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This thesis investigates the use of the numerical modeling tools LS-DYNA and USA in modeling general far-field underwater explosions (UNDEX) by modeling a three-dimensional box barge that is subjected to a far-field underwater explosion. Past UNDEX models using these tools have not been validated by experiment and most are limited to very specific problems because of the simplifying assumptions they make. USA is a boundary element code that requires only the structural model of the box barge. LS-DYNA is a dynamic finite element code and requires both the structural model and the surrounding fluid model, which is modeled with acoustic pressure elements. Analysis of the box barge problem results finds that the program USA is a valid tool for modeling the initial shock response of surface ships when cavitation effects are not considered. LS-DYNA models are found to be very dependent on the accuracy of the fluid mesh. The accuracy of the fluid mesh is determined by the ability of the mesh to adequately capture the peak pressure and discontinuity of the shock wave. The peak pressure captured by the model also determines the accuracy of the cavitation region captured in the fluid model. Assumptions made in the formulation of the fluid model causes potential inaccurate fluid-structure interaction and boundary condition problems cause further inaccuracies in the box barge model. These findings provide a base of knowledge for the current capabilities of UNDEX modeling in USA and LS-DYNA from which they can be improved in future work. / Master of Science

Crash tests of strong-post w-beam guardrail have focused entirely on the performance of new guardrail. The risk posed by minor damage modes, e.g. small deflections and missing posts, has never been evaluated. Using finite element models validated by real world crash tests, this study assessed the safety risk of crashes into guardrail with minor damage. The minor damage modes under consideration for this study were rail and post deflection, missing posts, rail flattening, and post/rail separation. Each of these damage modes was evaluated according to the testing protocols laid out in National Cooperative Highway Research Program (NCHRP) Report 350, test level 3. A number of minor damage modes were found to pose significant risks to vehicle occupants and should be repaired as soon as possible. In order of priority of repair, these modes are missing posts, rail and post deflection over 6â , and rail flattening over 50%. Damage modes of less concern were rail and post deflections less than 6â , rail only deflection up to 6â , flattening less than 50%, and separation of the posts from rails. These recommendations were on the conservative side because preventing occupant injury was the highest priority of guardrail performance. Guardrails with rail and post deflection posed a risk of vehicle vaulting due to lowered rail height and failure of the posts to separate from the rails. This risk would be even greater for guardrails embedded in soft soils, which allow for greater deflection. Guardrails with missing posts frequently resulted in snagging of the vehicle tire on the downstream posts, as well as large increases in the tension carried by the rails during impact. Flattened rails posed a risk of vehicle rollover as they provided a ramp-like surface which caused the side of the vehicle to move upward, greatly increasing the change of override. Flattening also occurs frequently with other damage modes. Pre-existing separation of posts from the rails was found to have very little effect on the crash outcome. Separation of the posts from the rails was desirable as it prevented failure modes that were observed for the rail and post deflection simulations while maintaining the post contributions to lateral strength of the guardrail. / Master of Science

As barreiras de concreto são dispositivos utilizados como componentes de segurança em rodovias, que visam absorver o choque lateral de veículos desgovernados, propiciando sua recondução à faixa de tráfego e minimizando os danos aos ocupantes do veículo. Neste trabalho é analisado o desempenho de barreiras de concreto com o uso de modelos experimentais e numéricos baseados nas recomendações das normas brasileiras e internacionais. O estudo consiste em analisar a eficiência estática e dinâmica dessas barreiras. A análise estática engloba o estudo de distribuição de tensões na barreira considerando diferentes tipos de conectores, modo de ruptura, bem como a resistência desses conectores através de ensaios experimentais. Os ensaios são realizados de acordo com os critérios estabelecidos pela norma americana AASHTO LRFD 2012. A análise numérica, realizada com o uso de software de elementos finitos LS-DYNA©, contempla a atuação da geometria e da rigidez da barreira no processo de absorção de energia de impacto entre a barreira e o veículo, a eficiência do seu redirecionamento e adequação para os níveis de contenção estabelecidos em normas internacionais. Os resultados evidenciaram que a geometria da barreira é um fator importante para o desempenho da mesma, e, também que o uso de conectores em barreiras temporárias são primordiais para o bom funcionamento do sistema de contenção. / Concrete barriers are devices used as safety components in roads, which aim at absorbing side impact of unguided vehicles, redirecting them to the traffic lane and minimizing damage to the vehicle occupants. The present work analyzes the performance of concrete barriers through experimental and numerical models based on the recommendations of the Brazilian and international standards. The study consists in analyzing the static and dynamic efficiency of these barriers. The static analysis includes determining the stress distribution and yield lines in the barrier for different types of connectors, as well as studying the resistance of these connectors by performing experimental tests; these tests were conducted according to the criteria established by the American Standard AASHTO LRFD 2012. The numerical analysis, conducted with the commercial finite element software LS-DYNA©, evaluates the effect of geometry and stiffness of the barrier on the energy absorption performance., efficiency in redirecting the vehicles and suitability for providing restraint levels established in international standards. The results showed that the geometry of the barrier is an important factor for the barrier performance. In addition, the use of connectors in temporary barriers is essential for the smooth operation of the containment system.

