Rotational stiffness in timber joinery connections: analytical and experimental characterizations of the Nuki joint

Demi L. Fang, Jan Brütting, Julieta Moradei, Corentin Fivet, Caitlin T. Mueller, 4th International Conference on Structures and Architecture, 2019 (Abstract accepted)

Historic timber structures feature timber joinery connections that use interlocking geometries rather than fasteners. While timber construction since has gradually favored metallic fasteners, the longevity of historic timber structures utilizing joinery connections demonstrates their feasibility in structural systems and potential to enable sustainable constructions. Advancements in digital fabrication imply the ability to revitalize these complex geometries in competition with conventional fasteners. However, characterization of the mechanical behavior of joinery connections remains to be calibrated across analytical, experimental, and numerical models, let alone systematized across different geometric variations. This research examines the calibration between analytical models and experimental tests for the Nuki joint, a simple beam-through-mortised-column joinery connection. This paper shows that general elastoplastic behavior matches between models, and the analytical model can be calibrated to predict initial stiffnesses within 20% of those determined experimentally. Mismatches between models reveal challenges in calibrating across models: material irregularity of wood and fabrication tolerances.

Group member authors:

• Demi Fang
• Caitlin Mueller

Related projects:

• Design, mechanics, and optimization of interlocking wood joints

Tags:

• collaboration
• fabrication
• digital-manufacturing
• timber
• joinery
• mechanics

Citation:

Fang, D. L., Brütting, J., Moradei, J., Fivet, C., & Mueller, C. T. (2019). Rotational stiffness in timber joinery connections: analytical and experimental characterizations of the Nuki joint. Presented at the 4th International Conference on Structures and Architecture, Lisbon, Portugal.

A Platform of Design Strategies for the Optimization of Concrete Floor Systems in India

Mohamed Ismail and Caitlin Mueller, International Conference on Structures and Architecture, 2019

This paper presents a developing platform of design strategies for concrete construction in India. More specifically, this paper will discuss three strategies for the design of horizontal spanning concrete elements. Each strategy involves a different method of structural optimization with varying performance levels based on material reduction and structural capacity. Designed for India’s affordable housing construction, the elements are constrained by the fabrication methods and materials available to India’s construction industry, merging structural design with the development of affordable housing technology. Material savings range from 16% to 50% depending on the strategy. The strategies are used to design, fabricate, and structurally test prototypes, exploring their potential for India’s construction needs.

Group member authors:

• Mohamed Ismail

Related projects:

• Low-Cost, Low-Carbon Structural Components for Housing in India

Tags:

• computation
• fabrication
• computational-design
• conceptual-structural-design
• conference
• digital-manufacturing
• structural-optimization

Citation:

Engineering a New Nation: Mahendra Raj and his collaborations across disciplines

Mohamed Ismail and Caitlin Mueller, BLACK BOX: Articulating Architecture’s Core in the Post-Digital Era, 2019

Mahendra Raj is an engineer that enjoys a challenge. Consequently, no two projects of his are the same. With a portfolio of over 250 projects and a career spanning nearly six decades, from Indian Independence to the time of this paper’s writing, there is no simple explanation for who Raj works with or how he works with them. In an attempt to understand the range and extent of Raj’s ability and influence on projects, this paper will examine three seminal projects from his early career. Each project will display a different facet of how Raj works with architects. The first will be Raj’s close collaboration with Pritzker laureate, Balkrishna Doshi: Tagore Memorial Hall in Ahmedabad, completed in 1965. Second, the Hall of Nations and Halls of Industries, designed with Raj Rewal and Kuldip Singh, and completed in 1972 in New Delhi. Last, the Hindon River Mills, designed with Kanvinde and Rai, and built in 1973 in Ghaziabad. Each project shows a visionary engineering solution where the structure makes a bold statement and becomes integral to the architecture. Yet between them, differences emerge in how Mahendra Raj works with the architects. This paper explores those differences.

Group member authors:

• Mohamed Ismail

Related projects:

• Low-Cost, Low-Carbon Structural Components for Housing in India

Tags:

• collaboration
• collaboration
• engineering
• history

Citation:

Structural Optimization of Cross-Laminated Timber Panels

Paul Mayencourt, Irina Rasid, and Caitlin Mueller, IASS 2018 Symposium, 2018

Cross-Laminated Timber (CLT) panels are gaining considerable attention in the United States as designers focus on building more ecological and sustainable cities. These panels can speed up construction on site due to their high degree of prefabrication, and consequently, CLT is deployed for slab systems, walls and composite systems in modern buildings. However, the structural use of the material is inefficient in CLT panels. The core of the material does not contribute to the structural behavior and acts merely as a spacer between the outer layers. This project offers an alternative design of an optimized CLT panel with the goal of reducing material consumption and increasing the efficiency of this building component, which can help it become more ubiquitous in building construction.
In this paper, a theoretical model for the behavior of optimized CLT panels is developed, and this model is compared with scaled physical load tests. The results demonstrate that the theoretical model accurately predicts physical behavior. Furthermore, around 20 % of material can be saved without major change in the structural behavior. The reduced material consumption and cost of the proposed optimized CLT panels can help mitigate the ecological impact of the construction industry, while offering a new competitive building product to the market.

Group member authors:

• Paul Mayencourt
• Caitlin Mueller

Full-text access:

• PDF Download

Tags:

• fabrication
• digital-manufacturing
• embodied-carbon
• load-testing
• structural-analysis
• structural-optimization
• timber

Citation:

Mayencourt, P., Rasid, I., & Mueller, C. (2018). Structural Optimization of Cross-Laminated Timber Panels. Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2018.

Automated sequence and motion planning for robotic spatial extrusion of 3D trusses

Yijiang Huang, Caelan R. Garrett and Caitlin T. Mueller, Preprint, arXiv:1810.00998, 2018

While robotics for architectural-scale construction has made significant progress in recent years, a major challenge remains in automatically planning robotic motion for the assembly of complex structures. This paper proposes a new hierarchical planning framework to solve the assembly planning problem for architectural discrete structures, which usually have a long planning horizon and 3D configuration complexity. By decoupling sequence and motion planning, the planning framework is able to efficiently solve the assembly sequence, end-effector poses, joint configurations, and transition trajectories for assembly of spatial structures with nonstandard topologies, which hasn't been demonstrated in previous literature. Together with the algorithmic results, this paper also presents an open-source and modularized software implementation called Choreo that is machine and application-agnostic. To demonstrate the power of this algorithmic framework, three case studies, including real fabrication and simulation results, are presented to show Choreo's application on spatial extrusion.

