Page 457 - Aircraft Stuctures for Engineering Student

438 Stress analysis of aircraft components

2

304 TI f mm

I 1- I

762 mm 508 mm

Fig. P.10.12
the distance xs of the shear centre S aft of the web 34. The shear modulus G is the
same for all walls.

Wall Length (mm) Thickness (mm) Boom Area (mm2) Cell Area (mm’)
12, 56 510 0.559 1,6 645 I 93 000
23,45 165 0.915 2, 5 1290 I1 258 000
34: 1015 0.559 3,4 1935
38 304 2.030
25 304 1.625
Ans. 241.4mm.

P.10.13 A portion of a tapered, three-cell wing has singly symmetrical idealized
cross-sections 1OOOmm apart as shown in Fig. P.10.13. A bending moment
M, = 1800 N m and a shear load Sy = 12 000 N in the plane of the web 52 are applied
at the larger cross-section. Calculate the forces in the booms and the shear flow
distribution at this cross-section. The modulus G is constant throughout. Section
dimensions at the larger cross-section are given below.

Wall Length (mm) Thickness (mm) Boom Area (mm2) Cell Area (mm’)
12, 56 600 1 .o 1,6 600 I 100000
23,45 800 1 .o 2, 5 800 I1 260 000
34: 1200 0.6 3, 4 800 111 180000
3 4l 320 2.0
25 320 2.0
16 210 1.5

E E
E E
0 -- 0
(u (u

I- 790 mm \, 590mm A

Fig. P.10.13