在弹性薄壁杆件中,计算翘曲变形的理论常以“刚性周边”假定为基础,不考虑周边形状的改变.本文认为,在开口薄壁杆件中,“周边形状改变”与“周边形状不变”的翘曲变形都是同等重要的翘曲变形,不计前者是不恰当的;在闭口薄壁杆件中,在此假定的基础所导出的结论与实际不符。本文在中直线假定的基础上,用转角向径表示截面上各板的转角,用弯矩矢量表示各板的内力,使翘曲变形的基本方程的力学涵义和几何意义更为直观,从而较方便地导出计算各种翘曲变形的方法和结论.本文认为,在薄壁杆件中,不仅一对等值反向弯矩应组成力因素--双力矩;一对等值反向的双力矩,也应组成新的力因素--四力矩.同理,在截面图形中,不仅存在描述截面是否发生刚性扭转的扭转中心,而且存在描述截面是否发生相对扭转的双扭中心.它们都是同等重要的几何点.本文在建立新概念时,力求形象具体,推理方法尽量和计算平面变形的方法相同,使翘曲变形的计算和平面变形的计算能和谐地衔接成一体.目前,在工程中,随着材料质量的提高,溥壁杆件的应用更广,进一步探讨薄壁杆件的计算问题在实用上是有意义的. In elastic thin-walled members, the theory of calculating warpage is often based on the “rigid peripheral” assumption, without considering the change of the peripheral shape. This article believes that in the open thin-walled bar, the “peripheral shape change” The “warping deformation” of the “permanent shape” and “peripheral shape” are all equally important warping deformations. It is not appropriate to exclude the former; in the closed thin-walled rods, the conclusions derived from this assumed basis do not correspond to actual results. . In this paper, based on the assumption of medium straight line, the rotation angle of each plate in the cross section is represented by the angle of rotation and the internal force of each plate is represented by the moment vector, so that the mechanical and geometrical meanings of the basic equations of warping deformation are more intuitive, and thus It is convenient to derive methods and conclusions for calculating various warping deformations. This paper holds that in thin-walled members, not only a pair of equivalent reverse bending moments should constitute a force factor—double moments; a pair of equivalent reversed pairs The moment should also constitute a new force factor--four moments. Similarly, in the cross-sectional diagram, there is not only the center of torsion that describes whether the section is rigidly twisted, but also the center of double twist that describes whether the section is relatively twisted. They are both Equally important geometric points. In the establishment of new concepts, this article strives to be specific to the image, and the method of inference is the same as the method of calculating the plane deformation, so that the calculation of the warping deformation and the calculation of the plane deformation can be harmoniously connected into one. Currently, in the project In addition, with the improvement of material quality, the application of concrete wall members is wider. It is of practical significance to further investigate the calculation of thin-walled members.