Jul 19

Transfer of beam data to NASTRAN conventions

I will try to describe the translation of a single element definition from my own code's input data to a NASTRAN CBEAM element - at least how I understand it.

Looking at this part:

 Node => Wing Node 9; 0.45454·m; 0·m; 0.43741·m; Node => BC Node 9; 0.46029·m; 0.0035432·m; 0.43421·m; Node => D Node 9; 0.44726·m; 0.0035445·m; 0.44147·m; Node => Wing Node 10; 0.47882·m; 0·m; 0.48104·m; Node => BC Node 10; 0.48410·m; 0.0034008·m; 0.47810·m; Node => D Node 10; 0.47033·m; 0.0033959·m; 0.48576·m; -- Wing Element 10 -- Span from 0.43741·m to 0.48104·m -- Length 0.049926·m -- Mass 1.6659·kg Elastic_Material ... [read more]

Jul 14

Transfer check-out

I have been doing some basic checks between the original data and final data and want to post any progress/ updates here in an effort to avoid having anyone re-do work that has already been done.

So far I have verified that all grid coordinates are correct and observed the coordinate system change:

x_new = x_initial
y_new = z_initial
z_new = -y_initial

Grids 1-20 = Balance Nodes
Grids 21-60 = Wing Nodes
Grids 61,62 = Exciter nodes
Grids 1020-1023 = B nodes (1020 = Balance B node)
Grids 2020-2023 = C nodes ... [read more]

Jul 06

Nastran Beam FEM from Beam Model

Alexander Boucke provided the beam data information and I have been trying to get a Nastran model working - obtaining the same modal frequencies. I'm unsuccessful as yet.

Please add your comments here as to any progress you are making?

The resource to which this is referring is https://c3.nasa.gov/dashlink/resources/425/

The 2 frequencies which I provided were the 1st and 2nd bending mode

I had forgotten to include the spcfile that I have included in the FEM. I hesitate to post my matlab code which I use to generate the bdf files from the file provided by Alexander Boucke.

... [read more]