59 research outputs found
Maatbeperking in het architectonisch ontwerp; visuele relevantie van maatsystemen als Gulden Snede en Plastische Getal - Measure limitation in architectural design
No full textArchitectural Engineering and TechnologyArchitecture and The Built Environmen
Short time behaviour of density correlation functions
No full textIn this thesis the dynamical behaviour of the atoms in a fluid or gas is studied with time dependent correlation functions as the density-density correlation function and the velocity autocorrelation function. Theoretically it is not possible to calculate these correlation functions exactly for the whole time domain. An exact calculation is only possible for times small with respect to the duration of the collision (see Ch. 1), by using the moments expansion, and for times large with respect to the mean free time by solving the hydrodynamical equations. In chapter 2 a method is described, the Ursell expansion, which makes it possible to calculate the correlation functions for times up to the mean free time. Experimentally the density-density correlation function is known on this time scale from neutron scattering on noble gases with a low density. In the Ursell expansion the successive terms describe the effect of an increasing number of colliding particles. For times smaller than the mean free time the most dominant contribution to the correlation functions comes from those collisions in which not more as two particles, are involved. In chapter 2 a detailed expression for the two particle term is derived. It is shown, that due to an approximation for the static three particle correlation function, the moments of the two particle term do not agree completely with the exact raoments. Therefore for continuous potentials another expansion, the second derivative expansion, is derived; in this new expansion the two particle term has the exact moments. Chapter 3 gives the Ursell expansion for the case of a hard spheres interaction; the advantage of this interaction is that the mathematical expressions, that describes the collision, are very easy. Because the moments of the two particle term do not agree with the exact moraents, another expansion, the Ursell-2 expansion, will be derived. This expansion is only valid for hard spheres and reproduces the exact moments. At the end of chapter 3 the results of calculations on the hard spheres system are presented. It is shown that both expansions agree very well with molecular dynaraics calculations. Chapter 4 contains the results of calculations on a system with a Lennard-Jones interaction. It appears that both the Ursell expansion and the second derivative expansion agree very well with molecular dynamics calculations of the incoherent intermediate scattering function. The discrepancy between the theoretically calculated coherent intermediate scattering function and the experimental scattering function is substantial. This may be due to the large experimental error, which is of the same order of magnitude as the deviation of the correlation function from its ideal gas value.Applied Science
De kunst van versmelting
No full textDeze inaugurele rede is in verkorte vorm uitgesproken in het auditorium van de TU Delft op 19 april 2006.RMITArchitectur
Transport van tunnelelementen over zee
No full textVoor een tunnelproject wordt het steeds moeilijker om een locatie voor het bouwdok te vinden, daarom is het aantrekkelijk om een bestaand bouwdok te gebruiken en de elementen over langere afstand te vervoeren en dus ook over zee. In het afstudeerproject is gekeken naar de mogelijkheden en beperkingen van het transport over zee en met name naar de golfbelasting op het element. Na de mogelijkheden van de bestaande bouwdokken te hebben bekeken, is gekozen voor het bouwdok in Amsterdam; waarbij er vanuit is gegaan dat het dok al zodaning is aangepast dat het aan de huidige normen voldoet. Het transport vindt plaats met behulp van sleepboten, het vervoeren van een element op een ponton is te duur en te omslachtig. Aan de hand van de werkbare dagen op zee, vinden we het aantal transportmogelijkheden voor verschillende golfhoogtes. Deze golfhoogtes worden de verschillende ontwerpgolfhoogtes voor de constructie. Er is gebruik gemaakt van een dynamisch rekenprogramma, dat de bewegingen van en de dwarskrachten, momenten en de wringing in het element bepaald. De input van de golven op zee gebeurt door het opgeven van een golfspectrum gekarakteriseerd door een significante golfhoogte en een golfperiode. Dit programma geeft als output voor de bewegingen van en belastingen op het element weer een significante amplitude en een bijbehorende periode. Hieruit blijkt dat deze theoretische benadering een probabilistische aanpak van het probleem tot gevolg heeft. Nu is eerst naar de bewegingen van het element gekeken of deze niet te groot worden en naar de stabiliteit van het element op zee. De bewegingen bleken gering te zijn en de stabiliteit is tijdens de volledige transportduur gegarandeerd. Vervolgens zijn de dwarskrachten, momenten en de wringing bepaald. De constructie is voor het opnemen van de momenten in de gebruiksfase gedimensioneerd door het aanbrengen van voorspankabels. Dimensionering op dwarskracht en wringing is gebeurd in de bezwijkfase, waarbij eventueel nog dwarskrachtwapening dient te worden aangebracht. Vervolgens zijn de constructies voor de verschillende ontwerpgolfhoogtes met elkaar vergeleken, waarbij voor het meest economische ontwerp is gekozen in verhouding tot het aantal werkbare dagen voor het transport over zee.Hydraulic EngineeringCivil Engineering and Geoscience
Three-dimensional numerical analysis of tunnelling induced damage: The influence of masonry building geometry and location
No full textRecent tunnelling projects have received a great amount of media attention due to settlement induced damage. Due to the simplified approach of existing risk assessment methods, a new assessment system is in development, which can account for three-dimensional structural aspects of buildings. The aim of this study is to investigate the influence of the position and geometry of masonry buildings on the development of damage, while undergoing tunnelling induced settlements. In line with previous research, three-dimensional finite element analyses are used as a tool to perform a parametric study. A parametric study consists of an evaluation of the parameters position, aspect-ratio, grouping and orientation. The position parameter is divided into three characteristics: the sagging zone, a combined settlement profile and the hogging zone. The aspect-ratio parameter is also divided into three characteristics: shallow buildings, square buildings and deep buildings. The grouping effect parameter also distinguishes three characteristics: small and large isolated buildings and grouped buildings. The orientation parameter includes seven different increasing angles of the building main axis with respect to the tunnelling axis. The maximum measured crack width in the buildings gives input for a classification of damage, according the system of Burland et al. (1977). An average trend in the damage classification indicates the sensitivity to tunnelling induced settlements of the parameters. Both during and after tunnelling, a position of the building in the combined settlement profile appears to be the most sensitive to differential settlements. Buildings far away from the tunnelling axis generally obtain no more than slight damage. Structures with a low aspect-ratio seem on average to obtain equal amounts of damage as buildings with an aspect-ratio of 1. Structures with a higher aspect-ratio are less affected, both during and after tunnelling. Grouping of the buildings seems to be an influential parameter. Small isolated buildings obtain far less damage than large or grouped buildings. In relation to the numerical analyses, the empirical Limiting Tensile Strain Method (LTSM) seems to overestimate the damage for an isolated small building, but underestimate the damage in large or grouped buildings. For buildings in the sagging zone, a building with a low orientation angle is the least sensitive to differential settlement, while the maximum measured crack width increases by increasing the angle. The difference in maximum crack width can grow to a factor 3. A building in the combined settlement profile or in the hogging zone displays opposite behaviour. Cases with low orientation angles are the most susceptible to damage, while increasing the angle to 90 degrees lowers the maximum measured crack width. The difference in results can grow up to a factor 2.Structural MechanicsStructural EngineeringCivil Engineering and Geoscience
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