Harmonic form-finding for the design of doubly-curved shells

AbstractPurposeShell structures are highly efficient and are an elegant way of covering large uninterrupted spaces, but their complex geometry is notoriously difficult to model and analyse. This paper aims to describe a novel free-form shell modelling technique based on structural harmonics.Design/methodology/approachThe method builds on work using weighted eigenmodes for three-dimensional mesh modelling in a computer graphics setting and extends it by specifically adapting the technique to an architectural design context. This not only enables the sculpting of free-form architectural surfaces using only a few control parameters but also takes advantage of the synergies between eigenmodes and structural buckling modes, to provide an efficient means of stiffening a shell against failure by buckling.FindingsThe result is a flexible free-form modelling tool that not only enables the creation of arbitrary doubly curved surfaces but also allows simultan. The tool helps to assist in the design of shells at the conceptual stage and encourages an interaction between the architect and engineer. A number of initiatives, including a single degree of freedom design, boundary constraints, visualisation aids and guidelines towards specific spatial configurations have been introduced to satisfactorily adapt the method to an architectural context.Originality/valueThe tool helps to assist in the design of shells at the conceptual stage and encourages an interaction between the architect and engineer. A number of initiatives, including a single degree of freedom design, boundary constraints, visualisation aids and guidelines towards specific spatial configurations have been introduced to satisfactorily adapt the method to an architectural context. This paper includes a full case study of the iconic British Museum Great Court Roof to demonstrate the applicability of the developed framework to real-world problems and the software developed to implement the method is available as an open-source download.<br/

The design , fabrication and assembly of an asymptotic timber gridshell

This paper describes and discuss the design, fabrication and assembly of an asymptotic gridshellbuilt of plywood laths. The overall question concerns how geometry, structural action, andecient production can interplay and inform spatial design. The environment is a two-dayworkshop where architects, engineers and researchers with specialization in structural and digitaldesign cooperate with undergraduate students in a compulsory parametric design and digitalfabrication course. The gridshell shape is based on an Enneper surface of threefold rotationalsymmetry with a boundary baseplate inscribed within a circle of 4.5 m in radius. Utilizing theconcept of asymptotic curves, which are surface curves whose osculating plane coincides withthe tangent plane of the surface, the structure was built using planar straight laths of plywoodmade using manually operated drills and saws

Design, fabrication and assembly of a geodesic gridshell in a student workshop

This paper describes the design, fabrication and assembly of an 11x11 m gridshell built of plywood laths during a two and a half day workshop in a new undergraduate course about parametric design and digital fabrication. The question was how to use full-scale prototyping to summarize and integrate the learning outcomes in this course. A challenge was how to execute all production during two consecutive days utilizing all 35 students. Exploiting a geodesic grid design, that is curves whose curvature vector is parallel with the surface normal, the gridshell was made of straight predrilled laths that were bent and locked into shape using a sequential erection method. The design was incorporated in a full parametric model including automated design checks and the generation of all necessary production drawings.The workshop and the preparatory work described in this paper was a collaboration between Chalmers, BIG Engineering, Buro Happold and Thornton Tomasetti\u27s CORE studio

Activation of multiple stress responses in Staphylococcus aureus substantially lowers the minimal inhibitory concentration when combining two novel antibiotic drug candidates

The past few decades have been plagued by an increasing number of infections caused by antibiotic resistant bacteria. To mitigate the rise in untreatable infections, we need new antibiotics with novel targets and drug combinations that reduce resistance development. The novel β-clamp targeting antimicrobial peptide BTP-001 was recently shown to have a strong additive effect in combination with the halogenated pyrrolopyrimidine JK-274. In this study, the molecular basis for this effect was examined by a comprehensive proteomic and metabolomic study of the individual and combined effects on Staphylococcus aureus. We found that JK-274 reduced activation of several TCA cycle enzymes, likely via increasing the cellular nitric oxide stress, and BTP-001 induced oxidative stress in addition to inhibiting replication, translation, and DNA repair processes. Analysis indicated that several proteins linked to stress were only activated in the combination and not in the single treatments. These results suggest that the strong additive effect is due to the activation of multiple stress responses that can only be triggered by the combined effect of the individual mechanisms. Importantly, the combination dose required to eradicate S. aureus was well tolerated and did not affect cell viability of immortalized human keratinocyte cells, suggesting a species-specific response. Our findings demonstrate the potential of JK-274 and BTP-001 as antibiotic drug candidates and warrant further studies

Biomorpher: interactive evolution for parametric design

Combining graph-based parametric design with metaheuristic solvers has to date focussed solely on performance based criteria and solving clearly defined objectives. In this paper, we outline a new method for combining a parametric modelling environment with an interactive Cluster-Orientated Genetic Algorithm (COGA). In addition to performance criteria, evolutionary design exploration can be guided through choice alone, with user motivation that cannot be easily defined. As well as numeric parameters forming a genotype, the evolution of whole parametric definitions is discussed through the use of genetic programming. Visualisation techniques that enable mixing small populations for interactive evolution with large populations for performance-based optimisation are discussed, with examples from both academia and industry showing a wide range of applications