A MODIFIED EIGENSTRUCTURE ASSIGNMENT TECHNIQUE FOR FINITE-ELEMENT MODEL UPDATING

This article deals with an extended application of the constrained eig enstructure assignment method (CEAM) to finite element model updating. The existing formulation is modified to accommodate larger systems by developing a quadratic linear optimization procedure that is uncondit ionally stable. Further refinements include the updating of the mass m atrix, a hysteretic damping model, and the introduction of elemental c orrection factors. Six numerical test cases, dealing with effects of d amping and measurement noise, mode shape incompleteness, and discretiz ation differences, were conducted in the case of a 3-D frame model wit h 114 coordinates. The performance of the CEAM was evaluated systemati cally for both the purpose of error location and the global correction of the initial model. The same cases were also studied using another model updating approach, namely the response function method (RFM). It was found that the CEAM had a number of distinct advantages, such as yielding a noniterative direct solution, requiring much less computing power, and providing acceptable results for cases, that could not be handled using the RFM. (C) 1996 John Wiley & Sons, Inc.