Group member authors:

• Yijiang Huang

Related projects:

• Automatic Path Planning Framework for Robotic Construction

Full-text access:

• PDF Download
• DOI

Tags:

• computation
• fabrication
• construction-planning
• robotic-fabrication

Citation:

Huang, Y., Garrett, C. R., & Mueller, C. T. (2018). Automated motion planning for robotic assembly of discrete architectural structures. ArXiv:1810.00998 [Cs]. http://arxiv.org/abs/1810.00998

Robotic extrusion of architectural structures with nonstandard topology

Yijiang Huang, Josephine Carstensen, Lavender Tessmer and Caitlin Mueller, ROB|ARCH 2018: Robotic Fabrication In Architecture, Art and Design 2018, 2018 (Under review)

This paper presents a fast and flexible method for robotic extrusion (or spatial 3D printing) of designs made of linear elements that are connected in non-standard, irregular, and complex topologies. Nonstandard topology has considerable potential in design, both for visual effect and material efficiency, but usually presents serious challenges for robotic assembly since repeating motions cannot be used. Powered by a new automatic motion planning framework called Choreo, this paper’s robotic extrusion process avoids human intervention for steps that are typically arduous and tedious in architectural robotics projects. Specifically, the assembly sequence, end effector pose, joint configuration, and transition trajectory are all generated automatically using state-of-the-art, open-source planning algorithms developed in the broader robotics community. Three case studies with topologies produced by structural optimization and generative design techniques are presented to demonstrate the potential of this approach.

Group member authors:

• Yijiang Huang
• Caitlin Mueller

Related projects:

• Automatic Path Planning Framework for Robotic Construction

Tags:

• fabrication
• construction-planning
• robotic-fabrication
• topology-optimization

Citation:

Huang, Y., Carstensen, J., Tessmer, L. & Mueller, C. (2018). Robotic extrusion of architectural structures with nonstandard topology. Rob|Arch 2018: Robotic Fabrication in Architecture, Art and Design 2018. Springer.

Gradient-based guidance for controlling performance in early design exploration

Nathan Brown and Caitlin Mueller, Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2018, 2018

In recent years, heuristic optimization techniques have become widely used in architectural and structural design practice. However, when used as a black box solver rather than an interactive design tool, such strategies become essentially passive, ceding considerable design control to the computer. Although researchers have developed interactive versions of common approaches such as evolutionary algorithms, there has been less focus on finding ways to use gradient-based optimization techniques in cases where designers seek increased creative control. This paper explores two ways in which gradient-based guidance can be exploited as part of an interactive design process: live gradient vector visualization for geometric design problems, and taking discrete steps in the design space based on performance information. These strategies are first demonstrated on a simple truss, before being tested on parametric models for a courtyard building and a long-span airport terminal. Initial results show that with further work, gradient-based guidance during interactive design exploration could be a viable strategy for designers seeking more control than is allowed by automated optimization algorithms.

Group member authors:

• Nathan Brown
• Caitlin Mueller

Full-text access:

• PDF Download

Citation:

Brown, N. & Mueller, C. (2017). Gradient-based guidance for controlling performance in early design exploration. Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2018, Cambridge, MA.

Quantifying Diversity in Parametric Design: A Comparison of Possible Metrics

Nathan Brown and Caitlin Mueller, Artificial Intelligence for Engineering Design, Analysis and Manufacturing, 2018

To be useful for architects and related designers searching for creative, expressive forms, performance-based digital tools must generate a diverse range of design solutions. This gives the designer flexibility to choose from a number of high-performing designs based on aesthetic preferences or other priorities. However, there is no single established method for measuring diversity in the context of computational design, especially in the field of architecture. This paper explores different metrics for quantifying diversity in parametric design, which is an increasingly common digital approach to early-stage exploration, and tests how human users perceive these diversity measurements. It first provides a review of existing methodologies for measuring diversity and describes how they can be adapted for parametrically formulated design spaces. The paper then tests how these different metrics align with human perception of design diversity through an online visual survey. Finally, it offers a quantitative comparison between the different methods, and a discussion of their attributes and potential applications. In general, the comparison indicates that at the level of diversity difference that becomes visually meaningful to humans, the measurable difference between metrics is small. This paper informs future researchers, developers, and designers about the measurement of diversity in parametric design, and can stimulate further studies into the perception of diversity within sets of design options, as well as new design methodologies that combine architectural novelty and performance.

Group member authors:

• Nathan Brown
• Caitlin Mueller

Related projects:

• Quantifying diversity in computational design

Full-text access:

• DOI

Tags:

• design-diversity;
• parametric-design
• creativity

Citation:

Brown, N.C., & Mueller, C. T. (2018). Quantifying diversity in parametric design: a comparison of possible metrics. Artificial Intelligence for Engineering Design, Analysis and Manufacturing.

Design variable analysis and generation for performance-based parametric modelling in architecture

Nathan Brown and Caitlin Mueller, International Journal of Architectural Computing, 2018 (In press)

Many architectural designers recognize the potential of parametric models as a worthwhile approach to performance-driven design. A variety of performance simulations are now possible within computational design environments, and the framework of design space exploration allows users to generate and navigate various possibilities while considering both qualitative and quantitative feedback. At the same time, it can be difficult to formulate a parametric design space in a way that leads to compelling solutions and does not limit flexibility. This paper proposes and tests the extension of machine learning and data analysis techniques to early problem setup in order to interrogate, modify, relate, transform, and automatically generate design variables for architectural investigations. Through analysis of two case studies involving structure and daylight, this paper demonstrates initial workflows for determining variable importance, finding overall control sliders that relate directly to performance, and automatically generating meaningful variables for specific typologies.

Group member authors:

• Nathan Brown
• Caitlin Mueller

Tags:

• computational-design
• parametric-design
• dimensionality-reduction

Citation:

Brown, N. C., & Mueller, C. T. (in press). Design variable analysis and generation for performance-based parametric modelling in architecture. International Journal of Architectural Computing.

Joinery connections in timber frames: analytical and experimental explorations of structural behavior

Demi Fang and Caitlin Mueller, International Association for Shell and Spatial Structures (IASS), 2018

Innovations in mass timber have ushered in a resurgence of timber construction. Historic timber structures feature joinery connections which geometrically interlock, rarely featuring in modern construction which utilizes steel fasteners for connection details. Research in the geometric potential and mechanical performance of joinery connections remain disparate. This study seeks to develop a performance-driven design framework for the geometry of joinery connections. Experimental and analytical models for three types of joinery connections are presented and compared. The T* type joint, which uses a T-shaped tenon instead of a dovetail, experimentally showed the highest rotational stiffness. The analytically predicted rotational stiffness of the T* type joint comes within 20% of the experimentally determined value. A preliminary parametric study through the analytical model demonstrates how geometric parameters can be varied to achieve desired rotational stiffness.

