CODEWITHSUNDEEP
pythonabaqus
Luis
Luis

Reputation: 11

Creating part elements with Element() constructor in abaqus python

I cannot create elements with the Element() constructor of a Part Object in Abaqus. There is no problem with the Node() constructor but when you try to create the elements using the previously generated nodes, it shows you the following error warning:

There is no mesh to edit

Before running the script, the part mesh appears empty in the Abaqus CAE tree (part Recuadro) and after running the script is no longer empty, so I understand that the mesh has been generated.

Here it is my script:

import sys
import mesh
import part

from abaqus import *
from odbAccess import *
from abaqusConstants import *
from caeModules import *
from driverUtils import executeOnCaeStartup

#
# Función que da el número del nodo en función de las fila y columna de  elementos
#
def nnodo(i,j,ne):
    n = (2*ne+1)*(i-1)+j
    return n    

filecae= 'E:\ESI\Fatiga\Cotacto Cilindrico\ABQ\CC-Crack-0.cae'
openMdb(filecae)

# Coordenadas del arranque de la grieta en "Recuadro"

x0 =0.0
y0 = -0.002
z0 = 0.0
delta=[0]

# Dimensiones del recuadro x € [x0-a,x0+a] y € [y0-b, y0]

a=0.2
b=0.2

# Tamaño deseado de los elementos ~ le x le

le = 0.05

# Tamaño inicial de los elementos ~ dx x dy

Nex = 2*int(a/le)
Ney = int(b/le)

Nnx = 2*Nex+1
Nny = 2*Ney+1

dx = 2*a/Nex
dy = b/Ney

Nnodos = Nnx*Nny
Nelems = Nex*Ney

inod = range(Nnodos-1)
ielm = range(Nelems-1)

for i in range(Nny):
    delta.append(0)

# Coordenadas de los nodos de la malla inicial

recuadro=mdb.models['P22'].parts['Recuadro']
recuadro1=mdb.models['P22'].rootAssembly.instances['Recuadro-1']
recuadro.generateMesh(regions=(recuadro.faces[0],))

for i in range(1,Nny+1):
    dx1 = (Nex*dx/2 - delta[i])/Nex
    dx2 = (Nex*dx/2 + delta[i])/Nex

    y = y0 - (i-1)*dy/2

    for j in range(1,Nnx+1):
        if float(i)/2. <> int(float(i)/2. ) or float(j)/2. <>int(float(j)/2. ): 
            k = (2*Nex+1)*(i-1)+j

            if j<=Nex+1:
                x = x0 - Nex*dx/2 + (j-1)*dx1

            else:
                x = x0 - delta[i] + (j-Nex-1)*dx2           

            recuadro.Node(label = k, coordinates=(x, y, 0.))


# Conectividades de los elementos de la malla inicial

for i in range(1,Ney+1):

    for j in range(1,Nex+1):

        k = Nex*(i-1)+j

        n1 = recuadro.nodes[nnodo(2*i+1, 2*j-1, Nex)]
        n2 = recuadro.nodes[nnodo(2*i+1, 2*j  , Nex)]
        n3 = recuadro.nodes[nnodo(2*i+1, 2*j+1, Nex)]
        n4 = recuadro.nodes[nnodo(2*i  , 2*j+1, Nex)]
        n5 = recuadro.nodes[nnodo(2*i-1, 2*j+1, Nex)]
        n6 = recuadro.nodes[nnodo(2*i-1, 2*j  , Nex)]
        n7 = recuadro.nodes[nnodo(2*i-1, 2*j-1, Nex)]
        n8 = recuadro.nodes[nnodo(2*i  , 2*j-1, Nex)]

        recuadro.Element(label = k, elemShape= QUAD8, nodes=(n1, n2, n3, n4, n5, n6, n7, n8))

Upvotes: 1

Views: 884

Answers (1)

Matt P
Matt P

Reputation: 2347

I recall being confused by this issue as well. Well, here's the thing - a Part instance hasn't actually been assigned to the elements you just created. Try mdb.models[MODELNAME].parts[PARTNAME].elements[ELEMENTLABEL].instanceName and you'll see it is None since there is no return value. I'm not sure if this is by design, or if it's a bug. But basically, the Part object has a method to fix this:

p = mdb.models[MODELNAME].parts[PARTNAME].PartFromMesh(name=PARTNAME, copySets=True)

and you're done.

PS: I might add, though - looping to create Nodes and Elements this way for moderate to large meshes seems spectacularly slow to me. (Hint: there are faster ways!)

Upvotes: 1

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