A parametric correction method for model update using measured static flexibility matrices

Abstract

A new method is presented for parametric correction of a large-order static finite element model using a dynamically measured static flexibility matrix of much smaller order. This is accomplished wit hout any model reduction or eigenvector expansion step. The parametric correction is formulated to minimize a residual which is formed using a pseudoinverse relationship between structural flexibility and stiffness matrices. By posing the update problem in terms of measured flexibility matrices instead of experimentally determined modal data, the problems of modal correspondence, mode selection, and modal truncation are avoided. In this paper, numerical simulation results demonstrate that the technique is capable of localizing and quantifying local stiffness errors in a full-order finite element model using a measured flexibility matrix obtained for a much smaller measurement degree-of-freedom set. This is accomplished even when the model error is contained entirely in an element not touching the measurement degree-of-freedom set. (Author)