Group member authors:

• Demi Fang
• Caitlin Mueller

Tags:

• computation
• conceptual-design
• conceptual-structural-design
• digital-manufacturing
• structural-analysis
• timber

Citation:

Fang, D., & Mueller, C. (2018). Joinery connections in timber frames: analytical and experimental explorations of structural behavior. Presented at the International Association for Shell and Spatial Structures, Cambridge, MA, USA.

3D truss topology optimization for automated robotic spatial extrusion

Yijiang Huang, Josephine V. Carstensen, Caitlin T. Mueller, International Association for Shell and Spatial Structures (IASS), 2018

This paper contributes new knowledge and results to the fields of topology optimization and robotic spatial extrusion through the consideration of how these methods can be used together. Specifically, a new topology optimization formulation is presented that accounts for the manufacturing constraints of uniform cross section and average member length. In addition, a new robotic assembly planning framework is demonstrated, which allows the complex but structurally efficient results of the topology optimization to be materialized in a reasonable amount of time. Three novel case studies produced by the proposed topology optimization framework are presented to demonstrate how automated assembly planning and robotic extrusion can enable a direct and efficient means to materialize a 3D topology-optimized truss.

Group member authors:

• Yijiang Huang
• Caitlin Mueller

Related projects:

• Automatic Path Planning Framework for Robotic Construction

Full-text access:

• PDF Download

Tags:

• computation
• fabrication
• additive-manufacturing
• construction-planning
• robotic-fabrication
• topology-optimization

Citation:

Huang, Y., Carstensen, J. & Mueller, C. (2018). 3D truss topology optimization for automated robotic spatial extrusion. Presented at the International Association for Shell and Spatial Structures, Cambridge, MA, USA.

Computational Structural Design and Fabrication of Hollow-Core Concrete Beams

Mohamed Ismail, Caitlin Mueller, IASS Symposium 2018: Creativity in Structural Design, 2018

The paper presents the results of the design method for a simply supported cavity beam, along with fabrication and load testing results. An optimization algorithm determines the location and rotation of empty plastic water bottles within a prismatic reinforced concrete beam in order to reduce material usage without reducing strength. Designed for India’s affordable housing construction, the beam is constrained by the fabrication methods and materials available to India’s construction industry. This is an effort to merge structural design tools with the development of affordable housing technology, potentially reducing the economic and environmental cost of construction through material efficiency. The designed beam results in a theoretical concrete volume reduction of 16%. Two cavity beams are designed and constructed, and then load-tested in comparison to two solid beams with the same dimensions.

Group member authors:

• Mohamed Ismail
• Caitlin Mueller

Related projects:

• Low-Cost, Low-Carbon Structural Components for Housing in India

Full-text access:

• PDF Download

Tags:

• computation
• fabrication
• conceptual-structural-design
• conference
• embodied-carbon
• grasshopper
• load-testing
• structural-analysis
• structural-optimization

Citation:

Automated performance-based design space simplification for parametric structural design

Nathan Brown and Caitlin Mueller, Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium, 2017

Group member authors:

• Nathan Brown

Full-text access:

• PDF Download

Tags:

• computation
• conceptual-structural-design
• computational-design
• variable-sensitivity
• design-space

Citation:

Brown, N. & Mueller, C. (2017). Automated performance-based design space simplification for parametric structural design. Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2017.

Designing with data: moving beyond the design space catalog

Nathan Brown and Caitlin Mueller, ACADIA, 2017

Group member authors:

• Nathan Brown
• Caitlin Mueller

Full-text access:

• DOI

Tags:

• computation
• design-space
• surrogate-modelling
• diversity
• simplification

Citation:

Brown, N. & Mueller, C. (2017). Designing with data: moving beyond the design space catalog. ACADIA 2017.

Computational Structural Optimization and Digital Fabrication of Timber Beams

Paul Mayencourt, Joaquin S. Giraldo, Eric Wong, and Caitlin Mueller, Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium, 2017

This paper focuses on optimizing beams made of solid timber sections through a CNC subtractive milling process. An optimization algorithm shapes beams and reduces the material quantities by up to 50% of their initial weight. A series of these beams are then fabricated and load tested, and their strength is compared to standard timber sections.

Group member authors:

• Paul Mayencourt
• Caitlin Mueller

Related projects:

• Computational Structural Optimization and Digital Fabrication of Timber Beams

Full-text access:

• PDF Download

Tags:

• fabrication
• computational-design
• load-testing
• structural-optimization
• timber

Citation:

Mayencourt, P, Giraldo J. S., Wong, E. & Mueller, C. (2017). Computational Structural Optimization and Digital Fabrication of Timber Beams. Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2017.

Form finding of deep exploration surface habitats

Valentina Sumini and Caitlin Mueller, Proceedings of the International Association for Shell and Spatial Structures (IASS), 2017

 A renewed interest in space exploration, mainly proved by the recent funding that NASA received for sending human to Mars by 2030, led to new challenges in architecture and structural engineering. Space architecture is deeply interdisciplinary and connects different fields of research such as aerospace engineering, architecture, design, space science, medicine, psychology and art.

This research aims to explore form finding strategies for deep space exploration habitats on extraplanetary surfaces such as the Moon and Mars. In this paper, a new sphere packing form finding approach has been studied, trying to optimize the location of different system and subsystems inside a space habitat and respond to the high pressure differentials required in these environments. 

The potential impact of this study relates to the possibility of designing in real-time the final layout of the habitat by simply defining the linkages between functions and subsystems. This method could be applied to different scales of the habitat, from the urban level down to the architectural one, and to even more complex systems.

Moreover, being the obtained functional diagram readily translated in a structural Finite Element model, it was possible to prove that the reduced gravity is a negligible load  when designing for space habitats that, have a differential pressure of about 100 kPa. Therefore the internal pressurization is the main load to consider. Future research could expand this study analyzing also other types of loads, such as the micrometeoroid impact, and the airlock systems.

Group member authors:

• Caitlin Mueller
• Valentina Sumini

Related projects:

• Space Architecture: form finding strategies and multiobjective optimization

Full-text access:

• PDF Download

Tags:

• computation
• form-finding
• inflatable-structures
• space-architecture
• sphere-packing

Citation:

Valentina Sumini and Caitlin Mueller, Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium, 2017

Gradient-based optimization of closest-fit funicular structures

Pierre Cuvilliers, Renaud Danhaive, and Caitlin Mueller, Proceedings of the International Association of Shell and Spatial Structures (IASS) Symposium 2016, 2016

The aim of this research is to solve an inverse form-finding problem: construct funicular, axial-only structures as close as possible to a target surface defined by the designer. The scope is limited to grid-like, node-and-branch only networks, which can be solved efficiently using the force density method (FDM). This problem is formulated as a least-squares nonlinear optimization problem, and is solved using the constrained nonlinear solvers implemented in MATLAB. Two nonlinear constrained solving methods, interior-point and trust-reflective region, are found to be the fastest with a large convergence domain. The first and second-order derivatives of the objective function are found analytically. Lastly, the problem is shown to have several degeneracies; one in particular cannot be removed with physical arguments and leads to new insights in the numerical form finding of funicular surfaces.

