Concrete slabs used in thepulp and paper industries are often situated outdoors, which means that theslabs are exposed to temperature variations due to different weatherconditions. These temperature variations together with operational temperaturesassociated with the manufacturing process, may introduce high temperaturegradients in the concrete. It is believed that the combination of these thermalloads have resulted in cracking in a slender concrete slab.The aim of this degree project has been to determine if the combination ofseasonal temperature and operational temperature is sufficient to introduce thetype of cracking seen in-situ in the concrete slab of a factory in Sundsvall,400 km north of Stockholm. This was achieved by simulating the development ofcracks in a slender concrete slab exposed to thermal loads using finite elementanalysis (FEA). In order to determine the accuracy of the model, the resultswere compared and evaluated against a crack mapping produced by Sweco. Furthersimulations were also carried out, in order to investigate if continuedcracking would occur beyond the time span of the Sweco investigation.The material model Concrete damage plasticity (CDP) in BRIGADE/Plus and Abaquswas used to predict the crack pattern and crack width in the concrete slab.Linear-elastic and non-linear material properties were used in the modelling ofthe concrete slab. The linear-elastic model indicated that thermal variationshowed significant risk of cracking. Thereafter, non-linear material propertieswere used in the modelling process. The cracking was simulated using ambienttemperature data and operational temperatures from the production plant.The results showed that cracking started when thermal loads were introduced tothe model. The ambient seasonal temperature alone was not enough to introducethe type of cracking seen in-situ on the slab. The combination of seasonalambient temperature and operational temperature was needed, in order for cracksto develop in the concrete slab. The results also indicated that the crackswill propagate further, but this can only be confirmed by performing additionalcrack mapping on site. / Betonggrunder som används för utrustning inom massa- och pappersindustrin befinner sig ofta utomhus vilket betyder att dessa är utsatta för vädrets förändringar. Temperaturvariationer i omgivningen och temperaturer som kommer från tillverkningsprocesserna kan medföra att höga temperaturgradienter skapas i betongen. Det är troligt att kombinationen av dessa termiska belastningar har gett upphov till sprick-bildning i en betonggrund.Målet för detta examensarbete har varit att bestämma, om huruvida kombinationen av års- temperaturer och temperaturer från industriprocessen är tillräckligt för att skapa den typ av sprickbildning i betonggrunden som iaktagits på plats hos en fabrik i Sundsvall. Det gjordes genom simulering av sprickbildning på betonggrunden, där grunden utsattes för termiska belastningar genom att använda finita element analys (FEA). För att bestämma tillförlitligheten hos metoden jämfördes och utvärderades resultatet mot en sprickkartering utförd av Sweco baserad på observationer ute på fabriken. Vidare gjordes ytterligare simuleringar utöver det tidsspann som Swecoundersökningarna visade, detta för att undersöka om huruvida sprickningen skulle fortgå.Materialmodellen Concrete damage plasticity (CDP) som finns i programmen BRIGADE/Plus och Abaqus användes för att förutse sprickbildning och sprickbredd i betonggrunden. Linjärelastiska och icke-linjära materialparametrar användes i modelleringen av betonggrunden. Utetemperatursdata tillsammans med temperaturer från industriprocessen användes för att undersöka anledningen till sprickbildningen.Resultaten av analyserna visade att sprickbildning uppkom när betonggrunden ut-sattes för termiska laster. Temperaturer från omgivningen var inte tillräckligt för att initiera sprickbildning. Kombinationen av temperaturer från omgivningen och industriprocessen behövdes för att sprickbildning skulle ske. Resultaten visade även att sprickbildningen kan fortsätta, med fler och bredare sprickor som följd.För att förhindra att sprickor uppstår i framtiden är det väsentligt att betona vikten av att minska uppkomsten av stora temperaturgradienter i betonggrunden.

