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An airbag inflates below a rigid cylinder, causing the cylinder to fly into the air.
Introduction
*AIRBAG_SIMPLE_AIRBAG_MODEL
Airbag Deploys into Cylinder
LS-DYNA Manual Section: *AIRBAG_SIMPLE_AIRBAG_MODEL
Additional Sections:
*CONTACT_NODES_TO_SURFACE
*RIGIDWALL_PLANAR
Example: Airbag Deploys into Cylinder
Filename: airbag.deploy.k
Description:
An airbag inflates below a rigid cylinder, causing the cylinder to fly
into the air.
Model:
The volume pressure relationships is defined by the Simple Airbag Model
for control volumes.
The bag inflates through the flow of mass into the bag.
Input:
The control volume defines the thermodynamic relationship for the gas in
terms of parameters such as heat capacity, gas temperature, incoming mass,
and out going mass (*AIRBAG_SIMPLE_AIRBAG_MODEL). A rigidwall is used below
the airbag to act as ground (*RIGIDWALL_PLANAR). A ground is displayed using
rigid shell elements, but is used only for visualization purposes. The contact
between the airbag and the cylinder is automatically generated by part id
(*CONTACT_NODES_TO_SURFACE).
Results:
The plots show the bag expanding. The ASCII file abstat contains information
on the computed pressure, volume, mass flow and internal energy of the control
volume (*DATABASE_ABSTAT).
Keywords
*AIRBAG_SIMPLE_AIRBAG_MODEL
*CONTACT_NODES_TO_SURFACE
*CONTROL_ENERGY
*CONTROL_OUTPUT
*CONTROL_TERMINATION
*DATABASE_ABSTAT
*DATABASE_BINARY_D3PLOT
*DATABASE_BINARY_D3THDT
*DATABASE_EXTENT_BINARY
*DATABASE_GLSTAT
*DATABASE_MATSUM
*DATABASE_RBDOUT
*DATABASE_RCFORC
*DATABASE_RWFORC
*DEFINE_CURVE
*ELEMENT_SHELL
*END
*KEYWORD
*MAT_FABRIC
*MAT_RIGID
*NODE
*PART
*RIGIDWALL_PLANAR
*SECTION_SHELL
*SET_PART_LIST
*TITLE
*KEYWORD
*TITLE
Airbag and Structure
$
$ LSTC Example
$
$ Last Modified: August 29, 1997
$
$ Airbag with a cylinder on top, deploys and pushes the cylinder into the air.
$
$ Airbag is approximately 19 x 25 inches, with 0.015 in thickness
$
$
$ Units: lbf-s^2/in, in, s, lbf, psi, lbf-in
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$$$$ Control Ouput
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
$
*CONTROL_TERMINATION
$ endtim endcyc dtmin endneg endmas
3.000E-02
$
*CONTROL_ENERGY
$ hgen rwen slnten rylen
2 2 2
$
*CONTROL_OUTPUT
$ npopt neecho nrefup iaccop opifs ipnint ikedit
1 3
$
*DATABASE_BINARY_D3PLOT
$ dt lcdt
5.000E-04
$
*DATABASE_EXTENT_BINARY
$ neiph neips maxint strflg sigflg epsflg rltflg engflg
$ cmpflg ieverp beamip
1
$
*DATABASE_BINARY_D3THDT
$ dt lcdt
999999
$
$
*DATABASE_ABSTAT
$ dt
2.000E-04
$
*DATABASE_GLSTAT
$ dt
2.000E-04
$
$
*DATABASE_MATSUM
$ dt
2.000E-04
$
*DATABASE_RCFORC
$ dt
2.000E-04
$
*DATABASE_RBDOUT
$ dt
2.000E-04
$
*DATABASE_RWFORC
$ dt
2.000E-04
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$$$$ Airbag
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
$
*AIRBAG_SIMPLE_AIRBAG_MODEL
$ sid sidtyp rbid vsca psca vini mwd spsf
1 1
$
$ cv cp t lcid mu a pe ro
1.736E+03 2.430E+03 1.200E+03 1 7.000E-01 0.000E+00 1.470E+01 3.821E-06
$
$ lou
$
*SET_PART_LIST
$ sid da1 da2 da3 da4
1
$
$ pid1 pid2 pid3 pid4 pid5 pid6 pid7 pid8
3
$
*DEFINE_CURVE
$ lcid sidr scla sclo offa offo
1
$
$ abscissa ordinate
0.000E+00 0.000E+00
3.200E-02 2.600E+01
4.500E-02 6.000E-01
8.000E-02 1.000E-01
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$$$$ Rigid Walls
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$$$$ Ground
$
*RIGIDWALL_PLANAR
$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
$ nsid nsidex boxid
0 0 0
$ xt yt zt xh yh zh fric
0.0 0.0 0.0 0.0 1.0 0.0 0.5
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$$$$ Define Contacts - Sliding Interfaces
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
$
$$$$ Contact between the airbag and the cylinder.
$
*CONTACT_NODES_TO_SURFACE
$
$ ssid msid sstyp mstyp sboxid mboxid spr mpr
3 2 3 3 1 1
$
$ fs fd dc vc vdc penchk bt dt
0.5 0.5
$
$ sfs sfm sst mst sfst sfmt fsf vsf
1.0000 0.06667
$
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$$$$ Define Parts and Materials
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
*PART
Plate - Rigid - Fixed (for viewing)
$ pid sid mid eosid hgid adpopt
1 1 1 0 0 0
$
*PART
Cylinder - Rigid
$ pid sid mid eosid hgid adpopt
2 1 2 0 0 0
$
*PART
Airbag - Fabric
$ pid sid mid eosid hgid adpopt
3 2 3 0 0 0
$
$
$$$$$$ Materials
$
$
*MAT_RIGID
$ mid ro e pr n couple m alias
1 7.84e-4 30.00e+6 0.30
$
$ cmo con1 con2
1 7 7
$
$ lco/a1 a2 a3 v1 v2 v3
$
$
*MAT_RIGID
$ mid ro e pr n couple m alias
2 1.96e-4 30.00e+6 0.30
$
$ cmo con1 con2
$
$ lco/a1 a2 a3 v1 v2 v3
$
$
*MAT_FABRIC
$ mid ro ea eb ec prba prca prcb
3 1.00e-4 2.00e+6 2.00e+6 2.00e+6 0.35 0.35 0.35
$
$ gab gbc gca gse el prl lratio damp
1.53e+6 1.53e+6 1.53e+6
$
$ aopt
$
$ xp yp zp a1 a2 a3
$
$ v1 v2 v3 d1 d2 d3
$
$$$$$$ Sections
$
*SECTION_SHELL
$ sid elform shrf nip propt qr/irid icomp
1 0
$
$ t1 t2 t3 t4 nloc
0.500 0.500 0.500 0.500
$
$
*SECTION_SHELL
$ sid elform shrf nip propt qr/irid icomp
2 9 4 1
$
$ t1 t2 t3 t4 nloc
0.015 0.015 0.015 0.015
$
$ b1 b2 b3 b4 b5 b6 b7 b8
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$$$$ Define Nodes and Elements
$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
$ nid x y z tc rc
$
*END
Animated Result
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