Parameter Estimation of Structures from Static Strain Measurements. I: Formulation

Abstract

A method for structural parameter identification utilizing elemental strain measurements is presented. By using a subset of applied static forces and a subset of measured strains, element stiffness parameters of all or a portion of a finite element model of the structure are identified. This method preserves the structural connectivity and determines changes in cross-sectional properties at the element level, including large changes or element failures for stable structures. Strain measurements do not require a frame of reference; this makes them superior to static displacement measurements. Strain measurements are also more accurate than ordinary displacement measurements and can easily be used on bridges, buildings, and space structures. The identified cross-sectional element properties can be used for damage assessment and load rating of structures. Two numerical examples, including two-dimensional (2D) truss and frame structures, are presented and the element stiffnesses are successfully and accurately evaluated.