Full-text access:

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Tags:

• computation

Citation:

Cuvilliers, P., Danhaive, R., & Mueller, C. (2016). Gradient-based optimization of closest-fit funicular structures. In K. Kawaguchi, M. Ohsaki, & T. Takeuchi (Eds.), Proceedings of the IASS Annual Symposium (p. 10).

The effect of performance feedback and optimization on the conceptual design process

Nathan Brown and Caitlin Mueller, Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium, 2016

Group member authors:

• Nathan Brown
• Caitlin Mueller

Full-text access:

• PDF Download

Tags:

• computation
• conceptual-structural-design
• design-study
• performance-feedback
• interaction

Citation:

Brown, N. & Mueller, C. (2016). The effect of performance feedback and optimization on the conceptual design process. Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2016.

Externally post-tensioned structures: validation through physical models

Leonardo Todisco and Caitlin Mueller, Proceedings of the 3rd International Conference on Structures and Architecture, 2016

Funicular structures, which follow the idealized shapes of hanging chains under a given loading, are recognized as materially efficient structural solutions because they exhibit no bending under normal loading conditions and minimize the amount of required members, often reducing the amount of material needed. However, non-structural conditions, such as aesthetics, functionality, and geotechnical issues, often prohibit selection of a structurally ideal funicular shape: bending moments inevitably arise, decreasing the structural efficiency of the design.

This paper briefly describes how a new design philosophy consisting in the introduction of additional loads, using external post-tensioning cables, can convert a non-funicular structure into a funicular one without changing its starting geometry. This system is based on the possibility of introducing external forces into the main structure through a system of stressed tension cables and compressive or tension struts resulting in changing internal force distribution.

The theoretical approach, based on graphic statics, has been generalized for any two-dimensional geometry. The method has been implemented in a parameterized and interactive environment allowing the fast exploration of different equilibrated solutions.

This paper focuses on the physical modeling, testing, and validation of structures implementing this approach. The structures are modelled through reduced-scale non-funicular geometries fabricated through additive manufacturing (3D printing), with the post-tensioning system constructed with thin cable and precise laser-cut struts. Slow motion video captures show how three different non funicular geometries (pointed-arch, circular arch and free form curve), made of discrete elements and without bending strength, stand only if the cable is working in the appropriate way, demonstrating the efficacy of the new system.

Furthermore, this paper introduces a built example on the scale of real building systems. The paper describes the design and construction process of a post-tensioned pavilion structure. This pavilion, called Funicular Explorations, serves as both a validation and demonstration of this new method, expressing the creative freedom of designers and the structural performance of the results. The design is an array of eight two-dimensional curves, made from custom-cut corrugated cardboard and nylon webbing. The array begins with a funicular parabolic arch, and progresses toward a visually expressive but structurally arbitrary shape. The external post-tensioning system contributes increasingly from one curve to the next, finally allowing the terminal free-form shape to be achieved with axial forces only.

The use of physical models, independent of their scale, is informative but also didactic, illustrating the possibilities and trade-offs in funicular explorations for architectural design. Furthermore such models demonstrate the structural concept behind the post-tensioning system in an intuitive way. The aim of this research is to allow architects and structural engineers a way to achieve high-performance, efficient, and safe designs, even when the global geometry departs from classical funicular shapes.

Group member authors:

• Caitlin Mueller
• Leonardo Todisco

Related projects:

• Externally post-tensioned curved structures

Tags:

• computation
• fabrication
• conceptual-structural-design
• graphic-statics
• design-tool
• physical-prototypes

Citation:

Todisco, L., & Mueller, C. (2016). Externally post-tensioned structures: validation through physical models. Proceedings of the 3rd International Conference on Structures and Architecture.

Early-Stage Integration of Architectural and Structural Performance in a Parametric Multi-Objective Design Tool

Nathan Brown, Jonathas de Oliveira, John Ochsendorf, and Caitlin Mueller, 3rd International Conference on Structures and Architecture, 2015

Group member authors:

• Nathan Brown
• Jonathas Felipe
• Caitlin Mueller

Full-text access:

• PDF Download

Tags:

• collaboration
• computation

Citation:

Brown, N.C., de Oliveira, J.I.F., Ochsendorf, J., & Mueller, C. (2016). Early-Stage Integration of Architectural and Structural Performance in a Parametric Multi-Objective Design Tool. Proceedings of the 3rd International Conference on Structures and Architecture, Guimarães, Portugal.

Design for structural and energy performance of long span buildings using geometric multi-objective optimization

Nathan Brown and Caitlin Mueller, Energy and Buildings, 2016

This paper addresses the potential of multi-objective optimization (MOO) in conceptual design to help designers generate and select solutions from a geometrically diverse range of high-performing building forms. With a focus on the long span building typology, this research employs a MOO approach that uses both finite element structural modeling and building energy simulations simultaneously to generate opti- mized building shapes that are not constrained to regular, rectilinear geometric configurations. Through a series of case studies that explore performance tradeoffs of enclosed arches and static overhangs in differ- ent climates, this paper shows how MOO can yield architecturally expressive, high-performing designs, which makes the process more attractive to designers searching for creative forms. It also provides new insight into specific design responses to various climatic constraints, since optimization that considers both structure and energy can shift best solutions in unexpected ways. Finally, by displaying performance results in terms of embodied and operational energy, this paper presents new data showing how consid- erations of structural material efficiency compare in magnitude to total building energy usage. Together, these three contributions can influence current sustainable design strategies for building typologies that have significant structural requirements.

Group member authors:

• Nathan Brown
• Caitlin Mueller

Related projects:

• Multi-objective optimization for early-stage architectural design

Tags:

• computation

Citation:

Brown, N.C. & Mueller, C. (2016). Design for structural and energy performance of long span buildings using geometric multi-objective optimization. Energy and Buildings, 127: 748-761.

Data-driven approximation algorithms for rapid performance evaluation and optimization of civil structures

Stavros Tseranidis, Nathan Brown, and Caitlin Mueller, Automation in Construction: Special Issue "BIG DATA IN CIVIL ENGINEERING", 2016

This paper explores the use of data-driven approximation algorithms, often called surrogate modeling, in the early-stage design of structures. The use of surrogate models to rapidly evaluate design performance can lead to a more in-depth exploration of a design space and reduce computational time of optimization algorithms. While this approach has been widely developed and used in related disciplines such as aerospace engineering, there are few examples of its application in civil engineering. This paper focuses on the general use of surrogate modeling in the design of civil structures and examines six model types that span a wide range of characteristics. Original contributions include novel metrics and visualization techniques for understanding model error and a new robustness framework that accounts for variability in model comparison. These concepts are applied to a multi-objective case study of an airport terminal design that considers both structural material volume and operational energy consumption.