Приведен обзор случаев использования изделий, изготовленных по аддитивной технологии для имплантации. Проанализирован международный стандарт на испытания пористых материалов, изготовленных по аддитивной технологии. Выявлены проблемы и предположительные пути их решения при использовании изделий, изготовленных аддитивным методом из сплавов на основе титана. решена краевая задача определения напряженно-деформированного состояния ячеистого имплантат методом конечных элементов в программном модуле ABAQUS. Рассмотрен вопрос влияния геометрии ячеек испытываемого материала на механические свойства конечного изделия для трех различных форм ячеек. Рассмотрен вопрос влияния трения между испытываемой заготовкой и бойками испытательной машины на свойства конечного изделия при различных уровнях трения. / An overview of the cases of using products made using additive technology for implantation is given. The international standard for testing porous materials manufactured by additive technology is analyzed. The problems and possible ways of their solution are revealed when using products manufactured by the additive method from titanium-based alloys. the boundary value problem of determining the stress-strain state of a cellular implant by the finite element method in the ABAQUS software module has been solved. The question of the influence of the geometry of the cells of the test material on the mechanical properties of the final product for three different cell shapes is considered. The question of the influence of friction between the tested workpiece and the strikers of the testing machine on the properties of the final product at various levels of friction is considered.

Masonry spires are a typical part of church architecture. Since it is rare that masonry is used as a load-bearing material in the western world today, it is important to maintain and increase the knowledge of modelling masonry structures both from a maintenance point of view and to build new masonry structures. The purpose of this master thesis is to look at and evaluate some different methods to model masonry spires exposed to common loads such as gravity, settlement and wind. The spire of the Salisbury Cathedral is used as a template regarding geometry and mechanical properties for the modelling methods. Two modelling methods are used in the master’s thesis. The first one is the limit analysis method applied to masonry. It is used to calculate a critical thickness for the masonry of the spire for a severe wind load. The second method is the Finite Element Method (FEM). The commercial finite element software Abaqus is used to create the model and the discretization used with the FE modelling is the macro-modelling approach. Concrete Damage Plasticity (CDP) in Abaqus is used as the material model and adapted to masonry. The finite element model consists of the spire itself along with the supporting structure beneath it down to the piers. Four different simulations (jobs) are run with varying wind direction and two of them have settling piers. The results from the finite element simulations indicate that the membrane stresses in the spire faces for the various jobs were not significantly different from one another. One of the jobs with settling piers could not be completed because the tensile stresses in the arches reached the tensile strength capacity of the material. The other simulation with a settlement that did complete did not have any significant difference in stress compared with the simulations without settlements. While the arches and the piers underwent plastic straining the spire itself did not. The stress levels there remained in the linear range for all the completed simulations. The finite element results also agree with the limit analysis. These findings call into question some of the modelling choices. The inclusion of the structure beneath the spire in the finite element model, as a way to study the effect of settlements, did not give more insight into the spire’s behaviour. Furthermore, the method to implement settlements was too inaccurate and another approach should be used to study the effect of settlements on the state of spires. Further work needs to be done on that topic. Improvements can also be made regarding how CDP was adapted for masonry. / Murade tornspiror är en vanlig takkonstruktion inom kyrkoarkitekturen. Eftersom det numera är sällsynt att murverk fungerar som lastbärande material i västvärlden, är det viktigt att upprätthålla och utöka kunskapen om murverkskonstruktioner för både underhåll och nybyggnation. Syftet med denna masteruppsats är att betrakta och utvärdera några olika modelleringsmetoder för murade tornspiror som är utsatta för några typiska laster såsom egentyngd, sättningar och vind. Katedralen i Salisbury används som en modelleringsmall i uppsatsen med avseende på katedralens geometri och materialegenskaper. Två modelleringsmetoder används i uppsatsen. Den första är gränsanalys tillämpad på murverkskonstruktioner. Den används för att beräkna en kritisk tjocklek för tornspiran under en stor vindlast. Den andra metoden är Finita Elementmetoden (FEM). Den kommersiella finita elementprogramvaran Abaqus används för finita elementanalysen och diskretiseringen som används för murverket i finita elementmodellen är makromodellering. Concrete Damage Plasticity (CDP) i Abaqus används som materialmodell och anpassas för murverk. Finita elementmodellen består utav själva tornspiran inklusive de bärande delarna under spiran och ned till pelarna. Fyra olika simuleringar ("jobb") körs med vindlast som angriper från olika riktningar och två av simuleringarna har pelare som sätter sig. Resultaten från simuleringarna visar att membranspänningarna i tornspirans väggar, för de olika jobben, inte skilde sig i någon betydelig grad från varandra. Ett av jobben med pelare som satte sig kunde inte köras klart eftersom dragspänningarna i valvbågarna överskred draghållfastheten på murverket i modellen. Den andra simuleringen med sättningar som kördes klart uppvisade inte några avsevärda skillnader i spänningar i tornspiran jämfört med simuleringarna utan sättningar. Medan plastiska töjningar uppkom i både valvbågarna och pelarna i modellen, uppkom de inte i tornspiran. Spänningsnivåerna i tornspiran var inom det linjära intervallet för alla simuleringar. Resultaten från finita elementanalysen stämde överens med resultaten från gränsanalysen. Analysresultaten ifrågasätter vissa av modelleringsvalen. Att inkludera de bärande delarna under tornspiran i finita elementmodellen, för att undersöka effekten av sättningar, gav inte en större insikt i hur sättningar påverkar tornspiran. Dessutom, var metoden för att tillämpa sättningar för oprecis och en annan metod borde användas. Mer arbete måste utföras vad gäller det ämnet. Sättet att tillämpa CDP för murverk kan också förbättras.

