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Title: Modal Substructuring of Geometrically Nonlinear Finite Element Models with Interface Reduction

Substructuring methods have been widely used in structural dynamics to divide large, complicated finite element models into smaller substructures. For linear systems, many methods have been developed to reduce the subcomponents down to a low order set of equations using a special set of component modes, and these are then assembled to approximate the dynamics of a large scale model. In this paper, a substructuring approach is developed for coupling geometrically nonlinear structures, where each subcomponent is drastically reduced to a low order set of nonlinear equations using a truncated set of fixedinterface and characteristic constraint modes. The method used to extract the coefficients of the nonlinear reduced order model (NLROM) is non-intrusive in that it does not require any modification to the commercial FEA code, but computes the NLROM from the results of several nonlinear static analyses. The NLROMs are then assembled to approximate the nonlinear differential equations of the global assembly. The method is demonstrated on the coupling of two geometrically nonlinear plates with simple supports at all edges. The plates are joined at a continuous interface through the rotational degrees-of-freedom (DOF), and the nonlinear normal modes (NNMs) of the assembled equations are computed to validate the models.more » The proposed substructuring approach reduces a 12,861 DOF nonlinear finite element model down to only 23 DOF, while still accurately reproducing the first three NNMs of the full order model.« less
 [1] ;  [2] ;  [3]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  2. Univ. of Wisconsin, Madison, WI (United States). Dept. of Engineering Physics
  3. Air Force Research Lab. (AFRL), Wright-Patterson AFB, OH (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0001-1452; 619965
Grant/Contract Number:
AC04-94AL85000; FA9550-11-1-0035
Accepted Manuscript
Journal Name:
AIAA Journal
Additional Journal Information:
Journal Volume: 55; Journal Issue: 5; Journal ID: ISSN 0001-1452
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
US Air Force Office of Scientific Research (AFOSR); USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
42 ENGINEERING; substructuring; component mode synthesis; geometric nonlinearity; interface reduction; nonlinear normal modes
OSTI Identifier: