published_or_final_version / Architecture / Master / Master of Architecture

Thesis (Ph. D.)--University of Rhode Island, 2005. / Typescript. Includes bibliographical references (leaves 154-155).

Thesis (Ph. D.)--University of Rhode Island, 2005. / Typescript. Includes bibliographical references (leaves 122-131).

The use of cellular foam as a core material in light-weight structural applications is of considerable interest. However, advances in this technology have been limited due to the lack of information concerning the macroscopic material behavior of cellular foams. Of particular interest in the design of composite structures is the shear modulus, G, of the core material, which must be established with a high degree of accuracy. Current ASTM test methods for shear modulus determination were researched and found inadequate for testing cellular foam materials. The difficulty in testing foam and the inaccuracies associated with the standard test methods established the need for the development of a test method for these materials. The test method (test fixture and test procedure) developed for cellular foam materials is presented. The design of the test fixture and the finite element analysis performed to determine fixture accuracy are discussed in detail. Additionally, the test procedure is presented, as well as the results for the 32 tests performed.

Optimized slender and short-thick beams are used in building, aircraft and machine structures to increase performance at a lower material cost. A previous work proposes an optimum shape, material and size selection model to design lightweight slender beams under pure bending. In short-thick beams, the transverse shear effects are no longer negligible and impact the choice of the optimum shape. This work extends such an optimum selection model to consider both slender and short-thick beams, by formulating the total beam stiffness design requirement as a combination of shear and bending stiffness. Selection charts are developed to show the impact of design variables, such as shape, size, material and slenderness, on the total beam stiffness. The model of total beam stiffness is validated against computational results from finite element analyses of beam models. A case study demonstrates the use of the selection charts to compare the performance of beams at the conceptual design stage.

No description available.

Motivation - Komplexe Anforderungen an die Karosserie - Unbekannte Auswirkungen von Parametervariationen in der frühen Phase - Informationsdefizit führt zu Iterationsschleifen Ziel Beurteilung der Auswirkung von Parametervariationen von Werkstoffen, Produktionsverfahren, Geometrien auf die Karosserie-Eigenschaften

Thesis (MA--Art and Design) -- AUT University, 2007. / Includes bibliographical references. Also held in print (65 leaves : col. ill. ; 22 x 30 cm.) in City Campus Collection (T 658.5752 BOU)

The use of cold-formed steel as a framework for floor systems in multi-story buildings and single occupancy residences is becoming an increasingly popular alternative to traditional materials and techniques. Builders and designers have recognized that the high strength-to-weight ratio provided by the cross-section of cold-formed steel members permits lighter structures and longer spans. The longer spans and lighter structures associated with cold-formed steel floor systems can result in vibration serviceability issues if proper design considerations are not made. Providing sufficient damping within the structure is the most effective way to ensure that occupants are comfortable under typical residential and office service loads. The modern, open-concept interior has open floor plans with few partitions and long spans, which result in inherently low structural damping. Cold-formed steel floor systems also have less mass than traditional floor systems, which will increase the amplitude of acceleration response. The vibration problems that may be present in cold-formed steel floor systems, like any other floor system, can be addressed if proper consideration is given by designers. Traditional design approaches for vibration serviceability have proven inadequate, and there are no current methods available to designers for calculating the response of cold-formed steel floor systems. In order to design a floor system to properly address occupant comfort, consideration must be given for the type of dynamic loading, resonance, dynamic response, and stiffness of the floor system. The objective of this thesis is to improve the understanding of the dynamic characteristics of cold-formed steel floor systems, and recommend an adequate model for predicting the dynamic response and modal properties of floor systems, in order to aid the design process. This thesis presents the results of an extensive laboratory and field study on the vibration of cold-formed steel floor systems. Floor systems built with cold-formed steel TreadyReady® joists and subfloor assemblies containing OSB, FORTACRETE®, sound reduction board, cold-formed steel deck, and LEVELROCK® topping were examined. Previous research has presented the observed influence of construction details on the modal properties of the laboratory floor systems tested. This thesis discusses the influence of different details on the transverse stiffness of the floor systems. It was found that effectively restrained strongbacks, and cold-formed steel deck subfloor assemblies provided significant increases in transverse stiffness. Based on the analysis of the field testing data, recommended design damping ratios are provided for floor systems constructed with the materials investigated in this study. Floor response that can be compared to serviceability criteria is presented. The peak RMS acceleration from walking excitation was found to be within the acceptable range for the ISO criterion based on residential occupancy, and the static deflection from a 1 kN point load was found to be within the acceptable range of Onysko’s criterion. An adequate design criterion for vibration requires a limiting value, and a means of estimating floor response for comparison. The AISC, ATC, and Smith, Chui, and Hu Orthotropic Plate design methods were evaluated by comparing predicted frequency against measured frequency for the test floors. The ATC and Smith, Chui, and Hu Orthotropic Plate methods were evaluated by comparing predicted deflection against measured deflection for the test floors. The ATC method is recommended as the best method for calculating floor response based on current publications. A design procedure is recommended for cold-formed steel floor systems, using the ATC design guide. The ATC acceleration criterion for walking excitation must be met for floors with fundamental frequencies of less than 15 Hz, and the ATC static deflection criterion must be met for all floors. Proposed modifications to the ATC method to improve the design of cold-formed steel floors include: adopting the recommended design damping ratios from this thesis; adopting the frequency-weighted ISO limiting acceleration and, obtaining several coefficients and empirical expressions that are relevant to cold-formed steel floors from further testing. Recommendations for improving the floor testing procedures at the University of Waterloo are given.

