Page 506 - Aircraft Stuctures for Engineering Student

Problems 487

Am. 912 = q45 = 44.1 N/=, q23 = q34 = 42.9N/m,

q51 = 80.2N/mm, qx = 37.4N/m,
XR = 79.5mm, YR = 0 (referred to mid-point of web 24)
P.11.3 A singly symmetrical, thin-walled, closed section beam is built-in at one
end where a shear load of 10000N is applied as shown in Fig. P.11.3. Calculate
the resulting shear flow distribution at the built-in end if the cross-section of the
beam remains undistorted by the loading and the shear modulus G and wall thickness
t are each constant throughout the section.
Ans. 912 = 3992.9/R N/n~m, 923 = 71 1.3/R N/IIUTI:

431 = (1502.4 - 1894.7~0~4 2102.1 sinq5)/R N/mm
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1
Fig. P.11.3

P.11.4 A uniform, four-boom beam, built-in at one end, has the rectangular
cross-section shown in Fig. P. 11.4. The walls are assumed to be effective only in
shear, the thickness and shear modulus being the same for all walls while the
booms, which are of equal area, carry only direct stresses. Assuming that the cross-
section remains undistorted by the loading, calculate the twist at the free end due
to a uniformly distributed torque loading T = 20 N m/mm along its entire length.
Take G = 20000N/mm2 and G/E = 0.36.
Am. 5.9" anticlockwise.

00 mm2

1.0 mm

Fig. P.11.4