::CEL(1:N,1:N)!stiffness matrix
real:: YOUNG, NU, COHESION !rock properties
real::ALPHA, KAPPA! cohesion and frictional angle
real::F !function
real::FRICTION_DEG, FRICTION_RAD !friction angle
real::VARJ2 ,VARI1 !stress invariants (I1 and J2)(MPa)
real:: LAMBDA,GMODU !lames constant and shear modulus
real::SIGMA_1,SIGMA_2,SIGMA_3 !principle stresses(MPa)
real::SHEAR_4,SHEAR_5,SHEAR_6 !shear stresses
real,parameter::DEG_2_RAD = 0.01745329


!INPUT
NU = 0.25
COHESION = 15 ! in MPa
YOUNG = 20 ! in GPa
FRICTION_DEG = 30.0d0
FRICTION_RAD = FRICTION_DEG *(DEG_2_RAD)

!perform calculations
KAPPA=6.*COHESION *cos(FRICTION_DEG*DEG_2_RAD)/(sqrt(3.)*(3.-sin(FRICTION_DEG*DEG_2_RAD)))
ALPHA=2.*sin(FRICTION_DEG*DEG_2_RAD)/(sqrt(3.)*(3.-sin(FRICTION_DEG*DEG_2_RAD)))
GMODU=YOUNG/2.*(1.+NU)
LAMBDA=NU*YOUNG/((1.+NU)*(1.-(2.*NU)))


!Set up elastic stiffness matrix (CEL)
CEL(1:N,1:N)=0.0
    CEL (1,1)= LAMBDA-(2.*GMODU)
    CEL (2,2)= LAMBDA-(2.*GMODU)
    CEL (3,3)= LAMBDA-(2.*GMODU)
    CEL (4,4)= 2.*GMODU
    CEL (5,5)= 2.*GMODU
    CEL (6,6)= 2.*GMODU


  DO
    inc = inc + 1
    DSTRAIN(1)=0.00002
    DSIGMA = matmul (CEL(1:N,1:N), DSTRAIN)
    SIGMA =SIGMA +DSIGMA
    STRAIN=STRAIN+DSTRAIN

     !calculate I1 AND J2
VARI1=SIGMA_1+SIGMA_2+SIGMA_3
VARJ2=1./6.*((SIGMA_1-SIGMA_2)**2+(SIGMA_2-SIGMA_3)**2+(SIGMA_3- SIGMA_1)**2+SHEAR_4**2+SHEAR_5**2+SHEAR_6**2)


!Yield function (Drucker-prager)
F= ALPHA*VARI1+(sqrt(VARJ2)-KAPPA)

IF (F.LE.0.0d0)then !Elastic step (exit)
    SIGMA =SIGMA
    STRAIN=STRAIN
    exit
    endif

    if (F.GT.0.0d0)then !Plastic step (continue)
goto 20
end if
20 continue
write(11,*)STRAIN,SIGMA,inc

END DO

end

Answer 1

您不能使用变量静态定义数组。您必须使用常量。 例如以下将起作用：

real::STRAIN (1:5), SIGMA (1:5),DSIGMA (1:5),DSTRAIN (1:5)=0.0
real,Dimension(6)::CEL(1:5,1:5)!stiffness matrix

如果您在代码时不知道数组的大小，您可以使用“分配”语句。这称为“动态存储分配”。来自'Arrays and Parallel programming in Fortran 90/95'：

可分配数组的声明方式如下：

integer Nparticles               ! number of particles
integer, parameter :: dim=3      ! dimensionality of space
...
real, allocatable :: charge(:)   ! defines an array containing the charge of 
                                 ! each particle 
integer, allocatable :: xyz(:,:) ! coordinates of each particle

一旦读取了模拟中的实际粒子数，我们就可以分配这些数组：

read(*,*) Nparticles
allocate (charge(Nparticles),xyz(dim,Nparticles))