Group member authors:

• Nathan Brown
• Caitlin Mueller
• Stavros Tseranidis

Related projects:

• Surrogate modeling algorithms for conceptual design

Full-text access:

• DOI

Tags:

• computation
• surrogate-modelling
• machine-learning
• approximation
• conceptual-structural-design

Citation:

Tseranidis, S., Brown, N. C., & Mueller, C. (2016). Data-driven approximation algorithms for rapid performance evaluation and optimization of civil structures, Automation in Construction.

Robotics-enabled stress line additive manufacturing

Kam-Ming Mark Tam, Caitlin Mueller, James Coleman, and Nicholas Fine, Rob|Arch 2016: Robotic Fabrication in Architecture, Art and Design 2016, 2016

The presented research uses a 6-axis industrial robot arm and a custom-designed heated extruder to develop a new robotic additive manufacturing (AM) framework for 2.5-D surface designs that adds material explicitly along principal stress trajectories. AM technologies, such as fused deposition modelling (FDM), are typically based on processes that lead to anisotropic products with strength behaviour that varies according to filament orientation; this limits its application in both design prototypes and end-use parts and products. Since stress lines are curves that indicate the optimal paths of material continuity for a given design boundary, the proposed stress-line based oriented material deposition opens new possibilities for structurally-performative and geometrically-complex AM, which is supported here by fabrication and structural load testing results. Called stress line additive manufacturing (SLAM), the proposed method achieves an integrated workflow that synthesizes parametric design, structural optimization, robotic computation, and fabrication.

Group member authors:

• Caitlin Mueller
• Kam-Ming Mark Tam

Related projects:

• Stress line computation for structurally performative topology
• Stress line additive manufacturing (SLAM)

Tags:

• additive-manufacturing
• robotic-fabrication
• principal-stress-line
• oriented-material-deposition
• fused-deposition-modelling
• topology-optimization
• computation
• fabrication

Citation:

Tam, K.M.M., Coleman, J.R., Fine, N.W., & Mueller, C. (2016). Robotics-enabled stress line additive manufacturing. In Reinhardt, & R. Saunders (Eds.), Rob|Arch 2016: Robotic Fabrication in Architecture, Art and Design 2016. Cham, CH: Springer.

Design and exploration of externally post-tensioned structures using graphic statics

Leonardo Todisco, Corentin Fivet, Hugo Corres, and Caitlin Mueller, Journal of the IASS, 2015

Funicular structures, which follow the shapes of hanging chains, work in pure tension (cables) or pure compression (arches), and offer a materially efficient solution compared to structures that work through bending action. However, the set of geometries that are funicular under common loading conditions is limited. Non-structural design criteria, such as function, program, and aesthetics, often prohibit the selection of purely funicular shapes, resulting in large bending moments and excess material usage. In response to this issue, this paper explores the use of a new design approach that converts non-funicular planar curves into funicular shapes without changing the geometry; instead, funicularity is achieved through the introduction of new loads using external post-tensioning. The methodology is based on graphic statics, and is generalized for any two-dimensional shape. The problem is indeterminate, meaning that a large range of allowable solutions is possible for one initial geometry. Each solution within this range results in different internal force distributions and horizontal reactions. The method has been implemented in an interactive parametric design environment, empowering fast exploration of diverse axial-only solutions. In addition to presenting the approach and tool, this paper provides a series of case studies and numerical comparisons between new post-tensioned structures and classical bending solutions, demonstrating that significant material can be saved without compromising on geometrical requirements.

Group member authors:

• Caitlin Mueller
• Leonardo Todisco

Related projects:

• Externally post-tensioned curved structures

Full-text access:

• DOI

Tags:

• computation
• conceptual-structural-design
• design-tool
• graphic-statics

Citation:

Todisco, L., Fivet, C., Corres, H., Mueller, C. (2015). Design and exploration of externally post-tensioned structures using graphic statics. Journal of the IASS, 56(4), 249-258.

Stress line generation for structurally performative architectural design

Kam-Ming Mark Tam and Caitlin Mueller, Computational Ecologies: Proceedings of the 35th Annual Conference of the Association for Computer Aided Design in Architecture, 2015

Principal stress lines, which are pairs of orthogonal curves that indicate trajectories of internal forces and therefore idealized paths of material continuity, naturally encode the optimal topology for any structure for a given set of boundary conditions. Although stress line analysis has the potential to offer a direct, and geometrically provocative approach to optimization that can synthesize both design and structural objectives, its application in design has generally been limited due to the lack of standardization and parameterization of the process for generating and interpreting stress lines. Addressing these barriers that limit the application of the stress line methods, this paper proposes a new implementation framework that will enable designers to take advantage of stress line analysis to inform conceptual structural design. Central to the premise of this research is a new conception of structurally inspired design exploration that does not impose a singular solution, but instead allows for the exploration of a diverse high-performancedesign space in order to balance the combination of structural and architectural design objectives.

Group member authors:

• Caitlin Mueller
• Kam-Ming Mark Tam

Related projects:

• Stress line computation for structurally performative topology

Tags:

• computation
• principal-stress-lines
• structural-patterns
• topology-optimization
• shell-structures
• 2.5d-surfaces

Citation:

Tam., K.M.M., & Mueller, C. (2015). Stress line generation for structurally performative architectural design. In L. Combs, & C. Perry (Eds.), Computational Ecologies: Proceedings of the 35th Annual Conference of the Association for Computer Aided Design in Architecture, 22-24 October 2015. Cincinnati, OH: University of Cincinnati School of Architecture and Interior Design.

Funicularity through external post-tensioning: design philosophy and computational tool

Leonardo Todisco, Hugo Corres, and Caitlin Mueller, Journal of Structural Engineering (ASCE), 2015

Funicular geometries, which follow the idealized shapes of hanging chains under a given loading, are recognized as materially efficient structural solutions because they exhibit no bending under design loading, usually self-weight. However, there are circumstances in which non-structural conditions make a funicular geometry difficult or impossible. This paper presents a new design philosophy, based on graphic statics, that shows how bending moments in a non-funicular two-dimensional curved geometry can be eliminated by adding forces through an external post-tensioning system. An interactive parametric tool is introduced for finding the layout of a post-tensioning tendon for any structural geometry. The effectiveness of this approach is shown with several new design proposals.

Group member authors:

• Caitlin Mueller
• Leonardo Todisco

Related projects:

• Externally post-tensioned curved structures

Full-text access:

• DOI

Tags:

• computation
• conceptual-structural-design
• design-tool

Citation:

Todisco, L., Corres, H., & Mueller, C. (2015). Funicularity through external post-tensioning: design philosophy and computational tool Journal of Structural Engineering (ASCE), 142(2).

