Research On The Out-of-plane Stability And Design Method Of Arch Truss Structure

In the rise of modern steel structure,its instability is an important factor that causes structural collapse and collapse.For the stability of three-dimensional trusses,especially the non linear arched tube truss,most researches focus on in-plane stability research,and the design method of out-of-plane stability is not systematically established.As the new type of new structure in recent years,it is necessary to study the out-of-plane stability of the arch and put forward the relevant design methods.In this paper,the internal force distribution of arch truss is analyzed,and its out-of-plane stability form and the influence factors of buckling load are studied.Then in combination with the three-dimensional truss geometry relationship and using the balance method,an external elastic design method for arch tube truss is established.Finally,the elastic plastic out-of-plane stability design method of arched tubular truss is studied by finite element method.The following conclusions are obtained through the study:(1)The out-of-plane stability of the arch truss is affected by the ratio of span to height and the ratio of width to height.When the vector span ratio is between 0.1 and 0.4,the greater the span ratio is,the smaller the out-of-plane stability is,the larger the width to height ratio is,the greater the width to height ratio is,the greater the out-of-plane stability is,and the out-of-plane stability of the full span load arrangement is higher than the half span load cloth.The out-of-plane stability of the fixed arch foot and the pin supported arch foot is higher than that of the hinged arch foot.(2)In the elastic buckling analysis,the balance method derives the flexural stiffness and the free torsion stiffness of the component.When the vector span ratio is between 0.1 and 0.4 and the ratio of width to height is between 0.5 and 1.5,the design method of the elastic outer plane of the arch tube truss under the hinge support can follow the design method of the real abdominal arch and the solid support constraint.The elastic out of plane design method is determined by numerical fitting.The final integrated elastic out-of-plane stability design formula is verified by finite element method,all of which meet the accuracy requirements.(3)In elastic-plastic buckling analysis,when the vector span ratio is between 0.1 and 0.4 and the ratio of width to height is between 0.5 and 1.5,the effect of the initial defect on its plane can not be ignored that the greater the uniform defects and the lower out-of-plane stability is;The results of arch foot form and load form are the same as the results of elastic buckling research.Numerical fitting of pure pressure and pure bending design methods can be carried out by similar curves,in which the geometric size of chord and bar does not affect the out-of-plane stability which can be ignored.The length of the chord bar affects the out-of-plane stability that the influence coefficient of the internode length of the pure press string is 0.8,and the influence coefficient of the internode length of the pure bent string is 0.7.Finally,the elastic-plastic buckling out-of-plane stability design method is integrated,and the accuracy requirement is met by finite element verification,which provides the design basis for the arched tube truss in the engineering.