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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

SPH simulation of solitary wave interaction with a curtain-type breakwater / Simulation par la méthode SPH de l'interaction d'une onde solitaire avec un brise-lames de type rideau

Shao, Songdong January 2005 (has links)
An incompressible Smoothed Particle Hydrodynamics (SPH) method is put forward to simulate non-linear and dispersive solitary wave reflection and transmission characteristics after interacting with a partially immersed curtain-type breakwater. The Naviers¿Stokes equations in Lagrangian form are solved using a two-step split method. The method first integrates the velocity field in time without enforcing incompressibility. Then the resulting deviation of particle density is projected into a divergence-free space to satisfy incompressibility by solving a pressure Poisson equation. Basic SPH formulations are employed for the discretization of relevant gradient and divergence operators in the governing equations. The curtainwall and horizontal bottom are also numerically treated by fixed wall particles and the free surface of wave is tracked by particles with a lower density as compared with inner particles. The proposed SPH model is first verified by the test of a solitary wave with different amplitudes running against a vertical wall without opening underneath. Then it is applied to simulate solitary wave interacting with a partially immersed curtain wall with different immersion depths. The characteristics ofwave reflection, transmission, dissipation and impacting forces on the curtain breakwater are discussed based on computational results
12

The Environmental Performance of Brick Veneer / Steel Stud Curtain Wall Systems Subject to Air Pressure, Temperature and Vapour Pressure Differentials

Kluge, Andrew 05 1900 (has links)
Brick veneer / steel stud curtain wall systems have become a popular alternative in the ever competitive construction market. However, the application of such systems has preceded any formal scientific investigation into its long term serviceability and safety. Of particular interest to many parties is the performance of the wall system under typical winter conditions as would be encountered in cold climate countries such as Canada. In this study, an experimental investigation of three types of brick veneer / steel stud curtain walls was performed with a specially built apparatus used to impose air pressure, temperature and vapour pressure differentials across test specimens. In all, five wall specimens were tested for air leakage, thermal performance and moisture accumulation. An analytical investigation was also carried out with a simple, custom made finite difference computer program specially suited to determine temperature profiles in walls with a steel stud framing system. Six types of walls are evaluated with the model. A significant part of the research involved the design, construction and improvement of the test apparatus. Since the apparatus is unique, a chapter is devoted to its description. The conclusions presented indicate that certain wall designs perform poorly and that even small construction flaws can lead to serviceability problems. Conversely, care in choice and placement of the air barrier, vapour barrier and thermal insulation in the wall system can lead to a wall system that can sustain a small degree of construction errors and at the same time perform satisfactorily. It is furthermore concluded that the apparatus built for this study has real potential as a cost effective test tool suitable for adaptation for a standard test method to evaluate the environmental performance of wall systems in general. / Thesis / Master of Engineering (ME)
13

Improved Connections for Blast-Resistant Curtain Walls

Nasseralshariati, Ehsan 01 September 2023 (has links)
Curtain walls provide exterior façade to modern buildings. When subjected to blast shock waves, curtain walls may suffer significant damage, potentially causing serious injuries and casualties to building occupants. Protective films, laminated glass and strengthening of mullions and transoms are used to protect curtain wall components against blast loads. Limited research is available on blast protection of curtain wall components. On the other hand, connections of curtain wall mullions with the supporting substrate, as well as mullion-transom connections form potentially vulnerable locations under blast loads. Research on these connections is lacking in the literature. Therefore, a comprehensive research project has been undertaken in this thesis to address the behavior, analysis, and design of curtain wall connections, both between the mullions and supporting concrete slabs/beams and the mullions and transoms. The research project consists of three phases: i) Experimental research using the University of Ottawa Shock Tube as blast simulator, ii) Numerical investigation based on three-dimensional finite element method (FEM) using LS-DYNA, and iii) Non-linear dynamic analysis of curtain wall systems based on a single-degree-of-freedom (SDOF) to develop a connection design procedure. The experimental phase consisted of tests of three full-size curtain walls mounted on steel HSS sections of the Shock Tube to investigate mullion-to-transom connections and nine single mullions connected to concrete beams to investigate mullion-to-concrete substrate connection. The single mullions either represented floor-to-floor mullions or continuous mullions over the supporting slab. They were connected to concrete beams (representing floor slabs) by means of brackets, which provided high degree of rotational restraints and full translational restraints or connected through damping materials (springs or HRD rubber pads), which allowed translational movements as they dampened the effects of the shock wave. The numerical investigation involved FEM analysis and modeling of all the test specimens. The first step involved the validation of numerical models against test data. The analysis was then extended to conduct a parametric investigation to cover cases that have not been covered in the experiments. This resulted in the investigation of six different design parameters used in connection design. The numerical outcomes illustrated the importance of blast effects on connection design parameters, support reactions, curtain wall response, force and stress distributions on curtain wall components. The information gathered through experimental and numerical research on connection performance led to the formulation of a connection design procedure. Single-degree-of-freedom (SDOF) dynamic analysis technique was adopted to curtain wall analysis as a tool to compute connection design forces. Both the Uniform Facilities Criteria (UFC) charted solution (manual calculations) and two computer software developed at the University of Ottawa (RC-Blast and CW-Blast) were used to conduct SDOF analysis to validate the procedure against experimental and numerical results before they were recommended as design tools. Finally, the details of connection design are provided for different types of connections.
14

