Saturday, March 12, 2016

NX Nastran: To create concentrated mass / lumped mass in FEA NX advanced simulation

To create lumped mass in NX Nastran, Advanced simulation :

  1. Make .fem file as displayed part (active part)
  2. Now, In menu bar, Go to Insert → Element → Create element
  3. In element creation window , select element edit icon and select 0d element, CONMAS 2. CONMAS 2 means concentration mass type 2 in NX Nastran.
  4. Input the mass value in g or kg as per your information database.
  5. Leave the other variables as default
  6. Press OK
  7. Select the node where the lumped mass should be applied in the FEA mesh
  8. Press OK. Now you can see that a new Concentration mass collector is stored in your navigator.

More about Lumped mass :
Lumped mass which is also called as concentric mass is a lump of weight that can be applied in the mesh model. Sometimes, we may not need to focus on some parts (components) behavior like stress, displacement. At such time, we can apply those components mass as lumped mass.

For example, if we are studying the strength of a table that carries a TV on it , then we can mesh the table using 2D or 3D mesh and apply the weight of the TV as lumped mass in the Centre of Gravity point of CG and connect it with the table using rigid element connection (1D spider element connection)