Review and Evaluation of Shape Expansion Methods, #72

Abstract

Correlation criteria and modeshape expansion techniques deal with the spatial incompatibility linked to the measurement of modeshapes through a limited set of physical sensors and their analytical prediction at a (larger) number of finite element (FE) degrees of freedom (DOFs). Expansion techniques have two conflicting objectives : estimate the motion at all FE DOFs and smooth test errors. The paper first proposes a unified perspective that covers most existing expansion methods. Examples, based on a model of the GARTEUR SM-AG-19 testbed, are used then to analyze the performance of major expansion methods (modal, static, dynamic, minimum residual, and minimum residual with test error). The impact of three usual sources of errors is then considered : inaccuracies in the way true sensor locations are taken into account; error in the test data; errors in the FE model used for the expansion.