MODEL UPDATING FOR CONSTRAINT BOUNDARY CONDITIONS OF MEMBER STRUCTURES USING INCOMPLETE MEASURED MODES

The constraint boundary condition model updating a member structure was studied in this paper.Through building the boundary element stiffness matrixes,the present substructure correction factor updating method was extent to the boundary conditions.With an iterative procedure,the boundary conditions can be updated based on only a few measured modal frequencies.And also,a two-step method is proposed to update the whole structure(including the boundary and the superstructure) using lower incomplete measured modes,which can avoid the ill-condition problem.Numerical examples based on finite element models associated with a cantilever beam are chosen to investigate the accuracy of the proposed boundary conditions updating method and the two-step method.Furthermore,an experiment study associated with a steel cantilever beam is also conducted to examine the proposed methods.