/LEAK/MAT

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

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/LEAK/MAT/mat_ID/unit_ID
mat_title
Ileakage   AscaleT AscaleP        
Define leakage for area in contact
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
AC' fct_IDAC'   FscaleAC'        
Insert if Ileakage =1
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
LC AC            
Insert if Ileakage =2, 3 or 4
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
fct_IDLC fct_IDAC FscaleLC FscaleAC        
Insert if Ileakage =5
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
L R            
C1 C2 C3        
Insert if Ileakage =6
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
X0 X1 X2 X3    

Definitions

Field Contents SI Unit Example
mat_ID Material identifier

(Integer, maximum 10 digits)

 
unit_ID Unit Identifier

(Integer, maximum 10 digits)

 
mat_title Material title

(Character, maximum 100 characters)

 
Ileakage Effective leakage area formulation flag.
= 0
No leakage
= 1, 2, 3, 4
2
= 5
Fabric leakage model
= 6
Anagonye and Wang leakage model

(Integer)

 
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 A C ' 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 L C ( A r e a / A r e a 0 ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamitaiaado eadaqadaqaaiaadgeacaWGYbGaamyzaiaadggacaGGVaGaamyqaiaa dkhacaWGLbGaamyyamaaBaaaleaacaaIWaaabeaaaOGaayjkaiaawM caaaaa@41D5@ , if Ileakage =4

Default function is 0 (Integer)

 
FscaleLC Scale factor on function LC

Default = 1 (Real)

 
fct_IDAC Area coefficient function identifier A C ( P ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyqaiaado eadaqadaqaaiaadcfaaiaawIcacaGLPaaaaaa@39E2@ , if Ileakage =2.

Area coefficient function identifier A C ( P P e x t ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyqaiaado eadaqadaqaaiaadcfacqGHsislcaWGqbWaaSbaaSqaaiaadwgacaWG 4bGaamiDaaqabaaakiaawIcacaGLPaaaaaa@3EBA@ , if Ileakage =3.

Area coefficient function identifier A C ( P e x t / P ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyqaiaado eadaqadaqaaiaadcfadaWgaaWcbaGaamyzaiaadIhacaWG0baabeaa kiaac+cacaWGqbaacaGLOaGaayzkaaaaaa@3E80@ , if Ileakage =4.

Default function is 0 (Integer)

 
FscaleAC Scale factor on function AC

Default = 1 (Real)

 
L Characteristic length

Default = 1 (Real)

[ m ]
R Fiber thickness

Default = L (Real)

[ 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)

 

Comments

  1. The mat_ID must be the same as /MAT/LAW19 (FABRI) or /MAT/LAW58 (FABR_A). Material porosity is active only when corresponding components are referred as external surfaces in /MONVOL/AIRBAG1, /MONVOL/COMMU1, and /MONVOL/FVMBAG1 airbag cards.
  2. Effective leakage area ( A e f f ) formulation:
    Ileakage =1:(1)
    A e f f = n L C A C A r e a n
    Ileakage =2:(2)
    A e f f = n LC ( t ) AC ( P ) A r e a n
    Ileakage =3:(3)
    A e f f = n LC ( t ) AC ( P P e x t ) A r e a n
    Ileakage =4:(4)
    A e f f = n LC ( A r e a n / A r e a 0 ) AC ( P e x t / P ) A r e a n
    Where,
    A r e a 0
    Initial area of the airbag surface
    Note: By default all coefficients and functions are zero.
    Ileakage =5:(5)
    A e f f = n A r e a 0 L 2 [ ( C 1 Δ P C 2 C 3 ) ( L R ) 2 + C 3 ( L λ 1 R / λ 2 ) ( L λ 2 R / λ 1 ) ] sin α 12

    Δ P = P / P e x t 1

    Where, λ 1 and λ 2 are the stretches in warp and weft directions and α 12 is the angle between warp and weft directions.
    Note: For LAW19 α 12 = 90
    Ileakage =6:(6)
    A e f f = n A r e a 0 ( X 0 + X 1 r s + X 2 r p + X 3 r s r p )

    with r s = A r e a n / A r e a 0 and r p = P e x t / 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:
    (7)
    A r e a n = A r e a n o n _ i m p a c t e d + A C A r e a i m p a c t e d