Modelling with forces: grammar-based graphic statics for diverse architectural structures

Juney Lee, Corentin Fivet, and Caitlin Mueller, Modelling Behaviour: Proceedings of the Design Modelling Symposium, Copenhagen 2015, 2015

Most architectural modelling software provides the user with geometric freedom in absence of performance, while most engineering software mandates pre-determined forms before it can perform any numerical analysis. This trial-and-error process is not only time intensive, but it also hinders free exploration beyond standard designs. This paper proposes a new structural design methodology that integrates the generative (architectural) and the analytical (engineering) procedures into a simultaneous design process, by combining shape grammars and graphic statics. Design tests presented will demonstrate the applicability of this new methodology to various engineering design problems, and demonstrate how the user can explore diverse and unexpected structural alternatives to conventional solutions.

Group member authors:

• Juney Lee
• Caitlin Mueller

Full-text access:

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Tags:

• collaboration
• computation
• grammatical-design
• graphic-statics
• design-tool
• graphical-computation

Citation:

Lee, J., Fivet, C. & Mueller, C. (2015). Grammar-based generation of equilibrium structures through graphic statics. Modelling Behaviour: Proceedings of the Design Modelling Symposium, Copenhagen 2015.

3-D Sampling: structurally performative textures remixed from 3D scans

Sayjel Patel and Caitlin Mueller, Modelling Behaviour: Proceedings of the Design Modelling Symposium, Copenhagen 2015, 2015

3D Sampling is presented as a new method for comprehensive rearrangement and composition of 3D scan data, allowing multi-scale manipulation of surface texturing and subsequent fabrication and re-evaluation using 3D printing. Analogous to sample-based music, 3D Sampling contributes new frameworks, tools, and compositional strategies for the digital remixing, hacking, and appropriating of material qualities, performances, and behaviours directly from physical samples to produce new designs. Case studies are presented which demonstrate 3DJ: a prototype 3D modelling tool for synthesizing haptic and optically performing textures from 3D scan-generated source material, which can be applied in the context of other 3D modelling techniques.

Group member authors:

• Caitlin Mueller
• Sayjel Patel

Related projects:

• 3DJ: 3D Sampling of performative textures

Full-text access:

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Tags:

• computation
• fabrication
• 3d-scanning
• design-blending

Citation:

Patel, S., & Mueller, C. (2015). 3-D Sampling: structurally performative textures remixed from 3D scans. Modelling Behaviour: Proceedings of the Design Modelling Symposium, Copenhagen 2015.

Stress line additive manufacturing (SLAM) for 2.5-D shells

Kam-Ming Mark Tam, Caitlin Mueller, James Coleman, and Nicholas Fine, Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2015, 2015

In the field of digital fabrication, additive manufacturing (AM, sometimes called 3D printing) has enabled the fabrication of increasingly complex geometries, though the potential of this technology to convey both geometry and structural performance remains unmet. Typical AM processes produce anisotropic products with strength behavior that varies according to filament orientation, thereby limiting its applications in both structural prototypes and end-use parts and products. The paper presents a new integrated software and hardware process that reconsiders the traditional AM technique of fused deposition modelling (FDM) by adding material explicitly along the threedimensional principal stress trajectories, or stress lines, of 2.5-D structural surfaces. As curves that indicate paths of desired material continuity within a structure, stress lines encode the optimal topology of a structure for a given set of design boundary conditions. The use of a 6-axis industrial robot arm and a heated extruder, designed specifically for this research, provides an alternative to traditional layered manufacturing by allowing for oriented material deposition. The presented research opens new possibilities for structurally performative fabrication.

Group member authors:

• Caitlin Mueller
• Kam-Ming Mark Tam

Related projects:

• Stress line additive manufacturing (SLAM)

Full-text access:

• PDF Download

Tags:

• computation
• fabrication
• additive-manufacturing
• conceptual-structural-design
• digital-manufacturing
• topology-optimization
• principal-stress-lines

Citation:

Tam, K.M.M., Coleman, J.R., Fine, N.W., & Mueller, C. (2015). Stress line additive manufacturing (SLAM) for 2.5-D shells. Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2015.

Design and exploration of externally post-tensioned structures using graphic statics

Leonardo Todisco, Corentin Fivet, Hugo Corres, and Caitlin Mueller, Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2015, 2015

Funicular structures, which follow the shapes of hanging chains, work in pure tension (cables) or pure compression (arches), and offer a materially efficient solution compared to structures that work through bending action. However, the set of geometries that are funicular under common loading conditions is limited. Non-structural design criteria, such as function, program, and aesthetics, often prohibit the selection of purely funicular shapes, resulting in large bending moments and excess material usage. In response to this issue, this paper explores the use of a new design approach that converts non-funicular planar curves into funicular shapes without changing the geometry; instead, funicularity is achieved through the introduction of new loads using external post-tensioning. The methodology is based on graphic statics, and is generalized for any two-dimensional shape. The problem is indeterminate, meaning that a large range of allowable solutions is possible for one initial geometry. Each solution within this range results in different internal force distributions and horizontal reactions. The method has been implemented in an interactive parametric design environment, empowering fast exploration of diverse axial-only solutions. In addition to presenting the approach and tool, this paper provides a series of case studies and numerical comparisons between new post-tensioned structures and classical bending solutions, demonstrating that significant material can be saved without compromising on geometrical requirements.

Group member authors:

• Caitlin Mueller
• Leonardo Todisco

Related projects:

• Externally post-tensioned curved structures

Full-text access:

• PDF Download

Tags:

• computation
• conceptual-structural-design
• design-tool
• graphic-statics

Citation:

Todisco, L., Fivet, C., Corres, H., and Mueller, C. (2015). Design and exploration of externally post-tensioned structures using graphic statics. Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2015.

Multi-objective optimization for diversity and performance in conceptual structural design

Nathan Brown, Stavros Tseranidis, and Caitlin Mueller, Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2015, 2015

For most traditional applications of structural optimization and form finding for conceptual design, it is possible to pursue a single objective to arrive at an efficient, expressive form. However, when developing a modern building, the design team must consider many other aspects of performance, such as energy usage, architectural quality, and constructability in addition to structural efficiency. If used appropriately, multi-objective optimization (MOO) can accurately account for designers’ needs and guide them towards high-performing solutions, while highlighting trade-offs between structural considerations and other performance objectives. In response to this potential, this paper presents a new MOO process that can be integrated into the typical workflow for conceptual building designs. This MOO process is original in how it allows for interaction with performance feedback across separate design disciplines while generating diverse, sometimes unexpected results. This paper applies the MOO process to a long-span roof design example while focusing on two quantitative optimization objectives—structural efficiency and operational energy efficiency—in a variety of climate contexts. The results generated in this case study include a diverse range of designs that exhibit clear trade-offs between objectives. Overall, this paper illustrates new potentials of the MOO approach in conceptual design for producing context-responsive, high-performing, geometrically diverse design solutions.

