基于反演推定的空间结构随机缺陷传播法

STOCHASTIC IMPERFECTION PROPAGATION METHOD FOR SPATIAL STRUCTURES BASED ON INVERSION RECKONING

在空间结构施工过程监测和检测评估等工作中,需依据部分已测节点几何位形推断结构全部节点几何位形。该文提出随机缺陷传播算法,建立几何位置偏差在节点之间的传播法则,利用有限已知节点几何位形偏差反演推定空间结构整体几何缺陷,进而确定结构整体几何位形,并用随机偏差理论证明所生成的结构随机缺陷服从正态分布。对一个缩尺K6单层网壳模型进行实测和稳定分析,结果表明:相对于随机缺陷法和一致缺陷模态法,采用随机缺陷传播法生成的结构几何缺陷与实测几何缺陷接近,据此计算得到的极限承载力更接近结构承载力理论值。基于随机缺陷传播法得到的空间结构整体稳定极限荷载因子中位数,可作为结构的实际极限承载能力代表值。

The geometric configuration of a spatial structure often needs to be determined by partial measured nodal location for the structural analysis in construction process monitoring and structure inspection. Thusly, an imperfection-introduced method, named stochastic imperfection propagation method （SIPM）, was proposed and the deviation propagation principle was established. This method can reckon the geometric imperfection according to the information of limited deviation-known nodes. Based on the stochastic deviation theory, it was verified that the distribution of imperfection introduced by SIPM is in accord with a normal distribution. Further, the coordinate measurement and stability analysis were carried out on a reduced-scaled K6 reticulated shell. The numerical results show that： compared with the stochastic imperfection method and consistent imperfection mode method, the goodness of fit of imperfection generated by SIPM is higher and the calculated load-carry capacity based on SIPM is more closed to the theoretical load-carry capacity of structure than those of these two methods. Meanwhile, the median load factor based on SIPM is more reasonable to be taken as the representative value of actual load-carry capacity.