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/LEAK/MAT

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/LEAK/MAT - Leakage option for Airbag Porous Fabric Materials

Description

Specifies effective leakage area of porous airbag fabric materials LAW19 and LAW58 as function of time, pressure, area and other parameters.

Format

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/LEAK/MAT/mat_ID/unit_ID

mat_title

Ileakage

 

AscaleT

AscaleP

 

 

 

 

 

Define leakage for area in contact

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AC'

fct_IDAC'

 

FscaleAC'

 

 

 

 

 

Insert if Ileakage =1

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LC

AC

 

 

 

 

 

 

 

Insert if Ileakage =2, 3 or 4

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fct_IDLC

fct_IDAC

FscaleLC

FscaleAC

 

 

 

 

 

Insert if Ileakage =5

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L

R

 

 

 

 

 

 

C1

C2

C3

 

 

 

 

 

Insert if Ileakage =6

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X0

X1

X2

X3

 

 
hmtoggle_plus1Flag Definition

Field

Contents

SI Unit Example

mat_ID

Material identifier

(Integer, maximum 10 digits)

 

unit_ID

Optional unit identifier

(Integer, maximum 10 digits)

 

mat_title

Material title

(Character, maximum 100 characters)

 

Ileakage

Effective leakage area formulation flag

(Integer)

= 0: No leakage

= 1, 2, 3, 4: see Comment 2

= 5: Fabric leakage model

= 6: Anagonye and Wang leakage model

 

AscaleT

Abscissa time scale factor on function

Default = 1  (Real)

 

AscaleP

Abscissa pressure scale factor on function

Default = 1  (Real)

 

AC'

Area coefficient for area in contact 0 < AC' < 1

Default = 0  (Real)

 

fct_IDAC'

Area coefficient function identifier AC’(t) if AC’ is equal to 0

(Integer)

 

FscaleAC'

Scale factor on function AC’

Default=1  (Real)

 

LC

Leakage coefficient

Default function is 0  (Real)

 

AC

Area coefficient

Default = 0  (Real)

 

fct_IDLC

Leakage coefficient function identifier LC(t), if Ileakage =2 or 3

Leakage coefficient function identifier LC(Area/Area0), if Ileakage =4

Default function is 0  (Integer)

 

FscaleLC

Scale factor on function LC

Default = 1  (Real)

 

fct_IDAC

Area coefficient function identifier AC(P), if Ileakage =2

Area coefficient function identifier AC(P-Pext), if Ileakage =3

Area coefficient function identifier AC(Pext/P), if Ileakage =4

Default function is 0  (Integer)

 

FscaleAC

Scale factor on function AC

Default = 1  (Real)

 

L

Characteristic length

Default = 1  (Real)

symbol_m

R

Fiber thickness

Default = L (Real)

symbol_m

C1

Coefficient C1

(Real)

 

C2

Coefficient C2

Default = 1 (Real)

 

C3

Coefficient C3

(Real)

 

X0, X1, X2, X3

Coefficients of Anagonye-Wang leakage area law

(Real)

 
hmtoggle_plus1Comments
1.The mat_ID must be the same as law type 19 or law type 58. Material porosity is active only when corresponding components are reffered as external surfaces in /MONVOL/AIRBAG1, /MONVOL/COMMU1, and /MONVOL/FVMBAG1 airbag cards.
2.Effective leakage area (Aeff) formulation:

Ileakage =1:

leak_mat1

Ileakage =2:

leak_mat2

Ileakage =3:

leak_mat3

Ileakage =4:

leak_mat4

where, Area0 is initial area of the airbag surface. Note that by default all coefficients and functions are zero.

Ileakage =5:

leak_mat5

symbol_triP = P/Pext - 1,

Where, symbol_exp1 and symbol_exp2 are the stretches in warp and weft directions and symbol_a_1412 is the angle between warp and weft directions.

Note: For law19 symbol_a_1412 = 90 degrees

Ileakage =6:

leak_mat6

with rs = Arean / Area0  and rp = Pext / P

3.Blockage of airbag fabric, due to contact, can be activated in corresponding /MONVOL card. Effective leakage area is calculated with account of the blockage as:

Arean = Areanon-impacted + AC' * Areaimpacted