Current Compatibilities
Kinematic Conditions
| • | Boundary conditions: /BCS |
| • | Tied contacts: /INTER/TYPE2 Spotflag 0, 1, 2 (kinematic formulation), 25, or 26 (penalty formulation) |
| - | rigid bodies: /RBODY (provided they are not sensor activated or deactivated) |
| - | fixed rigid walls: /RWALL with node_ID = 0 or blank (in case of friction, it is still advised to use a rigid meshed impactor, due to AMS cost) |
| - | moving rigid walls: /RWALL with node_ID > 0 (in case of friction, it is still advised to use a rigid meshed impactor, due to AMS cost) |
| • | Rigid bodies: can be activated and deactivated with /RBODY/ON and OFF as Engine keywords |
| • | Interpolation constraint elements: /RBE3 |
| - | All classical: trusses, beams, springs, shells, and solids |
| - | 4-node tetra: /TETRA4, only if Itetra=0 |
| - | QEPH Ishell =24 and all other Ishell options |
| • | Interfaces: /DT/AMS is only compatible with interfaces: |
| - | TYPE2 (see Tied contacts above) |
| • | /DT/Eltyp/Keyword3 is compatible with /DT/AMS (except, /DT/INTER/CST that only applies to the nodes not concerned by /DT/AMS, that is, nodes not belonging to the part group (grpart_ID) declared in Starter /AMS, similarly to /DT/NODA/CST). This includes /DT/Eltyp/CST for which the small strain formulation is activated for an element when
Where, l is the element characteristic length, and c is the speed of sound into the material. |
| • | /DT/AMS applied to selected parts (in /AMS from Starter Input file) does not exclude a joint usage of /DT/NODA/CST applied to non-AMS designated parts of the rest of the model. This is even advised in order to minimize computing time in models where AMS only applies to selected parts. Note that it is pointless to use a higher time step in AMS than the one used in classic mass scaling since the smaller time step limits the performance. |
| • | Airbags without reference metrics: should work |
Current Limitations (may coexist but out of the selected AMS part group)
| • | Caution: /PARITH/ON is not yet insured with AMS, if the number of domains changes. But, for one same domain number, results are same whatever the number of threads. |
| • | SPH: AMS does not increase time step of SPH (example: tank sloshing in crash) |
| • | ALE - Euler - FVM: formulations are not supported (but can be put out of /AMS part, if time step is decent) |
| • | 2D analysis: /AMS is not available |
| - | Lagrange multipliers: /MPC and /GJOINT |
In such cases, a warning is output by RADIOSS Engine and the computation may even diverge.
| - | 4-node tetra: /TETRA4 with Itetra=1 or 3 |
In such cases, the computation will most likely diverge.
| • | Rigid bodies: cannot be activated and deactivated with sensors |
| • | Interfaces: /DT/INTER/CST is not compatible with /DT/AMS |
| - | Nodes that are slave of both: a tied interface TYPE2 and a contact interface (TYPE7 or TYPE11) will have their contact stiffness removed a Starter message in the 0.out file is then issued: |
** WARNING SLAVE NODE OF AN INTERFACE TYPE2 & AMS
INTERFACE TYPE[7 or 11], ID=xxxxxx:
SLAVE NODE ID=yyyyyyy IS ALSO SLAVE NODE OF AN INTERFACE TYPE2
THE NODE CONTACT STIFFNESS WILL BE DE-ACTIVATED CASE OF /DT/AMS
This contact deactivation can be avoided by using Spotflag=25 or 26 (TYPE2 penalty formulation)
| - | Kinematic formulation (TYPE2) for spotwelds may alter AMS performances when there are many spotwelds, particularly hexa spotwelds |
| • | Airbags with reference metrics: /REFSTA or /XREF do not benefit AMS speedup |
|
Elementary time step for AMS
/DT/AMS in RADIOSS Engine Input
|
Lagrange Multipliers
|
Does not work
|
16-node thick shells and 20-node bricks
|
Free element time step is applied to these elements
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Rigid bodies activated, deactivated with sensors
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Does not work
|
Interfaces
|
Only TYPE2, TYPE7, TYPE10, TYPE11, TYPE19, TYPE20, TYPE21, and TYPE24 are supported
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Table 1: Main Advanced Mass Scaling limitation summary
See Also:
/AMS
/DT/AMS
