Welcome, Guest
You have to register before you can post on our site.

Username
  

Password
  





Search Forums

(Advanced Search)

Latest Threads
Intel Compile
Forum: MYSTRAN Development
Last Post: Admin
2 hours ago
» Replies: 5
» Views: 54
Open Source Compiler
Forum: MYSTRAN Development
Last Post: Admin
3 hours ago
» Replies: 2
» Views: 36
Sparse Solver
Forum: MYSTRAN Development
Last Post: Admin
5 hours ago
» Replies: 2
» Views: 33
PRE/POST processing
Forum: MYSTRAN Other
Last Post: vittorio
9 hours ago
» Replies: 4
» Views: 15
Some Notes about NASTRAN
Forum: NASTRAN-95
Last Post: Admin
Yesterday, 06:48 AM
» Replies: 3
» Views: 35
Pre/Post Options for MYST...
Forum: MYSTRAN Other
Last Post: Admin
Yesterday, 02:28 AM
» Replies: 0
» Views: 27
**** OLD FORUM LINK ****
Forum: MYSTRAN Development
Last Post: Admin
01-11-2020, 12:37 AM
» Replies: 0
» Views: 29
Developer Items to Consid...
Forum: MYSTRAN Development
Last Post: Admin
01-11-2020, 12:04 AM
» Replies: 0
» Views: 50
1D Elements Pre/Post with...
Forum: MYSTRAN Other
Last Post: Admin
01-11-2020, 12:02 AM
» Replies: 0
» Views: 27
NASTRAN-95 vs MYSTRAN
Forum: NASTRAN-95
Last Post: Admin
01-11-2020, 12:01 AM
» Replies: 0
» Views: 53

 
  Pre/Post Options for MYSTRAN
Posted by: Admin - Yesterday, 02:28 AM - Forum: MYSTRAN Other - No Replies

MYSTRAN is largely compatible with programs that support BDF files. However, it does not currently have an OP2 output (will be developed later). While there are commercial programs that can use MYSTRAN, such as MSC Patran and Femap, these programs are expensive and are usually combined with their own solvers. Instead, this thread will present low cost or free/open pre/post software that works with MYSTRAN.


-------------FULL PRE/POST OPTIONS:-------------
A "Full Pre/Post Option" is considered to be a software that can create a BDF/mesh, apply loads/constraints, run the MYSTRAN solver, read MYSTRAN output, and post-process the results.

1D Elements (https://www.structuralfea.com/ )
A program that can use beam, rod, and spring elements in 2D space (linear static analysis, buckling analysis, natural frequency analysis). It has complete documentation and series of videos that explain how the program works.


-------------PARTIAL PRE/POST OPTIONS:-------------
A "Partial Pre/Post Option" is considered to be a software that read, modify, etc. BDF files (or output files). These programs can be used to interrogate models, but are not used to create a mesh, apply loads, etc. After the OP2 option is implemented in MYSTRAN, some of these programs can read results files.

pyNastran ( https://github.com/SteveDoyle2/pyNastran )
Using the BDF interface, you can read/edit/write Nastran geometry without worrying about field formatting. Many checks are also performed to verify that your model is correct. Using the OP2 interface, you can read large result files quckly and efficiently. Additionally, you can also extract a subset of the result data and write OP2/F06 result files.

FEX ( http://www.f-e-x.com/ )
A lightweight program (only 3MB) that can read and interrogate BDF files. It can be used to visually show the model, discover issues, measure, and perform various other operations. It has a built in tutorial and low learning curve. I found this to be a simple tool that is quite useful. It does not have post processing capabilities.


-------------TBD:-------------
M3DFEA ( http://www.m3dfea.com )
Pending Evaluation

CalculiX GraphiX

Print this item

  PRE/POST processing
Posted by: vittorio - 01-18-2020, 08:03 PM - Forum: MYSTRAN Other - Replies (4)

Dear all,
have a look at 
http://www.f-e-x.com/
FEX is a free program that can read  Nastran INPUT and view/check the model
Bye
Vittorio

Print this item

  Sparse Solver
Posted by: Admin - 01-16-2020, 07:23 AM - Forum: MYSTRAN Development - Replies (2)

As discussed in this thread (https://www.mystran.com/forums/showthread.php?tid=6), one of the top priorities is to address the sparse solver.