A cultura da cana-de-açúcar é a segunda maior movimentação econômica na cadeia do agronegócio no Brasil. Gera riquezas através da fabricação de açúcar, etanol e cogeração de energia elétrica, além de outros subprodutos. Considerada fonte de energia renovável, a cana-de- açúcar a princípio tinha sua imagem associada a impactos negativos principalmente devido as queimadas realizadas nas lavouras para colheita manual. Nos últimos anos, baseado em decretos e no Protocolo Agro-ambiental, essa prática vem sendo abolida. Para se manter e até mesmo aumentar o rendimento das colhedoras nos canaviais, os gestores têm adotado práticas para reduzir os terraços agrícolas, com impacto nos sistemas de conservação de solos. Assim, este trabalho teve como objetivo identificar os impactos ambientais provocados pela mecanização agrícola decorrente do mau manejo e dimensionamento dos mecanismos de conservação do solo. Neste estudo também se realizou uma análise à Equação Universal de Perdas de Solo (EUPS), como ferramenta para o dimensionamento de terraços agrícolas. O estudo foi realizado em uma microbacia hidrográfica, denominada Ribeirão da Bocaina, localizada na UGRHI-13 (Tietê - Jacaré). Foi possível identificar a variabilidade amostral do solo para o dimensionamento conservacionista, gerando curvas de nível com Desníveis Verticais (D.V) desuniformes, contrariando a sistemática atual de terraços que respeita cotas múltiplas ou mesmo dimensionamentos empiristas, segundo o conhecimento local e o histórico recente da área. Algumas sugestões também foram feitas afim de torná-la uma ferramenta ainda mais eficiente, considerando condições particulares à cultura da cana-de-açúcar, tais como a influência da palhada, sulcos de plantio e diversos tipos de terraços como meios de controle à erosão. A metodologia foi satisfatória, no que tange a compreensão pelos meios de correlação entre as práticas conservacionistas e modelos de predição de perda de solo, trazendo luz à ciência na interpretação das ferramentas existentes e as lacunas a serem preenchidas. / Sugarcane culture is the second largest economic movement in the Brazilian agribusiness chain. It generates wealth through the manufacture of sugar and ethanol and cogeneration of electricity and other products. Although sugarcane has been considered a renewable energy source, its image was first associated with negative impacts mainly due to burnings in fields for manual harvesting. In recent years, decrees and Protocolo Agro-ambiental have abolished such a practice. To maintain and even increase the yield of harvesters in cane fields, managers have adopted practices so as to reduce agricultural terraces, which have impacted on soil conservation systems. This study identified the environmental impacts caused by agricultural mechanization resulting from mismanagement and design of soil conservation mechanisms. An analysis of Universal Soil Loss Equation (USLE) was conducted for the design of agricultural terraces. The study was developed in a watershed, called Ribeirão da Bocaina, located in UGRHI-13 (Tietê - Jacaré). The sample variability of soil for the conservation design was identified and contours with unsteady Vertical Gaps (VG) were generated. Such gaps contradict the current system of multiple terraces, which respects quotas or even empiricist sizing, according to the local knowledge and the recent history of the area. Some suggestions are provided for improvements in the tool, based on specific conditions for the cultivation of sugarcane, such as influence of trash, planting furrows and various terraces as erosion control means. The methodology was satisfactory regarding the understanding of the correlation between conservation practices and soil loss prediction models and has brought light to science for the interpretation of the existing tools and gaps to be filled.

