圆管拱结构平面外弹塑性二次分岔屈曲性能  

OUT-OF-PLANE SECONDARY BIFURCATION BUCKLING BEHAVIOR OF ELASTIC-PLASTIC CIRCLE TUBE ARCH

作　　者：剧锦三[1] 丁敏[1] 郭彦林[2] 蒋秀根[1] 

机构地区：[1]中国农业大学土木系,北京100083 [2]清华大学土木系,北京100084

出　　处：《工程力学》2012年第2期89-93,共5页Engineering Mechanics

基　　金：国家自然科学基金项目(50979108);新世纪优秀人才支持计划项目(NCET-08-0542);博士学科点基金项目(20100008110010)

摘　　要：该文使用一种新的数值跟踪策略对无平面外支撑和有顶点平面外支撑的弹塑性圆管拱的平面外二次分岔屈曲的荷载-位移曲线的全过程进行跟踪分析,得到了跨中集中荷载和全跨均布荷载作用下,相同截面不同矢跨比的拱的平面外弹塑性二次分岔屈曲荷载,将其与平面内二次分岔屈曲荷载比较。计算结果表明:对于具有相同截面的无平面外支撑弹塑性圆管拱,在跨中集中荷载作用下,平面内二次分岔屈曲荷载小于平面外二次分岔屈曲荷载,平面内二次分岔屈曲会先于平面外屈曲发生,矢跨比0.2时平面外二次分岔屈曲荷载最大。全跨均布荷载作用下的拱平面外二次分岔屈曲会先于平面内二次分岔屈曲发生;矢跨比0.3时平面外二次分岔屈曲荷载最大。矢跨比为0.1时,拱的平面内与平面外屈曲荷载相差最大。对于有顶点平面外支撑拱,在集中荷载作用下,支撑对分岔屈曲荷载作用不明显,只是改变了屈曲形式。全跨均布荷载作用下,支撑可以大幅提高全跨均布荷载作用下拱的平面外屈曲荷载,尤其是对矢跨比小的拱的影响更大一些,平面外二次分岔屈曲会先于平面屈曲发生。The out-of-plane secondary bifurcation buckling load-displacement equilibrium paths of an elastic-plastic arch are traced by a high-efficient tracing strategy.The elastic-plastic out-of-plane secondary bifurcation buckling load under a concentrated load at the top of the arch and a full-span distributed load are obtained,which are compared with that under in-plane ones.The calculation results show that： for elasto-plastic arches with the same section and without an out-of-plane brace,the in-plane secondary bifurcation buckling load is less than that of out-of-plane one under a concentrated load and it will occur before out-of-plane buckling;The out-of-plane secondary bifurcation load of the arch with a 0.2 rise-span ratio is the biggest.The out-of-plane secondary bifurcation buckling will occur before in-plane buckling when the arch is under a full-span distributed load and the out-of-plane secondary bifurcation load of the arch with a 0.3 rise-span ratio is the biggest.When the rise-span ratio is 0.1,the difference between in-plane and out-of-plane secondary buckling loads is biggest.For elasto-plastic arches with the out-of-plane brace at the arch apex,the effect of the brace on bifurcation buckling load is not obvious under a concentrated load and only the buckling modality is changed.However,the brace may improve the out-of-plane buckling load significantly under a full span load especially for the arch with small rise-span ratios.The out-of-plane secondary bifurcation buckling will occur before in-plane one.

关 键 词：拱结构 弹塑性屈曲 二次分岔屈曲 平面外 支撑 

分 类 号：TU318[建筑科学—结构工程] TU391