NaxToPy 1.0.1

Package for postprocessing FEM results in Python

NaxToPy

NaxToPy is the NaxTo library designed for Python, which allows reading and manipulating FEM analysis results files from the most common tools: Nastran (op2, xdb, h5), Abaqus (odb), Optistruct (h3d, op2) and Ansys (rst); and stores them in a user-friendly Python structure. Additionally, it can read input files from Nastran (bdf, fem).

It could be easily combined with other Python packages as Matplotlib or Pandas. This provides access to the full coding power of Python to interpret and process the results, without the need to install any additional software other than having NaxTo already installed (see the Download and Homepage links on the left).

NaxToPy is a powerful tool for FEM analysis post-processing!

Installation

If python is callable from the command line:

py -m pip install NaxToPy

For Visual Studio users:

• Open "Python Environments" window

• Change the "general information" label to "Packages(Pypi)"

• Write the name of the package and press enter:

• NaxToPy + enter

For Spyder users:

• If pip is installed: !pip install NaxToPy

• If pip is not installed, download and run get-pip.py located in https://bootstrap.pypa.io/get-pip.py . Then, run the !pip ... command

• If no method worked, download the sorce ditribution of the package NaxToPy from Test PyPi and the source distribution of the packages from PyPi pythonnet, clr-loader, cffi, pycparser. Copy and paste the five folder in the same directory. When ever you want to use the NaxToPy package add the following lines to your script:

  import sys
  sys.path.append("...\directory")
  import NaxToPy as n2p
  

Updating NaxToPy

If python is callable from the command line:

py -m pip install -U NaxToPy

For Visual Studio users:

• Open "Python Environments" window

• Change the "general information" label to "Packages(Pypi)"

• Write the following command on the search bar and press enter:

  -U NaxToPy + enter

Version updates:

To see previous version see the pre-release versions in https://test.pypi.org/project/NaxToPy/

v.1.0.1

1. Bug Fix: A new dependece is added to support python 3.12
2. Bug Fix: N2PLog.set_directory now works correctly
3. New download page for NaxTo and NaxToPy

Documentation

NaxToPy is a package developed by Idaero Solutions© as a part of the NaxTo software.

This version is only compatible with NaxTo 2024.0.0. Check in Programs and Features the NaxTo version that is installed.

NaxToPy only use three dependeces:

• NumPy: https://numpy.org/
• PythonNET: https://pythonnet.github.io/
• Setuptools: https://setuptools.pypa.io/en/latest/index.html

Supported Files

Result files:

• Nastran: .op2, .h5, .xdb
• Optistruct: .op2, .h3d
• Abaqus: .odb
• Ansys: .rst, .rth(beta)

Input files:

• Nastran (bdf)

Initialize your model

Load your model:

# results_fem.py
import NaxToPy as N2P

path = "results_fem.op2"

model = N2P.load_model(path)

Load mesh items

# results_fem.py

# Load a list with all the nodes (as N2PNode object) of the model
nodes = model.get_nodes()

# Load the nodes in the list [1, 2, 3] (as a list of N2PNode objects)
nodelist = model.get_nodes([1, 2, 3]) 

# Load the node with the id 1000 (as a N2PNode object)
node1000 = model.get_nodes(1000)

# Load a list with all the elements (as N2PElement object) of the model
element = model.get_elements()

# Load the elements in the list [10, 20, 30] (as a list of N2PElement objects)
elementlist = model.get_nodes([10, 20, 30])

# Load the connectors as N2PConnector:
connectorslist = model.get_connectors()

# Load the coordinate systems of the model:
coordslist = model.get_coords()

Add your own messages to the .log

# results_fem.py

N2P.N2PLog.Info.user("INFO-1000: Running results_fem.py")

Look for LoadCases, Results and Components

# results_fem.py

# Load the list of load cases as N2PLoadCase object
loadcaseslist = model.LoadCases

# Look for the Load Case with the name pressure
pressure_lc = model.get_load_case("pressure")

# Change the active increment (by default is the last one):
pressure_lc.ActiveIncrement = 10

# Look for all results
all_results = pressure_lc.Results

# Look for the Result with the name DISPLACEMENT
displacement = pressure_lc.get_result("DISPLACEMENT")

# Load all the components of the result
all_components = displacement.Components

# Look for the component X:
x_coord = displacement.get_component("X")

Load the result data as a list

# results_fem.py

# Obtain the result array as a list for a component
x_list = x_coord.get_result_array()[0]

Load the result data as a NumPy array

# results_fem.py

# Call the get_result_ndarray method of a N2PComponent to obtain a numpy array
# with the results of the component.
x_df = x_coord.get_result_ndarray()

