Unreinforced masonry walls subjected to blast loading are vulnerable to collapse and fragmentation. The objective of this thesis is to conduct experimental and analytical research for developing a blast retrofit methodology that utilizes polyurea. A total of four unreinforced masonry walls were constructed and tested under various shock tube induced blast pressures at the University of Ottawa Shock Tube Testing Facility. Two of the retrofitted walls had surface-sprayed polyurea. The results indicate that the use of polyurea effectively controlled fragmentation while significantly increased the load capacity and stiffness of masonry walls. Polyurea proved to be an excellent retrofit material for dissipating blast induced energy by providing ductility to the system and changing the failure mode from brittle to ductile. Single degree of freedom (SDOF) dynamic analyses were conducted as part of the analytical investigation. The results show that the analytical model provides reasonably accurate predictions of the specimen response.

Condition assessment of existing concrete bridge pier caps using the general shear provisions of the AASHTO LRFD Bridge Design Specification has caused the Georgia Department of Transportation (GDOT) to post a large number of bridges in the State of Georgia. Posting of bridges disrupts the free flow of goods within the region served by the bridge and has a negative economic impact. To prevent structural deterioration, diagonal cracking or failure of concrete pier caps in shear, the GDOT employs an in-situ strengthening technique that utilizes an external vertical post-tensioning system. However, the fundamental mechanics of this system and its effectiveness under service load have not been examined previously. This research examines the behavior of reinforced concrete pier caps that utilize the above strengthening system in a combined analytical and experimental program. In the experimental part of the study, two groups of full-scale reinforced concrete deep beam specimens were tested. The first group consisted of six deep beams with shear span/depth ratios of approximately 1.0, which is typical of bridge pier caps; of these six, two included the external post-tensioning system. In the second group, nine deep beam specimens that included a segment of the column representing the pier were tested; four of those tests included the external post-tensioning system. The tests revealed that the shear capacity computed using the AASHTO LRFD Bridge Design Specifications provided a conservative estimate of the specimen capacity in all but one case when compared to the experimental results. However, the AASHTO strut and tie provisions were found to provide a much closer assessment of the load carrying mechanism in the pier cap than the general shear provisions, in that they were able to predict the load at which yielding of the tension reinforcement occurred as well as the angle of the compression strut. The presence of the column segment in the second group had a significant impact on the failure mechanism developed in the specimen near ultimate load. The stress concentration at the reentrant corner between the pier cap and column interface served as an attractor for the formation of diagonal shear cracks, a mechanism not observed in previous deep beam tests in shear. The research has led to recommendations for improving the design of pier caps and the external post-tensioning system, where required, based on mechanics which are consistent with the results of the experimental program.

Unreinforced masonry walls subjected to blast loading are vulnerable to collapse and fragmentation. The objective of this thesis is to conduct experimental and analytical research for developing a blast retrofit methodology that utilizes polyurea. A total of four unreinforced masonry walls were constructed and tested under various shock tube induced blast pressures at the University of Ottawa Shock Tube Testing Facility. Two of the retrofitted walls had surface-sprayed polyurea. The results indicate that the use of polyurea effectively controlled fragmentation while significantly increased the load capacity and stiffness of masonry walls. Polyurea proved to be an excellent retrofit material for dissipating blast induced energy by providing ductility to the system and changing the failure mode from brittle to ductile. Single degree of freedom (SDOF) dynamic analyses were conducted as part of the analytical investigation. The results show that the analytical model provides reasonably accurate predictions of the specimen response.

Tidal power, or the use of tides for electricity production, exists in many forms including tidal barrages, which exploit tidal head differentials, and turbines placed directly in regions with large tidal current velocities. The latter is actively being investigated in many countries around the world as a means of providing renewable and wholly predictable electricity (cf. wind, solar and wave power). The expansion of the in-stream tidal industry is hindered however by several factors including: turbine durability, deployment and maintenance costs, and the lack of abundant locations which meet the necessary current velocities for turbine start-up and economic power production. A new novel type of augmentation device, entitled the ‘Tidal Acceleration Structure’ or TAS (Canadian patent pending 2644792), has been proposed as a solution to the limited number of coastal regions which exhibit fast tidal currents. In preliminary investigations, the TAS, a simple Venturi section consisting of walls extending from the seafloor to above the high water mark in an hourglass shape, was found as able to more than double current velocities entering the device. The results indicated a significant advantage over other current channeling technologies and thus the need for more in-depth investigations. The main objective of the present study was to optimise the design of the TAS and to predict the power that a turbine placed within it could extract from flow. To do this, two principal methods were employed. Firstly, a 1:50 scale model of the TAS was tested and its shape optimised in a 1.5 m wide flume. Secondly, a 3D numerical model (ANSYS Fluent) was used for comparison with the experimental results. During the tests, a TAS configuration was found that could accelerate upstream velocities by a factor of 2.12. In separate tests, turbines were simulated using Actuator Disc Theory and porous plates. The TAS-plate combination was found to be able to extract up to 4.2 times more power from flow than the stand-alone plate, demonstrating that the TAS could provide turbines with a significant advantage in slower currents. Though further research is needed, including the testing of a larger TAS model in conjunction with a small in-stream turbine, the results of this thesis clearly demonstrate the potential of the TAS concept to unlock vast new areas for tidal energy development.