The use of cold-formed steel as a framework for floor systems in multi-story buildings and single occupancy residences is becoming an increasingly popular alternative to traditional materials and techniques. Builders and designers have recognized that the high strength-to-weight ratio provided by the cross-section of cold-formed steel members permits lighter structures and longer spans. The longer spans and lighter structures associated with cold-formed steel floor systems can result in vibration serviceability issues if proper design considerations are not made. Providing sufficient damping within the structure is the most effective way to ensure that occupants are comfortable under typical residential and office service loads. The modern, open-concept interior has open floor plans with few partitions and long spans, which result in inherently low structural damping. Cold-formed steel floor systems also have less mass than traditional floor systems, which will increase the amplitude of acceleration response. The vibration problems that may be present in cold-formed steel floor systems, like any other floor system, can be addressed if proper consideration is given by designers. Traditional design approaches for vibration serviceability have proven inadequate, and there are no current methods available to designers for calculating the response of cold-formed steel floor systems. In order to design a floor system to properly address occupant comfort, consideration must be given for the type of dynamic loading, resonance, dynamic response, and stiffness of the floor system. The objective of this thesis is to improve the understanding of the dynamic characteristics of cold-formed steel floor systems, and recommend an adequate model for predicting the dynamic response and modal properties of floor systems, in order to aid the design process. This thesis presents the results of an extensive laboratory and field study on the vibration of cold-formed steel floor systems. Floor systems built with cold-formed steel TreadyReady® joists and subfloor assemblies containing OSB, FORTACRETE®, sound reduction board, cold-formed steel deck, and LEVELROCK® topping were examined. Previous research has presented the observed influence of construction details on the modal properties of the laboratory floor systems tested. This thesis discusses the influence of different details on the transverse stiffness of the floor systems. It was found that effectively restrained strongbacks, and cold-formed steel deck subfloor assemblies provided significant increases in transverse stiffness. Based on the analysis of the field testing data, recommended design damping ratios are provided for floor systems constructed with the materials investigated in this study. Floor response that can be compared to serviceability criteria is presented. The peak RMS acceleration from walking excitation was found to be within the acceptable range for the ISO criterion based on residential occupancy, and the static deflection from a 1 kN point load was found to be within the acceptable range of Onysko’s criterion. An adequate design criterion for vibration requires a limiting value, and a means of estimating floor response for comparison. The AISC, ATC, and Smith, Chui, and Hu Orthotropic Plate design methods were evaluated by comparing predicted frequency against measured frequency for the test floors. The ATC and Smith, Chui, and Hu Orthotropic Plate methods were evaluated by comparing predicted deflection against measured deflection for the test floors. The ATC method is recommended as the best method for calculating floor response based on current publications. A design procedure is recommended for cold-formed steel floor systems, using the ATC design guide. The ATC acceleration criterion for walking excitation must be met for floors with fundamental frequencies of less than 15 Hz, and the ATC static deflection criterion must be met for all floors. Proposed modifications to the ATC method to improve the design of cold-formed steel floors include: adopting the recommended design damping ratios from this thesis; adopting the frequency-weighted ISO limiting acceleration and, obtaining several coefficients and empirical expressions that are relevant to cold-formed steel floors from further testing. Recommendations for improving the floor testing procedures at the University of Waterloo are given.