ask the experts mpc contact
TRANSCRIPT
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8/13/2019 Ask the Experts MPC Contact
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2009 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary
WEBINAR onMulti-pointConstraint (MPC)Technology
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8/13/2019 Ask the Experts MPC Contact
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AgendaMultipoint Constraint (MPC)
What are Multipoint Constraints or MPCs?
Where do we use MPCs?
Advantages of MPC over traditional contact
What is new at 12.0 for MPC
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8/13/2019 Ask the Experts MPC Contact
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2009 ANSYS, Inc. All rights reserved. 3 ANSYS, Inc. Proprietary
Multi-point constraints enforce compatibility atan interface using internally generated
constraint equations. For example, the constraint equation that would transfer action
between ROTZ at node 2 and UY at nodes 1 and 3 has this form:
0 = UY3 - UY1 - 10*ROTZ2
What is MPC?
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8/13/2019 Ask the Experts MPC Contact
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MPC can be used to bond different element typesat interfaces with incompatible mesh regions:
Where do we use MPC?
Two solid element surfaces
Solid/Shells surfaces or edges
Beam to Shells/Solids
I am happy to share the lecturing duties with you. Let me know what chapters you would like to teach.
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8/13/2019 Ask the Experts MPC Contact
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MPC is the surface based constraint technologybehind:
Remote forces and displacements
Remote points
Structural and Thermal Point Mass
Joints and Springs
Where do we use MPC?
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8/13/2019 Ask the Experts MPC Contact
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x-axis Revolute joint
z-axis Revolute joint
Universal joint
Slot joint
Point-in-plane joint
Translational joint
x-axis Cylindrical joint
z-axis Cylindrical joint
x-axis Planar joint
z-axis Planar joint
Weld joint
Orient joint
Spherical joint
General joint
Screw joint
MPC is the technology behind the joint optionsavailable in workbench
A Joint between flexible bodies typically consists of
two surface based constraints tied together at the
respective pilot nodes with an MPC184 element
Where do we use MPC?
http://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184revo.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184revo.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184univ.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184slot.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184poin.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184tran.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184cyl.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184cyl.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184plan.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184plan.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184weld.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184orie.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184sphe.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184gen.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184scr.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184scr.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184gen.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184sphe.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184orie.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184weld.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184plan.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184plan.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184plan.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184plan.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184plan.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184plan.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184cyl.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184cyl.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184cyl.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184cyl.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184cyl.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184cyl.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184tran.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184poin.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184poin.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184poin.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184poin.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184poin.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184slot.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184univ.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184revo.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184revo.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184revo.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184revo.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184revo.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_4/Hlp_E_MPC184revo.html -
8/13/2019 Ask the Experts MPC Contact
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Flexible Usual 3D meshed models
Nonlinear material options
Rigid Point mass representation of
3D geometry
Force-distributedconstraint Connect flexible bodies to
joints
MPC is also the technology behind connectingrigid bodies to flex bodies in workbench
Where do we use MPC?
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8/13/2019 Ask the Experts MPC Contact
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Lumped mass of rigid body is representedby MASS21 element tied to the pilot node of
flex body surface based constraints via a
TARGE170 line element
Where do we use MPC?
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8/13/2019 Ask the Experts MPC Contact
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Limitations of traditional bonded or no-separation contact:
Only translational DOFs apply.
Results depend on specified contact stiffness.
Multiple iterations are required to adjustpenetration in order to satisfy equilibrium evenfor small deformation problems.
Occasionally spurious natural frequencies canoccur in modal analysis.
How does MPC differ from
traditional contact ?
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8/13/2019 Ask the Experts MPC Contact
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Limitations of manual constraint tools (CERIGand RBE3)
Only suitable for small strain.
RBE3 only supports force constraints applied on
the master node, not displacements.RBE3 requires manual definition of weighing
factors. MPC surface constraints calculate weighing factors
automatically.
How does MPC differ from manually
generated constraints?
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8/13/2019 Ask the Experts MPC Contact
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Improved solution efficiency over traditionalbonded contact:
For a large assemblies with MPC bonded (or
no-separation) contact, the CPU run time is
faster than the same analysis using defaultalgorithm.
ContactAlgorithm
Iterations CPU Time(seconds)
Aug-Lagrange 4 2710
MPC 1 880
Advantages of MPC
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8/13/2019 Ask the Experts MPC Contact
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Advantages of MPC(contd): Ease of use:
No contact stiffness is required as an input.
Internal Multi-Point Constraints will be generated
automatically at the execution of a Solve
For large deformation problems, the MPC
equations are updated during each iteration.
Shape functions are taken into accountautomatically for RBE3-type of surface constraint
(force distributed); no weight factor is needed
Advantages of MPC
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8/13/2019 Ask the Experts MPC Contact
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Overconstraint detection and elimination When a degree of freedom is subjected to multiple
constraints, overconstraint occurs
results in solver-failure convergence difficulties or inaccurate
solutions.
The program automatically eliminates a limited set of
overconstraints detected during solution and issues
appropriate warning messages.
For troubleshooting purposes, you can display certain
eliminated constraints in the POST1 postprocessor
New at 12 0
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8/13/2019 Ask the Experts MPC Contact
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The assembly is connected with MPC contacts
In these regions, Parts are
not correctly connected
Contact status
Solution in R12:
2 elements in sweep
direction
Contact status
New at 12.0
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8/13/2019 Ask the Experts MPC Contact
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Advanced tools to improve shell and beamconnections
New at 12.0
At 12.0 Constraint equations
always built as long ascontact node(s) and target
segments are inside the
pinball region.
At 11.0,constraint
equations only built at
nodes whose target and
contact normals
intersection