摘要
为明确子午线型参数对冷却塔结构特性的影响以便子午线型优化,以一座代表性冷却塔为例,通过子午线型方程的参数调整获得五组线型,独立分析了塔筒上下缘直线段、喉部以上线型、下缘倾角、喉部高度、整体半径对结构在多种荷载下受力性能的影响,并通过结构设计评价了各参数对塔筒材料用量的影响;同时考虑上述参数对结构基频和稳定性的影响,结合结构振型解释了子午线型对基频的影响机理。结果表明:子午线型参数对结构受力的影响主要表现在对自重作用下的环向轴力和风荷载效应的影响,对自重作用下的子午向轴力和温度效应几乎没有影响;塔筒下缘直线段长度较小时,对结构特性的影响并不明显;增加塔筒下缘倾角并降低喉部高度可以有效改善结构性能、降低塔筒配筋且增加结构基频;喉部以上线型越趋竖直线,塔筒的配筋和基频均有所增加;子午线型对塔筒配筋的影响主要体现在对子午向配筋的影响,而子午向配筋的变化完全来自风荷载作用下子午向轴力的变化,故在受力性能的子午线型因素分析时可仅关注子午线型对风荷载作用下子午向轴力的影响;除整体半径外,结构在自重和风荷载作用下的分支点稳定因子受子午线型的影响可以忽略。
For further interpretation of influences of shell geometry parameters on structural behavior of hyperbolic cooling towers(HCTs), five parameters are selected and adjusted individually, including the straight lines on both ends of meridian line, the meridian line above the throat, the angle of base lintel α, the height of throat ZT and the global radius. Their influences on the internal forces of each load are analyzed firstly and then the reinforcement amounts. Furthermore, their influences on the fundamental frequency and global bifurcation stability are also presented. Influences of shell geometry parameters reflected always on the latitude axial force of gravity and the internal forces of wind, whereas the meridian axial force of gravity and the internal forces of temperature show little change. The structural behavior has little relationship between the bottom meridian straight line because its length is limited. With the increase of α and the decrease of ZT, the structural behavior is improved, results in less reinforcement and higher fundament frequency. When the upper shell above throat takes the minimum radius, almost like a cylinder shell, the reinforcement and fundamental frequency increase simultaneously. The variation of reinforcement due to meridian line lies in the meridian direction, and this is the direct indication of the variation of the meridian axial tension under wind. Therefore, the meridian axial tension under wind would be the only indicator for further study on the relationship between the meridian line and the mechanics performance. For the global bifurcation study, the stability factors of gravity and wind shows little sensitivity to the meridian line except for the global radius, which would decrease the stability factors as it increase.
作者
张军锋
刘庆帅
葛耀君
赵林
Zhang Junfeng;Liu Qingshuai;Ge Yaojun;Zhao Lin(School of Civil Engineering,Zhengzhou University,450001,Zhengzhou,China;State Key Laboratory for Disaster Reduction in Civil Engineering,Tongji University,200092,Shanghai,China)
出处
《应用力学学报》
CAS
CSCD
北大核心
2020年第4期1597-1606,I0015,共11页
Chinese Journal of Applied Mechanics
基金
国家自然科学基金(51508523)。
关键词
子午线型
下缘倾角
喉部高度
结构特性
受力特性
基频
稳定性
meridian line
the angle of base lintel
the height of throat
structural behavior
mechanics performance
fundamental frequency
bifurcation stability