For small DOF problems, this card "PARAM, SOLLIB, ZZPACK" can be used and is reliable (banded solver). However, for larger DOF programs, a sparse solver may be required. MYSTRAN currently uses an older Intel solver for this case (this only exists for the complied EXE but ***NOT*** for the files on GitHub, which is a known issue). However, this older sparse solver is not very reliable. This challenge has increased in priority because we can not use the older Intel MKL solver that Bill used in the past (so MYSTRAN only has the banded solvers LAPACK/ARPACK).

We are investigating various sparse solvers. We previously looked at BCSLIB-EXT, but the cost is relatively high and it appears there may be other solvers that are just as good (if not better).

1. The SPOOLES solver is an option, but it seems to be relatively slow compared to other options.
2. PARDSIO with Intel MKL is an option, but requires an Intel compiler and the user must also download the Intel MKL (personal information is required).
3. PARDISO 6 is more improved than PARDISO MKL, but requires the user download a free license every year (personal information is required).
4. PaStiX may be the best option since it is modern and free. We can take a page from CalculiX and see how their investigation is going since they looking at other solvers.

CalculiX has historically used SPOOLES, but recently added an option for the PARDISO MKL.

My personal feeling is to incorporate the SPOOLES solver for the time being and continue to investigate other solvers (and keep on eye on what CalculiX is doing). The SPOOLES solver has been around for a while and including it as an option would not be a disadvantage (even if we later add other sparse solver options). If anyone is interested in looking into this, go ahead and create a thread about it.

Brian Esp

Print this item

  Some Notes about NASTRAN
Posted by: Admin - 01-15-2020, 08:09 PM - Forum: NASTRAN-95 - Replies (3)

These are some notes about NASTRAN, which may help to shed light about the state of NASTRAN-95:
-------------------------------

The FTC settlement with MSC resulted in the sale of UAI NASTRAN to a competitor. It wasn't made public. As I recall SDRC was the purchaser. They eventually were taken over by Siemens and UAI Nastran is part of their engineering software offering. The original NASA NASTRAN is still available but I don't know the details about that. 

The original Nastran was written in a subset of FORTRAN IV that would compile on IBM, CDC and Univac machines. Starting around 1979 <name omitted> led a project to put NASA Nastran on the Digital Equipment VAX computers running VMS. MSC complained about our doing what they had shown little interest in doing. MSC then did an updated version themselves that ran on VAX and other brands with FORTRAN 77 compilers. 

Meanwhile UAI also migrated their version to the VAX and other platforms including PCs running Windows. I provided the VAX computer UAI used for a lot of their debugging. You may recall that we had a rather rocky start with UAI Nastran but I helped them in various ways to use our VAX via a phone dial up connection (1200 baud!). Given the three hour difference in California time, the arrangement worked fairly well as they used our VAX after we went home. Eventually UAI's version worked as well as MSC's did. As you know, UAI had better sub structuring. Eventually MSC took over UAI and then CSA for good measure. Somebody (not us) sicced the FTC on them and that eventually led to the anti-trust trial that almost happened. The day before the trial, MSC folded and negotiated the settlement that led ultimately to the Siemens version.

Print this item

  Intel Compile
Posted by: Admin - 01-15-2020, 08:03 PM - Forum: MYSTRAN Development - Replies (5)

This is the initial findings from an attempt at compiling with Intel (note: this was not the Admin's effort, but was done by someone else):
------------------------

So, I thought I'd give things a whirl and see what happened if I tried to compile and link using Intel Fortran integrated into Visual Studio 2019.  I presumed that at some point, you'd like to have it so it would compile and link using several different flavors of Fortran.  So, maybe a good thing to try.

