Page 377 - Aircraft Stuctures for Engineering Student

358 Open and closed, thin-walled beams

~225 mml 50mm
--
I

100

2.54 mm 1.27 mm
Fig. P.9.26

theory of torsion for thin-walled sections. Ignore any effects of stress concentration at
the corners. Find also the distribution of warping along the middle line of the section,
illustrating your results by means of a sketch.
hs. Tma = f 297.4N/m2, W1 = -5.48m = -Wg,
w2 = 5.48mm = -w5, w3 = 17.98mm = -w4

P.9.27 The thin-walled section shown in Fig. P.9.27 is symmetrical about the x
axis. The thickness to of the centre web 34 is constant, while the thickness of the
other walls varies linearly from to at points 3 and 4 to zero at the open ends 1, 6, 7
and 8.
Determine the St. Venant torsion constant J for the section and also the maximum
value of the shear stress due to a torque T. If the section is constrained to twist about
an axis through the origin 0, plot the relative warping displacements of the section
per unit rate of twist.