Blast resistance has recently become increasingly relevant for structural engineers. Blast loads are created by explosive devices that, upon detonation, create pressure loads that are much higher than most that a structure would ever experience. While there are many types of blast loads that are impossible to adequately prepare for, methods are presently being developed to mitigate these loads. This research investigates the possibility of using synthetic fiber ropes as a means of blast resistance. This is the third phase of a multi-stage research endeavor whose goal is to analyze Snapping-Cable Energy Dissipators (SCEDs) for reducing the effects of large-scale lateral loads. Finite element models of portal frames were developed using the commercial finite element program ABAQUS and dynamic models were run for varying blasts and frame systems. Blast pressures of 100, 2,000, and 4,000 psi were applied to a steel portal frame and comparisons were made between unbraced frames and frames braced with springs of different stiffnesses. Additional tests were run to examine the effects of strain rate dependent yield on the results of the models. Parallel research is being conducted on the specific material behavior of the synthetic fiber ropes so that the models developed for this research can be revised for a more accurate determination of the effects of the ropes on structural systems subjected to blast loads. / Master of Science

[pt] Na área de biologia computacional a busca por informações relevantes em meio a volumes de dados cada vez maiores é uma atividade fundamental. Dentre outras, uma tarefa importante é a execução da ferramenta BLAST (Basic Local Alignment Search Tool), que possibilita comparar biosseqüências a fim de se descobrir homologias entre elas e inferir as demais informações pertinentes. Um dos problemas a serem resolvidos no que diz respeito ao custo de execução do BLAST se refere ao tamanho da base de dados, que vem aumentando consideravelmente nos últimos anos. Avaliar o BLAST com estrat´egias paralelas e distribuídas com apoio de agrupamento de computadores tem sido uma das estratégias mais utilizadas para obter ganhos de desempenho. Nesta dissertação, é realizada uma alocação física replicada da base de dados (de seqüências), onde cada réplica é fragmentada em partes distintas, algumas delas escolhidas como primárias. Dessa forma, é possível mostrar que se aproveitam as principais vantagens das estratégias de execução sobre bases replicadas e fragmentadas convencionais, unindo flexibilidade e paralelismo de E/S. Associada a essa alocação particular da base, são sugeridas duas formas de balanceamento dinâmico da carga de trabalho. As abordagens propostas são realizadas de maneira não intrusiva no código BLAST. São efetuados testes de desempenho variados que demonstram não somente a eficácia no equilíbrio de carga como também eficiência no processamento como um todo. / [en] A fundamental task in the area of computational biology is the search for relevant information within the large amount of available data. Among others, it is important to run tools such as BLAST - Basic Local Alignment Search Tool - effciently, which enables the comparison of biological sequences and discovery of homologies and other related information. However, the execution cost of BLAST is highly dependent on the database size, which has considerably increased. The evaluation of BLAST in distributed and parallel environments like PC clusters has been largely investigated in order to obtain better performances. This work reports a replicated allocation of the (sequences) database where each copy is also physically fragmented, with some fragments assigned as primary. This way we show that it is possible to execute BLAST with some nice characteristics of both replicated and fragmented conventional strategies, like flexibility and I/O parallelism. We propose two dynamic workload balancing strategies associated with this data allocation. We have adopted a non- intrusive approach, i.e., the BLAST code remains unchanged. These methods are implemented and practical results show that we achieve not only a balanced workload but also very good performances.

