Hello dear forum members,
i am rather new to LS-Dyna. In the past i was working with Abaqus.
I am currently trying to set up a model of a wound solid structure that has initially penetrations, see attached figure.
What I would like to achieve is the following:
- relax the structure, so that the penetrations are removed and pre-stresses are introduced
- expand one of the solid layers with thermal expansion, pre-stresses increase further
- run either an implicit, quasi-static loading (wall impacting wound structure) or explicit, dynamic loading (ball impacting wound structure)
I am currently rahter lost after a few trials.
Essentially, thermal expansion works with these settings:
*LOAD_THERMAL_LOAD_CURVE
$ lcid lciddr
1
*DEFINE_CURVE
$ LCID SIDR SCLA SCLO OFFA OFFO
1
$ time temperature
0.0 0.0
1.0 200.0
2.0 200.0
*MAT_ADD_THERMAL_EXPANSION
$ PID LCID MULT LCIDY MULTY LCIDZ MULTZ
2 12.0E-06
4 12.0E-06
However, I was only able to make it run with explicit solver settings. Moreover, I am not sure how i would afterwards add the step where the impact occurs. just by shifting the curves (e.g. 0 - 2 s thermal, 2 - 5 s impact?).
Concerning removing intersections with interference contact i totally failed so far. I tried this:
$==================== Interference =================
*DEFINE_CURVE_TITLE
stiffness over time dynamic relaxation
$: Contact surface 1 : Factor on dyn rel stiffness vs time
$: X axis : Dynamic rel time (Units: Time)
$: Y axis : Factor on stiffness (Units: Scalar, no units)
$: Usage: Stress initialization
$: label sidr sfa sfo offa offo dattyp
$# lcid sidr sfa sfo offa offo dattyp lcint
5 1 0.0 0.0 0.0 0.0 0 0
$: xvals yvals
$# a1 o1
0.0 0.0
5.0 1.0
10.0 1.0
*DEFINE_CURVE_TITLE
constant stiffness over time transient
$: Contact surface 1 : Factor on transient stiffness vs time
$: X axis : Transient time (Units: Time)
$: Y axis : Factor on stiffness (Units: Scalar, no units)
$: Usage: Transient analysis
$: label sidr sfa sfo offa offo dattyp
$# lcid sidr sfa sfo offa offo dattyp lcint
6 0 0.0 0.0 0.0 0.0 0 0
$: xvals yvals
$# a1 o1
0.0 1.0
10.0 1.0
*CONTACT_SURFACE_TO_SURFACE_INTERFERENCE_ID
$# cid title
3AM_to_Sep
$# ssid msid sstyp mstyp sboxid mboxid spr mpr
1 3 2 3 0 0 0 0
$# fs fd dc vc vdc penchk bt dt
0.5 0.2 0.0 0.0 10.0 0 0.0 0.0
$# sfs sfm sst mst sfst sfmt fsf vsf
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
$# lcid1 lcid2
5 6
$# soft sofscl lcidab maxpar sbopt depth bsort frcfrq
2 0.1 0 1.025 3.0 5 10 1
The model just explodes.
I attached all the explicit files.
In the end ideally I would be able to do the relaxation+thermal expansion in one simulation, save the results incl. pre-stresses and then run different impact szenarios. is that possible in LS-DYNA?
Thank you very much for any kind of support.