A cultura da cana-de-açúcar é a segunda maior movimentação econômica na cadeia do agronegócio no Brasil. Gera riquezas através da fabricação de açúcar, etanol e cogeração de energia elétrica, além de outros subprodutos. Considerada fonte de energia renovável, a cana-de- açúcar a princípio tinha sua imagem associada a impactos negativos principalmente devido as queimadas realizadas nas lavouras para colheita manual. Nos últimos anos, baseado em decretos e no Protocolo Agro-ambiental, essa prática vem sendo abolida. Para se manter e até mesmo aumentar o rendimento das colhedoras nos canaviais, os gestores têm adotado práticas para reduzir os terraços agrícolas, com impacto nos sistemas de conservação de solos. Assim, este trabalho teve como objetivo identificar os impactos ambientais provocados pela mecanização agrícola decorrente do mau manejo e dimensionamento dos mecanismos de conservação do solo. Neste estudo também se realizou uma análise à Equação Universal de Perdas de Solo (EUPS), como ferramenta para o dimensionamento de terraços agrícolas. O estudo foi realizado em uma microbacia hidrográfica, denominada Ribeirão da Bocaina, localizada na UGRHI-13 (Tietê - Jacaré). Foi possível identificar a variabilidade amostral do solo para o dimensionamento conservacionista, gerando curvas de nível com Desníveis Verticais (D.V) desuniformes, contrariando a sistemática atual de terraços que respeita cotas múltiplas ou mesmo dimensionamentos empiristas, segundo o conhecimento local e o histórico recente da área. Algumas sugestões também foram feitas afim de torná-la uma ferramenta ainda mais eficiente, considerando condições particulares à cultura da cana-de-açúcar, tais como a influência da palhada, sulcos de plantio e diversos tipos de terraços como meios de controle à erosão. A metodologia foi satisfatória, no que tange a compreensão pelos meios de correlação entre as práticas conservacionistas e modelos de predição de perda de solo, trazendo luz à ciência na interpretação das ferramentas existentes e as lacunas a serem preenchidas. / Sugarcane culture is the second largest economic movement in the Brazilian agribusiness chain. It generates wealth through the manufacture of sugar and ethanol and cogeneration of electricity and other products. Although sugarcane has been considered a renewable energy source, its image was first associated with negative impacts mainly due to burnings in fields for manual harvesting. In recent years, decrees and Protocolo Agro-ambiental have abolished such a practice. To maintain and even increase the yield of harvesters in cane fields, managers have adopted practices so as to reduce agricultural terraces, which have impacted on soil conservation systems. This study identified the environmental impacts caused by agricultural mechanization resulting from mismanagement and design of soil conservation mechanisms. An analysis of Universal Soil Loss Equation (USLE) was conducted for the design of agricultural terraces. The study was developed in a watershed, called Ribeirão da Bocaina, located in UGRHI-13 (Tietê - Jacaré). The sample variability of soil for the conservation design was identified and contours with unsteady Vertical Gaps (VG) were generated. Such gaps contradict the current system of multiple terraces, which respects quotas or even empiricist sizing, according to the local knowledge and the recent history of the area. Some suggestions are provided for improvements in the tool, based on specific conditions for the cultivation of sugarcane, such as influence of trash, planting furrows and various terraces as erosion control means. The methodology was satisfactory regarding the understanding of the correlation between conservation practices and soil loss prediction models and has brought light to science for the interpretation of the existing tools and gaps to be filled.

As barreiras de concreto são dispositivos utilizados como componentes de segurança em rodovias, que visam absorver o choque lateral de veículos desgovernados, propiciando sua recondução à faixa de tráfego e minimizando os danos aos ocupantes do veículo. Neste trabalho é analisado o desempenho de barreiras de concreto com o uso de modelos experimentais e numéricos baseados nas recomendações das normas brasileiras e internacionais. O estudo consiste em analisar a eficiência estática e dinâmica dessas barreiras. A análise estática engloba o estudo de distribuição de tensões na barreira considerando diferentes tipos de conectores, modo de ruptura, bem como a resistência desses conectores através de ensaios experimentais. Os ensaios são realizados de acordo com os critérios estabelecidos pela norma americana AASHTO LRFD 2012. A análise numérica, realizada com o uso de software de elementos finitos LS-DYNA©, contempla a atuação da geometria e da rigidez da barreira no processo de absorção de energia de impacto entre a barreira e o veículo, a eficiência do seu redirecionamento e adequação para os níveis de contenção estabelecidos em normas internacionais. Os resultados evidenciaram que a geometria da barreira é um fator importante para o desempenho da mesma, e, também que o uso de conectores em barreiras temporárias são primordiais para o bom funcionamento do sistema de contenção. / Concrete barriers are devices used as safety components in roads, which aim at absorbing side impact of unguided vehicles, redirecting them to the traffic lane and minimizing damage to the vehicle occupants. The present work analyzes the performance of concrete barriers through experimental and numerical models based on the recommendations of the Brazilian and international standards. The study consists in analyzing the static and dynamic efficiency of these barriers. The static analysis includes determining the stress distribution and yield lines in the barrier for different types of connectors, as well as studying the resistance of these connectors by performing experimental tests; these tests were conducted according to the criteria established by the American Standard AASHTO LRFD 2012. The numerical analysis, conducted with the commercial finite element software LS-DYNA©, evaluates the effect of geometry and stiffness of the barrier on the energy absorption performance., efficiency in redirecting the vehicles and suitability for providing restraint levels established in international standards. The results showed that the geometry of the barrier is an important factor for the barrier performance. In addition, the use of connectors in temporary barriers is essential for the smooth operation of the containment system.

