Questions tagged [nastran]
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17
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Linear Nastran model not converging
I am running a SOL 101 linear statics FEA. If I fix down the whole geometry it converges. But anything less than around 90% fix down and it will sit there crunching away at the numbers forever. This ...
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How quadrilateral elements represented in most FEA solvers for structural mechanics problems?
How quadrilateral elements represented in most FEA solvers for structural mechanics problems?
I know that Nastran-95 represent quadrilaterals for membrane and bending elements as a set of triangles:
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2
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Are there any instructions on how to install and run Natran-95?
there is a source code for Natran-95 on Github. I need to install it on Window 10
but searching on the web there is no clear tutorial on installation. while I click on the nastran.exe on this package ...
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In Nastran, how to ignore fatal error due to failed convergence and move on to next subcase?
At the moment the whole analysis stops when 1 subcase fails to converge. How can I keep the analysis going such that all subcases are are run, even if they all might produce an error?
I'm pretty sure ...
- 67
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In a nonlinear static two-step subcase, why does the load step decrease after the first step?
I am using MSC Nastran for nonlinear static analysis (sol 400).
Step 1 contains a small perturbation load laterally on a thin-walled cylinder.
Step 2 contains a very large compressive load.
...
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274
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For arc-length method in nastran, how to analyse post-buckling behaviour with load decrease
I am currently trying to model the buckling behaviour of a cylinder using sol 400 nonlinear static analysis using Nastran. I am using the arc-length (modified Riks) method as apparently it can ...
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716
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Free pre-processor for Nastran?
I want to do a non-linear analysis (possibly SOL 400) on Nastran. I used PyNastran (python module) to set-up the BDF file for a Linear buckling analysis (sol 105). However I feel like it might be too ...
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How would I do a buckling analysis with an additional fixed known lateral force?
I am using Nastran for buckling analysis, and I'm new to all of this so please bear with me.
For a linear buckling analysis, I understand that you must first apply any compressive load in the static ...
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315
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Nastran / Frequency Response / Free-Free
There are examples of using SOL 108 and SOL 111 to create a frequency response. In Siemens Simcenter (NX Nastran), the examples focus on a tower with a seismic mass. The model drives the mass with ...
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441
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MSC Nastran - BAR3/4 elements - can't assign any properties
I'm modeling a pipe in Patran, and I'd like to try bar3 and bar4 elements.
I assing the properties CBEAM to my geometry, but when I create the mesh, Patran tell me bar3 and bar4 don't support that ...
- 111
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MSC Nastran CQUAD8 on a pipe - excessive pivot ratio
I'm modelling a pipe in Patran with CQUAD8 elements, but I get this error, like the structure is not costrained. I do have costrains on both ends of the pipe. What can the problem be?
If I use ...
- 111
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3
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284
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Do internal / external stresses affect modal frequency?
Imagine a cantilevered beam, fixed on one end and with a tension line connecting the other end to ground (e.g. perpendicular to the length of the beam).
If I increase the tension, does the modal ...
- 163
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201
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Boundary Conditions fro Static Structural Analysis of a Turbine Rotor Using FEM
I am trying to perform static structural analysis of a turbine rotor which is rotating at a given angular speed, say 1000 rad/s. I also know the pressure distribution from CFD analysis. What are the ...
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557
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How to create a non uniform pressure load in MSC Patran
I need to simulate an external pressure load that varies sinusoidally along a circular arc. The sinusoidal variation is with arc length.
I know how to create a uniform pressure load in Patran but do ...
- 101
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762
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How to use failure criteria in isotropic material (NASTRAN)
I'm quite new in NASTRAN enviroment, and I am wondering how to use failure criteria which I can define when creating my isotropic MAT1 material for 1D elements (like CBEAM).
From the Quick Reference ...
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2k
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Inertia Relief and Buckling SOL105 in Nastran
Has anyone ever tried running buckling simulations in Nastran where inertia relief is invoked? I am just using a simple plate and I am getting "funny" modes (unrealistically low eigenvalues which ...
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Where does weight mass conversion ratio '0.00259' come from in Nastran?
I think this is very fundamental question.
I am wondering why 0.00259 is used as weight-mass conversion ratio, when inch/pound unit is used in Nastran.
Could anyone explain the reasons?
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