烟囱是一种柔性的结构物,它的第一周期总在1秒以上,所以按照苏联的“地震区建筑规范”及我国的规范草案,都需要考虑它的高振型影响[1][2]。虽然它的外形相当简单,但由于是变截面的杆件而且它的变形主要是挠曲作用,所以在进行动力分析时,就感到了很大的麻烦。普通常用的李滋法、伽辽金法、逐渐代入法以及迭次代入法等近似分析法,都未能满足简化计算的要求。为了配合新规范的使用,苏联于1960年6月28日举行的建筑结构研究所学术委员会结构理论和试验方法组扩大会議中,曾经提出需要编制确定结构物自振频率及振动形式的简单实用方法[3]。由此可見:如何寻求简便的但精确度又满足要求的动力分析方 The chimney is a flexible structure, its first cycle is always more than 1 second, so according to the Soviet “earthquake zone building code” and our country’s draft specifications, all need to consider its high-impact type effects [1] [2 ]. Although its shape is quite simple, it is a great deal of trouble when performing dynamic analysis because it is a variable cross-section rod and its deformation is mainly deflection. Commonly used approximation methods such as the Lizi method, the Galerkin method, the gradual substitution method, and the subdivision substitution method all failed to meet the requirements for simplified calculation. In order to cooperate with the use of the new norms, the Soviet Union held an extended meeting of the Institute of Building Structures Academic Committee Structure Theory and Test Methodology held on June 28, 1960. It has proposed a simple and practical method for determining the natural vibration frequency and vibration form of structures. [3]. From this it can be seen: how to seek a simple but accurate dynamic analysis that meets the requirements