Page 482 - Aircraft Stuctures for Engineering Student

11.4 Shear lag 463

t

Fig. 11.21 Compatibility condition for combined bending and axial load.

which agrees with the assumed direction of shear flow and that y1 and increase
with z. Thus

where y1 and v are functions of z only. Thus

(1 1.41)

Similarly, for an element of the lower panel

( 1 1.42)

Subtraction of Eq. (1 1.42) from Eq. (1 1.41) eliminates d2v/ck2, i.e.
dyl 1
dz
d
d7 dyz - -@&A - EB1 - EB2)
or, as before
dql dq2 - Gt (2pA pB1 pB2) (1 1.43)
dz dz dE A B B
In this particular problem the simplest method of solution is to choose PA as the
unknown since, from Eqs (1 1.39)
dql dq2 -
dz dz az2