Inverse Analysis of Structure by Filter Theory of Stochastic Dynamic System

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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.