By ANSYS-LSDYNA I am trying to simulate the Split-Hopkinson Pressure Bar (SHPB) test. Can anyone give me details idea, about what kind of contact I have to define between Striker Bar and Incident Bar, Incident Bar and Specimen, and so on..
Hello Imrose, there is a good documentation, maybe you already seen, about contact definitions in LS-DYNA. Maybe you can refer to the following for general sense of contact modelling.
http://www.dynasupport.com/tutorial/contact-modeling-in-ls-dyna
http://www.dynalook.com/fea-newsletters/fea-newsletters-2001/fea-newsletter-december-2001.pdf
But to model SHPB test, between striker and incident bar automatic surface to surface contact is OK. Between specimen - bars interfaces you may simply use automatic surface to surface contacts (may be nodes to nodes or segment based all works OK and must be tried if there is a problem). If there is erosion (damage) in your specimen (actually of course there must not be erosion in bars those are elastically modeled) you have to use eroding surface to surface contact to account for eroding pieces possibly contacting after fracture occurs.
If your specimen material is a challenging one (it may be soft like foam) you can use SOFT options of contacts. If for example your material is a harder material than your bar material (ie stiffness is higher than the bar, it is not possible in real experiment, but we can use some indent preventer disks but you dont have to model them in the simulations), you can simply scale down the stiffness of specimen by SFS.
Generally specimens treated as slave surfaces and bars treated as master surfaces. You can look up for friction coefficients through the internet between surfaces or you can use trial and error method and if it is not changing your results a lot you can select a generic friction coefficient.
Even all pieces can be included in one Automatic/Eroding_Single_Surface card and Force_Transducer_Penalty card can be used to determine contact forces.
For contact forces you have to include a DATABASE_ASCII_OPTION RCFORC must be checked and must be assigned with a DT which is generally (or can be) smaller than the DT of the d3plot.
This is all I can imagine right now. You can ask if I forget to mention about something. Sincerely.
Thanks once again Mr. Ali Kara. My material is Aluminum Foam (Density around 200 Kg/m3). I will try to follow your instruction and hope so it will works.
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