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Innovation Intelligence ®
RADIOSS: Sub - modeling (cut approach)
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
RADIOSS : Sub-modeling (cut approach)
2
• Method: The target of this approach is to study one area of the model with taking into account the
deformation of the full model through a section force.
In the defined section, displacement will be imposed in order to represent the "sub" part of the model.
Model Submodel Cut section
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RADIOSS : Sub-modeling (cut approach)
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• Method
• Scheme
• From the full model, a section force is
created on the boundary of the selected
area.
• This section force, with specific
parameters, is added in the full model.
• The sub-model is created with all entities
which are inside the boundary and the
section force.
Full model
A files
T files
L files
SC files
Sub - model
RADIOSS
RADIOSS
HyperCrash
Section force
A files
T files
L files
Full model
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RADIOSS : Sub-modeling (cut approach)
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• Method
• Scheme
• The full model is computed in order to get
the information on the section force.
• The information are stored in
<rootname>SC01 output file.
Full model
A files
T files
L files
SC files
Sub - model
RADIOSS
RADIOSS
HyperCrash
Section force
A files
T files
L files
Full model
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
RADIOSS : Sub-modeling (cut approach)
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• Method
• Scheme
• The sub-model can be computed using the
information of the <rootname>SC01 file.
• In the time history files (<rootname> T01 file),
forces balances are computed with the force
imported force the <rootname>SC01 file and the
force computed in the sub-model.
• The force differences are usually very small. In
the other case, it means the section force is not
correctly defined and do not take into account all
crash evens.
Full model
A files
T files
L files
SC files
Sub - model
RADIOSS
RADIOSS
HyperCrash
Section force
A files
T files
L files
Full model
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RADIOSS : Sub-modeling (cut approach)
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• Industrial Applications
• Dummy analysis :
• Keep only the dummy and its direct environment
• 90% CPU cost of the full car model save
• Low speed impact :
• Keep only the deformed area
• 30% CPU cost of the full car model save
• Beginning of impact with high speed
• Keep only the deformed area
• 30% CPU cost of the full car model save
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RADIOSS : Sub-modeling (cut approach)
7
• Example 1
• The target of this simple sample is to show that
we can used this method for any type of element.
• Three plates are modeled with beam, shell and
solid elements. Imposed displacement is set on 1
side of the plate and the other one is clamped.
• The section is created like shown is the picture
red line ). (
Imposed displacement section Boundary
conditions
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RADIOSS : Sub-modeling (cut approach)
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• Example 1 • The deformation of the both models are the same.
• The full model is displayed with red color and the sub-model with blue color.
• The deformation of the both model is the same even if the section force is strongly deformed.
1 2
3 4
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RADIOSS : Sub-modeling (cut approach)
9
• Example 1 • The force in the section force and in the rigid body which model the clamping are the same
between the both models.
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RADIOSS : Sub-modeling (cut approach)
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• Example 2 • The NEON full car crash model is cut on the middle of the front door in order to study the front
• This task is done using HyperCrash. The user defined the area he wants to keep and HyperCrash
defines automatically the section force, proposes to save the full model with the section and the sub-
model with the same section and the right parameters.
part of the car
car.
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RADIOSS : Sub-modeling (cut approach)
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• Example 2
• Full model section
• The section defined for the full model contains all the entities cut defined by group of nodes,
bricks, shells, trusses, beams, springs and Interface ID.
• The time frequency (around10 times the minimum time step of model) and the data to store in
the <rootname>SC01 file is also set in the section.
• Isave = 1 : save only displacement
• Isave = 2 : save displacement and force
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----| /SECT/1 SECTION_SUBMODELING # N1 N2 N3 GrNod Isave time-step filter
39927 113302 113306 2978 2 1E-4 0 # File name
# GrBrick GrShell GrTruss GrBeam GrSprg GrSh3N N-inter Iframe 0 2979 0 0 0 2980 0 12 #---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
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RADIOSS : Sub-modeling (cut approach)
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• Example 2
• Sub-model section
• The same section is defined for the cut model with the name of the <rootname>SC01 file
and the data to read :
• Isave = 100 : read only displacement
• Isave = 101 : read displacement and force
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----| /SECT/1 SECTION_SUBMODELING # N1 N2 N3 GrNod Isave time-step filter
39927 113302 113306 2978 101 1E-4 0 # File name NEON_000 # GrBrick GrShell GrTruss GrBeam GrSprg GrSh3N N-inter Iframe 0 2979 0 0 0 2980 0 12 #---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
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RADIOSS : Sub-modeling (cut approach)
13
• Example 2
• Results
• The sub-model contains only less than 50% of the
elements of the full model and the CPU time is
also divided by 2.
• The force on the frontal rigid wall, the
displacement and the velocity of the nodes are
almost the same between the both models.
Full model Sub-model diff.
Node 294411 127049 -57% Springs 4074 1664 -59% Shells 269245 114500 -57% CPU time 9.02E+05 3.97E+05 -56% Nb cycles 301500 301500 0%
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RADIOSS : Sub-modeling (cut approach)
14
• Example 2
• Global deformation
1 2
3 4
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RADIOSS : Sub-modeling (cut approach)
15
• Example 2
• Global deformation
• Section Z=500
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RADIOSS : Sub-modeling (cut approach)
16
• Example 2
• Global deformation
• Section Y=0
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RADIOSS : Sub-modeling (cut approach)
17
• Example 2
• Displacement and velocity of the engine
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RADIOSS : Sub-modeling (cut approach)
18
• Example 2
• Displacement and velocity of dashboard upper
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19
RADIOSS : Sub-modeling (cut approach)
• Conclusion
• The sub-modeling method allows to study one area of the full model with taking into account
the displacement and forces on the boundary of the selected area.
• This method give good results. The deformation of the cut model is almost the same as the full
model.
• The CPU saved is proportional to the ratio of number of node kept in the sub-model and the
number of node of the full model.