The focus of this thesis was to increase the knowledge in the area of "dynamic friction" during oblique helmet impacts, both experimentally and numerically. Physical experiments have been performed with multiple helmets, different angles of the anvil and different surface materials, with results of impact forces from the anvil and accelerations of the head. By the use of the Coulomb friction model the friction, over time, during the impact of the head and helmet has been calculated. Finite element method has then been used in LS-DYNA to try and replicate the physical results with the goal of creating an accurate friction model. There has been previous work done where the commonly used abrasive paper has been compared to asphalt as ground material in the drop tests. A similar study has been performed in this project which has been compared to the previous work. The results when comparing asphalt to abrasive paper and stainless steel shows that abrasive paper has a higher friction and rotational acceleration of the head compared to asphalt. Stainless steel however displays similar characteristics as asphalt in both friction and accelerations. The load cell used during the experimental testing has been examined carefully since the value of the friction coefficient has differed depending on the angle and the impact location on the anvil. There are still uncertainties surrounding the reliability of the results from the load cell. LS-DYNA has two different ways of modelling friction, one where LS-DYNA uses a modified equation of the Coulomb friction model and another one where the user can insert a table of values on coefficient of friction and relative velocity. Both methods have been used, however the latter method has proven to be more suitable for the kind of tests used in this project. / Fokuset för denna rapport var att öka förståelsen inom området ”dynamisk friktion” under sneda hjälmislag, både experimentellt och numeriskt. Fysiska experiment har genomförts med flertalet hjälmar och olika vinklar samt underlag på städet, med resultat på både krafter från städet samt accelerationer från huvudet. Genom användandet av Coulombs friktionsmodell har friktionen, över tid, under islag med en hjälm beräknats. Finita elementmetoden har använts i LS-DYNA för att försöka efterlikna resultaten från de fysiska experimenten med målet att kunna skapa en friktionsmodell. Det har gjorts liknande arbete tidigare där sandpapper har jämförts mot asfalt som underlagsmaterial i falltesterna. En liknande studie har genomförts i detta projekt vilket har jämförts med den tidigare gjorda studien. Resultaten när asfalt jämförs mot sandpapper och rostfritt stål visar att sandpapper har en högre friktion samt rotations acceleration av huvudet jämfört med asfalt. Rostfritt stål uppvisar dock liknande egenskaper som asfalt när det kommer till både friktion och acceleration. Lastcellen som har använts har undersökts noggrant, då värdet på friktionskoefficienten har förändrats beroende på vinkeln och träffpunkten på städet. Osäkerheter kring trovärdigheten på resultatet från lastcellen kvarstår. LS-DYNA har två olika sätt att modellera friktionen på, antingen så används en modifierad ekvation av Coulombs friktionsmodell eller så skapar användaren en tabell med värden på friktionskoefficienten och den relativa hastigheten. Båda metoderna har använts men det har visat sig att den senare metoden är bättre anpassad för de test som har utförts i detta projekt.

In dieser Arbeit sollen die maßgeblichen nationalen Zugbeeinflussungssysteme der Länder Polen (SHP, Radio-Stop, KHP), Slowakei und Tschechien (LS, MIREL VZ1) vorgestellt und miteinander verglichen werden. Der Fokus liegt dabei auf einer funktionellen Betrachtung, wobei auch der technische Hintergrund nicht unberücksichtigt bleibt. Ein Ausblick auf die zukünftigen Bemühungen hinsichtlich ETCS rundet den Überblick ab. / This paper compares the major national train protection systems of Poland (SHP, Radio-Stop, KHP), the Slovak Republic and Czechia (LS, MIREL VZ1). The emphasis is placed on a functional description, while mentioning the relevant technical background where necessary. An outlook on future developments regarding ETCS in the respective countries concludes each chapter.