An Investigation On The Performance Of Aluminium Panel Curtain Wall System In Relation To The Facade Tests

Sengun Dogan, Banu Nur 01 January 2013 (has links) (PDF)
Extruded aluminium has become the material of choice for building envelope owing to its lightness, wide range of possibilities for profile design, durability and the eco-friendly attitude. In the light of recent technological developments in metal and glass industries, there has been various new approaches towards aluminum curtain wall systems which are mostly preferred by architects in high-rise buildings. Herein, the panel curtain wall system is determined as innovative and the modern aluminium curtain wall system. Furthermore, in the recent prestigious high-rise buildings, the demand of the architects and the contractors begins to replace the conventional curtain wall system which is constructed via stick construction technique, with panel curtain wall system which is applied to the building in a modular form . The main aim of this study is to investigate why the panel curtain wall system comes to the forefront especially for high-rise buildings. Accordingly, the basic architectural, structural and constructional design principles of unitized aluminium curtain wall systems are defined, analyzed and then the advantages and disadvantages of this system are pointed out from an architectural point of view. In order to evaluate the performance of panel curtain wall system against environmental factors, the facade tests, which are new and still-developing methods in Turkey, are used. The extensive facade tests have been conducted on full-scale specimen under field conditions reproduced in an equipped test chamber by authorized facade testing company and the assessment of this curtain wall performance was provided accordance with related standards. The two story full-size specimen, was 3000 mm to 7600 mm, belongs to one of the prestigious office towers constructed in Istanbul. The facade tests conducted to the specimen include watertightness, air permeability, wind resistance and building movement tests. In this study, the performance criteria of panel curtain wall system were investigated not only against environmental factors but also against human sourced factors. It is expected that this study will provide a guideline for system designers on the future research and development phase and for architects on the selection of curtain wall systems for their buildings due to the conducted test results and other advantages taken throughout this study.
15

Aktivt Pansar : Att nå verkan med dagens vapensystem i morgondagens pansar

Johansson, Arvid January 2014 (has links)
Då dagens vapensystem blir allt effektivare med högre penetration och större verkan är det inte längre möjligt att endast lägga på mer pansar för att få tillräckligt skydd. Fordonen blir för tunga och rörligheten påverkas negativt i allt för stor grad, därför börjar nu system för aktivt skydd slå sig in på marknaden. Dessa system söker aktivt av fordonets omgivning och skjuter ner inkommande hot såsom raketer och robotar och finns redan implementerade i en rad länder i vårt närområde. Infanteriets huvudbeväpning, som mot bepansrade hot traditionellt sett varit just robotar, raketer och granater, är i många fall verkanslös i mötet med aktivt pansar. Uppsatsen undersöker vilka möjligheter som finns att med den utrustning som dagens svenska försvarsmakt är utrustad med nå verkan i mål som är skyddade av aktivt pansar. De befintliga systemen för aktivt pansar Trophy, Iron Curtain och Arena har valts som exempelsystem. De vapensystem som granskas är STRIX, Rb56, Pskott m/86, Grg m/86 samt fordonsmina 14. En slutsats är att de granskade systemen alla saknar förmåga att skydda fordonet från hot som kommer rakt ovanifrån, detta medför att STRIX är fullt fungerande mot ett fordon skyddat av aktivt pansar. / Since today's weapons systems are becoming more efficient with higher penetration and greater efficacy, it is no longer possible to only put on more armor to get adequate protection. The vehicles become too heavy and mobility is adversely affected to an excessive degree, because of this systems for active protection are now breaking into the market. These systems are actively scanning the vehicle's surroundings and shoot down incoming threats such as rockets and robots and are already implemented in a number of countries in our region. The infantry's main armament against armored units, which traditionally have been just missiles, rockets and grenades are in many cases useless meeting with active protection systems. The paper examines the possibilities of reaching effect in targets equipped with active armor using the equipment available to the Swedish armed forces today. The existing active protection systems Trophy, Iron Curtain and Arena have been chosen as example systems. The weapons systems examined are STRIX , Rb56 , Pskott m/86 , Grg m/86 and Fordonsmina 14. One conclusion is that the audited systems all lack the ability to protect the vehicle from threats that come from directly above; this means that STRIX is fully functional to a vehicle protected by an active protection system.
16

