Parametric exploration of discrete structures using evolutionary computation

p. 577-588Parametric modelling software is being employed in architectural design exploration with increasing frequency. Examples of systems used in architectural design include Generative Components (Bentley Systems), Grasshopper (Robert NcNeel), Digital Project (Gehry Technologies - Dassault Systemes) and others. All of these systems are basically geometry modellers and do not provide quantitative information regarding structural behaviour or environmental quality. This paper shows an example which couples a parametric modeller with a finite element analysis guided by a genetic algorithm to explore families of structural form. In this example, the Generative Components parametric modeller is used to generate different geometries and topologies based on a programmed set of rules. The forms are then evaluated using an FEA program to determine the overall weight. The genetic algorithm is used to guide the population of solutions in the direction of least weight. In addition, human interaction is also possible through the selection of breeding pairs. The selection process is carried out visually though a web interface which allows multiple designers to act in parallel while the program is running. As a result the analysis of the individual solutions in the population occurs in parallel over a distributed network (the internet). The parameters which act as chromosome strings in the genetic algorithm become input variables for the parametric modeller, which then generates new structural forms as the cycle repeats. The full cycle includes the following steps: 1. Selection - through a web based interface 2. Breeding - within the genetic algorithm 3. Form Generation - using the parametric modeller 4. Analysis and Member Design - with FE computation 5. Ranking in the Population - collected over the internet Finally, advantages and limitations to the procedure are discussed. Details from an actual example are show with graphic results, and recommendations are made for continued development of the procedure.Von Buelow, P. (2010). Parametric exploration of discrete structures using evolutionary computation. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/730

A Geometric Comparison of Branching Structures in Tension and in Compression versus Minimal Paths

Branching structures are based on geometric systems that expand through bifurcation without returning to form closed cells. In this sense, branching structures resemble the structure of trees that branch continually outward. In architectural engineering, these forms can be used either as tension or compression systems. Numerous built examples have been produced since the initial inspiring studies made by Frei Otto in the early 1960's. Form finding techniques based on models have been used in the past to study these forms. Although thread models can be effective in the study of force paths, they cannot distinguish between tension and compression and have no way to take member buckling into account. But buckling does have an influence on appropriate geometry of a compression system. Also, minimal paths (or pseudo minimal paths based on surface tension thread models) have been used to explore possible geometries for branching structures. In this paper, both surface tension thread models dipped in water, and weighted string models are shown in comparison with ideal tension and compression forms found with a computational method based on Genetic Algorithms. The same computational model is used to find geometries with minimal overall member length. Both 2D and 3D geometries are derived.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58599/1/pvb_IASS07.pd

Using Evolutionary Computation to explore geometry and topology without ground structures

Extended abstract for IASS-IACM 2008 International Conference in Ithaca, NY (Cornell University)Over the past two decades there has been an increasing interest in using what has come to be called Evolutionary Computation (EC) in the analysis and optimization of structural systems. These methods include Genetic Algorithms (GA), Evolution Strategies (ES), Simulated Annealing and other stochastic based numerical methods. Each of these methods shares the drawback that they are very computationally intensive compared to deterministic methods. Furthermore, the computational burden can rapidly increase as the size of the analyzed structure increases. This paper suggests that the level of computation can be significantly reduced by avoiding the common practice of using ground structures in coding the topology. Additionally, comparative examples show that a broader range of good solutions can be reached when the use of ground structures is avoided.http://deepblue.lib.umich.edu/bitstream/2027.42/58661/6/tp_full.avihttp://deepblue.lib.umich.edu/bitstream/2027.42/58661/5/tp_best.avihttp://deepblue.lib.umich.edu/bitstream/2027.42/58661/4/tr_best.avihttp://deepblue.lib.umich.edu/bitstream/2027.42/58661/3/IASS_IACM_2008_PPT_PvB.PPThttp://deepblue.lib.umich.edu/bitstream/2027.42/58661/2/IASS-IACM_2008_slides_PvB.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/58661/1/IASS-IACM_2008_PvB.pd

