Page 392 - Aircraft Stuctures for Engineering Student

10.1 Tapered beams 373

Fig. 10.9 Change in boom loads/unit length of beam.

The situation is illustrated in Fig. 10.9. Suppose now that the shear flows in the panels
12,23,24, etc. are 912, 923, q34, etc. and consider the equilibrium of boom 2, as shown
in Fig. 10.10, with adjacent portions of the panels 12 and 23. Thus
423 4- 43.8 - 912 = 0
or

923 q12 - 43.8
Similarly
934 = 923 - 32.85 = q12 - 76.65
945 = 934 + 32.85 = 912 - 43.8

The moment resultant of the internal shear flows, together with the moments of the
components Py;, of the boom loads about any point in the cross-section, is equivalent
to the moment of the externally applied load about the same point. We note from

Fig. 10.10 Equilibrium of boom.