MONVOL

Bulk Data Entry Defines a one-chamber gas filled structure with hybrid input of inflated gas.

Attention: Valid for Explicit Analysis only

Format

(1)	(2)	(3)	(4)
MONVOL	`MID`		`UNIT`
	`SURF`	`SID`
	`AMBIENT`	`PATM`	`TATM`

Optional continuation line to define properties of the initial gas inside the structure.

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
	`IAIR`	`PAIR`	`TAIR`
		`XMAIR`	`Cpa_air`	`Cpb_air`	`Cpc_air`	`Cpd_air`	`Cpe_air`

Optional continuation line to define a vent hole. It can be repeated as required.

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
+	`VENT`	`SIDV`	`C23`	`LCTC23`	`LCPC23`	`PDEF`

Optional continuation line to define properties of the injected gas. It can be repeated as required.

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
+	`MATGAS`	`LCM`	`LCT`
		`XM`	$C p a$	$C p b$	$C p c$	$C p d$	$C p e$

Example

(1)	(2)	(3)	(4)	(5)	(6)
MONVOL	1
	`SURF`	10
	`AMBIENT`	1.013E5	293.0
	`MATGAS`	3	4
		0.004	40.0	0.0	0.0
	`IAIR`	1.013E5	293.0
		0.028	28.0	0.0	0.0

Description

Field	Contents	SI Unit Example
`MID`	Monitor volume identification number. No default (Integer > 0)
`UNIT`	Unit system. 0 (Default) kg-mm-ms-K 1 kg-m-s-K (SI units) 2 ton-mm-s-K
`SURF`	Flag to indicate the external surface of enclosed volume.
`SID`	External surface identification defined by a set of elements. No default (Integer > 0)
`ATM`	Flag to indicate that the two following fields define atmospheric pressure and temperature.
`TATM`	Ambient temperature. Default=293 K (Real ≥ 0.0)
`PATM`	Ambient pressure. Default=1 atm (Real ≥ 0.0)
`VENT`	Flag to indicate that the following five fields indicate the vent hole properties.
`SIDV`	Vent hole area surface identification number. No default (Integer > 0)
`C23`	Scale factor on vent hole area. Default=1.0 (Real > 0.0)
`LCTC23`	Curve defining vent hole coefficient as a function of time. No default (Integer > 0)
`LCPC23`	Curve defining vent hole coefficient as a function of pressure. No default (Integer > 0)
`PDEF`	Pressure difference between interior and ambient pressure to open vent hole. Default=0.0
`MATGAS`	Flag to indicate that the following four fields define the inflated gas properties.
`LCM`	Table that defines mass flow rate curve for the gas component.
`LCT`	Table that defines temperature curve for the gas component.
`XM`	Molar mass of the gas component.
`Cpa`, `Cpb`, `Cpc`, `Cpd`, `Cpe`	Molar heat capacity coefficients of the inflow gas at constant pressure. 4
`IAIR`	Flag to indicate that the following four fields define properties of the initial gas inside the structure.
`PAIR`	Initial pressure inside structure. Default=PATM (Real ≥ 0.0)
`TAIR`	Initial temperature inside structure. Default=TATM (Real ≥ 0.0)
`XMAIR`	Molar mass of air initially inside structure. No default (Real ≥ 0.0)
`Cpa_air`, `Cpb_air`, `Cpc_air`, `Cpd_air`, `Cpe_air`	Molar heat capacity coefficients of the initial air at constant pressure. 4 No default (Real ≥ 0.0)

Comments

The volume must be a completely enclosed volume and the norm must be oriented outwards. If the structure contains a vent hole, the vent hole must be meshed with a shell element.
The value of the total vent hole coefficient must be between 0.0 and 1.0:(1)
Total vent hole coefficient = min(max(C23 × LCTC23 × LCPC23, 0.0), 1.0).
There is no limit on the number of gas components.
Heat capacity at constant pressure:(2)
$C p = C p a + C p b T + C p c T^{2} + C p d T^{3} + \frac{C p e}{T}$

Where, $T$ is temperature.
Support information for MONVOL:

Supported Analysis Types

Explicit Dynamic Analysis