Seminar 14th April 2010 4 p.m. University of Southampton, Lanchester 7/3031
Subdivision shells for integrated finite element analysis and geometric modelling
Dr. Fehmi Cirak
Department of Engineering, University of Cambridge
- Biomedical, C++, CFD, Finite elements, Flight simulation, Fortran, HDF5, HPCx, Linux, Multi-physics, Structural dynamics, VisIt, Windows
- Georges Limbert
The unification of shape parameterisation techniques used in Computer Aided Design (CAD) and the discretization techniques used in finite element analysis gained lately momentum with the introduction of the isogeometric analysis paradigm. The basic idea of isogeometric analysis is to use the same set of shape, or basis, functions for geometric modelling and finite element analysis. In practice, one uses for finite element analysis shape functions from CAD since the conventional finite element shape functions are not sufficiently versatile for geometric modelling. One of the promises of isogeometric analysis is that a unified representation paradigm may facilitate a tighter integration of the presently disparate geometric modelling and analysis tools. In addition, spline based CAD shape functions have a number of superior approximation properties, such as positivity, higher order smoothness, variation diminishing property and refinability. In the spirit of isogeometric analysis, subdivision shells use the subdivision surfaces for finite element analysis and geometric modelling of shell structures. Subdivision surfaces are the generalisation of splines to arbitrary connectivity meshes and are on logically Cartesian meshes identical to usual tensor product splines. This presentation will give an overview of subdivision shells and introduce their use in selected applications, such as the stability analysis of thin and ultra-thin shells, aeroelastic stability of parachutes and shape optimisation of shell structures.