A simple model of a tire is placed under gravity loading and drops onto rigid solid elements. Fully integrated shell elements are used for the tire to prevent hourglassing from damping out the model. Additionally, rigid solid elements are used for modeling the ground instead of a rigidwall because the rigidwall will also damp the system because of its perfectly plastic contact definition. Thus, to damp out the bouncing, global damping is applied to the system.
*DAMPING_GLOBAL Tire Bounces on the Ground and Damps Out LS-DYNA Manual Section: *DAMPING_GLOBAL Additional Sections: *CONTROL_DAMPING *LOAD_BODY_Z Example: Tire Bounces on the Ground and Damps Out Filename: damping.tire.k Description: A simple model of a tire is placed under gravity loading and drops onto rigid solid elements. Fully integrated shell elements are used for the tire to prevent hourglassing from damping out the model. Additionally, rigid solid elements are used for modeling the ground instead of a rigidwall because the rigidwall will also damp the system because of its perfectly plastic contact definition. Thus, to damp out the bouncing, global damping is applied to the system. Model: Global damping of 0.5 is applied to the system using the *DAMPING_GLOBAL keyword. Contact between the tire and ground is defined using node to surface contact. Gravity is applied with the *LOAD_BODY_Z command. Results: The total energy of the system comes from the external energy of gravity (potential energy of "mgh"). This energy is absorbed by the damping in the model.
*CONTACT_NODES_TO_SURFACE *CONTROL_DYNAMIC_RELAXATION *CONTROL_ENERGY *CONTROL_OUTPUT *CONTROL_TERMINATION *DAMPING_GLOBAL *DATABASE_BINARY_D3PLOT *DATABASE_BINARY_D3THDT *DATABASE_GLSTAT *DATABASE_HISTORY_NODE *DATABASE_MATSUM *DATABASE_NODOUT *DATABASE_RCFORC *DATABASE_RWFORC *DEFINE_CURVE *ELEMENT_MASS *ELEMENT_SHELL *ELEMENT_SOLID *END *KEYWORD *LOAD_BODY_Z *MAT_PIECEWISE_LINEAR_PLASTICITY *MAT_RIGID *NODE *PART *SECTION_SHELL *SECTION_SOLID *TITLE
*KEYWORD
*TITLE
A simple tire bouncing on the ground with damping.
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$ LSTC Example
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$ Last Modified: October 13, 1997
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$ Units: mm, kg, ms, kN, GPa, kN-mm
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$$$$ Control Ouput
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$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
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*CONTROL_TERMINATION
$ endtim endcyc dtmin endeng endmas
40.01
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*CONTROL_ENERGY
$ hgen rwen slnten rylen
2 2 2 2
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*CONTROL_OUTPUT
$ npopt neecho nrefup iaccop opifs ipnint ikedit
1 3
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*DATABASE_BINARY_D3PLOT
$ dt lcdt
10.0
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*DATABASE_BINARY_D3THDT
$ dt lcdt
999999
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*DATABASE_GLSTAT
$ dt
0.1
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*DATABASE_MATSUM
$ dt
0.1
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*DATABASE_NODOUT
$ dt
0.1
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*DATABASE_HISTORY_NODE
$ id1 id2 id3 id4 id5 id6 id7 id8
8914 8746 8918
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*DATABASE_RCFORC
$ dt
0.1
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*DATABASE_RWFORC
$ dt
0.1
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$$$$ Damping
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*DAMPING_GLOBAL
$ lcid valdmp
0 0.5
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*CONTROL_DYNAMIC_RELAXATION
$ nrcyck drtol drfctr drterm tssfdr irelal edttl idrflg
100 1.0e-3 0.995 0.9
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$$$$ Gravity
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$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
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*LOAD_BODY_Z
$ lcid df lciddr xc yc zc
1 9.810E-03
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*DEFINE_CURVE
$ lcid sidr scla sclo offa offo
1
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$ abscissa ordinate
0.00 1.000
1000.00 1.000
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$$$$ Define Contacts - sliding interface definitions
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$$$$ Prevent the nodes of the tire from penetrating the ground.
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*CONTACT_NODES_TO_SURFACE
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$ ssid msid sstyp mstyp sboxid mboxid spr mpr
36 76 3 3
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$ fs fd dc vc vdc penchk bt dt
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$ sfs sfm sst mst sfst sfmt fsf vsf
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$$$$ Define Parts and Materials
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$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
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*PART
$ pid sid mid eosid hgid grav adpopt
wheel
35 1 1
tire
36 1 1
ground
76 76 2
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$$$$ Materials
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*MAT_PIECEWISE_LINEAR_PLASTICITY
$ mid ro e pr sigy etan eppf tdel
1 0.783E-05 200.0 0.3 0.207 0.750
$ Cowper/Symonds Strain Rate Parameters
$ C p lcss lcsr
40 5
$ Plastic stress/strain curves
0.000 0.080 0.160 0.400 1.000
0.207 0.250 0.275 0.290 0.300
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*MAT_RIGID
$ mid ro e pr n couple m alias
2 0.783E-05 200.0 0.3
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$ cmo con1 con2
1.0 7 7
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$ lco/a1 a2 a3 v1 v2 v3
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$$$$ Sections
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*SECTION_SHELL
$ sid elform shrf nip propt qr/irid icomp
1 6 3.0000
$ t1 t2 t3 t4 nloc
1.00 1.00 1.00 1.00
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*SECTION_SOLID
76 1
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$$$$ Define Nodes and Elements
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*END
