摘要
在膜结构找形中,力密度法引入了"力密度"的概念,使问题简化。但力密度法需要多次试算后才能确定合适的力密度取值,这给找形过程带来困难。该课题组对力密度法的找形过程进行改进,避开其中"力密度"的概念,使找形计算过程简洁高效。该文即对这种"改进力密度"法进行了试验研究,以验证该方法的正确性。试验模型为一平面尺寸为4m×4m柔性索边界、四点支承的马鞍形张拉膜结构。张拉过程采用应力和位移同时控制,量测模型零状态、中间状态和张拉成形后状态边索和膜面的应变值及膜面监测点的空间坐标。通过试验值与理论值在膜面应变、索应变及膜面空间坐标的比较及与ANSYS法、解析法的比较,说明改进力密度法是正确的,可用于实际工程的膜结构找形分析。另外,通过本次实验,我们对膜面应变的量测也得到了一些经验教训。
The force-density method can simplify the form finding process of membrane structures via the concept of force density. However, the value of force density has to be determined through several trial calculations, which greatly depends on personal experience and may result in the process of form finding being inefficient and even invalid. The modified force-density method is proposed in order to overcome the disadvantages of the force-density method. A form-finding experiment of the membrane structure using Fluotop T2 is conducted to verify the modified force-density method. The tensioning process in the experiment followed the tensioning technology of the actual project. It is a saddle-shaped tensile membrane with plane size of 4mx4m, 4 cable boundaries and 4 supports. The tension process is controlled by both strains of the cable and displacements of the membrane. The cable strains, the membrane strains and the coordinates of several points on the membrane surface in three states, named zero-state, intermediate-state and final-state, are selected to be measured. By comparing the membrane surface strains, cable strains and the coordinates of testing points in the experiment results, calculation results, ANSYS results and analytical results, the modified force-density method is verified and can be used in form-finding analysis of practical membrane structures. Moreover, some experiences and lessons in measuring the strains of membrane surface are summarized.
出处
《工程力学》
EI
CSCD
北大核心
2010年第4期117-124,140,共9页
Engineering Mechanics
基金
江苏省"六大人才高峰"项目(建筑B类)
关键词
张拉膜结构
找形方法
力密度法
算法改进
实验研究
membrane structures
form finding method
force-density method
improved algorithm
experimental research
