BALANCE_SURFACE_MASS
Loads
*BALANCE_SURFACE_MASS
"Optional title"
coid
pid, gid
"Optional title"
coid
pid, gid
Parameter definition
Variable
Description
coid
Command ID (optional)
pid
Part ID
gid
Optional geometry ID
Description
This command is used to balance node masses on the surface of a part, with the aim to achieve a uniform surface acceleration field at a uniform hydrostatic stress state. gid is optional an limits the mass balancing to the elements enclosed by the geometry.
Example
Predetonated explosive
A pre-detonated explosive charge is modelled with quadratic tetrahedra elements. Having a uniform pressure field, the acceleration should be of the same magnitude everywhere on the material surface. With the default node mass distribution this is not the case. The mass balancing command can be invoked to improve the behavior.
*UNIT_SYSTEM
SI
#
# --- TIME ---
#
*TIME
1.0e-6
#
# --- MESH ---
#
*INCLUDE
mesh.k
*CHANGE_P-ORDER
P, 1, 2
#
# --- MATERIAL ---
#
*MAT_EXPLOSIVE_JWL
"TNT"
1, 1630.0, 5.0e9, 0.4
1.0e7, 1.0e7, 5.0, 1.5, 2.0
371.2e9, 3.23e9, 4.15, 0.95, 0.3, 7.0e9, 6930.0
*DETONATION
1
P, 1, 0, 0, 0, -1.0
#
# --- PART ---
#
*PART
"TNT"
1, 1
#
# --- BALANCE MASS --
#
*BALANCE_SURFACE_MASS
"TNT surface"
1
1
#
# --- BC ---
#
*BC_SYMMETRY
YZ
*END
