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Inverse Analysis of Structure by Filter Theory of Stochastic Dynamic System

随机动力系统滤波理论的结构反分析

基本信息

批准号：
07650670
负责人：
TOSAKA Nobuyoshi
金额：
$ 1.41万
依托单位：
Nihon University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

项目摘要

1.Novel Solution Procedure for Inverse ProblemsFrom view-point of computational mechanics, noval solution procedures to solve various inverse problems in structure are proposed. These procedures are a combination of the finite element method or the boundary element method to solve numerically continuous fild and the filtering algorithms based on the Wiener filter or the projection filter to estimate the unknown state vector.Especially, for complicated inverse problems, two step solution procedure to be expected more efficiency is also proposed. The first step analysis is performed to guess some apriori information on the unknowns and the second analysis to identify the unknowns is subsequently performed with use of the obtained apriori information.2.Application to Various Inverse ProbelmsApplicability and effectiveness of the procedures are demonstrated with numerical simulations on the following problems.(1)Indetification of Spatial Distribution of Material ConstantsThe solution procedure can be applied to identification analysis of spatial distribution of elastic constants (Young's modulus and Poisson's ratio) in elastic body with use of displacement components measured on the boundary.(2)Defect(s) IdentificationThe procedure can be applied to identification of unknown defect in elastic field or in thermal field. Especially, numerical simulation is carried out for identification of a circular defect in a two dimensional body by using transient temparature measured at several boundary points as additional information. The unknown plural defects in elastic body can be identification from the measured displacement components by using effectively two step solution procedure.(3)Damage DetectionThe procedure is applied to a structural damage detection problems. Both location and stiffness on damage in the unit-linked floating structure can be defected with natural frequencies of structure.

1.从计算力学的观点出发，提出了求解各种结构反问题的新方法。这些方法是将有限元法或边界元法用于求解数值连续场与基于维纳滤波器或投影滤波器的滤波算法用于估计未知状态向量相结合，特别是对于复杂的反问题，还提出了两步求解方法，以提高求解效率。第一步分析的目的是猜测未知量的一些先验信息，第二步分析的目的是利用所获得的先验信息识别未知量。2.应用于各种反问题通过数值模拟，证明了该方法的适用性和有效性。（1）材料常数的空间分布的识别利用在边界上测得的位移分量，可以将该求解过程应用于弹性体中的弹性常数（杨氏模量和泊松比）的空间分布的识别分析。（2）缺陷识别该方法可用于弹性场或温度场中未知缺陷的识别。特别地，通过利用在多个边界点处测量的瞬态温度作为附加信息，对二维物体中的圆形缺陷的识别进行了数值模拟。采用有效的两步求解方法，可以从测量的位移分量中识别出弹性体中的未知多个缺陷。（3）损伤检测将该程序应用于一个结构损伤检测问题。单元联浮式结构损伤的位置和刚度都可以通过结构的固有频率来确定。