Gravity
A simple model of a tire is placed under gravity loaded and bounces on a rigid wall.
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Gravity
A simple model of a tire is placed under gravity loaded and bounces on a rigid wall.
*LOAD_BODY_Z Tire Under Gravity Loading Bounces on a Rigid Wall LS-DYNA Manual Section: *LOAD_BODY_Z Additional Sections: *RIGIDWALL_PLANAR Example: Tire Under Gravity Loading Bounces on a Rigid Wall Filename: load_body.gravity.k Description: A simple model of a tire is placed under gravity loaded and bounces on a rigid wall. Model: A positive gravity constant of 0.00981 mm/ms 2 is used to make the tire drop in the negative z-direction. A *RIGIDWALL_PLANAR keyword is used to define the ground. Nodes on the bottom of the tire are prevented from penetrating the rigid wall by specifying them within the *RIGIDWALL_PLANAR command (using a *SET_NODE_COLUMN keyword). Results: The rigid wall forces oscillate about the steady state, which is the weight of the tire (W = 0.26 kN). Curiously, the tire damps out even though no damping is specified within the model. See the example in *DAMPING_GLOBAL for an explanation and fix.
$ * 2 discrete masses (10 kg each) at center of wheel to obtain proper weight $ * Gap between tire and ground = 0.2 mm $ * Mild steel (with strain rate effect) $ * Part 35 - wheel $ * Part 36 - tire $ * Shells (1 mm thick) *CONTROL_ENERGY *CONTROL_TERMINATION *DATABASE_BINARY_D3PLOT *DATABASE_BINARY_D3THDT *DATABASE_GLSTAT *DATABASE_HISTORY_NODE *DATABASE_MATSUM *DATABASE_NODOUT *DATABASE_RWFORC *DEFINE_CURVE *ELEMENT_MASS *ELEMENT_SHELL *END *KEYWORD *LOAD_BODY_Z *MAT_PIECEWISE_LINEAR_PLASTICITY *NODE *PART *RIGIDWALL_PLANAR *SECTION_SHELL *SET_NODE_COLUMN *TITLE
*KEYWORD
*TITLE
A simple tire bouncing on the ground.
$
$ LSTC Example
$
$ Last Modified: October 10, 1997
$
$ --- GRAVITY CHECK ---
$
$ steady state is reached around 150 ms
$ m = 26.5534 kg ==> W = 0.26 kN
$ Damping oscillations around s.s., which is 0.26 kN (from RWFORC file)
$ Nodes demonstrate bouncing off ground (NODOUT)
$
$ Gravity modeled successfully using load curve and
$ BASE ACCELERATION IN Z-DIRECTION - Body Load in Z
$
$ Note: The acceleration is in the negative z-direction even though
$ all values needed to define acc. are positive.
$
$ * Shells (1 mm thick)
$ * Mild steel (with strain rate effect)
$ * Part 35 - wheel
$ * Part 36 - tire
$ * 2 discrete masses (10 kg each) at center of wheel to obtain proper weight
$ * Gap between tire and ground = 0.2 mm
$
$ Units: mm, kg, ms, kN, GPa, kN-mm
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
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$$$$ Control Ouput
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$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
$
*CONTROL_TERMINATION
$ endtim endcyc dtmin endeng endmas
150.01 0 0.0 0.0 0.0
$
*CONTROL_ENERGY
$ hgen rwen slnten rylen
2 2
$
$
*DATABASE_BINARY_D3PLOT
$ dt lcdt
10.0
$
*DATABASE_BINARY_D3THDT
$ dt lcdt
999999
$
*DATABASE_GLSTAT
$ dt
0.2
$
*DATABASE_MATSUM
$ dt
0.2
$
*DATABASE_NODOUT
$ dt
0.2
$
*DATABASE_HISTORY_NODE
$ id1 id2 id3 id4 id5 id6 id7 id8
8914 8746 8918
$
*DATABASE_RWFORC
$ dt
0.2
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
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$$$$ Gravity
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$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
$
*LOAD_BODY_Z
$
$ lcid df lciddr xc yc zc
1 9.810E-03
$
$
*DEFINE_CURVE
$
$ lcid sidr scla sclo offa offo
1
$
$ abscissa ordinate
0.00 1.000
1000.00 1.000
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$$$$ Rigid Wall - The Ground
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$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
$
*RIGIDWALL_PLANAR
$ nsid nsidex boxid
1 0 0
$ xt yt zt xh yh zh fric
0.0 0.0 -279.2 0.0 0.0 -279.0 1.0
$
$
*SET_NODE_COLUMN
$ sid
1
$ nid
8901
8904
8911
8912
8913
8914
8919
8920
8921
8922
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
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$$$$ Define Parts and Materials
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$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
$
*PART
$ pid sid mid eosid hgid grav adpopt
wheel
35 1 1
tire
36 1 1
$
$
$$$$ Materials
$
*MAT_PIECEWISE_LINEAR_PLASTICITY
$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
$ mid ro e pr sigy etan eppf tdel
1 0.783E-05 200.0 0.3 0.207 0.750
$ Cowper/Symonds Strain Rate Parameters
$ C p lcss lcsr
40 5
$ Plastic stress/strain curves
0.000 0.080 0.160 0.400 1.000
0.207 0.250 0.275 0.290 0.300
$
$
$$$$ Sections
$
*SECTION_SHELL
$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
$ sid elform shrf nip propt qr/irid icomp
1 2 3.0000
$ t1 t2 t3 t4 nloc
1.00 1.00 1.00 1.00
$
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$$$$ Define Nodes and Elements
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$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
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$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
$
$
$$$$$$$ Nodal Mass Elements
$
*ELEMENT_MASS
$ eid nid mass
8730 8730 10.0
8746 8746 10.0
$
*END