Reads a mesh from CalcluliX input (.inp) files.
Only supports a limited set of keywords defining the mesh. See Supported Keywords for details.
from ccxmeshreader import read_mesh
mesh = read_mesh('path/to/some.inp')Nodes and their coordinates are parsed and added to the dictionary returned by read_mesh in the node_coordinates_by_number key.
The node_coordinates_by_number key contains a dictionary where the key is the node number, and value is the coordinates as a three-element tuple with float values.
For example, given the following *NODE definition:
*NODE, NSET=Nall
1, 1.0, 0.0, 0.1
2, 3.0, 1.0, 2.0
3, 0.9, 5.0, 7.0
mesh = read_mesh('example.inp')
print(mesh['node_coordinates_by_number']){
1: (1.0, 0.0, 0.1),
2: (3.0, 1.0, 2.0),
3: (0.9, 5.0, 7.0)
}
Currently node sets are not supported, and the optional NSET parameter is ignored.
Elements and their associated nodes are parsed and added to the dictionary returned by read_mesh in the element_dict_by_type key.
The element_dict_by_type key contains a dictionary where the key is the element type, and value is another dictionary where the key is the element number,
and value is a list of node numbers associated to the element.
For example, given the following *ELEMENT definition:
*ELEMENT, TYPE=C3D20R, ELSET=Eall
1, 1, 2, 3
2, 4, 5, 6
mesh = read_mesh('example.inp')
print(mesh['element_dict_by_type']){
'C3D20R': {
1: [1, 2, 3]
2: [4, 5, 6]
}
}
Continuation of data-lines ending with a comma , is supported. For example:
*ELEMENT, TYPE=C3D20R, ELSET=Eall
1, 1, 2, 3,
4, 5, 6
2, 7, 8, 9
mesh = read_mesh('example.inp')
print(mesh['element_dict_by_type']){
'C3D20R': {
1: [1, 2, 3, 4, 5, 6]
2: [7, 8, 9]
}
}
If the ELSET parameter is provided, then the element set will be added to the element_set_by_name dictionary returned in the mesh of read_mesh with the corresponding element numbers.
For example, from the above *ELEMENT definition:
mesh = read_mesh('example.inp')
print(mesh['element_set_by_name']){
'Eall': {1, 2}
}
Element set definitions are parsed and added to the dictionary returned by read_mesh in the element_set_by_name key.
The element_set_by_name key contains a dictionary where the key is the name of the element set, and value is a set of element numbers.
For example, given the following *ELEMENT and *ELSET definitions:
*ELEMENT, TYPE=S4, ELSET=E1
1, 1, 2, 3,
4, 5, 6
2, 7, 8, 9
*ELSET, ELSET=E2, GENERATE
1, 4
*ELSET,ELSET=E3
E2, 5, 6
mesh = read_mesh('example.inp')
print(mesh['element_set_by_name']){
'E1': {1, 2},
'E2': {1, 2, 3, 4}
'E3': {1, 2, 3, 4, 5, 6}
}
The optional GENERATE parameter is respected with start, end, and step.
Materials are parsed and added to the dictionary returned by read_mesh in the materials key.
The materials key contains a list of material dictionaries with properties depending upon subsequent material definition cards with the exception of the required name property.
For example, given the following *MATERIAL definition:
*MATERIAL, NAME=SolidMaterial
*ELASTIC
210000, 0.300
mesh = read_mesh('example.inp')
print(mesh['materials'])[
{
'name': 'SolidMaterial',
'elastic': {
'type': 'ISO',
'youngs_modulus': 210000,
'poissons_ratio': 0.300
}
}
]
Currently only elastic properties of type ISO are supported.
ORTHO, ENGINEERING CONSTANTS, and ANISO types are ignored.
For type ISO, the Young's modulus and Poisson's ratio are parsed and added under the elastic key in the material dictionary.
For example, given the following *MATERIAL definition:
*MATERIAL, NAME=SolidMaterial
*ELASTIC
210000, 0.300
mesh = read_mesh('example.inp')
print(mesh['materials'])[
{
'name': 'SolidMaterial',
'elastic': {
'type': 'ISO',
'youngs_modulus': 210000,
'poissons_ratio': 0.300
}
}
]
Files specified by the *INCLUDE keyword are read, but currently limited to relative file paths, and assumed to be relative to the path passed to read_mesh.
Recursive includes (i.e. *INCLUDE statements in a previously included file) are not yet supported.
The approach this library takes is to read the .inp file in a while loop, line-by-line, until there are no lines left, and collect the nodes and elements that make up the mesh into a dictionary.
It does not use an intermediate step of parsing the .inp file into an abstract syntax tree -- as doing so would be costly and likely involve a parsing library.
Thus, ccxmeshreader can be considered light-weight and performant.
Continuation of keyword lines is not supported.
For example, trying to read the following .inp file:
*ELEMENT, TYPE=C3D20R,
ELSET=Eall
raises a ccxmeshreader.ParserError.
Unit tests are included in the tests/ directory, and can be ran with the following command:
python -m unittest discover tests "*_test.py"