Page 443 - Aircraft Stuctures for Engineering Student

424 Stress analysis of aircraft components

Window
cut-out

I I
Fig. 10.65 Fuselage panel with windows.

situations, for example door openings in passenger aircraft, it is not possible to
provide rigid frames on either side of the opening because the cabin space must not
be restricted. In these cases a rigid frame is inserted to resist the shear loads and
transmit loads around the opening.
The effects of smaller cut-outs, such as those required for rows of windows in
passenger aircraft, may be found approximately as follows. Figure 10.65 shows a
fuselage panel provided with cut-outs for windows which are spaced a distance I
apart. The panel is subjected to an average shear flow qav which would be the value
of the shear flow in the panel without cut-outs. Considering a horizontal length of
the panel through the cut-outs we see that
4111 = qavl
or
I
41 = -4av (10.41)
11
Now considering a vertical length of the panel through the cut-outs

or
(10.42)