Hi all!
We have been running modal dynamic simulations for an aerospace structural system, and I run into a basic, even tough tricky question: what is the physical meaning of modal participation factor (MPF)? What is the difference in terms of physical meaning with respect to modal effective...
I have been reading old posts in this forum from back in the 2004, 2005 regarding NX Nastran vs MSC Nastran capabilities. It is clear that on those times UGS had just gained access to the 2001 version of MSC Nastran original solver and started developing its own version. But what about in 2022...
Hi,
I am running into a structural verification criterion for an aerospace component, and as we know FEA packages offer the ability to show either nodal stresses and element stresses (at the centroid for instance).
I realized that the nodal stresses values are much higher than the element...
Let's assume we have the most general structural FEM model, which is being simulated with a classical linear FEA solution (no source of non-linearity is being considered). We know that if we run with load 1.0*P, 2.0*P, or even 3.0*P, we can predict deflections (displacements) will be the...
Hi,
I have 3 different load subcases for 1G loads in X, Y and Z directions. I would need to have Nastran write 3 different different OP2 output files, one for each subcase. Is it possible? What case control cards should I use?
For instance:
==
SUBCASE 1 ---> 1GX ---> output file: ...1GX.op2...
Hi,
I have been reading simple example problems of FEM vs analytical solutions, and I run into a very simple (and maybe stupid) doubt which answer I couldn't find over days after searching in FEM textbooks!
Let's assume we have a classical cantilever Euler-Bernoulli beam, clamped at the root...
We are checking out the mass of a model in Nastran (by using the WEIGHTCHECK or PARAM,GRDPNT commands), and the first mass matrix that appears on the .f06 print file is a M O, which looks like the 6x6 rigid-body mass matrix.
We understand the meaning of the diagonal terms to represent the total...
I would like to suppress the echo of the CASE CONTROL SECTION in the .f06 file, equivalent to suppress the BULK DATA SECTION by using the Case Control Command ECHO=NONE.
Is there any way to do it? Any PARAM or config to set up?
Thank you!
I have different sets defined in the Case Control. My understanding is that output request variables are limited to only one SET, so my question is how can I combine multiple sets into a single one, and then reference this later one in the output variable?
For instance:
$* CASE CONTROL
SET 1 =...
Hi,
I know it is possible to check the mass properties and CG position of the FEM model by using the Grid Point Weight Generator (PARAM,GRDPNT,0). But it is also available the Weight Check command (WEIGHTCHECK) at the Case Control.
What is the real difference between using one or the other...
Hi,
I am working with a Nastran input deck file directly. I saw it is possible to define PARAM (parameters) whether in the Case Control Section or in the Bulk Data Section.
1. What is the difference? Which section is better to define them?
2. Any recommendation of where to place them as per...
We are modeling a cylindrical shell with CQUADR elements. This shell contains several regions (along the axial dir z and theta sectors in a cylindrical CSYS) with different values of NSM.
For instance:
Region 1
0<z<10m
0<theta<90°
NSM (2D=CQUADR)=1kg/m2
Region 2
0<z<10m
90°<theta<270°
NSM...
Hi,
I would like to know the technical meaning of Coupled Load Analysis (CLA) for a spacecraft, mainly a satellite. Is CLA related to computer simulation (FEM) or testing?
If you have any technical reference or textbook, I would really appreciate.
Thank you.
Hello,
We are modeling a FEM model for an aerospace company. This structural system is built of several components, attached via jointed bolts (screws).
What would be the difference of using these techniques for FEM modeling the jointed bolts in NX / MSC Nastran?
1- CFAST elements
2-...
Hello,
We are modeling a FEM model for an aerospace company. This structural system is built of several components, attached via jointed bolts (screws).
What would be the difference of using these techniques for FEM modeling the jointed bolts in NX / MSC Nastran?
1- CFAST elements
2-...
Hello,
We are working in an aerospace project using MSC Nastran, and we have to model external loads acting on our system.
The question arises due to the several possibilities of modelling the external effect in a static analysis.
What is the difference between modelling using a prescribed...
