Architectural design methods used in engineering Master\u27s thesis projects

By letting structural engineering thesis students explore questions using architectural design\ua0methods, they creatively and systematically addressed\ua0 holistic questions while maintaining\ua0a technical depth. The approach may serve as a model to increase engineering students\u27\ua0ability to insightfully contribute to solutions for complex societal problems

Should Torroja’s prestressed concrete Alloz aqueduct be thought of as a beam or a shell?

This paper examines the structural action of Eduardo Torroja’s Alloz aqueduct, completed in 1939, to see whether we should think of it as acting as a beam or a shell. This is of interest regarding the Alloz aqueduct itself, but also in the design of similar structures in the future, where we must have a simple conceptual understanding of how we want it to work.We apply two alternative approaches available at that time, before computers. Firstly, the membrane theory of shells, effectively assuming the aqueduct walls are infinitely flexible in bending, and secondly, the Euler–Bernoulli ‘plane sections remain plane’ elementary beam theory. We also review Torroja’s calculations which were based on an elaboration of the Euler–Bernoulli beam theory know as the Griffith–Taylor theory for the bending of cantilevers, although we are uncertain as to why he decided to use the Griffith–Taylor theory for a thin walled structure.Both the membrane shell and Euler–Bernoulli beam theory require a prestress to be applied along the longitudinal edges of the channel. However, the level of prestress in the Alloz aqueduct is consistent with the beam theory, which seams the most appropriate approach.Whether or not a structure of this type acts as a shell depends upon the thickness of the wall. The thinner the wall, the more it act as a shell. The wall thickness of the Alloz aqueduct is sufficient for it to act mainly as a beam

CALFEM as a Tool for Teaching University Mechanics

Classical mechanics benefits greatly from the ability to demonstrate many concepts experimentally. However, modern mechanics relies more and more on new analysis methods such as the finite element method. In the teaching of mechanics these methods should be introduced, but the desire to experiment and build should be retained as a core issue. One tool for tackling this topic is given by CALFEM1. CALFEM is an acronym for Computer Aided Learning of the Finite Element Method. It is a tool developed for teaching the finite element method but it is also used in research as well as engineering design. The aim of CALFEM has been to provide a transparent link, such that the student can fully appreciate the intimate relationship between the mathematical models of a phenomenon, the finite element method and its computer implementation. This knowledge is not obtained by operation of commercial finite element programs. The pedagogical aspect of CALFEM has been part of the design from the beginning. In research, CALFEM has proven to be an efficient link between ideas and implemented solutions. CALFEM runs as a toolbox to MATLAB2 and provides all of the necessary tools for finite element calculations. The program has been carefully documented in an extensive manual that consists of a reference and a user's manual. The introduction and usage of CALFEM are strengthened by the close connection to teaching materials such as textbooks and exercises. The effectiveness of the system relies upon the widespread use of MATLAB at Lund University. The implementation of a web-based CALFEM has increased the availability of the package and allows for feedback and distribution of updates and additional material

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

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Genome-wide association identifies nine common variants associated with fasting proinsulin levels and provides new insights into the pathophysiology of type 2 diabetes.

OBJECTIVE: Proinsulin is a precursor of mature insulin and C-peptide. Higher circulating proinsulin levels are associated with impaired β-cell function, raised glucose levels, insulin resistance, and type 2 diabetes (T2D). Studies of the insulin processing pathway could provide new insights about T2D pathophysiology. RESEARCH DESIGN AND METHODS: We have conducted a meta-analysis of genome-wide association tests of ∼2.5 million genotyped or imputed single nucleotide polymorphisms (SNPs) and fasting proinsulin levels in 10,701 nondiabetic adults of European ancestry, with follow-up of 23 loci in up to 16,378 individuals, using additive genetic models adjusted for age, sex, fasting insulin, and study-specific covariates. RESULTS: Nine SNPs at eight loci were associated with proinsulin levels (P < 5 × 10(-8)). Two loci (LARP6 and SGSM2) have not been previously related to metabolic traits, one (MADD) has been associated with fasting glucose, one (PCSK1) has been implicated in obesity, and four (TCF7L2, SLC30A8, VPS13C/C2CD4A/B, and ARAP1, formerly CENTD2) increase T2D risk. The proinsulin-raising allele of ARAP1 was associated with a lower fasting glucose (P = 1.7 × 10(-4)), improved β-cell function (P = 1.1 × 10(-5)), and lower risk of T2D (odds ratio 0.88; P = 7.8 × 10(-6)). Notably, PCSK1 encodes the protein prohormone convertase 1/3, the first enzyme in the insulin processing pathway. A genotype score composed of the nine proinsulin-raising alleles was not associated with coronary disease in two large case-control datasets. CONCLUSIONS: We have identified nine genetic variants associated with fasting proinsulin. Our findings illuminate the biology underlying glucose homeostasis and T2D development in humans and argue against a direct role of proinsulin in coronary artery disease pathogenesis

Strukturmekanik & arkitektur Om strukturmekanisk f\uf6rst\ue5else i gestaltningsprocessen

Organizing material to produce space and a load-carrying structure are central tasks in the architectural design process. In trying out and examining design ideas, use of language and tools appropriate to the purpose is fundamental.The thesis begins with reflections on the different processes that utilize knowledge of structural mechanics, how that subject is commonly presented,and how the presentation of it is affected by various tacit aims. There are two main tasks of the structural engineer: description and analysis of structural behaviour through mathematical modelling, and evaluation of safety and reliability as expressed in design codes. These tasks are comparedwith those of the architect in developing load-carrying structures that interact in a logical and meaningful way with spatial functions and with the needs and aims of architectural expression.The thesis, which takes as its point of departure Structural Mechanical traditions, considers concepts and approaches that help provide a better qualitative understanding of compound and complex structural behaviour. Alongside the concept of equilibrium, that of stiffness is examined as a means of achieving structural mechanical understanding.A new design conception, that of canonical stiffness, is proposed as a means of gaining insight into the static behaviour of structures, allowing patterns (modes) of deformation for which a structure is weak to be determinedon the basis of the stiffness of its various parts. From these patterns, the static load cases that produce the largest deformations of the structure can also be determined. Computational tools are proposed that can support a dialog between the architect and the engineer at early stages of the design process. Three computer codes ForcePAD, pointSketch and CALFEM are presented and discussed as examples of proposals initiated and/or developed within the spirit of the thesis