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A coarsely meshed wheel and tire assembly is ‘kicked’ by a brief transient load. The dynamic response of a node at the top of the tire is monitored.
Introduction
LS-DYNA Implicit Workshop
Problem #2: Car Tire
Objective
* Learn to set up and run implicit dynamic and eigenvalue
analyses.
* Learn the advantages of implicit dynamic compared with
explicit dynamic analysis.
Problem Description
A coarsely meshed wheel and tire assembly is 'kicked' by a
brief transient load. The dynamic response of a node at the
top of the tire is monitored.
Input Filename: tire.k
Procedure
Copy the input file to your local directory. Using an editor,
view the input file and answer the following questions:
1. What loads and boundary conditions are applied to the tire?
Run the (explicit) simulation using the original input file.
Note the times below.
Copy the input deck to a new directory. Modify the input to run
an implicit eigenvalue analysis, computing the lowest 20
eigenvalues. Run the simulation and postprocess the results.
3. What is the lowest frequency? Hz
What is it period? sec.
Copy the input deck to a new directory. Modify the input to
run a linear implicit dynamic analysis. Increase the
termination time to 1.0 seconds and run the simulation.
Plot the Y-displacement of node ID 1000982 from the NODOUT
file, and compare with results from the explicit simulation.
5. Do the explicit and implicit results agree?
6. How much faster is the implicit simulation for this
(tiny) model?
7. How could results of the eigenvalue analysis be used to
select the time-step and output interval?
Copy the input deck to a new directory. Introduce some Newmark
damping (try GAMMA=0.60 and BETA=0.38). Run, plot the
Y-displacement of node ID 1000982 from the NODOUT file, and
compare with results from the previous simulations.
8. Does the damping most affect high or low frequency response?
Optional:
Copy the input deck to a new directory, and modify it to
perform a nonlinear implicit dynamic simulation. Reset the
termination time to 0.1 seconds and run the simulation.
Compare results for node ID 1000982.
Keywords
*BOUNDARY_SPC_SET
*CONTROL_IMPLICIT_DYNAMICS
*CONTROL_IMPLICIT_EIGENVALUE
*CONTROL_IMPLICIT_GENERAL
*CONTROL_IMPLICIT_SOLUTION
*CONTROL_IMPLICIT_SOLVER
*CONTROL_TERMINATION
*DATABASE_BINARY_D3PLOT
*DATABASE_HISTORY_NODE
*DATABASE_NODOUT
*DEFINE_CURVE
*ELEMENT_SHELL
*END
*KEYWORD
*LOAD_SEGMENT_SET
*MAT_ELASTIC
*MAT_RIGID
*NODE
*PART
*SECTION_SHELL
*SET_NODE_LIST
*SET_SEGMENT
*TITLE
*KEYWORD
*TITLE
dynamic tire kick
$
$----------------------------------------------
$
*CONTROL_TERMINATION
$# endtim endcyc dtmin endeng endmas
0.100000 0 0.0 0.0 0.0
$ 1.000000 0 0.0 0.0 0.0
$
$----------------------------------------------
$
*CONTROL_IMPLICIT_GENERAL
$# imflag dt0 imform nsbs igs cnstn form
0 0.001000
*CONTROL_IMPLICIT_DYNAMICS
$# imass gamma beta
1 0.0 0.0
$ 1 0.60 0.38
*CONTROL_IMPLICIT_EIGENVALUE
$# neig center lflag lftend rflag rhtend eigmth shfscl
0 0.0 0 0.0 0 0.0 0 0.0