ARCH 324 - Structures 2, Winter 2009

This course covers the basic principles of elastic behavior for different materials such as wood, steel, concrete, and composite materials and compares the properties and applications of materials generally. It investigates cross sectional stress and strain behavior in flexure and in shear, and torsion as well as the stability of beams and columns. The qualitative behavior of combined stresses and fracture in materials is also 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Computational Form Exploration of Branching Columns Using Concepts of Formex Algebra and the Paragen Method

This study addresses the relationship between the geometry and structural performance of branching columns using an example case based on a square grid shell supported by four branching columns. The branching columns are configured with three levels of members, bifurcating into four members as each member branches upwards. A range of solutions is parametrically generated using the concepts of formex algebra and its associated software system, Formian 2.0. The form exploration uses the GAbased method, ParaGen which incorporates both quantitative structural performance and qualitative architectural considerations in the exploration process. Certain design constraints, as well as multiple objectives, are established including minimizing structural weight and deflection, and increasing vibration stiffness, in addition to the designer’s satisfaction with the visual appearance of the columns. Within the iterative process of form generation, the structural performance of the branching columns under a combination of self-weight and snow load is evaluated using the Finite Element Analysis (FEA) software, STAAD.Pro. The branching members are sized based on the AISC LRFD steel code. ParaGen creates a database of suitable solutions, which can be explored by filtering and sorting based on a variety of performance parameters. Different techniques are demonstrated in the exploration of good solutions including scatter point graphs, Pareto front analysis, and images of the design alternatives

Design Exploration by Using a Genetic Algorithm and the Theory of Inventive Problem Solving (TRIZ)

This paper presents a computational design exploration method called GA+TRIZ, which aids designers in defining the design problem clearly, making a parametric model where pertinent variables are included, obtaining a series of suitable solutions, and resolving existing conflicts among design objectives. The goal is to include the designer\u27s qualitative and performance-based quantitative design goals in the design process, while promoting innovative ideas for resolving contradictory design objectives. The method employed is a Genetic Algorithm (GA), earlier implemented in an automated design exploration process called ParaGen, in combination with the Theory of Inventive Problem Solving (TRIZ), a novel methodology to assist architects and structural engineers in the conceptual phase of design. The GA+TRIZ method promotes automated design exploration, investigation of unexpected solutions, and continuous interaction with the computational generating system. Finally, this paper presents two examples that illustrate how the GA+TRIZ method assists designers in problem structuring, design exploration, and decision-making

Multivariate Interactive Visualization of Data in Generative Design

SimAUD 2016 conference paper with high resolution images and presentation slidesIn this paper we describe our work on providing support for design decision making in generative design systems producing large quantities of simulation data. The work is motivated by the continuing challenge of making sense of large design and simulation result datasets. Our approach is to provide methods and tools for multivariate interactive data visualization of the generated designs and simulation results. These enable designers to focus not only on high-performing results but also to examine suboptimal designs’ attributes and outcomes so as to discover relationships giving greater insight to design performance and facilitating guidance of further design generation. We illustrate this with an example exploring building massing and envelope design (fenestration arrangement and external shading) with simulations of daylighting and heat gain. We conclude that the visualization techniques investigated are potentially useful in helping designers to better comprehend the inter-relationships between variable parameters, constraints and outcomes, with consequent benefits in finding good design outcomes as well as in verifying that simulation results are reliable and understanding characteristics of the fitness landscape.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117408/1/Figure1.jpgDescription of Figure1.jpg : Figure 1. Examples of different design solution images

Shanghai Spatial Structures -Permanent and Temporary

Abstract The work described in this paper aims at developing the interrelation and overall effects of interaction between a folded plate roof structure and a system of branching column supports. In the context of architectural performance it is of interest to discuss the effects of the material on environmental conditions. The current study is complementary to a project on environmental and architectural performance of a freeform roof and will discuss modelling, environmental performance and material related issues such as material properties considering thermal and moisture buffering effects on the resulting architectural context. The currently presented paper aims at initiating a further developed study of system action in a broad architectural sense, sub-system interaction and material-specific considerations