[Truncated abstract] As a consequence of the increase in terrorist incidents, many comprehensive researches, both experimental and numerical modelling of structure and blast interaction, have been conducted to examine the behaviour of civilian structures under dynamic explosion and its impact. Nevertheless most of the works in literature are limited to response of simple structures such as masonry walls, reinforced concrete beams, columns and slabs. Although these studies can provide researchers and structural engineers a good fundamental knowledge regarding blast load effect, it is more likely for blast load to act upon entire structures in actual explosion events. The interaction between blast load and structures, as well as the interaction among structural members may well affect the structural response and damage. Therefore it is necessary to analyse more realistic reinforced concrete structures in order to gain an extensive knowledge on the possible structural response under blast load effect. Among all the civilian structures, bridges are considered to be the most vulnerable to terrorist threat and hence detailed investigation in the dynamic response of these structures is essential. This thesis focuses on the study of the response of a modern cable-stayed bridge under blast loadings. ... Firstly, analysis is conducted to examine the failure of four main components namely pier, tower, concrete back span and steel composite main span under close proximity dynamic impact of a 1000 kg TNT equivalent blast load. Secondly, based on such results, the remainder of the bridge structure is then tested by utilizing the loading condition specified in the US Department of Defence (DoD) guideline with the aim to investigate the possibility of bridge collapse after the damage of these components. It is found that failure of the vertical load bearing elements (i.e. pier and tower) will lead to catastrophic collapse of the bridge. Assuming that terrorist threat cannot be avoided, hence protective measures must be implemented into the bridge structure to reduce the damage induced by explosive blast impact and to prevent bridge from collapse. As such, a safe standoff distance is determined for both the pier and tower under the blast impact of 10000 kg TNT equivalent. This information would allow the bridge designer to identify the critical location for placing blast barriers for protection purpose. For the case of bridge deck explosion, carbon fibre reinforced polymer (CFRP) is employed to examine in respect of its effectiveness in strengthening the concrete structure against blast load. In this research, appropriate contact is employed for the numerical model to account for the epoxy resin layer between the CFRP and concrete. In addition, to ensure that the CFRP can perform to its full capacity, anchors are also considered in the numerical study to minimize the chance of debonding due to the weakening of the epoxy. The results reveal that although severe damage can still be seen for locations in close proximity to the explosive charge, the use of CFRP did reduce the dynamic response of the bridge deck as compared to the unprotected case scenario. Further investigation is also carried out to examine the change in damaged zone and global response through variation in CFRP thickness.

No description available.

This work deals with character-based DNA barcoding. DNA barcoding and character-based DNA barcoding methods are described in the introduction. Another part contains information of method CAOS (Characteristic Attributes Organization), method BLOG (Barcoding with LOGic) and method BLAST. Programs are described in the practical part. The end contains results.

Explosives have become increasingly common on the battlefield worldwide. Military personnel and civilians often experience blast loading to the lower extremity due to its direct contact with the ground and floor of vehicles. The pressure and axial loading from these incidents often lead to detrimental injuries. These injuries can be due to a number of mechanisms terming them primary, secondary, tertiary, or quaternary blast injuries. Of these injuries, this study will focus on primary and tertiary injuries, specifically bone fractures, compartment syndrome, and soft tissue disruption which often result from blast loading due to these mechanisms. However, the pressure and load levels causing these injuries are unknown. Currently, the methodologies, which study the injury criteria and design of blast mitigating structures, are limited. The main limitations are the lower rates of testing (automobile), specimen limitation (cadavers, surrogates, etc.), cost, and testing repeatability. Consequently, the goal of this dissertation is to develop a realistic computational model which can be used to improve the injury criteria, personal protective equipment (PPE), and vehicular structure in a cost effective and timely manner. Three Aims were thus pursued. For Specific Aim 1, a standing lower extremity was developed, verified, and simulated with several open-air blast loading conditions. Specific Aim 2 focused on validating the lower extremity model using experimental drop tower test results. In the drop tower simulation, the lower extremity model was successfully converted into a seated posture model and setup with similar loading and boundary conditions as the experiment. Specific Aim 3 involved incorporating a boot into the standing lower extremity model and evaluating its ability to mitigate pressure waves. In summary, Specific Aims 1 and 2 developed, verified, and validated a realistic human lower extremity model for the use in blast simulations. Specific Aim 3 further confirmed the models use in developing PPE.

