Stability And Fatigue Analysis Of Single-layer Reticulated Shell

Compared with double-layer reticulated shell, single-layer reticulated shell is softer. Stability and fatigue analysis of single-layer reticulated shell are two key problems in the study of single-layer reticulated shell.After reviewing the development and actuality of single-layer dome structures, this thesis thoroughly analyzes the static stability properties of single-layer reticulated shells with nonlinear finite element method. Starting with the large-scale geometric parameters analyses, the thesis firstly studies the stability properties of K8 ellipsoid reticulated shells, including analyzing the relation between the limit load and the short span, rise-to-span, sizes of member sections, and so on. Considering the practical application, the thesis further studies the influence on the static stability acted by initial geometrical imperfections, unsymmetrical distribution of loads and supporting condition. And then, the scientific regression analysis of the large data is done. For the convenience of designs, the thesis offers the fitting formulae for the limit loads of the K8 ellipsoid reticulated shells.By simulating fluctuating wind speed in time history according to Kaimal power spectrum with AR methods, load spectrums were obtained. After time history analyses of FEM and statistics of stress cycles history by rainflow counting algorithms, the total life method was adopted to obtain the fatigue damage of members. Fatigue performance of the single-1ayer reticulated shells was analyzed under different rise-span ratios and average wind speeds. The procedure of the fatigue analysis was programmed by APDL in Ansys.At the end of the thesis, the researchs of the thesis are summarized, and the problems must be solved in next research are indicated.