Numerical model of a bolt-ball joint system is established using software ANSYS and verified through experiments. Based on the bendingrotation curves of the bolt-ball joints obtained through numerical simulation, a finite element model of single-layer reticulated domes with bolt-ball joint system is established using nonlinear beam element with end spring elements in software ANSYS. The analyses of the domes are carried out with different parameters including bending stiffness, ratio of rise to span, rotation-stiffness, ball size, asymmetric load distribution, tube section, support condition and initial imperfection. Several key parameters having influence on the load carrying capacity of a semi-rigidly jointed single-layer reticulated dome are thus identified. Finally, formulas are established for direct estimation of critical loads of semi-rigidly jointed single-layer reticulated domes under symmetric and asymmetric loading conditions.

The effect of a non-uniform solar temperature field on the cable-net structure of the reflector of a five-hundred-meter aperture spherical radio telescope-FAST was analyzed using the thermal analysis module of ANSYS. The integral parametric finite element model of the reflector structure with its measured landform was built, and the boundary conditions of periodic air temperature, solar radiation, long-wave radiation and shadows of surrounding environment, etc, were computed at intervals of half an hour under a cloudless sky on a summer day, as one of the worst-case climate conditions. The transient structural temperatures were then analyzed under sunshine which lasted for several days with a rational initial structural temperature distribution until the whole set of structural temperatures converged to the results obtained the day before. The corresponding structural analysis was then carried out. The results indicate that the highest local temperature difference goes up to 11° and the maximum r.m.s. error of fitting of the reflector geometry is about 2.2mm.

A considerable number of studies have been carried out for predicting snowdrifts on roofs over the years. However, few studies have focused on snowdrifts on complex long-span roofs, as the complex shape and fine structure pose significant challenges. In this study, to simplify the calculation requirements of snow load on such roofs, work was conducted to decompose the snowdrift on a complex roof into snowdrifts on several simple roofs. First, the snow–wind tunnel test similarity criteria were investigated based on a combined air–snow–wind experimental system. Thereafter, with reference to the validated experimental similarity criteria, a series of snow–wind tunnel tests were performed for snowdrifts on a complex long-span structure under the conditions of different inflow directions. Finally, based on empirical orthogonal function (EOF) analysis, the snowdrifts on the complex roof were decomposed into basic characteristic distribution modes, including snowdrifts caused by the local and overall roof forms. The snow distribution under a specific inflow direction could be derived from the weighted combination of the basic characteristic modes, based on the wind direction coefficients. Therefore, it is possible for the snow load on a complex roof to be estimated preliminarily based on the snow distributions on several simple roofs.