Search

Isogeometric analysis (IGA) consists of using the same higher-order and smooth spline functions for the representation of geometry in Computer Aided Design as for the approximation of solution fields in Finite Element Analysis. Now, about fifteen years after its creation, substantial works are being reported in IGA, which make it very competitive in scientific computing. This book provides a contemporary vision of IGA by first discussing the current challenges in achieving a true bridge between design and analysis, then proposing original solutions that answer the issues from an analytical point of view, and, eventually, studying the shape optimization of structures, which is one of the greatest applications of IGA. To handle complex structures, a full analysis-to-optimization framework is developed, based on non-invasive coupling, parallel domain decomposition and immersed geometrical modeling. This seems to be very robust, taking on all of the attractive features of IGA (the design–analysis link, numerical efficiency and natural regularization), giving us the opportunity to explore new types of design.

Designing structural parts against the material limits, the impact of loads, and many other constraints, is of standard interest in engineering. However, improving the design of a structure can be long and drawn out, especially when a clear understanding of cause-effect relationships is missing. Finding the best possible design, namely the optimal design, is a complex task because it requires several competences. Usually, efficient geometric modeling is needed to accurately represent the structure. Conjointly, the geometric model should provide high flexibility during the design exploration. In addition, structural analysis must be fast enough to shorten the overall process. Besides, for the sake of compactness, a close connection between the geometric model and the structural analysis seems essential. Finally, all modeling choices are deeply related, and thus, they should be thought and built accordingly to the others. Therefore, IsoGeometric Analysis appears as a powerful tool for structural optimization since it uses a unique model with both high quality geometric and analysis properties. Here, we present a compact framework built on the core idea of IGA. We strive to construct unified models with new opportunities for structural design with a direct application to stiffened Aerostructures. More specifically, we present a solid-shell approach to impose continuous thickness variations. We formulate analytical sensitivities for standard and shell formulations. Then, we introduce an embedded technique that enables to impose complex shape updates. From the analysis point of view, we design a specific solver based on Domain Decomposition methods and Mortar approach for the coupling of non-conforming discretizations. Different examples with increasing level of complexity show the performances of the adopted methodologies.