The construction of Songlin rock-filled concrete gravity dam, located in the Yunnan province, China began in the end of 2015. In this master thesis the finite element method (FEM) based software Abaqus has been used to perform a computational analysis on tension stresses, compression stresses and sliding stability for static conditions. One overflow section and one non-overflow section of the dam have been analysed. The results of the analysis have been evaluated by comparing with Chinese standards for dam safety and is intended to help engineers with making decisions in the construction process of the dam. The measured compressive stress values of both the overflow and non-overflow section are not evaluated to be within safe levels, further evaluation is required to ensure the safety of the dam. The dam is considered to be safe from vertical tension in the analysed region, however an extended evaluation including the whole dam base is recommended. The analysed cross-sections for sliding stability can be considered safe, but further analysis is required to make a conclusion of the sliding stability of the full dam base.

Soil nail walls are a form of mechanical earth stabilization for cut situations. They consist of the introduction of passive inclusions (nails) into soil cut lifts. These nailed lifts are then tied together with a structural facing (usually shotcrete) . The wall lifts are constructed incrementally from the top of cut down. Soil nail walls are being recognized as having potential for large cost savings over other alternatives. The increasing need to provide high capacity roadways in restricted rights of way under structures such as bridges will require increasing use of techniques such as combined soil nail and piling walls. The Swift Delta Soil Nail wall required installing nails between some of the existing pipe piling on the Oregon Slough Bridge. This raised questions of whether the piling would undergo internal stress changes due to the nail wall construction. Thus, it was considered necessary to understand the soil nail wall structure interaction in relation to the existing pile supported abutment. The purpose of this study was to investigate the Swift Delta Wall using finite element (FE) modeling techniques. Valuable data were available from the instrumentation of the swift Delta Wall. These data were compared with the results of the FE modeling. This study attempts to answer the following two questions: 1. Is there potential for the introduction of new bending stresses to the existing piling? 2. Is the soil nail wall system influenced by the presence of the piling? A general purpose FE code called ABAQUS was used to perform both linear and non-linear analyses. The analyses showed that the piling definitely underwent some stress changes. In addition they also indicated that piling influence resulted in lower nail stresses. Comparison of measured data to predicted behavior showed good agreement in wall face deflection but inconsistent agreement in nail stresses. This demonstrated the difficulty of modeling a soil nail due to the many variables resulting from nail installation.

La modélisation des renforts fibreux combine la prise en compte d'une architecture tridimensionnelle enchevêtrée de mèches et de leur comportement élémentaire anisotrope, résultant, lui-même, d'une microstructure complexe. Notre travail consiste en la mise au point de modèles éléments finis en grandes transformations permettant de caractériser numériquement le comportement des cellules élémentaires représentatives afin de simuler les procédés de mise en forme. Un modèle géométrique de la maille de tricot à l'échelle mésoscopique est construit afin de supporter un modèle éléments finis 3D cohérent. Le comportement, orthotrope et hypo-élastique, est formulé à l'aide de l'outil tensoriel. Cela nous permet de proposer et d'analyser un nouveau modèle : le Milieu Continu Equivalent Orthotrope Fibreux. Enfin, des perspectives pour des modèles de Milieux Continus Equivalents Anisotropes Fibreux, où les directions fortes d'anisotropie sont non-orthogonales, sont développées.