Create an executable file of your code

Using a different script:

# extra_script.py

import NaxToPy as N2P
path1 = "results_fem.py"
path2 = "results_fem_abaqus.py"

N2P.n2ptoexe(path1, console=True, solver="NASTRAN")
N2P.n2ptoexe(path2, console=True, solver="ABAQUS", abaqusversion=["2021", "2022"])

Create your own functions to work with other python packages:

Private function that generates the proper index for a data frame using the elemnts or nodes ids:

# results_fem.py

import pandas as pd

def _index_dataframe(model: "N2PModelContent", component: "N2PComponent", sections, aveSections, cornerData, aveNodes,
                     variation, realPolar, coordsys, v1, v2) -> pd.Index:
    """ Function that returns the proper index for each component asked
    """
    # It is look if there is one part or several's:
    parts = len(model.Parts) - (model.Solver == "Abaqus")

    # Then the result array and where there results are placed is obtained
    on_items = component.get_result_ndarray(sections, aveSections, cornerData, aveNodes,
                                            variation, realPolar, coordsys, v1, v2)[1]

    # The ids and the index are selected. It takes into account where the results are and the number of parts
    if on_items == "NODES":
        nodes = model.get_nodes()
        ids = [(nodo.PartID, nodo.ID) if parts > 1 else nodo.ID for nodo in nodes]
        indexname = ["Part", "Grid"] if parts > 1 else ["Grid"]

    elif on_items == "ELEMENTS":
        elements = model.get_elements()
        connectors = model.get_connectors()
        ids = [(element.PartID, element.ID) if parts > 1 else element.ID for element in elements] + \
              [(co.PartID, co.ID) if parts > 1 else co.ID for con in connectors for co in (con if isinstance(con, list) else [con])]
        indexname = ["Part", "Element"] if parts > 1 else ["Element"]

    elif on_items == "ELEMENT NODAL":
        ids = model.elementnodal().values()
        indexname = ["Part", "Grid", "Element"]

    else:
        return None

    # If there are several parts, or it is corner data, MultiIndex is used:
    if isinstance(ids[0], tuple):
        index = pd.MultiIndex.from_tuples(ids, names=indexname)
    else:
        index = ids

    return index

Function that generates a DataFrame with the results of a component

# results_fem.py

def dataframe_result(model: "N2PModelContent", component: "N2PComponent",sections=None, aveSections=-1, cornerData=False,
                     aveNodes=-1, variation=100, realPolar=0, coordsys: int = -1000,
                     v1: tuple = (1,0,0), v2: tuple = (0,1,0)) -> pd.DataFrame:
    """Function that returns as a dataframe of pandas the result array of a component
    """

    # DataFrame generation
    return pd.DataFrame(data={component.Name:
                              component.get_result_ndarray(sections, aveSections, cornerData, aveNodes, variation,
                                                           realPolar, coordsys, v1, v2)[0]},
                        index=_index_dataframe(model, component, sections, aveSections, cornerData, aveNodes, variation,
                                               realPolar, coordsys, v1, v2),
                        columns=[component.Name])

Function that generates a DataFrame for all the components of a result

# results_fem.py

def dataframe_results(model: "N2PModelContent", result: "N2PResult", sections=None, aveSections=-1, cornerData=False,
                     aveNodes=-1, variation=100, realPolar=0, coordsys: int = -1000,
                     v1: tuple = (1,0,0), v2: tuple = (0,1,0)) -> pd.DataFrame:
    """Function that generates a DataFrame of pandas with all the components of a result. It uses dataframe_result.
    It uses sequential computing.
    """
    return pd.DataFrame(data={component.Name:
                                  component.get_result_ndarray(sections, aveSections, cornerData, aveNodes, variation,
                                                               realPolar, coordsys, v1, v2)[0]
                                                               for component in result.Components.values()},
                        index=_index_dataframe(model, next(iter(result.Components.values())), sections, aveSections,
                                               cornerData, aveNodes, variation, realPolar, coordsys, v1, v2),
                        columns=[component.Name for component in result.Components.values()])

For more documentation visit https://idaerosolutions.com/Home/NaxTo

License

Copyright is owned by Idaero Solutions©