INFLATOR_CHAR

Parent

FE_MODEL

MADYMO

SYSTEM.MODEL

SYSTEM.REF_SPACE

Description

Inflator characteristic.

Attributes

AttributeTypeDefaultUnitDescription
IDInt  Numerical identifier
NAMEName  Alphanumerical identifier[1]
OUTFLOW_TYPEStringSONIC Type of inflator flow model[2]
MASS_FLOW_RATE_FUNCRef  Ref to FUNCTION.CONTROL_SIGNAL | FUNCTION.XY. Mass flow rate function – mass flow rate [kg/s] vs. time [s][3][4]
TEMP_FUNCRef  Ref to FUNCTION.CONTROL_SIGNAL | FUNCTION.XY. Inflator exit temperature function – temperature [K] vs. time [s][3][5][6]
EXIT_PRES_FUNCRef  Ref to FUNCTION.CONTROL_SIGNAL | FUNCTION.XY. Inflator exit pressure function ‐ pressure [N/m2] vs. time [s][3][6][7]
POLYTROPIC_CONSTANTReal1.0 Polytropic constant[8]
Notes:
1. The total length of a full path of a NAME attribute (including ID and NAME and strings generated by madymo) may not exceed 256 characters.
2. Domain: [SONIC | VARIABLE].
3. The following combinations of functions are valid (combinations indicated per row):


4. The mass flow rate stops at the last time point specified after triggering of inflator. So, no extrapolation will take place.
5. The function defines the gas temperature in the inflator exit plane.
6. When used in an Uniform Pressure simulation the following applies: For POLYTROPIC_CONSTANT >1 the EXIT_PRES_FUNC must be defined to calculate the supply temperature Ts (see Table above). In the limit of isothermal expansion (POLYTROPIC_CONSTANT = 1) the supply temperature Ts is identical to the gas temperature in the inflator exit plane Texit given by TEMP_FUNC. In case of isothermal expansion and SONIC specified as OUTFLOW_TYPE, EXIT_PRES_FUNC can be omitted.
7. The function defines the gas pressure in the inflator exit plane.
8. Applicable only to Uniform Pressure method. The valid range is 1 ≤ POLYTROPIC_CONSTANT ≤ γ with γ representing the ratio of the constant pressure heat capacity Cp and the constant volume heat capacity Cv of the inflator gas mixture. The limiting values of 1 and γ represent isothermal and isentropic expansion, respectively.

Related Elements

Related ElementsOne/ManyDescription
GAS_MIXTURE.CONSTANTOneGas mixture with a fixed composition.
GAS_MIXTURE.VARIABLEManyGas mixture at a fixed time after inflator triggering.
GASManySpecify a gas (molecular weight and specific heat coefficients).
FUNCTION.*ManyFunction.
FUNC_USAGE.2DManyUsed to select interpolation type for X-Y function descriptions, or to modify function data by shifting and/or scaling.

Examples

INFLATOR_CHAR can be defined under MADYMO, SYSTEM or FE_MODEL and contains all inflator characteristics, except switches and jets.
Note that GAS and FUNCTION can be defined on multiple levels. When defined as children of either the parent of INFLATOR_CHAR or INFLATOR_CHAR itself, the reference can be without a path.

<MADYMO>
   <INFLATOR_CHAR
      ...
   />
   <SYSTEM.REF_SPACE>
      <INFLATOR_CHAR
         ...
      />
      <FE_MODEL>
         <INFLATOR_CHAR
            ID = "1"
            NAME = "InflatorChar_SupplierA_ichr"
            MASS_FLOW_RATE_FUNC = "MassFlow_func"
            TEMP_FUNC = "Temp_func"
            >
            <GAS_MIXTURE.CONSTANT>
               <GAS_FRACTION 
                  GAS_NAME = "AR_SupplierA_gas"
                  MOL_FRACTION = "0.8"
               />
                <GAS_FRACTION 
                  GAS_NAME = "HE_OemX_gas"
                  MOL_FRACTION = "0.2"
               />
            </GAS_MIXTURE.CONSTANT>
            <GAS
               ID   = "2"
               NAME = "AR_SupplierA_gas"
               MW   = "0.03995"
               CP_A = "25.79"
               ...
               >
            </GAS
            <FUNCTION.XY
               ID   = "2"
               NAME = "Temp_func"
               >
            ...
            </FUNCTION.XY>
         </INFLATOR_CHAR>

         <GAS
            ID = "1"
            NAME = "HE_OemX_gas"
            MW = "0.0040"
            CP_A = "20.785"
            ...
            >
         </GAS
         <FUNCTION.XY
            ID   = "1"
            NAME = "MassFlow_func"
            >
         ...
         </FUNCTION.XY>
      </FE_MODEL>
   </SYSTEM.REF_SPACE>
</MADYMO>