8.2 Basic elastic behavior of sections subjected to torsion Circular sections Plane section before torsion remain plane after torsion Te TR tmax T= I,—Polar moment of inertia(极惯性矩) 元R4 TR 2T. T 1。= max 2 I。zR W W Torsional elastic section modulus(受扭弹性抵抗矩) W。= 28.2 Basic elastic behavior of sections subjected to torsion Circular sections Plane section before torsion remain plane after torsion 0 TeR I   I 0——Polar moment of inertia (极惯性矩) 2 4 0 R I   te e e e W T R T I T R    3 0 max 2   Wte ——Torsional elastic section modulus （受扭弹性抵抗矩） 3 2 Wte R   τmax R Te