• Smart Structures and Systems
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• v.16 no.1
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• pp.47-65
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• 2015

A novel finite element (FE) model updating method based on multi-resolution analysis (MRA) is proposed. The true stiffness of the FE model is considered as the superposition of two pieces of stiffness information of different resolutions: the pre-defined stiffness information and updating stiffness information. While the resolution of former is solely decided by the meshing density of the FE model, the resolution of latter is decided by the limited information obtained from the experiment. The latter resolution is considerably lower than the former. Second generation wavelet is adopted to describe the updating stiffness information in the framework of MRA. This updating stiffness in MRA is realized at low level of resolution, therefore, needs less number of updating parameters. The efficiency of the optimization process is thus enhanced. The proposed method is suitable for the identification of multiple irregular cracks and performs well in capturing the global features of the structural damage. After the global features are identified, a refinement process proposed in the paper can be carried out to improve the performance of the MRA of the updating information. The effectiveness of the method is verified by numerical simulations of a box girder and the experiment of a three-span continues pre-stressed concrete bridge. It is shown that the proposed method corresponds well to the global features of the structural damage and is stable against the perturbation of modal parameters and small variations of the damage.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.71-74
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• 2003

The cell modeling homogenization method to derive the constitutive equation considering the microstructures of the fiber reinforced composites has been previously developed for composites with simple microstructures such as 2D plane composites and 3D rectangular shaped composites. Here, the method has been further extended for 3D circular braided composites, utilizing B-spline curves to properly describe the more complex geometry of 3D braided composites. For verification purposes, the method has been applied for orthotropic elastic properties of the 3D circular braided glass fiber reinforced composite, in particular for the tensile property. Prepregs of the specimen have been fabricated using the 3D braiding machine through RTM (resin transfer molding) with epoxy as a matrix. Experimentally measured uniaxial tensile properties agreed well with predicted values obtained fer two volume fractions.

• Fibers and Polymers
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• v.4 no.2
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• pp.77-83
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• 2003

The cell modeling homogenization method to derive the constitutive equation considering the microstructures of the fiber reinforced composites has been previously developed for composites with simple microstructures such as 2D plane composites and 3D rectangular shaped composites. Here, the method has been further extended for 3D circular braided com-posites, utilizing B-spline curves to properly describe the more complex geometry of 3D braided composites. For verification purposes, the method has been applied for orthotropic elastic properties of the 3D circular braided glass fiber reinforced com-posite, in particular for the tensile property. Prepregs of the specimen have been fabricated using the 3D braiding machine through RTM (resin transfer molding) with epoxy as a matrix. Experimentally measured uniaxial tensile properties agreed well with predicted values obtained for two volume fractions.