In this thesis, the dynamic structural response of six scaled flexural masonry walls to scaled blast loading is experimentally investigated. These walls have been tested in at an open range with charge masses ranging from 5 kg to 25 kg of Pentex-D explosive material with a TNT equivalency of 1.2, and with a constant stand-off distance of 5 m throughout testing. The field properties of the blast wave, which includes the reflected and free field pressures, were recorded. Additionally, the displacement response histories of the wall over the blast test were recorded and the post-blast damage was documented. This study puts forth several potential models for the analysis of the experimental data. The experimentally obtained blast characteristics were compared to predictions of the Kingery and Bulmash (K-B) model. The strain rates used during the study are equivalent to those developed by a number of studies for the materials used in the construction of the specimens. The results obtained through the experimental program are compared to those from a variety of single degree of freedom models, ranging from simplified linear relationships to complex stress-strain relations accounting for the effects that arise because of the increased strain rate due to blast testing. The simplified model assumes a constant stiffness, mass, and triangular pressure profile to determine the peak deflection of the specimen during an experimental test. The bilinear and nonlinear models are based on the discretization of the wall sections into a number of layers, and using strain-rate dependent, stress-strain relations of the constituent materials to generate stresses within the layers. These stresses then iv form the basis of the resistance function to determine the structural response of the test specimens. In this study, the effect of higher modes of vibration on the test specimens is not included. The bilinear and nonlinear models are then implemented to develop Pressure-Impulse (P-I) diagrams, and the effect of the strain rate on P-I diagrams is investigated. The P-I are then available to be implemented into the recent blast code for reinforced masonry flexural walls. The fitted results of the recorded experimental blast pressure parameters are shown to be adequately approximated by the software ConWep in terms of the peak pressure and specific impulse. Comparing the K-B model, which forms the theoretical basis of ConWep, to the raw pressure profile data obtained from the experimental testing, a significant variations is found in the pressure data while significant scatter is found in the impulse. The analytical results show that increasing the nonlinearity of the material accounts for; the response predicted by the single degree of freedom model more closely relates to the response of the specimens. In addition, strain rate effects have a significant impact on the potential level of protection (LOP) provided by masonry flexural walls, as it has a noticeable effect on the curves of the P-I diagram. / Thesis / Master of Applied Science (MASc)

No description available.

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.

<p>The focus of this study is on evaluating the performance of nine, one-third scale, arching, reinforced masonry (RM) walls subjected to blast loads and three, one-third scale arching, RM walls subjected to out-of-plane static airbag loads. These RM walls were supported on four sides to enforce two-way arching allowing the ability to monitor individual response to varying levels of blast loads and standoff distances. The uniformity of the blast pressure and impulse were ensured by a specifically designed test enclosure, diminishing the wrap-around and clearing effects, allowing valuable data to be documented. The damage levels noted, ranged from Superficial to Blowout compared directly to the CSA S850-12 performance limits. The outcome of this experiment demonstrates the beneficial effect of two-way arching on the flexural behaviour of RM walls under impulsive loading. The use of two-way arching RM walls significantly reduces structural damage and increases out-of-plane resistance, which in turn enhances the overall structural integrity and building preservation. Further, when subjected to blast, two-way arching RM walls considerably reduces debris and their dispersal, thus increasing public safety and minimizing hazard levels. When using the experimental test data results to calibrate finite element models (FEM), more analytical data points can be obtained and therefore getting a larger range of scaled distances and trials. The validation of the LS-DYNA model can be used as an alternative to the costly experimental data, as the information collected concluded that the FEM gave damage patterns and failure modes that were comparable with experimental results. The test data collected provides a better understanding of RM wall response to blast loads and to the ongoing Masonry Blast Performance Database (MBPD) project at McMaster University. The generated MBPD will in turn contribute to masonry design clauses in the future editions of the recently introduced Canadian Standards CSA S850-12 “Design and Assessment of Buildings Subjected to Blast Loads”.</p> / Master of Applied Science (MASc)