Stability Analysis Of Single Laver Reticulated Shell With Calla Lily Appearance

The stability of reticulated shells has always been a concern in the design and analysis of reticulated shells.At present,research on the stability of the reticulated shells with common surface is mature,but with the development of the society and the progress of technology,more and more reticulated shell structures have been derived,the object of this article is one of them.Compared with the common reticulated shells,the structural calculation and analysis of these reticulated shells with peculiar shape are different,and the stability problem is more prominent.Studying the stability bearing capacity of these structure and clarifying the influence of various factors on its stability is of great significance to guide the future engineering design.The article takes ground sightseeing ladder project of Tiantian square on Wuhan Rail Transit Line 8 as background.By linear buckling analysis,geometrically nonlinear buckling analysis,geometric material double nonlinear buckling analysis and pushover,the stability of single laver reticulated shells with calla lily appearance was systematically studied.The study contains the following major work:(1)The wind load shape coefficient of this structure is discussed and confirmed.For this structure,when referring to?Load code for the design of building structures?(GB 50009-2012)by using the shape coefficient of the circular section and the maximum value of all kinds,the value of the wind load shape coefficient is 1.2,however,through the ANSYS FLUENT simulation calculation,the wind load shape coefficient of the different parts of the structure is confirmed,the lowest is 1.2,the highest is 1.8.Comparison shows that the wind load shape coefficient is lower based on the code,which will be too low to consider the wind load value of the structure.(2)The structural modeling is carried out by using Midas Gen,and the stress and displacement changes under different working conditions are analyzed.For this structure,the stress of the component is very small,the maximum stress value of the component is only 60Mpa,and the corresponding stress ratio is 0.189,but the deflection of the structure is close to the allowable value stipulated in the code.When designing the structure,we should focus on the displacement and deformation of the structure.(3)The linear buckling analysis,geometrically nonlinear buckling analysis and geometric material double nonlinear buckling analysis are carried out for the structure.The results show that the critical buckling load coefficient of this structure satisfies the requirements in?Technical specification for space frame structures?(JGJ7-2010),and this structure has a higher safety margin.It is worth noting that the nonlinear stability bearing capacity of this structure is greatly reduced when the material nonlinearity is considered,which the biggest reduction is 26%,and the material nonlinearity should be considered in the design.Otherwise,the bearing capacity of the structure will be overestimated.Meanwhile,in the nonlinear buckling analysis,the influence of initial imperfection on the bearing capacity of the structure is studied.The calculation results show that the stability carrying capacity of the Calla shape structure is reduced but not obvious after considering the initial defects,and the reduction is about 10%.The stable bearing capacity of this Calla shape structure is not very sensitive to initial defects.(4)The influence of structural stiffness on the sensitivity of structural defects is discussed.By reducing the cross section of vertical members to decrease the structural stiffness,the imperfection sensitivity analysis is carried out.When the structural stiffness is reduced by 10%,the decrease of the critical load coefficient of the structural buckling is still around 10%.Therefore,it is considered that the change of structural stiffness has no obvious effect on the sensitivity of the structural defects.