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Mass report in D3HSP file

Considering one single 4 noded shell element with mass equal to vol * density = 2*2*2*0.07 = 0.56.
From this it follows that each node has a mass of 0.56/4 = 0.14.

In addition, there are two lumped masses defined via *element_mass:
at node 2, lumped mass = 0.10
at node 3, lumped mass = 0.20

This means that:
node 1: 0.14 (nodal structual mass)
node 2: 0.14 + 0.10 = 0.24 (nodal structual + lumped mass)
node 3: 0.14 + 0.20 = 0.34 (nodal structual + lumped mass)
node 4: 0.14 (nodal structual mass)

Furthermore, Nodes 1 and 3 are included in a nodal rigid body via *constrained_nodal_rigid_body.

Within D3HSP file one can find the following messages:

 

"total mass of body          =0.86" and "t o t a l  m a s s          = 0.86"
  • total mass is 0.56 + 0.10 + 0.20 = 0.86 (structual + lumped mass = total mass)
"total mass of lumped masses = 0.30"
"mass of nodal rigid body    = 0.48"
  • mass of NRB = 2*0.14 + 0.20 = 0.48  (nodal structual + lumped mass)
"m a s s   p r o p e r t i e s   o f   p a r t #       1
    total mass of part          = 0.28"
  • This is the mass of the shell material NOT included in the nodal rigid body (total mass - mass of nodal rigid body).

 

"summary of mass" section,

"lumped mass in deformable
 part of structure      mass= 0.10".
  • This is the lumped mass at node 2. The lumped mass at node 3 is included in the nodal rigid body and thus is not in the deformable part of the structure.
"part id   =        1   mass= 0.56 mass in rigid body= 0.28"
  • The first number is the shell material mass (structual mass); the second number is the portion of that mass included in the nodal rigid body. No contribution of lumped masses is included on this line.
"nodal rigid body ID      100  mass= 0.48"

"total nodal rigid body mass= 0.48"