Group member authors:

• Nathan Brown
• Caitlin Mueller
• Stavros Tseranidis

Related projects:

• Multi-objective optimization for early-stage architectural design
• Design optimization for structural performance and energy efficiency

Full-text access:

• PDF Download

Tags:

• computation

Citation:

Grammar-based generation of equilibrium structures through graphic statics

Juney Lee, Corentin Fivet, and Caitlin Mueller, Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2015, 2015

This paper proposes a grammar-based structural design methodology using graphic statics. By combining shape grammars with graphic statics, this method enables the designer to: 1) rapidly generate unique, yet functional structures that fall outside of the expected solution space, 2) explore various design spaces unbiasedly, and 3) customize the combination of grammar rules or design objectives for unique formulation of the problem. Design tests presented in this paper will show the powerful new potential of combining computational graphic statics with shape grammars, and demonstrate the possibility for exploring richer and broader design spaces with much more trial, and less error.

Group member authors:

• Juney Lee
• Caitlin Mueller

Full-text access:

• PDF Download

Tags:

• computation
• graphic-statics

Citation:

Lee, J., Fivet, C., & Mueller, C. (2015). Grammar-based generation of equilibrium structures through graphic statics. Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2015.

Combining parametric modeling and interactive optimization for high-performance and creative structural design

Renaud Danhaive and Caitlin Mueller, Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2015, 2015

In architectural and structural design, current modeling and analysis tools are extremely powerful and allow one to generate and analyze virtually any structural shape. However, most of them do not allow designers to integrate structural performance as an objective during conceptual design. As structural performance is highly linked to architectural geometry, there is a need for computational strategies allowing for performance-oriented structural design in architecture. In order to address these issues, the research presented in this paper combines interactive evolutionary optimization and parametric modeling to develop a new computational strategy for creative and high-performance conceptual structural design. Parametric modeling allows for quick exploration of complex geometries and can be combined with analysis and optimization algorithms for performance-driven design. However, this methodology often limits the designer’s authorship, since it is based on the use of black-box optimizers. On the other hand, interactive evolutionary optimization empowers the user by acknowledging his or her input as fundamental and includes it in the evolutionary optimization process. This approach aims at improving the structural performance of a concept without limiting the creative freedom of designers. Taking advantage of the two frameworks, this research implements an interactive evolutionary structural optimization framework in the widely used parametric modeling environment constituted by Rhinoceros and Grasshopper. The implemented design tool capitalizes on Grasshopper’s versatility for geometry generation but supplements the visual programming interface with a flexible GUI portal, increasing the designer’s creative freedom through enhanced interactivity. The tool can accommodate a wide range of structural typologies and geometrical forms in an integrated environment. The paper includes a description of the tool and demonstrates its applications and benefits through several conceptual design case studies.

Group member authors:

• Renaud Danhaive
• Caitlin Mueller

Related projects:

• Stormcloud: Interactive evolutionary exploration for Grasshopper

Full-text access:

• PDF Download

Tags:

• computation

Citation:

Danhaive, R., & Mueller, C. Combining parametric modeling and interactive optimization for high-performance and creative structural design. Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2015.

Drone-based additive manufacturing of architectural structures

Pierre Latteur, Sébastien Goessens, Jean-Sébastien Breton, Justin Leplat, Zhao Ma, and Caitlin Mueller, Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2015, 2015

The paper presents the first results of a new collaboration project between MIT and UCL (MISTI MIT-UCL seed fund), which investigates the feasibility of the construction of building-scale structures with unmanned aerial vehicles, commonly called drones, according to a procedure described below: (1) Designing the building by the architect and the engineer; (2) Modeling the building into a CAD/BIM tool; (3) Translating the CAD/BIM model into remote control instructions compatible with the drones; (4) Assembling the structure with the drones.

The major components of the project consists of choosing the best drone-compatible assembly processes and materials, developing the guiding systems for the drones for both broad large-scale movements and precise small-scale motions and developing the best possible translation tools between the CAD/BIM models, and the drone’s remote control instructions. The paper will emphasize on the results of the first part of the project, related to the construction of structures made of geometrically modified blocks bonded together, called dricks and droxels.

Group member authors:

• Caitlin Mueller

Related projects:

• Drone-based additive manufacturing of architectural structures

Full-text access:

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Tags:

• computation
• fabrication

Citation:

Latteur et al. (2015). Drone-based additive manufacturing of architectural structures. Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2015.

Thin concrete shells at MIT: Kresge Auditorium and the 1954 conference

William Plunkett and Caitlin Mueller, Proceedings of the 5th International Congress on Construction History, 2015

This paper presents original research on two historical developments in the field of thin-shell concrete structures in the United States, both at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts in the 1950s. The first topic is the design and construction of MIT’s Kresge Auditorium (1953-1955), enclosed by a concrete shell on three supports designed by architect Eero Saarinen (1910-1961). The second topic is a seminal conference on the architecture, engineering, and construction of thin concrete shells hosted by MIT in 1954, which included presentations by architect-engineer Felix Candela (1910-1997), engineer Anton Tedesko (1903-1994), architect Philip Johnson (1906-2005), among many important designers and scholars.

Both the building and the conference are historically significant, and together, they mark the peak of a design era optimistic about the enduring value of thin-shell concrete structures. However, they also reflect the underlying tensions and contradictions of thin-shell concrete technology that contributed to its limited use in subsequent decades. The project therefore serves as an early example illustrating the limitations of thin-shell concrete applied to arbitrary formal ideas.

The concurrent conference often related directly to the design and construction of Kresge Auditorium: both its structural engineer (Charles Whitney, Ammann and Whitney) and contractor (Douglas Bates, George A. Fuller Company) presented papers, and a proceedings summary notes that “this conference has…cantilevered out from Saarinen’s dome.” The conference highlights broad enthusiasm for thin-shell concrete structures, but also reveals disagreements between theoreticians and practitioners, architects and engineers, and designers and builders. This paper gives a critical review of the influential conference, based on conference proceedings and supporting historical documents.

In summary, this paper contributes new knowledge on the history and significance of paired events in thin-shell concrete in the 1950s at MIT. In addition to detailed accounts of both the building and conference, the paper offers original insight about their contextual role in the rise and fall of thin-shell concrete technology in the design and construction community.

Group member authors:

• Caitlin Mueller

Full-text access:

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Tags:

• collaboration
• shell-structures

Citation:

Plunkett, W., & Mueller, C. (2015). Thin concrete shells at MIT: Kresge Auditorium and the 1954 conference. Proceedings of the 5th International Congress on Construction History.

