两种单杆型圆弧拱塑料大棚平面内稳定性分析

针对单杆型圆弧拱塑料大棚平面内稳定性研究较少的现状,基于有限元平面梁大变形几何非线性屈曲理论,应用ANSYS有限元软件,研究了无边立柱及带边立柱两种形式单杆型圆弧拱塑料大棚骨架承受竖向均布荷载下的几何非线性屈曲性能。研究结果表明:在相同的几何参数条件下,无边柱骨架的极限承载力远高于带边柱骨架,且结构的破坏点集中于1/2跨、1/4跨和底部柱脚处;单杆型圆弧拱塑料大棚结构的极限承载力随着矢跨比的增加而增加;无边立柱骨架合理的矢跨比在0.3左右,带边柱单杆骨架无最优矢跨比;单杆型圆弧拱塑料大棚结构的极限承载力随着长细比的增加而减小;带边立柱单杆圆弧拱塑料大棚结构表现出更强的几何非线性。

Analysis of in-plane stability of two kinds of single-bar circular arch plastic greenhouse frames

Given that little research has been done on in-plane stability of single-bar circular arch plastic greenhouse frame,based on the finite element of large beam deformation theory of geometrical nonlinear buckling,two styles of finite element models （ANSYS）for greenhouse frames with and without side columns were established in order to investigate the geometrical nonlinear buckling subjected to vertical uniform load.The results indicate that：under the same geometrical parameters,the ultimate bear-ing capacity of greenhouse frame without side columns is much larger than that of greenhouse frame with side columns.And the failure position occurs at half-span,quarter-span and bottom foot.The variation of ultimate bearing capacity of circular arch plas-tic greenhouse frame with rise-span ratio was analyzed,and then it was found that the ultimate bearing capacity increases with the increase of rise-span ratio.The optimal rise-span ratio of greenhouse frame without side columns is 0.3,and there is no optimal rise to span ratio for the frame with side columns.The variation of ultimate bearing capacity of circular arch plastic greenhouse frame with slenderness ratio was analyzed,and it was found that the ultimate bearing capacity decreases with the increase of rise-span ratio.It suggests that the circular arch plastic greenhouse frame without side columns is much stronger in geometrical non-linearity than the circular arch plastic greenhouse frame with side columns.