The document discusses numerical treatment of contact problems for crashworthiness simulations using LS-Dyna. It covers topics such as contact stiffness, penalty values, sliding interface energy, single surface contacts, and modeling considerations for contact such as avoiding initial penetrations and tangled meshes.

1. Engineering Learning Center
LS Dyna Contacts

2. Company Confidential2
Engineering Learning Center
ELENO Engg. Learning Center, Pune, INDIA www.eleno-elc.com
Numerical treatment
of contact problems :
Crashworthiness using LS-Dyna

3. Company Confidential3
Engineering Learning Center
ELENO Engg. Learning Center, Pune, INDIA www.eleno-elc.com
Numerical treatment
of contact problems :
Crashworthiness using LS-Dyna

4. Company Confidential4
Engineering Learning Center
ELENO Engg. Learning Center, Pune, INDIA www.eleno-elc.com
Numerical treatment
of contact problems :
Crashworthiness using LS-Dyna

5. Company Confidential5
Engineering Learning Center
ELENO Engg. Learning Center, Pune, INDIA www.eleno-elc.com
Numerical treatment
of contact problems :
Example on Contact Stiffness
Crashworthiness using LS-Dyna

6. Company Confidential6
Engineering Learning Center
ELENO Engg. Learning Center, Pune, INDIA www.eleno-elc.com
Numerical treatment of contact problems :
Choice of Penalty Values
Crashworthiness using LS-Dyna

7. Company Confidential7
Engineering Learning Center
ELENO Engg. Learning Center, Pune, INDIA www.eleno-elc.com
Numerical treatment of contact problems :
Choice of Penalty Values
Crashworthiness using LS-Dyna

8. Company Confidential8
Engineering Learning Center
ELENO Engg. Learning Center, Pune, INDIA www.eleno-elc.com
Numerical treatment of contact problems :
Choice of Penalty Values
Crashworthiness using LS-Dyna

9. Company Confidential9
Engineering Learning Center
ELENO Engg. Learning Center, Pune, INDIA www.eleno-elc.com
Numerical treatment of contact
problems :
Sliding Interface Energy
Crashworthiness using LS-Dyna

10. Company Confidential10
Engineering Learning Center
ELENO Engg. Learning Center, Pune, INDIA www.eleno-elc.com
Numerical treatment
of contact problems :
Sliding Interface Energy
Crashworthiness using LS-Dyna

11. Company Confidential11
Engineering Learning Center
ELENO Engg. Learning Center, Pune, INDIA www.eleno-elc.com
Contact algorithms for
automotive crash :
Single surface contacts :
Crashworthiness using LS-Dyna

12. Company Confidential12
Engineering Learning Center
ELENO Engg. Learning Center, Pune, INDIA www.eleno-elc.com
Contact algorithms for automotive crash :
Modeling for Contact
Avoid initial penetrations at all cost
Avoid tangled meshes at all cost
The previous require adequate offset of the metal sheets, carefull thickness
definition and regular meshing
use old contacts only for smooth, convex, if possible closed master surfaces
type 13 general contact is very reliable, due to segment searching 1 large
contact zone is not more expensive then several overlapping small ones
Crashworthiness using LS-Dyna

13. Company Confidential13
Engineering Learning Center
ELENO Engg. Learning Center, Pune, INDIA www.eleno-elc.com
• this becomes particularly important if
aluminium structures are considered
because of the relatively high sheet thickness
Use contact thickness values that are close
to real sheet thicknesses in order to avoid
creating unrealistic gaps that decrease the
structural stiffness of the model :
Contact algorithms for
automotive crash :
Modeling for Contact
Crashworthiness using LS-Dyna