1. Dr.-Ing. Andreas Apostolatos
Technical University of Munich
Department of Civil, Geo and Environmental Engineering
Chair of Structural Analysis
Isogeometric Analysis of Lightweight Structures
with application to Fluid-Structure Interaction and
Stochastic Optimization
2. Motivation
Isogeometric Analysis on Multipatch Surfaces
Isogeometric Membrane Analysis on Multipatches
Isogeometric Kirchhoff-Love Shell Analysis on Multipatches
Fluid-Structure Interaction
Stochastic Optimization
Conclusions & Outlook
3. a) Roof of the olympia stadion in Munich
b) Inflatable hangar
c) NREL phase VI wind turbine
http://www.cimne.com/websasp/ulites/
1
Simms, D., Schreck, S., Hand, M., Fingersh, L.J.: Nrel unsteady aerodynamics experiment in the nasa-ames wind tunnel:
a comparison of predictions to measurements. National Renewable Energy Laboratory Colorado, USA (2001)
2
Motivation
1
2
9. Motivation
Isogeometric Analysis on Multipatch Surfaces
Isogeometric Membrane Analysis on Multipatches
Isogeometric Kirchhoff-Love Shell Analysis on Multipatches
Fluid-Structure Interaction
Stochastic Optimization
Conclusions & Outlook
10. Isogeometric Membrane Analysis on Multipatches
A. Apostolatos, K.-U. Bletzinger, R. Wüchner (in press). “Weak imposition of constraints for membrane structures in transient geome-
trically nonlinear multipatch isogeometric analysis.” Computer Methods in Applied Mechanics and Engineering (2019)
11. Isogeometric Membrane Analysis on Multipatches
Fig. Form-finding for structural membranes
a. Reference geometry b. Form-found shape
12. Fig. Middle sail of the olympic stadium roof in Munich (form-found shape)
Isogeometric Membrane Analysis on Multipatches
Fig. Middle sail of the olympic stadium roof in Munich (form-finding)
13. Isogeometric Membrane Analysis on Multipatches
Fig. Middle sail of the roof of the Olympic stadium in Munich (mode shapes)
14. Motivation
Isogeometric Analysis on Multipatch Surfaces
Isogeometric Membrane Analysis on Multipatches
Isogeometric Kirchhoff-Love Shell Analysis on Multipatches
Fluid-Structure Interaction
Stochastic Optimization
Conclusions & Outlook
15. Isogeometric Kirchhoff-Love Shell Analysis on Multipatches
A. Apostolatos, M. Breitenberger, K.-U. Bletzinger, R. Wüchner: Domain Decomposition Methods and Kirchhoff-Love Shell Multipatch
Coupling in Isogeometric Analysis. Isogeometric Analysis and Applications 2014. Springer, Cham, 2015. 73-101
21. Motivation
Isogeometric Analysis on Multipatch Surfaces
Isogeometric Membrane Analysis on Multipatches
Isogeometric Kirchhoff-Love Shell Analysis on Multipatches
Fluid-Structure Interaction
Stochastic Optimization
Conclusions & Outlook
22. Fluid-Structure Interaction
A. Apostolatos, G. De Nayer, K.-U. Bletzinger, M. Breuer, R. Wüchner (in press). “Systematic evaluation of the interface description for
fluid-structure interaction simulations using the isogeometric mortar-based mapping”. Journal of Fluids and Structures (2019)
30. Motivation
Isogeometric Analysis on Multipatch Surfaces
Isogeometric Membrane Analysis on Multipatches
Isogeometric Kirchhoff-Love Shell Analysis on Multipatches
Fluid-Structure Interaction
Conclusions & Outlook
31. Conclusions & Outlook
Achievements
• Constraint enforcement methods for the multipatch coupling in IGA
• Penalty
• Lagrange Multipliers
• Augmented Lagrange Multipliers
• Nitsche-type
• Isogeometric membrane analysis on multipatches
• Form-finding analysis using the URS
• Geometrically nonlinear, modal and transient analysis
• Isogeometric Kirchhoff-Love shell analysis on multipatches
• Shell obstacle course
• Geometrically nonlinear, modal and transient analysis
• Development of an isogeometric mortar-based surface mapping method
• Development of a stochastic optimization framework based on the exact CAD geometry
32. • A. Apostolatos, R. Schmidt, R. Wüchner, K.-U. Bletzinger. „A Nitsche-type formulation and comparison of the most
common domain decomposition methods in isogeometric analysis.“ In: International Journal for Numerical Methods in
Engineering 97.7 (2014) pp. 473-504.
• A. Apostolatos, M. Breitenberger, R. Wüchner, K.-U. Bletzinger. „Domain Decomposition Methods and Kirchhoff-
Love Shell Multipatch Coupling in Isogeometric Analysis“. In: Isogeometric analysis and applications 2014. Ed. by B.
Simeon. Vol. 107. Lecture Notes in Computational science and Engineering. Cham, Heildelberg and New York:
Springer, 2015, pp. 73-101. ISBN:978-3-319-23314-7.
• M. Breitenberger, A. Apostolatos, B. Philipp, R. Wüchner, K.-U. Bletzinger. „Analysis in computer aided design:
Nonlinear isogeometric B-Rep analysis of shell structures“. In: Computer Methods in Applied Mechanics and
Engineering 284 (2015), pp. 401-457.
• A. Apostolatos, R. Wüchner, K.U. Bletzinger (in press). „Weak enforcement of constraints for membrane structures
in transient geometrically nonlinear multipatch isogeometric analysis“. In: Computer Methods in Applied Mechanics
and Engineering (2019).
• G. de Nayer, A. Apostolatos, J.N. Wood, K.-U. Bletzinger, R. Wüchner, M. Breuer.. „Numerical studies on the fluid-
structure interaction of an air-inflated flexible hemisphere in turbulent flows.“ In: Journal of Fluids and Structures 82
(2018) pp. 577-609.
• A. Apostolatos, G. de Nayer, K.-U. Bletzinger, M. Breuer, R. Wüchner (in press). „Systematic evaluation of the
interface description for fluid-structure interaction simulations using the isogeometric mortar-based mapping.“ In:
Journal of Fluids and Structures (2019).
Literature