双曲冷却塔与土壤相互作用时的随机阵风响应

本文在文[6]的基础上,应用随机振动的谱分析法和全尺寸风压的实测数据,分析了双曲冷却塔壳-支承系统-基础-无限域土壤这一完整系统的随机阵风响应,得到壳体和环形基础的阵风响应因子。文中考虑了不同类型的土壤和风压相关性等因素对阵风响应因子的影响,并给出数值计算结果。     

FINITE LAYER ANALYSIS FOR SEMI-INFINITE SOILS (Ⅰ)——GENERAL THEORY

In the present paper a finite layer method is studied for the elastodynamics of transverse isotropic bodies. With this method, semi-infinite soils can be considered as an transverse isotropic half-space, its material functions varying with depth. Dividing the half.space into a series of layers in the direction of depth the material fimetioms in each layer are simulated by exponential fumctions Consequently, the fundamental equations to be solved can be simplified if the fouricr transform with repsect to coordinates is used. We have obtained the relationship between the "layer forces" and "layer displacements". This finite layer method, in fact, can also be called a semi-analytical method. It possesses those advantages as the usual semi-analytical methods do, and can be used to analyse the problem of the interaction between soils and structures.     

受压矩形截面柱在塑性阶段的缺陷敏感性分析

对加载到塑性阶段的矩形截面柱，本文研究了几何缺陷对屈曲的影响，在分析中考虑了弹性卸载的影响，求出了荷载、缺陷大小及分叉模态幅值之间的精确渐近关系式，结果表明在塑性阶段最大承载力对小缺陷非常敏感，但当缺陷大小达到某一值后，可能不存在最大载荷。     

IMPERFECTION SENSITIVITY ANALYSIS OF A RECTANGULAR COLUMN COMPRESSED INTO THE PLASTIC RANGE

I.IntroductionSinceelasticunloadingoccursinthedeformationprocess,theimperfectionsensitivityanalysisofstructuresloadedintotheplasticrangeismuchcomplicated.TheproblemisfirststudiedintheorybyHutchinson(1973,1974)l"ZI.HeusedKoiter'stheorytoanalysethebehaviorpriortotheonsetofelasticunloadingandtoobtaintheloadandthedisplacementatwhichelasticunloadingbegins.NeedlemanandTvergaard(1982)l'jpresentedananalysisofimperfeCtionsensitivityintheplasticrangethatignoreselasticunloading,thatis,substituteshypo-…     

带有环向肋的双曲冷却塔的线性稳定分析

在对带有环向肋的双曲冷却塔的稳定问题的分析中,本文提出了线性前屈曲一致稳定理论.计算结果表明,本文的这种线性分析方法用于研究以承受风压为主的双曲冷却塔的临界载荷以及各种设计因素对塔壳屈曲的影响,其精度达到了非线性分析的水平,是工程分析中的一种很实用的有效方法.在此基础上,本文还较详细地讨论了加肋位置、数量及其自重对塔壳临界失稳风压值的影响,得到了一些于工程设计有用的结果.     

解决谐波间耦合动力问题的摄动法

本文针对具有谐波间弱耦合作用的振动问题,利用摄动展开,将耦合的问题化成了若干个无耦合的问题,给出了解决谐波间弱耦合动力问题的摄动方法.     

具有非轴对称缺陷双曲冷却塔的动力有限元解

本文针对双曲冷却塔非轴对称缺陷的动力问题,提出了一种解决谐波间耦合问题的近似方法.利用这种方法,本文对具有一般局部几何缺陷双曲冷却塔旋转壳的频率和动力响应进行了分析和计算.     

Nonlinear buckling analysis of hyperbolic cooling tower shell with ring-stiffeners

This paper is concerned with a numerical solution of hyperbolic cooling tower shell, a class of full nonlinear problems in solid mechanics of considerable interest in engineering applications. In this analysis, the post-buckling analysis of cooling tower shell with discrete fixed support and under the action of wind loads and dead load is studied. The influences of ring-stiffener on instability load are also discussed. In addition, a new solution procedure for nonlinear problems which is the combination of load increment iteration with modified R-C are- length method is suggested. Finally, some conclusions having important significance for practice engineering are given.The Project Supported by National Natural Science Foundation of China.     

非均匀弹性双曲冷却塔的动力计算

本文分析讨论了工程中钢筋混凝土结构的材料特性,提出了一种考虑非均匀配筋的钢筋混凝土材料本构关系——非均匀弹性本构方程。在此基础上,本文又进一步研究了混凝土出现裂纹后的钢筋混凝土材料本构关系式,提出了一种计算混凝土具有局部裂纹群的钢筋混凝土材料本构方程式。 根据文中所提的本构方程,本文采用轴对称有限单元对双曲冷却塔的动力特性、阵风响应分别作了计算,其数值结果同分别按等效各向同性、正交各向异性所计算得到的结果进行了对比,比较结果表明,这三种模型除了频率比较相近之外,振型和风振系数都有较大的差异。