Graphic statics and interactive optimization for engineering education

Caitlin Mueller, Corentin Fivet, and John Ochsendorf, Proceedings of Structures Congress 2015, 2015

Although conventional structural analysis software is widely used by practicing engineers, its pedagogical value for students is limited, especially in design applications. Nevertheless, there is an established value in students exploring engineering problems through computational means. This paper presents alternative computational techniques and tools that are effective improvements upon structural analysis software in the university classroom. The first set focuses on graphic statics. The second involves interactive evolutionary optimization. The paper provides feedback about their effective implementation in classrooms and demonstrates how the new tools can continue to be used by students beyond the classroom, to expand explorative opportunities for conceptual structural design in practice.

Full-text access:

• DOI

Citation:

Mueller, C., Fivet, C., & Ochsendorf, J. (2015). Graphic statics and interactive optimization for engineering education. Structures Congress 2015, 2577-2589.

Combining structural performance and designer preferences in evolutionary design space exploration

Caitlin Mueller and John Ochsendorf, Automation in Construction, 2015

This paper addresses the need to consider both quantitative performance goals and qualitative requirements in conceptual design. A new computational approach for design space exploration is proposed that extends existing interactive evolutionary algorithms for increased inclusion of designer preferences, overcoming the weaknesses of traditional optimization that have limited its use in practice. This approach allows designers to set the evolutionary parameters of mutation rate and generation size, in addition to parent selection, in order to steer design space exploration. This paper demonstrates the potential of this approach through a numerical parametric study, a software implementation, and series of case studies.

Group member authors:

• Caitlin Mueller

Full-text access:

• DOI

Tags:

• computation
• evolutionary-algorithm
• design-tool

Citation:

Mueller, C. T., & Ochsendorf, J. A. (2015). Combining structural performance and designer preferences in evolutionary design space exploration. Automation in Construction, 52, 70-82.

Additive manufacturing of structural prototypes for conceptual design

Caitlin T. Mueller, Ali Irani, and Benjamin E. Jenett, Proceedings of the IASS-SLTE 2014 Symposium, 2014

Additive manufacturing, also known as 3D printing, is a powerful technique for quickly fabricating complex geometrical models. This paper investigates the potential of using this technique for producing structural prototypes, or models that can be used in conceptual design to understand and compare the structural behavior of design alternatives. The main challenge is the anisotropy of the printed parts, which exhibit significant reductions in tensile capacity when loaded across printed layers. This paper characterizes this challenge through experimental results, and proposes and tests several new techniques to address anisotropy limitations.

Group member authors:

• Caitlin Mueller

Related projects:

• Discretization and connections for 3D-printed trusses

Full-text access:

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Tags:

• fabrication
• additive-manufacturing

Citation:

Mueller, C. T., Irani, A., & Jennet, B. E. (2014). Additive manufacturing of structural prototypes for conceptual design. Proceedings of the IASS-SLTE 2014 Symposium.

The state of the art of computational tools for conceptual structural design

Anke Rolvink, Caitlin Mueller, and Jeroen Coenders, Proceedings of the IASS-SLTE 2014 Symposium, 2014

This paper presents a review of existing research, projects, developments and applications in the domain of design tools for conceptual structural engineering. The availability of these tools and research into software for conceptual structural design stages has shown a number of interesting developments over the last past few years. The purpose of this investigation is to understand the requirements for software for the early stages of structural design. It investigates the current conceptual design practice, discusses a number of novel trends, and characterizes the relative effectiveness of the available technologies in relation to the nature of the early design stages.

Group member authors:

• Caitlin Mueller

Full-text access:

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Tags:

• computation
• conceptual-design
• structural-design-tools

Citation:

Rolvink, A., Mueller, C., & Coenders, J. (2014). State of the art of computational tools for conceptual structural design. Proceedings of the IASS-SLTE 2014 Symposium.

An integrated computational approach for creative conceptual structural design

Caitlin Mueller and John Ochsendorf, Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2013, 2013

This paper introduces a new computational approach for creative conceptual structural design, synthesizing an interactive evolutionary framework, a structural grammar strategy for trans-typological design, and a performance-focused surrogate modelling technique. By developing and integrating these three strategies into a unified design approach, this research enables architects and structural designers to explore broad ranges of conceptual design alternatives in an interactive way.

Group member authors:

• Caitlin Mueller

Full-text access:

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Tags:

• computation
• grammatical-design
• evolutionary-algorithm
• surrogate-modelling
• conceptual-design

Citation:

Mueller, C., & Ochsendorf, J. (2013). An integrated computational approach for creative conceptual structural design. Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium 2013.

From analysis to design: a new computational strategy for structural creativity

Caitlin Mueller and John Ochsendorf, Proceedings of the 2nd International Workshop on Design in Civil and Environmental Engineering, 2013

Since the introduction of finite element analysis software in the 1970s, structural engineers have become increasingly reliant on computational tools to carry out sophisticated simulations of structural performance. However, most structural analysis tools can only be used once there is a structure to be analyzed; they are not directly applicable in the design or synthesis of a new structural solution. This paper presents new research that expands the applicability of computation from structural analysis to structural design, with an emphasis on conceptual design applications. Specifically, this paper introduces a new interactive evolutionary framework implemented in a web-based structural design tool, structureFIT. This approach enables users to explore structural design options through an interactive evolutionary algorithm, and to further refine designs through a real-time analysis mode. This paper includes a critical background on optimization and its applications in structural design, an overview of the original interactive evolutionary framework, a description of the design tool, and a discussion of potential applications.

Group member authors:

• Caitlin Mueller

Full-text access:

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Tags:

• computation
• evolutionary-algorithm
• conceptual-design

Citation:

Mueller, C., & Ochsendorf, J. From analysis to design: a new computational strategy for structural creativity. Proceedings of the 2nd International Workshop on Design in Civil and Environmental Engineering, 46-56.

An interactive evolutionary framework for structural design

Caitlin Mueller and John Ochsendorf, 7th International Seminar of the the Structural Morphology Group (SMG), IASS Working Group 15, 2011

This paper presents a novel interactive evolutionary framework for conceptual structural design. In contrast with tools for structural analysis, tools for structural design should guide the design process by suggesting structurally efficient options, while allowing for a diversity of design choice. The framework proposed here implements an interactive evolutionary algorithm to achieve this behaviour. Additionally, a cohesive and intuitive graphical user interface is introduced. Finally, a novel approach to approximate the design space, and thereby improve the speed of the algorithm, using non-parametric regression is discussed.

Group member authors:

• Caitlin Mueller

Full-text access:

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Tags:

• computation
• evolutionary-algorithm

Citation:

Mueller, C., & Ochsendorf, J. (2011). An interactive evolutionary framework for structural design. 7th International Seminar of the the Structural Morphology Group (SMG), IASS Working Group 15.