·Rectangular section Warping(翘曲) Plane section does not remain plane after torsion. There exist axial stress as well as circumferential(圆周向的) shear stress 2 T。 T max ab'h Wre We一Torsional elastic section modulus.(受扭弹性抵抗矩) h/b 1 1.2 1.5 0。 0.208 0.219 0.231• Rectangular section Warping (翘曲) Plane section does not remain plane after torsion. There exist axial stress as well as circumferential （圆周向的） shear stress te e e e W T b h T   max 2   Wte—Torsional elastic section modulus. (受扭弹性抵抗矩) h/b 1 1.2 1.5 αe 0.208 0.219 0.231