A SUBSTRUCTURE SYNTHESIS METHOD FOR NONSYMMETRICAL VISCOELASTIC SYSTEMS

Based on a new variational principle in the time domain, a substructur e synthesis method is developed for non-symmetric viscoelastic systems without precluding a symmetric formulation. The viscoelastic damping is assumed to be generally non-proportional and in an hereditary integ ral form. The traditional state space formulation is avoided by the pr oposed substructure synthesis method so that the approach is independe nt of viscoelastic models. On the basis of the Rayleigh-Ritz approach, each substructure is approximated by a set of admissible trial vector s. In accordance with substructure order reduction, the geometric comp atibility conditions can be approximated by a weighted residual method . The method is independent of the viscoelastic damping models and the effort on the reduction process is similar to that of classic methods for undamped systems. If all the coefficient matrices are symmetric, the formulation preserves the symmetry in the reduced systems by choos ing the same trial vectors and weighting vectors for both the original and adjoint systems. In the absence of damping, the method is further reduced to classical component mode synthesis if undamped substructur e modes are used as trial vectors. (C) 1995 Academic Press Limited.