This article provides a comparison of the various Radioss interfaces.
Here is a table comparing Lagrangian contact interfaces:
Here is a table comparing ALE interfaces:
The behavior of a Type 2 interface changes based on the selected SpotFlag parameter.
Based on the SpotFlag parameter, a tied interface can have failure defined and even switch to penalty formulation, as opposed to being a kinematic constraint. Below is a table comparing all the available options for the SpotFlag parameter in /INTER/TYPE2
Regarding the choice between Spotflag = 27 or 28:
- These 2 formulations transmit moments from secondary nodes to elements on the master surface
(see notes #19 and #20 in the documentation for /INTER/TYPE2)
- Spotflag = 28 is the only formulation that transmits the drilling moment
(But only if the master surface is based on shell elements)
For this reason, SpotFlag = 28 should be used when modelling spotwelds
- With Spotflag = 27, there is no addition of mass at t = 0
This differs from Spotflag = 28, which can add mass when the main surface is based on solid elements
(see note #21 in the documentation for /INTER/TYPE2)
- Spotflag = 27 should be used for connections to solid components
- Spotflag = 28 should be used for connections to shell components
Below is a link to the "Contact Definition for Crash Analysis" YouTube video comparing interfaces as well:
https://www.youtube.com/watch?v=kQnMhFM9iAE
This video covers the following topics:
- Typical Applications of Interfaces
- Variations of Interfaces
- Most Used Interfaces Types for Impact
- Interface Type 7
- Interface Type 25
- Example Model Description
- Results
- Interface Stiffness Formulation
- Sub Interface: /INTER/SUB
- Thickness at /PART
