MULTISCALE REDUCED ORDER MODELING OF COMPLEX MULTI-BAY STRUCTURES

Project: Research project

Description

The development of a multiscale reduced order modeling (MROM) method is proposed here for the nonlinear geometric dynamic response of complex multi-bay structures such as wings/fuselage with stress hot spots (e.g. cracks, debonds, fasteners, shock impingement points), see Fig. 1.1, to achieve better system level structural designs, enable their health monitoring, and improve mission planning. The advantage of this method over the current state-of-the-art is that the nonlinear behavior of the different scales, micro-meso-macro, will be coupled together to achieve higher fidelity and computational efficiency than the current reliance on separate analyses at each scale. This is expected to be particularly important in the present context of strongly nonlinear behavior in which superposition concepts do not apply. A critical issue in the development of this multiscale reduced order modeling approach is to break the curse of dimensionality, i.e. the rapid increase in the number of degrees of freedom with increased range of scales of the analysis. To achieve these goals, the proposed investigation will focus on: (1) the characterization of the displacement and stress fields in the nonlinear response of cracked panels (considered here as important, representative examples of panels with hot spots) to permit the downscaling of the current capabilities to the micro scale in which stress hot spots exists. It is anticipated that this extension will require the enrichment of the basis used in the reduced order modeling to include localized motions and their associated stresses in the neighborhood of a crack. A first tentative approach to determine the enrichment to the basis is proposed. (2) the formulation and validation of two different upscaling methods to extend the current mesocale nonlinear reduced order modeling capabilities to the macroscale consisting of a complex multi-bay structure. These proposed approaches are based on substructuring concepts and on a nonlinear extension of component mode synthesis. (3) understanding the physical interactions at the meso-macro and micro-meso scales. Points of particular interests will be the mechanisms of interaction between different panels and the extent of this interaction. At the micro-meso scale, the investigation will focus on uncovering the poorly known effects of an existing crack on the nonlinear geometric dynamic response, displacements and stresses, of panels and more specifically the form and spatial extent of these effects.
StatusFinished
Effective start/end date4/15/104/14/13

Funding

  • DOD-USAF-AFRL: Air Force Office of Scientific Research (AFOSR): $331,513.00

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Cracks
Dynamic response
Macros
Fuselages
Fasteners
Computational efficiency
Structural design
Health
Planning
Monitoring