Micromechanics-based finite element modeling of sandwich structures

ended

The use of novel steel sandwich panels in ship decks instead of conventional stiffened plates offers more economical and energy-efficient designs through material, space and fuel savings. To analyse the global structural response of a large ship within computational limits, the sandwich panels need to be modeled in an averaged (homogenized) sense without accounting for every small detail. Motivated by this, my objective is to develop simplified theoretical and computational micromechanics-based beam and plate models for sandwich panels that have unidirectional structural cores and flexible joints. The key theoretical modeling idea is to consider periodic panels as discrete lattices which are replaced by energetically equivalent, linear micropolar continuum beam and plate models. Subsequently, finite element models for the substitute-continuum beams and plates are formulated. Contrary to existing methods, the proposed approach includes all the necessary features. First, it fully accounts for flexible (e.g. laser-welded) joints of the panels. Second, the determination of all model parameters is straightforward. Third, the derived models can be easily implemented later in various readily available finite element software. In addition to shipbuilding, structural core sandwich panels have applications in bridge engineering and residential buildings. The micromechanical aspect of this project is expected to provide new understanding of interdisciplinary issues in higher-order continuum theories. Such theories form a central topic in my host’s, Prof. J.N. Reddy’s research group at Texas A&M University in addition to beam and plate theories and finite elements. The results of this project are disseminated in workshops to shipbuilders at Meyer Turku shipyard (Finland) and to bridge researchers at Chalmers University of Technology (Sweden) during the return phase in the Advanced Marine Structures research group at Aalto University, Finland.