I had a few compilation issues owing to minor differences between how Lahey and Intel view things, but got past them OK.  We can discuss that more at some later point.  Back in the day, I had developed some techniques to make my Fortran code mostly (but not completely) agnostic to the compiler vendor.

But, during the linking phase, I encountered several missing references.  They are noted in the attached file that Intel Fortran generated.

I suspect one of two possibilities occurred:

1. Not all of the source code was in the ZIP file that I downloaded.  (or perhaps I missed something somewhere).
2. I included some files in the link list that shouldn't have been included.  (I just included all the source code files I found in the directory hierarchy.) (I didn't try to un-ravel any of the Lahey-specific documents to try to discern what the link list actually was.)

https://www.mystran.com/misc/BuildLog.htm

Print this item

  **** OLD FORUM LINK ****
Posted by: Admin - 01-11-2020, 12:37 AM - Forum: MYSTRAN Development - No Replies

This is the new forum. The older forum is located here (for temporary archival purposes)

https://www.structuralfea.com/forums/

Print this item

  Open Source Compiler
Posted by: Admin - 01-11-2020, 12:06 AM - Forum: MYSTRAN Development - Replies (2)

Vittorio has been working on using compiling MYSTRAN with gFortran. We will add more information later.

Print this item

  Developer Items to Consider
Posted by: Admin - 01-11-2020, 12:04 AM - Forum: MYSTRAN Development - No Replies

This is a list of items for developers to consider. Developers are free take on any project they like. These are just some basic ideas:

MOST STRAIGHTFORWARD:

1. Define and verify an open source Fortran compiler that works with MYSTRAN. MYSTRAN has currently been compiled with the Lahey Fortran compiler. We are now working towards using gFortran to compile MYSTRAN (In-Work item).

2. Investigate a 64 bit option. According to Bill, this is likely to be straightforward.

INTERMEDIATE:

1. For small DOF problems, the option the card "PARAM, SOLLIB, ZZPACK" can be used and is reliable (banded solver). However, for larger DOF programs, a sparse solver may be required. MYSTRAN currently uses an older Intel solver for this case (this only exists for the complied EXE but ***NOT*** for the files on GitHub, which is a known issue). However, this older sparse solver is not very reliable. We are investigating various sparse solvers. We previously looked at BCSLIB-EXT, but the cost is relatively high and it appears there may be other solvers that are just as good (if not better). The SPOOLES solver is an option, but it seems to be relatively slow compared to other options. PARDSIO with Intel MKL is an option, but requires an Intel compiler and the user must also download the Intel MKL. PARDISO 6 is more improved than PARDISO MKL, but requires the user download a free license every year. PaStiX may be the best option since it is modern and free. We can take a page from CalculiX and see how their investigation is going since they looking at other solvers. CalculiX has historically used SPOOLES, but recently added an option for the PARDISO MKL.

2. For the Eigen solution, beam elements have a differential stiffness matrix implemented in MYSTRAN. However, the shell and solid elements do not have the differential stiffness martrix coded. This would need to occur for them to be available for the Eigen solution.

LONG TERM - PRE/POST

1a. pyNastran is capable of reading a BDF input file: ( https://pynastran-git.readthedocs.io/en/latest/ ). However, it can not read MYSTRAN ouptut files. It is capable of reading MSC Nastran OP2 files, but MYSTRAN would have to be coded to create an OP2 file to view the results in pyNastran.

1b. CalculiX GraphiX is a pre/post that works with open source CalculiX solver ( http://www.dhondt.de/ ). It has basic functionality and is a lightweight program. This make it rather convenient and I have used it with some routines to generate deflection/contour plots and pass them to Excel in real time ( https://www.espcomposites.com/software/advanced.html ). It does not support MYSTRAN, but it may be possible for MYSTRAN to create output files that are compatible with CGX (CalculiX GraphiX). One challenge is that CalculiX only uses solid elements (it expands beams and shells into 3D solids), so this could pose an issue that requires time to modify either the CGX or MYSTRAN programs.

