Milos Dimcic

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Romain Mesnil

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Oskar Gámez Bohórquez

Luleå University of Technology

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gautam tanwar

Ergun Akleman

Texas A&M University

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Papers by Milos Dimcic

Free-form Grid Shell Design Based on Genetic Algorithms

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Structural Optimization of Free-Form Grid Shells

35th Annual Symposium of IABSE / 52nd Annual Symposium of IASS / 6th International Conference on Space Structures, London, September 2011, 2011

In the 21 st century, as free-form design gains popularity, free-form grid shells are becoming a ... more In the 21 st century, as free-form design gains popularity, free-form grid shells are becoming a universal structural solution, enabling merger of structure and façade into a single layer – a skin [1]. This paper shows some of the results of a research project concerned with the optimization of grid structures over some predefined free form shape, with the goal of generating a stable and statically efficient structure. It shows how combining design and FEM software in an iterative, Genetic Algorithms based, optimization process, stress and displacements in grid shell structures can be significantly reduced, whereby material can be saved and stability enhanced.

Integration of FEM, NURBS and Genetic Algorithms in Free-Form Grid Shell Design

Springer eBooks, 2011

Popularity of free-form grid shells grows every day since they represent a universal structural s... more Popularity of free-form grid shells grows every day since they represent a universal structural solution for free-form shaped architecture, enabling the conflation of structure and facade into one element [1]. The infinite number of possibilities of generating a grid structure over some surface calls for an automated method of design and optimization, in contrast to the standard trial-and-error routine. This paper presents some results of the comprehensive research dealing with the optimization of grid shells over some predefined free-form shape. By combining static analysis and design software on a basic C++ level we try to statically optimize a grid shell generated over a given surface. Using Genetic Algorithms for the optimization we are able to significantly reduce stress and displacement in a structure, thus save material and enhance stability. The presented method of structural optimization is constructed as a C++ based plug-in for Rhinoceros 3D, one of the main NURBS (Non Uniform Rational B-Splines) geometry based modeling tools used by architects for free-form design today. The plug-in communicates iteratively with Oasys GSA, a commercial FEM software.

