Error when creating an element type COMBIN14

[arun-maniam]

Hello,

I'm trying to create a mass-spring system attached to a plate with element type COMBIN14 for the spring and MASS21 for the mass.
I have created the nodes needed to attach the mass and the spring. I have used this command to create the element type COMBIN14:

# ...
mapdl.et(2)  
mapdl.real(2)  


for j in range(1, 10):
        mapdl.e(node_number_i[j - 1], node_number_j[j - 1])

But when i run this command i am getting the following error:

*** ERROR ***                           CP =      15.156   TIME= 11:38:07
 Element 1001 does not have all of its required nodes defined.  The E
 command is aborted.
 *** ERROR

Could anyone tell me what is the problem here?

[germa89]

Hi @arun-maniam

It seems that Element 1001 does not have all of its required nodes defined. How many nodes does it need? It depends on what type of element it is.
COMBIN14 has 2 nodes (i,j).
MASS21 only has one (i).
I think because the code you are using mapdl.e(node_number_i[j - 1], node_number_j[j - 1]) I would say you want to do a COMBIN14.

Assuming nodes node_number_i[j - 1] and node_number_j[j - 1] exists, I wonder if you are using the right element. Is the element type number 2, a COMBIN14 element??

I think it could also help if you post the full code. Presumably the error output seems incomplete.

[arun-maniam]

Yes, element type number 2 is a COMBIN14.

As requested, I have attached the a part of the code below.
Error_COMBIN14_and_MASS21.txt

[mikerife]

Hi @arun-maniam & @germa89
In the input file you supplied (thank you for that) the type of element is not being switched via the 'type' command before creating the elements. The 'et' without arguments command is being issued instead. For example this is given:

mapdl.et(3)  
mapdl.real(3)  


for j in range(1, 26):
    if vmask_res[j - 1] == 1:
        mapdl.prep7()  # Enter PREP7 environment
        mapdl.e(Res_knoten_mass[j - 1])

But element type 3 was already defined. No 'type' command was issued, and guessing that the shell element mentioned in the file is type 1, means that MAPDL was expecting more shell elements to be created, not mass elements. So use instead:

mapdl.type(3)  
mapdl.real(3)  

for j in range(1, 26):
    if vmask_res[j - 1] == 1:
        mapdl.prep7()  # Enter PREP7 environment
        mapdl.e(Res_knoten_mass[j - 1])

Then same change when defining combin14 elements.

Mike

[arun-maniam]

Hi @mikerife . Thanks alot for the feedback, Your solution worked! :)