【作者】 王燕；

【导师】 鹿晓阳；

【作者基本信息】 山东建筑大学 ， 结构工程， 2010， 硕士

【摘要】 网壳具有优美的建筑造型,不论在建筑平面、立面或型体都能给设计师以充分的创造自由。薄壳与网架结构不能实现的形态,网壳结构几乎都可以实现。这种结构形式既能表现静态美,又可通过平面与立面切割以及网格、支承与杆件等变化表现动态美。现在,网壳结构已广泛应用于体育建筑、机场建筑、展览馆、工业厂房等各类建筑中。带肋局部双层球面网壳是单双层球面网壳的一种,这种网壳能够将单层和双层网壳各自的优点很好结合在一起。近些年来,出现了不少这种网壳形式的应用。凯威特型网壳结构网格均匀,刚度大,是一种应用最为广泛的网壳结构形式之一。但凯威特型单层球面网壳的稳定性能较差；凯威特型双层球面网壳杆件、节点数量大,杆件视觉效果不好。为了克服这两种网壳的缺点,根据网壳结构主要传力路线特点、建筑美观以及经济指标的要求,在凯威特型单层球面网壳主肋处增加下弦杆和腹杆,由此形成凯威特型带肋局部双层网壳。这是一种受力合理、结构性能优异、形式简洁美观、经济实用的局部双层网壳结构形式。目前,国内外的研究重点主要集中在单层网壳的稳定性和极限承载力以及双层网壳的优化和应用等方面,而有关带肋局部双层网壳体系的研究相对较少,特别是形状优化方面的研究更是少见。本文主要研究的是凯威特型带肋局部双层网壳的形状优化。首先运用大型有限元分析软件ALGOR对不同跨度、双层区厚度下的凯威特型带肋局部双层网壳进行静力分析,研究网壳结构随矢跨比和厚跨比变化时的受力特性和位移特性,为下面凯威特型带肋局部双层网壳结构形状优化初始宏观曲面参数和杆件截面的选取提供依据。这将有助于减少网壳结构形状优化的迭代次数。然后针对球面网壳的特点,本文提出了网壳结构形状优化的两级算法。采用FORTRAN语言编写网壳形状优化两级算法设计程序,并与大型有限元分析软件ALGOR连接。对不同跨度、不同类型的凯威特型单层球面网壳进行优化并分析验证此算法是否具有有效性和可靠性。在此基础上利用上述算法对凯威特型带肋局部双层网壳进行形状优化设计,探究网壳最优矢跨比、厚跨比的分布范围及网壳单层区网格划分密度对网壳优化结果的影响。在带肋局部双层网壳的选型过程中,若已确定使用凯威特型带肋局部双层网壳,这些结果将对其宏观曲面参数、网格尺寸及杆件截面的选择具有一定的参考价值。随着结构优化的发展,网壳优化的结果总的趋势是跨度越来越大,厚度越来越薄；但与此同时,网壳结构稳定性问题也变的突出起来。因此本文利用ALGOR软件对优化后的凯威特型带肋局部双层网壳进行屈曲分析(特征值屈曲分析、考虑初始缺陷的非线性屈曲分析),确定优化后凯威特型带肋局部双层网壳的屈曲模态及优化后网壳的屈曲荷载与设计荷载的比值。以此作为评价本文网壳优化结果优劣的依据。更多还原

【Abstract】 Dome has a beautiful architectural style, whether in architecture, facade, or type body. It can give designers the creative freedom to the full. Shape can not be achieved with the grid structure, almost all the dome structure can do. This structure not only can performance static beauty,but also dynamic beauty by plane and cross cutting and the grid, supporting such changes and pole.Now, dome structure has been widely used in sports buildings, airport buildings, exhibition halls, industrial plants and other kinds of buildings.Partial double-ribbed dome is a single layer of a spherical dome,and it can combine the strengths of single-dome and double dome. In recent years,many forms of application of this dome appear. Because of uniform grid dome structure and rigidity, Kiewitt dome is the most widely used form of dome structure.But, Kiewitt spherical dome has poor stability and Kiewitt double spherical dome with a large number of bars and nodes has poor visual effects bar. According to the main power line transmission characteristics, aesthetic and economic indicators of construction demand of Dome structure,adding chords and belly bars in the bottom of the main rib of Kiewitt spherical dome, Kiewitt dome with partial double rib can be formed.It is a Double-dome local structure which is Reasonable force,Structure-performance, Simple and beautiful form,and ecomomical. Currently, Research priorities at home and abroad focus on optimization and application dome of Double dome and Stability and ultimate load of Single-layer dome,but the study of Partial double-ribbed dome System is seldom, especially in respect to the optimization of the shape.This paper studies primarily the partial double Kiewitt ribbed shell shape optimization. First, we use finite element analysis software ALGOR to analysis Static characteristics of the Kiewitt partial double ribbed dome,which has different span and the thickness of double area. With span ratio and thick span ratio changes, Force characteristics and displacement characteristics of dome can be obtained.It can provide the basis for selection of dome structure for the following initial macroscopic surface shape optimization parameters.Then, shape optimization of dome structure of the two algorithms accounted for the characteristics of spherical dome in this paper. FORTRAN language is adopted for writing program about the Sequential two-level algorithm of dome shape optimization,and connect to finite element analysis software named ALGOR. Using the optimized results of different span and types of dome show the validity and reliability of the algorithm. Then Shape Optimization of the dome, using the above algorithm,can get the optimal span ratios, the ratio of thickness to span the scope and parameters of surface macro-dome dome optimization results. In the double-dome ribbed local selection process, if the designer has identified to use Kiewitt partial double ribbed dome, these results can provide a reference value for selection macro-surface parameters for the dome, mesh size and bar section.With the development of structural optimization, the trend of optimization results is that the span is growing and Thickness is getting thin. At the same time, Stability of dome structures also become prominent.This paper use ALGOR to analysis of stability of optimized Kiewitt dome with partial double rib, including Eigenvalue buckling analysis、Nonlinear buckling of a rational analysis of dome and Initial defect of nonlinear buckling analysis. Buckling mode and Buckling load and the ratio of design load of optimized Kiewitt dome with partial double rib can be obtained. So,it can be used to evaluate the advantage and disadvantages of Dome optimization results.更多还原