Artificial intelligence in architecture

De Gruyter eBooks, Oct 10, 2017

Structural optimization of grid shells based on genetic algorithms

In the 21 st century, as free form design gains popularity, free-form grid shells are becoming a ... more In the 21 st century, as free form design gains popularity, free-form grid shells are becoming a universal structural solution, enabling merger of structure and facade into a single layer-a skin [31]. The subject of the presented work is the optimization of grid structures over some predefined free form shape, with the goal of generating a stable and statically efficient structure. It is shown how combining design and FEM software in an iterative, Genetic Algorithms based, optimization process, stress and displacements in grid shell structures can be significantly reduced, whereby material can be saved and stability enhanced. Within this research, design and static analysis software are combined in order to perform a statical optimization of grid shells, generated over a given free form surface. A plug-in for Rhinoceros 3D (software based on NURBS [44] geometry representation) is developed, that uses Genetic Algorithms as an optimization method and implements automated iterative calls to Oasys GSA (commercial FEM static analysis software) in order to generate a statically optimal grid shell. To make this possible, within this research some new types of automatic grid generation are developed. Voronoi diagrams [11] were used together with the adapted Force-Density method [38] to develop a new type of grid structure that we called Voronax. In the presented work it was shown that, using the same free form surface, and using the same number of joints and structural members, we can generate much more efficient grid shells, when compared to the standard (uniform) grid structures, simply by modifying the structural grid, i.e., rearranging the structural members of the grid shell. The work presented offers an explanation of the entire method and how it can be constructed. The results of the experiments are there to prove its efficiency and credibility. Once it is proved that the method works, its application can take various forms and be left to the creativity of the user and the requirements of the specific project. IX Zusammenfassung Motivation Die Produktion von Bauteilen durch CNC (Computer Numerical Control)-gesteuerte Maschinen revolutionierte, gegen Ende des 20. Jahrhunderts, den architektonischen Entwurf. Tragwerke mussten nicht mehr vereinfacht werden, um so viele gleiche Elemente wie möglich zu erhalten. Heutzutage können Gebäude mit Tausenden verschiedener (einzigartiger) Trag-oder Fassadenelemente zu akzeptablen Kosten gebaut werden, indem der ganze Prozess automatisiert wird. Die Automatisierung bezieht sich in diesem Fall auf die Programmierungstechniken, die automatische Zeichnung, statische Berechnung und Herstellung individueller Elemente möglich macht, wo der "manuelle" Prozess (ein Teil nach dem anderen) zu viel Zeit in Anspruch nehmen würde. Diese Revolution im Herstellungsprozess erlaubte eine größere Freiheit im Entwurf. So genannte Freiformen, wie sie hauptsächlich im Industriedesign verwendet werden, konnten nun auch in der Architektur zu erschwinglichen Kosten eingesetzt werden. Die Tatsache, dass die Generierung der Struktur auf Basis freier Formen zu lauter Einzelstücken führt, ist nicht länger ein Hemmnis. Aber mit der Freiheit kommt die Verantwortung und die Frage effizienten Entwerfens freier Formen ist die Grundlage der vorgelegten Forschung. Die Gitterschale ist eine Tragstruktur, bei welcher man versucht, das Verhalten einer Schale mit der Gitterform zu kombinieren. Die Kräfte sollen axial (mit so wenig Biegung wie möglich)über die Oberfläche verteilt werden und gleichzeitig soll dies mit einer Gitterstruktur geschehen, weil diese vorgefertigt und einfach zusammengesetzt werden kann. Dies erweist sich als gute Lösung, da Gitterschalen große Distanzen mit einer leichten einlagigen Konstruktionüberspannen können. Das Gitter, dasüblicherweise aus Stahlelementen besteht, ist oft mit Glas gedeckt, hoch transparent und somit geeignet für Dachkonstruktionen (Freiform-Dachkonstruktionen), wie in Bild 0.1 zu sehen. Gitterschalen werden gegenwärtig meist so entworfen, dass die Stäbe gleichmäßig verteilt werden (wie in den Beispielen in Bild 0.1). Aber schon die Intuition sagt uns, dass für eine unregelmäßige Form die beste und statisch wirksamste Verteilung nicht regelmäßig sein kann. Auch Tragwerkslösungen, die man in der Natur findet, zeigen uns, wie die Dichte in tragenden XI Zusammenfassung

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Free-form Grid Shell Design Based on Genetic Algorithms

In the 21st century, as free-form design grows in popularity, grid shells are becoming a universa... more In the 21st century, as free-form design grows in popularity, grid shells are becoming a universal structural solution, enabling the conflation of structure and skin (facade) into one single element (Kolarevic 2003). This paper presents some of the results of a comprehensive research project focused on the automated design and optimization of grid structures over some predefined free form shape, with the goal of generating a stable and statically efficient structure. It shows that by combining design and FEM software in an iterative, Genetic Algorithms-based optimization process, stress and deformation in grid shell structures can be significantly reduced, material can be saved and stability enhanced.

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Parametric Engineering: Everything is Possible

With the 300.000m2 three dimensional folded façade, Bao’an International Airport in Shenzhen is o... more With the 300.000m2 three dimensional folded façade, Bao’an International Airport in Shenzhen is one of the largest parametrically defined buildings in the world. This paper is addressing the application of automated, parametric procedures, used to design some of the world largest free form structures. By comparing different projects realized by Knippers Helbig Advanced Engineering, different approaches for achieving a structually and visually optimal design are explained, as well as principal methods of cooperation between architects and engineers.

Artificial intelligence in architecture

Structural Optimization of Free-Form Grid Shells