Stack Overflow
Stack Overflow

Questions tagged [nastran]

NASTRAN is a finite element analysis (FEA) program that was originally developed for NASA in the late 1960s under United States government funding for the aerospace industry.

NASTRAN is a finite element analysis (FEA) program that was originally developed for NASA in the late 1960s under United States government funding for the aerospace industry.

Source: https://en.wikipedia.org/wiki/Nastran

16 questions
3
votes
1 answer

How to define output variable with dynamic shape in OpenMDAO

I am currently simulating a structural optimization problem in which the gradients of responses are extracted from Nastran and provided to SLSQP optimizer in OpenMDAO. The number of constraints changes in subsequent iterations, because the design…
H.Rahman
  • 31
  • 1
2
votes
1 answer

Reading nastran geometry file with python

What I want to do I am trying to parse the geometry information of a nastran file using python. My current attempts use NumPy as well as regular expressions. It is important to read the data fast and that the result is a NumPy array. Nastran file…
Woltan
  • 13,723
  • 15
  • 78
  • 104
2
votes
1 answer

fastest way to read an f06 file (Nastran) with matlab

I have to read several file of results from Nastran with MATLAB. I need to import the information about the displacement vector, which is located in the middle of the file, (but I know the line where the section about displacements starts and…
Pierpaolo
  • 1,721
  • 4
  • 20
  • 34
1
vote
1 answer

How do I fix USER FATAL MESSAGE 740?

How do I fix USER FATAL MESSAGE 740? This error is generated by Nastran when I try to run a BDF/DAT file of mine. *** USER FATAL MESSAGE 740 (RDASGN) UNIT NUMBER 5 HAS ALREADY BEEN ASSIGNED TO THE LOGICAL NAME INPUT USER ACTION: CHANGE…
Chris A.
  • 91
  • 5
1
vote
2 answers

PyTables vs Matlab HDF5 read times

I have an HDF5 output file from NASTRAN that contains mode shape data. I am trying to read them into Matlab and Python to check various post-processing techniques. The file in question is in the local directory for both of these tests. The file…
Matt
  • 2,554
  • 2
  • 24
  • 45
1
vote
1 answer

What's 'D' stands for on the numbers of MSC Nastran .f06 output file?

I performed flutter analysis using MSC Nastran, and I want to extract the generalized aerodynamic matrix, which is Qhh in the .f06 output file. I have kinda succeeded, but as shown in the figure, the numbers include 'D', not 'E', which is quite new…
Jongmin Yun
  • 11
  • 2
1
vote
1 answer

Reading nastran grid with exponent coordinate

Nastran GRID format I have a problem to read the some negative exponent values from NASTRAN.bdf file. For example, this list contains z co-ordinates. How to convert -5.75-3 into -5.75e-3 ?
Chetan Patil
  • 11
  • 3
0
votes
1 answer

KSComp with variable-size constraint vector input

Summary I'm trying to perform structural optimization coupling Nastran SOL 106 and OpenMDAO. I want to minimize mass subject to nonlinear stress and stability constraints. My structure is a box beam reinforced with ribs and stiffeners clamped at the…
fma
  • 219
  • 2
  • 14
0
votes
0 answers

Get Table Data from op2 file using pyNastran

I am trying to read final separation distances from an op2 file. I can see the table name (OSPDS1) is included in model.table_names, where model is the return value from read_op2(file_name, build_dataframe=True, debug=False). I have read every page…
Nathan Pyle
  • 481
  • 6
  • 9
0
votes
3 answers

PANDAS pd.read_hdf works with some, but not all tables in my HDF5 file

I am using Pandas in Python 3.7 in order to read data from a HDF5 file. The HDF5 file contains tables of results from MSC Nastran. The HDF5 file is named 'ave_01.h5' The HDF5 table of displacements looks like this: Using the following works just…
MegaDamo
  • 23
  • 5
0
votes
2 answers

For a buckling analysis, must all forces be multiplied by the resulting eigenvalue, or only the compressive load?

I am trying to do a linear buckling analysis (sol 105) with Nastran on a cylindrical shell structure. My understanding is that the compressive load that I apply to the structure must be multiplied by the resulting eigenvalue to get the buckling…
Jeroen
  • 119
  • 2
  • 2
  • 8
0
votes
1 answer

Python Nastran subprocess polling

I am running a Nastran simulation through Python. nastran=subprocess.run([nastrandir,fn,"parallel = 4","old=no",outputarg]) These simulations tend to run for quite some time without feedback, so I am trying to automate reading the output file for…
Jarn
  • 13
  • 2
0
votes
1 answer

Read and decoding binary file to get results

I would like to read and decodinga binary file in order to get values. Below the code I use to read the file : with open("modele_petite_zone.op2", "rb") as op2File : for lines in op2File : byte = op2File.read() print(byte) and here a part…
mnekkach
  • 191
  • 2
  • 11
0
votes
1 answer

Difference in bdf format between Patran and Virtual Lab

Here is my problem, i received a body-in-white in the bdf format which, by reading the file, seems to have been created through Patran 2013 and i need to make some changes to the body-in-white. I use LMS Virtual Lab in order to make my modifications…
Guillaume
  • 35
  • 5
0
votes
2 answers

Import nastran nodes deck in Python using numpy

If I want to import a Nastran Deck into a Python Array, in one fell swoop using numpy. How can I go about it? Where am I going wrong? I have a file with only Grids in it. Grids are all equally spaced with Nastran's Short translator (8 characters) $…
CromeX
  • 445
  • 1
  • 7
  • 20
1
2