Deflection gap study for cold‐formed steel curtain wall systems

Monroy, Barbara L. January 1900 (has links)
Master of Science / Department of Architectural Engineering and Construction Science / Sutton F. Stephens / Cold‐formed steel has become a preferred building material for wall framing in many different types of structures. One of its main uses has been as non‐structural members in curtain wall assemblies of structural steel framed buildings. In an exterior wall application, the main purpose of the curtain wall is to transfer out of plane loads to the steel frame while not supporting any superimposed gravity loads. Therefore, when the curtain wall is in the plane of the structural steel frame, the vertical deflection of the spandrel beam directly above the wall must be known to provide the appropriate deflection gap between the beam and the curtain wall so that gravity loads are not transferred to the wall. Common practice is to size the gap for the deflection from 100% of the live load. In some cases, the deflection gap may be significant, and since this gap must also be provided in the exterior cladding of the wall, it creates a design issue for the architect. This report presents the results of an investigation into the feasibility of reducing the size of the deflection gap when the wall is located directly under the spandrel beam. In this study, analytical models were developed for common design situations of curtain walls constructed of cold‐formed steel studs in structural steel framed buildings. This study investigates two common stud heights combined with different floor live loads. Taking into account that wall studs have some available axial compressive strength, a procedure was developed to determine an appropriate reduction for the gap. Using an iterative process a relationship is made between the axial compressive strength of the stud and the amount of axial load the stud can support to establish a factor which gives the percentage the live load gap for 100% live load can be safely reduced by.
17

Malované opony české provenience v poslední čtvrtině 19. století / Painted curtains of Czech provenance in the last quarter of the 19th century

Rozinek, Josef January 2013 (has links)
Main task of this work is to present painted curtains of the Czech provenance and situated on the Czech territory during last quarter of th 19th century. At the beginning I will present the development of theater curtains in general. There will be also described Czech painted curtains from the end of 18th and 1st half of the 19th century and the foreign examples. Subsequently will be analyzed the curtains of the national Czech and German theaters ant there will be made comparison between these two types. At the end will be described the specific element of painted curtains. Powered by TCPDF (www.tcpdf.org)
18

Angled curtain coating : an experimental study : an experimental investigation into the effect of die angle on air entrainment velocity in curtain coating under a range of operating conditions

Elgadafi, Mansour Masoud January 2010 (has links)
In all coating applications, a liquid film displaces air in contact with a dry solid substrate. At a low substrate speed a thin uniform wetting line is formed on the substrates surface, but at a high speed the wetting line becomes segmented and unsteady as air becomes entrained between the substrate and the liquid. These air bubbles affect the quality of the coated product and any means to postpone this at higher speeds without changing the specifications of the coating liquid is desirable. This research assesses the validity of a theoretically based concept developed by Blake and Rushack [1] and exploited by Cohu and Benkreira [2] for dip coating. The concept suggests that angling the wetting line by an angle ß would increase the speed at which air is entrained by a factor 1/cos ß. In practice, if achieved this is a significant increase that would result in more economical operation. This concept was tested in a fast coating operation that of curtain coating which is already enhanced by what is known as hydrodynamic assistance [2]. Here we are effectively checking an additional assistance to wetting. The work, performed on a purposed built curtain coater and a rotating die, with a range of fluids showed the concept to hold but provided the data are processed in a way that separate the effect of curtain impingement from the slanting of the wetting line.
19

The manufacturing of curtain wall materials in Hong Kong : research report.

January 1982 (has links)
by Ng Cho-yin, Tony, Ha Woon-chun, Mary. / Bibliography : leaf 70 / Thesis (M.B.A.)--Chinese University of Hong Kong, 1982
20

Tecnologia de fachada: cortina com placas de grês porcelanato. / Technology of porcelain tiles curtain wall.

Amaury Antunes de Siqueira Junior 28 February 2003 (has links)
O trabalho apresenta o estado-da-arte das fachadas-cortina executadas com placas de grês porcelanato, discutindo os principais parâmetros para a elaboração de projetos e produção desta tipologia de revestimentos. Acredita-se ser este um dos primeiros trabalhos acadêmicos elaborados no Brasil sobre o assunto, pretendendo-se contribuir quando da implantação desse sistema no país. Procura-se estabelecer os principais conceitos e definições sobre as fachadas-cortina e fachadas ventiladas, objetivando fundamentar a utilização desses termos que vêm sendo empregados sem precisão pelo meio técnico brasileiro. São abordadas as principais características e propriedades dos componentes, elementos construtivos e dispositivos empregados, como também os principais requisitos a serem considerados quando da elaboração do projeto. São destacadas as vantagens relativas desta tecnologia construtiva quando comparada aos revestimentos tradicionais aderidos, ressaltando-se sua importância como alternativa e potencialidades quando comercializado como um sistema de produção. / This report approaches the state-of-art of the porcelain tiles curtain wall. Both design and installations methods are discussed, including main features and properties of the components, elements and devices necessary. Main requirements considered to the design process are also take into consideration. It is believed that this study is one of the first academic studies developed in Brazil concerning this theme, and it is intended to contribute to the implementation of this system in the country. It aims at establishing the main concepts and the definitions on the curtain walls and ventilated facades. The prime objective is to base the correct use of these terms, since they have been used without accuracy by the Brazilian technicians. main features and properties of the components, elements and devices necessary. Main requirements considered to the design process are also take into consideration. Several advantages concerning this type of cladding are emphasized when compared with traditional coverings, standing out the comportance of the method as an interesting technology alternative.

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