*AIRBAG_PARTICLE

LS-DYNA Input Interface KeywordDefines a Finite Volume Method airbag.

Format


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*AIRBAG_PARTICLE_{OPTION}

If OPTION = ID, insert the following line


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`monvol_ID`	`Title`


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`surf_ID`_ex	`Surf_type_ex`	`surf_ID`_in	`Surf_type_in`
			`Text`	`P`_ext	`Nvent`	`Tswitch`
`Iair`	`Ngas`	`Ninj`

Add Nvent cards for each vent


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`surf_ID`_v	`Surf_type_v`	`Avent`	`FUNCT_ID`	`FUNCP_ID`

If Iair > 0, add the card


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`Pair`	`Tair`	`Mw_air`	`A_air`	`B_air`	`C_air`

Add Ngas cards for definition of multi-component gas injection


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`FM_ID (I)`	`FT_ID (I)`	`Mw (I)`	`A (I)`	`B (I)`	`C (I)`

Add Ninj cards for definition of injection holes through shell elements on external surface


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`EID (I)`		`VID (I)`

Definition


Field	Contents	SI Unit Example
`OPTION`	ID
`monvol_ID`	Airbag identifier. (Integer)
`Title`	Title. (Character)
`surf_ID`_ex	Airbag external surface identifier. (Integer)
`Surf_type_ex`	External set type. = 0 (Default) The `surf_ID`_ex is a segment set. ≠ 0 The `surf_ID`_ex is a set of parts. (Integer)
`surf_ID`_in	Airbag internal surface identifier. (Integer)
`Surf_type_in`	Internal set type. = 0 (Default) The `surf_ID`_in is a segment set. ≠ 0 The `surf_ID`_in is a set of parts. (Integer)
`Text`	External temperature. Default = 295 K (Real)	$[K]$
`P`_ext	External pressure. (Real)	$[Pa]$
`Nvent`	Number of vent holes. (Integer)
`Tswitch`	Time to switch from finite volume airbag to uniform pressure airbag. (Real)	$[s]$
`Iair`	Material definition for external air. = 0 (Default) Predefined material for air created. > 0 Air material is created according to the airbag card input. (Integer)
`Ngas`	Number of injected gas components. (Integer)
`Ninj`	Number of injection holes. (Integer)
`surf_ID`_v	Airbag vent surface identifier. (Integer)
`Surf_type_v`	Surface set type. = 0 (Default) The `surf_ID`_v is a part ID. ≠ 0 The `surf_ID`_v is a set of parts. (Integer)
`Avent`	Scaling coefficient for vent area. Default = 1 (Real)
`FUNCT_ID`	Function identifier for vent area scaling coefficient as function of time. (Integer)
`FUNCP_ID`	Function identifier for vent area scaling coefficient as function of overpressure. (Integer)
`Pair`	External pressure (overwrites `P`_ext). Default = `P`_ext (Real)	$[Pa]$
`Tair`	External temperature (overwrites `Text`). Default = `Text` (Real)	$[K]$
`MW_air`	Molar molecular weight of air. (Real)
`A_air`	Constant head capacity parameter for air. (Real)	$[\frac{J}{mole}]$
`B_air`	Linear head capacity parameter for air. (Real)	$[\frac{J}{mole .K}]$
`C_air`	Quadratic head capacity parameter for air. (Real)	$[\frac{J}{m o l e \cdot K^{2}}]$
`FM_ID (I)`	Function identifier of gas component mass flow as function of time. (Integer)
`FT_ID (I)`	Function identifier of gas component temperature as function of time. (Integer)
`MW (I)`	Molar molecular weight of gas component. (Real)
`A (I)`	Constant head capacity parameter for gas component. (Real)	$[\frac{J}{mole}]$
`B (I)`	Linear head capacity parameter for gas component. (Real)	$[\frac{J}{mole .K}]$
`C (I)`	Quadratic head capacity parameter for gas component. (Real)	$[\frac{J}{m o l e \cdot K^{2}}]$
`EID (I)`	Shell element number defining position of injector. (Integer)	$[\frac{J}{kg \cdot K}]$
`VID (I)`	Initial direction of gas inflow at nozzle. = -1 (Default) Direction of gas inflow is in shell normal direction. = -2 Direction of gas inflow is reversed relative to shell normal. (Integer)	$[\frac{J}{kg \cdot K}]$

Comments

This keyword maps to /MONVOL/FVMBAG2, /MAT/GAS, and /PROP/INJECT1.
External surfaces of airbag should form a closed volume.
Airbag external and internal surfaces should not have any intersections.
Injector holes are defined by shell elements on external surfaces.