Stability of Two-way Grid Cylindrical Shell Greenhouse with Tension Members

Single layer two-way grid cylindrical shell is superior in providing high transparency, material efficiency, and it is suitable for greenhouse structure design. To widen the span range, the tension members are installed to stiffen the rigidity of two-way grid cylindrical shell of greenhouse, a large-span single-layer cylindrical reticulated shell greenhouse system has been developed. More than 800 examples of single-layer two-way grid cylindrical shell were calculated by commercial finite element software ANSYS and self-compiled pre-post-processing programs based on large scale parameter analyses. To demonstrate the validity of tension member arrangement, elastic and elasto-plastic complete-process analysis have been carried out. Some characteristic responses such as critical loads, buckling modes, plastic development levels were used to investigate the effect of length-wide ratio, rise-span ratio, tension member prestress, initial geometric imperfection and unsymmetrical distribution of loads. To reevaluate the plasticity reduction coefficient, “3σ” principle is suggested to determine the effect of initial geometric imperfection on the stability of cylindrical shells, ensured the safety and reliability of the greenhouse latticed shell. The plastic reduced coefficients of cylindrical shells are summarized to be 0.60~0.88.