The aim of this diploma thesis is experimental testing and evaluation of the suitability of lubricants for drawing stainless chromium - nickel austenitic steel X5CrNi18-10 and comparison of the results obtained from the work [51]. The testing was performed by modeling the friction between the traction edge and the retainer, which corresponds to the real production process at ACO Industries. The introductory part of the thesis describes the process of deep drawing, followed by a description of tribology and the effect of friction. The individual types and properties of lubricants are described in more detail. The main part of the work deals with the testing of lubricants. The results are then described and evaluated.

This thesis deals with a summary of different types and characteristics of coatings used for increasing the lifetime of cemented carbide tools. Besides, the thesis includes solving the issue regarding edge chipping during machining interrupted pipe ends at the pipe line, selecting a new type of indexable inserts and indexable inserts holders to increase line productivity and decrease tool costs in the related operation.

The thesis describes movement optimization of a linear thermoelectric actuator that is used for operating floor heating valves in modern buildings. Featuring experimental nature, the thesis deals with a problem specified by an industrial company within the following steps; definition of possible solutions based on problem research, experimental verification of selected propositions, the best solution selection resulting from the analysis of executed measurements, final verification with all product versions, benchmarking.

The Bridge House is a steel building structure located in Poly Canyon, a rural area inside the campus of California Polytechnic State University, San Luis Obispo. The Bridge House is a one story steel structure supported on 4 concrete piers with a lateral force resisting system (LFRS) composed of ordinary moment frames in the N-S direction and braced frames in the E-W direction and vertically supported by a pair of trusses. The dynamic response of the Bridge House was investigated by means of system identification through ambient and forced vibration testing. Interesting findings such as diaphragm flexibility, foundation flexibility and frequency shifts due to thermal effects were all found throughout the mode shape mapping process. Nine apparent mode shapes were experimentally identified, N-S and E-W translational, rotational and 6 vertical modes. A computational model was also created and refined through correlation with the modal parameters obtained through FVTs. When compared to the experimental results, the computational model estimated the experimentally determined building period within 8% and 10% for both N-S and E-W translational modes and within 10% for 4 of the vertical modes.

Die im Forschungsprojekt MAI Skelett erarbeitete Skelettbauweise konnte das Potential endlos, kohlenstofffaserverstärkter Thermoplastprofile aufzeigen. Um das gesamte wirtschaftliche Potential dieser Hybridbauweise nutzten zu können, bedarf es der weitergehenden Analyse des parallelen Einsatzes unterschiedlicher Verstärkungsfasern. In dieser Arbeit wird das Verhalten von Kohlenstofffaser-, Glasfaser- und deren Hybridprofilen mit einem Querschnitt von exemplarisch 10 mm x 10 mm unter den Hauptbelastungsarten betrachtet. Hierfür werden die Profile mechanisch charakterisiert und die Übertragbarkeit der Eigenschaften auf reale Bauteile am Beispiel des Windlaufs einer Fahrzeugkarosserie simulativ und experimentell überprüft. Zudem wird eine Materialauswahl, unter Nutzung von Optimierungsalgorithmen, in den Auslegungsworkflow der Skelettbauweise integriert. Diese werden zur Minimierung der Materialkosten bei Einhaltung der mechanischen Randbedingungen genutzt.:1 Einleitung und Motivation 2 Stand der Technik und Wissenschaft 3 Zielsetzung und Vorgehensweise 4 Betrachtete Materialien 5 Charakterisierung endlosfaserverstärkter Thermoplastprofile 6 Bauteilauswahl und -optimierung 7 Experimentelle Validierung der Optimierung am Beispiel des Windlaufs 8 Zusammenfassung und Ausblick / The so called „Skeleton Design“ was developed within the research project MAI Skelett. It showed the potential of continuous fiber reinforced thermoplastic materials. In order to exploit the total economic potential of this hybrid design, the parallel usage of different reinforcement fibers must be investigated. In this thesis the mechanical behavior of carbon, glass and hybrid fiber reinforced profiles with a cross-section of exemplary 10 mm x 10 mm under the main loading conditions are examined. These mechanical properties are investigated regarding their potential to be transferred to real parts using experimental testing and simulation. In order to identify suitable parts within the automotive body in white structure a valuation method is developed for objective selection of expedient parts using the load exposure and function of the single part within the whole body in white structure. Furthermore, a material selection method is integrated into the design process of parts in „Skeleton Design“. Therefore, optimization algorithms are used in order to minimize the material costs under mechanical boundary conditions.:1 Einleitung und Motivation 2 Stand der Technik und Wissenschaft 3 Zielsetzung und Vorgehensweise 4 Betrachtete Materialien 5 Charakterisierung endlosfaserverstärkter Thermoplastprofile 6 Bauteilauswahl und -optimierung 7 Experimentelle Validierung der Optimierung am Beispiel des Windlaufs 8 Zusammenfassung und Ausblick

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