*CONTROL_IMPLICIT_SOLUTION
$# nsolvr ilimit maxref dctol ectol rctol lstol
0 0 0 0.0 0.0 0.0 0.0
$# dnorm diverg istif nlprint nlnorm
0 0 0 0
$ 0 0 9999 0
$# arcctl arcdir arclen arcmth arcdmp
0 0 0.0
*CONTROL_IMPLICIT_SOLVER
$ lsolvr lprint negeig order drill dparm autospc aspctl
0 0 0 0 0 0 0 0
$ 6 1 0 0 0 0 0 0
$ lcpack kdump
0 0
$
$----------------------------------------------
$
*DATABASE_NODOUT
$# dt binary
0.001000
*DATABASE_BINARY_D3PLOT
$# dt lcdt beam npltc
0.100000
*DATABASE_HISTORY_NODE
$# id1 id2 id3 id4 id5 id6 id7 id8
1000982
$
$----------------------------------------------
$
*BOUNDARY_SPC_SET
$# nsid cid dofx dofy dofz dofrx dofry dofrz
522 0 1 1 1 1 1 1
*SET_NODE_LIST
$# sid da1 da2 da3 da4
522 0.0 0.0 0.0 0.0
$# nid1 nid2 nid3 nid4 nid5 nid6 nid7 nid8
1001284 1001299 1001300 1001285 1000973 1000975 1000908 1000909
1000893 1000894 1000895 1000896 1000911 1000910 1000979 1000977
1001301 1001302 1001286 1001287 1001303 1001288 1000981 1000912
1000897
$
$----------------------------------------------
$
*LOAD_SEGMENT_SET
$# ssid lcid sf at
99 99 0.001 0.0
*DEFINE_CURVE
$# lcid sidr sfa sfo offa offo dattyp
99 0 0.0 0.0 0.0 0.0
$# a1 o1
0.0 0.0
0.01000000 1.0
0.05000000 0.0
9.00000000 0.0
*SET_SEGMENT
$# sid da1 da2 da3 da4
99 0.0 0.0 0.0 0.0
$# n1 n2 n3 n4 a1 a2 a3 a4
1001246 1001261 1001262 1001247 0.0 0.0 0.0 0.0
1001231 1001246 1001247 1001232 0.0 0.0 0.0 0.0
1001216 1001231 1001232 1001217 0.0 0.0 0.0 0.0
1001215 1001230 1001231 1001216 0.0 0.0 0.0 0.0
1001214 1001229 1001230 1001215 0.0 0.0 0.0 0.0
1001229 1001244 1001245 1001230 0.0 0.0 0.0 0.0
1001244 1001259 1001260 1001245 0.0 0.0 0.0 0.0
1001245 1001260 1001261 1001246 0.0 0.0 0.0 0.0
1001230 1001245 1001246 1001231 0.0 0.0 0.0 0.0
$
$----------------------------------------------
$
*PART
$# title
tire
$# pid secid mid eosid hgid grav adpopt tmid
24001 24001 200092
*SECTION_SHELL
$# secid elform shrf nip propt qr/irid icomp setyp
24001 16 1.000000 2 0 0.0
$# t1 t2 t3 t4 nloc marea
4.000000 4.000000 4.000000 4.000000 0 0.0
*MAT_ELASTIC
$# mid ro e pr da db not used
2000929.1000e-10 50.000000 0.300000 0.0 0.0 0.0
$
$
*PART
$# title
wheel
$# pid secid mid eosid hgid grav adpopt tmid
24005 24005 200194
*SECTION_SHELL
$# secid elform shrf nip propt qr/irid icomp setyp
24005 2 1.000000 2 0 0.0
$# t1 t2 t3 t4 nloc marea
3.000000 3.000000 3.000000 3.000000 0 0.0
*MAT_RIGID
$# mid ro e pr n couple m alias
2001947.7999e-092.0000e+05 0.300000 0.0 0.0 0.0
$# cmo con1 con2
1.000000 0 0
$#lco or a1 a2 a3 v1 v2 v3
0.0 0.0 0.0 0.0 0.0 0.0
$
$
*PART
$# title
belt
$# pid secid mid eosid hgid grav adpopt tmid
24011 24003 200089
*SECTION_SHELL
$# secid elform shrf nip propt qr/irid icomp setyp
24003 16 1.000000 2 0 0.0
$# t1 t2 t3 t4 nloc marea
2.250000 2.250000 2.250000 2.250000 0 0.0
*MAT_ELASTIC
$# mid ro e pr da db not used
2000897.8299e-092.0684e+05 0.280000 0.0 0.0 0.0
$
$----------------------------------------------
$
*ELEMENT_SHELL
$# eid pid n1 n2 n3 n4
*END
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