Page 543 - Automotive Engineering Powertrain Chassis System and Vehicle Body

CHAP TER 1 6. 2 Standard sedan (saloon) – baseline load paths

Careful inspection of this equation and of Fig. 16.2-14
Table 16.2-1 (a)
reveals that the coefficients of the Qs must be their
Edge force Moment about G Moment arm about G moment arms r 2 , r 3 , etc., about point G as given in
equation (16.2.27). Moment arms r 2 to r 7 are listed in
Lower A-pillar Q 2 X r 2 ¼ X
Tables 16.2-1(a) and (b).
Header (roof rail) Q 4 ðH ZÞ r 4 ¼ H Z

Lower C-pillar Q 6 ðL 5 XÞ r 6 ¼ L 5 X
16.2.3.5 Summary – baseline closed
Rocker Q 7 Z r 7 ¼ Z
sedan
Parcel shelf Moment about G
reactions Front and rear inner fenders:
Front Q x1 ðh 1 ZÞ h 1 Z
R FT ¼ T=S F R RT ¼ T=S R ¼ R FT S F =S R
Rear Q x2 ðh 2 ZÞ h 2 Z P FT ¼ TL 1 =S F h 1 P RT ¼ TL 2 =S R h 2
Parcel shelves:

Q X1 ¼ P FT S F =B ¼ TL 1 =h 1 B (16.2.19)
Q X2 ¼ P RT S R =B ¼ TL 2 =h 2 B (16.2.20)
For sideframe equilibrium, all moments acting about
G will sum to zero (SM ¼ 0): Passenger compartment (with some re-arrangements):

Q 2 X þ Q 3 fðh 1 ZÞ sinðq Þþ X cosðq Þg The input moment is Tand P FT ,P RT ,Q x1 and Q x2 are
A
A
known in terms of T. The remaining seven unknown
þ Q ðH ZÞþQ 5 fðh 2 ZÞ sinðq Þ
4
C
edge forces (Q 1 to Q 7 ) can be solved using the seven
þðL 5 XÞ cosðq Þg Q 6 ðL 5 XÞþ Q 7 Z simultaneous equations (16.2.21)–(16.2.27) if T is
C
Q X1 ðh 1 ZÞ Q X2 ðh 2 ZÞ known. This could be done by hand (the equations are
linear and relatively ‘sparse’). Alternatively, if the
¼ 0
equations are rearranged slightly and put in matrix
form, they become:

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