1c. Another pre/post option is to work on Roshaz. There is a separate forum for that ( https://www.structuralfea.com/forums/for...php?fid=11 )

LONG TERM - NONLINEAR

1. A nonlinear solver could be implemented. I think geometric nonlinearity would be the first and easiest to implement. Material nonlinearity could be addressed after that. This would be similar to the MSC Nastran SOL 106, which has some basic nonlinear capabilities. A full nonlinear implementation (with contact, etc.) would probably be beyond the scope though.

2. As a solver option, it may be possible to use the SPOOLES solver. This is what CalculiX uses (another open source finite element program that has nonlinear functionality).

LONG TERM - HIGHER ORDER ELEMENTS

1. An 8-node quad and 6-node tri could be developed in MYSTRAN. This would take quite a bit of work though.

--

Brian Esp

Print this item

  1D Elements Pre/Post with MYSTRAN
Posted by: Admin - 01-11-2020, 12:02 AM - Forum: MYSTRAN Other - No Replies

1D Elements© is a finite element program that uses beam, rod, and spring elements in 2D space. The program is an Excel based pre/post processor and can be used with the included free MYSTRAN solver or the MSC Nastran solver.

It can be found at:
https://www.structuralfea.com/software/software.html

This forum is for reporting bugs, discussing features, questions about the program, etc.

--

Brian Esp

Print this item

  NASTRAN-95 vs MYSTRAN
Posted by: Admin - 01-11-2020, 12:01 AM - Forum: NASTRAN-95 - No Replies

It is relevant to compare MYSTRAN to NASTRAN-95 and also discuss the state of NASTRAN-95.

-----------------------------------------------------

NASTRAN-95 (Usability):

There is a complied version for Linux here:
https://github.com/ldallolio/NASTRAN-95

For windows, "bash for Windows" can be used to access the Linux version.

There is also some information about Windows here:
https://github.com/ldallolio/NASTRAN-95/issues/2

NASTRAN-95 (Advantages):
- More developed and includes aero and fluid elements. A list of elements is shown here ( https://github.com/SteveDoyle2/pyNastran/issues/583 )
- More history of use (more well known)
- The Eigen solutions are more developed (MYSTRAN only supports beam elements for Eigen solutions).

NASTRAN-95 (Disadvantages):
- The user manual is very old and many current NASTRAN users will not recognize it.
- Some of the element names are not consistent with current names. For example, what is a CTRIA1, CTRIA2, and CTRIA3? This is related to the state of the manual as well (difficult to interpret for modern users).
- The code may be very difficult to develop. It was written with very old standards. The concern is that there would be a very big learning curve for developers before anything could be added.
- The solver that is used may be outdated by today's standards (considering the solver is at least 25 years old).

NASTRAN-95 (Unknowns):
- Nonlinear analysis?

-----------------------------------------------------

MYSTRAN (Usability)
- A compiled version for Windows exists.
- The state for Linux is less known, but a compiled version exists (may be an older version).
- For both cases, we are reworking how it is compiled so that is can be used with gFortran.

MYSTRAN (Advantages)
- Perhaps the biggest advantage of MYSTRAN is developers should find it more user friendly.
- Created with more modern software and hardware in mind.
- User manual is complete and consistent with modern NASTRAN user manuals.
- Newer solvers can be incorporated with relative ease

MYSTRAN (Disadvantages)
- Not as developed or well known as NASTRAN

-----------------------------------------------------

My current thoughts:
- For NASTRAN-95, it may be worthwhile to create a native Windows version and create a more user friendly and current manual. However, after that, it may be too difficult to develop further.
- For MYSTRAN, if a few improvements/features can be addressed, the capability may be close to NASTRAN-95 for many problems. Moving forward, MYSTRAN is more flexible and has more long term potential (modern solver, nonlinear analysis, improved Eigen solution, etc.)

Brian Esp

Print this item