Welding is a widely used method of connecting components because of its efficiency, great value and almost endless possibilities of join types. A great variability of geometrical configurations of welds is problematic due to the assessment of the weld joint. Depending on this topic this thesis was focused on the assessment of weld joints statically and cyclically. Work in the first part deals with the search of methods for evaluation of welds and depending on identified options is subsequently selected American standard AISC assessment of welded joints. The method is applied into FEA analysis and simple welded joints are evaluated. Using FEM are computed three examples on which a comparative analysis was performed. Comparisons were made with the analytical solution based on changes in the parameters of the computational model. The change is primarily related to material properties, mesh size and division of the weld on segments. On the basis of knowledge from analysis of simple joints, method was extended to more general welded joints with the possibility of determining the maximum loading force.

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<p>Complete Joint Penetration (CJP) welds are commonly used in many industries such as structural steel-fabrication, pressure vessels, pipelines, nuclear industries, etc. However, CJP weld could be susceptible to defects such as lack of fusion, slag, porosity, etc. The 1994 Northridge earthquake and the 1995 Kobe earthquake revealed that there was a significant loss in the ductility of CJP welded connections due to the presence of defects. There are very limited experimental and numerical studies available to understand the overall behavior and strength of CJP welded connection in the presence of defect. This study aims to bridge this gap. The objective of this study is to understand the influence of defects on ultimate strength and ductility of the CJP welded connection. To achieve this objective, a total of twelve specimens were tested, out of which four specimens were without any defect, while eight specimens had defects in the weld. A process was developed to introduce defects in the CJP weld specimens. A simplified lower bound approach using ductile damage criteria was proposed based on benchmarked finite element models to simulate the weld fracture. Moreover, a parametric study was performed to understand the effects of various parameters such as length and depth of defect, failure criteria, etc. on behavior and ductility of the welded connections. It was found that the welded specimens having no defect were able to reach the ultimate strength and ductility of the base metal. Whereas loss in ductility and strength was observed in the specimens with defects. The loss in ductility as compared to base metal ranges from 30% to 88% for different specimens. The maximum loss in strength was observed to be 12% only for specimens with the worst defect. The study concluded that the depth of defect had significant influence over ductility as compared to length of defect. If the depth of defect (d) is greater than half of plate thickness (d > t/2), it exhibits similar behavior regardless of actual depth. However, no significant influence of defect was observed if the depth of defect was less than t/8.</p>

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This thesis investigates the strength behavior of a representative highly skewed and horizontally curved bridge as well as analysis and design procedures for these types of structures. The bridge responses at and above a number of limits in the AASHTO (2007) Specifications are considered. The study includes the evaluation of various attributes of the elastic analysis of the subject bridge. These attributes include: (1) the accuracy of 3-D grid versus 3-D FEA models, (2) first-order versus second-order effects during the construction, (3) the ability to predict layover at bearing lines using simplified equations and (4) the benefit of combining the maximum and concurrent major-axis and flange lateral bending values due to live load compared to combining the maximums due to different live loads when checking the section resistances. The study also addresses the ability of different AASHTO 2007 resistance equations to capture the ultimate strength behavior. This is accomplished by comparing the results from full nonlinear 3-D FEA studies to the elastic design and analysis results. Specifically the use of the 2007 AASHTO moment based one-third rule equations is evaluated for composite sections in positive bending.

The aim of this thesis is to description and comparison of solutions, demountable connection of the lid and box enclosure air filters for motor vehicles, developed and used by the manufacturing concern MANN + HUMMEL, for which air filtration only one part of a broad portfolio of filtration systems for the automotive industry in the world scale. Another part of this thesis will be one of the chosen optimization methods of connection and implementation of alternative proposals design solutions, including the selection of the best solution, creating design calculation, 3D design, FEA analysis and prototyping of an alternative connection method laser sintering. When creating the optimization and design of alternative design solutions can count on the possibility that existing solutions are taking all possible factors and that the best alternative design proposals show an improvement over existing at the expense of all other cells throughout the development of the product.

Detta arbete kommer att fokusera på att ta fram och utforma en monterbar behållare för drönare så att de ska kunna användas för att leverera matvaror snabbt vid behov och med hänsyn till befintliga drönares kapacitet. I framtagningsprocessen så kommer de karaktäristiska punkterna för en strukturerad och faktabaserad utformning av en produkt att tillämpas vilket innefattar en identifiering av mål utifrån ett behov som produkten ska uppfylla och en faktainsamling av behovets karaktär och befintliga tekniska lösningar på liknande problem. Med den informationen som underlag så kan senare grundläggande konceptskisser utformas vilka i sin tur kan förädlas till färdiga 3D ritningar och renderingar av en slutgiltig produkt. För att ganska produktens effektivitet i förhållande till ändamålet så används därefter simuleringsverktyg för att genomföra termiska och luftflödesanalyser. Slutligen diskuteras även passande tillverkningsmetoder och produktens hållbarhet, potentiella problem med hela leveransmetoden, förslag till djupare studier och en utvärdering av framtagningsprocessens genomförande. / Technical advancements in fields like battery technology, software engineering and remote-control technology has made commercial unmanned aerial vehicles (UAVs) or “drones” cheaper while also allowing for longer flight times, higher payload capacities and longer effective ranges. This combined with the growing market trend of home delivery services within the restaurant and food industries paves the way for studies on how this relatively new means of transportation can be used to deliver food to customers within range. This paper will focus on developing and designing a third party mountable container from a mechanical engineering perspective that will allow commercially available quadcopter drones to deliver food items from one point to another. This means that the design process will be dictated by a set of identified core needs that the container is meant to satisfy while results from relevant calculations such as load simulations are taken into account. Further information and discussion like proposed manufacturing methods, sustainability and the prospects of further studies will also be brought up as it pertains to the containers design process.