In this paper the mechanical behaviour, both elastic and plastic, of single-crystal nickel-based superalloys has been investigated. A theoretic base has been established in crystal plasticity, with concern taken to the shearing rate on the slip systems. A model of the mechanical behaviour has been implemented, by using FORTRAN, as a user defined material model in three major FEM-programmes. To evaluate the model a simulated pole figure has been compared to an experimental one. These pole figures match each other very well. Yielding a realistic behaviour of the model.

<p>In this paper the mechanical behaviour, both elastic and plastic, of single-crystal nickel-based superalloys has been investigated. A theoretic base has been established in crystal plasticity, with concern taken to the shearing rate on the slip systems. A model of the mechanical behaviour has been implemented, by using FORTRAN, as a user defined material model in three major FEM-programmes. To evaluate the model a simulated pole figure has been compared to an experimental one. These pole figures match each other very well. Yielding a realistic behaviour of the model.</p>

In this study, excavation of jet-grouted tunnels in ground with strong time-dependent behavior is analyzed. The constant growth of population has led to a constant increase in the price of lands and thus infrastructures. Underground alternatives are becoming more economical. Furthermore, advances in the construction technology have made it feasible to construct tunnels in difficult ground conditions. By providing a grouted arch ahead of the tunnel face, jet-grouting has proved effective for the stability and performance of tunnels in difficult conditions. Given the limited depth of jet-grouting into the face, the jet-grouted arch is loaded soon after installation, when the rigidity of the grouted material is growing significantly. The simultaneous loading and hardening of the jet-grouting makes the tunnel response depend on the excavation rate. Furthermore, in difficult tunneling conditions, the ground material is associated with highly viscous behavior. This behavior is synonymous with delayed deformation depending on the level and duration of the ground loading by the tunnel excavation. In order to show the importance of the time-dependent behaviors, the full-face and the sequential excavation method are compared using three-dimensional and two-dimensional finite element analyses. First, a three-dimensional model is constructed and its results are validated against available analytical solutions for time-independent behaviors. The hardening of the jet-grouting is then introduced into the model by embedding jet-grouting elements through the analysis. In order to account for the ground viscous behavior, an advanced viscoplastic constitutive model is adopted, numerically implemented in FORTRAN, and used in conjunction with finite element software ABAQUS. The excavation methods are compared for the well documented study case of Tartaiguille tunnel. The results indicate that the full-face method outperforms the sequential method in the studied case by installing the tunnel invert closer to the face. The two-dimensional analysis of the tunnel is conducted by using the convergence-confinement method. To this end, a new approach is introduced to use the method for tunnels in time-dependent conditions. The effect of the jet-grouting hardening and the ground viscous behavior is characterized within the new approach by deriving the ground convergence curves. The reverse dependency of these mechanisms on the tunnel advance rate leads to an optimum advance rate, at which minimum tunnel convergence develops. / text

Recycling of plastics always plays an important role in keeping our environment better and safe. With the rise in usage of plastics and industrialization, the need for recycling the plastics has become a big business and is getting bigger. This thesis work was done for a company called Rapid Granulator AB, which works with the recycling of plastics as a big trade in Sweden. Like all the industries across the globe are trying to be economical in every way, Rapid Granulator AB wanted to develop an economical design of their high quality granulating knife. For achieving the economical design, they wanted to study the behaviour of the rotating knife during the process of producing plastic granules. The granulator cutting process was simulated and numerical analysis was done on the rotating knife of a plastic granulator machine by using the finite element code ABAQUS with 3D stress elements to find out the critical stresses and forces acting on the rotating knife. The bolt preload was applied by Abaqus/Standard, and the results of implicit analysis were imported to Abaqus/Explicit for the impact analysis where the flow of stresses on the rotating knife during the impact with materials were simulated and studied. The study was done on knife models of different thickness to see if the thickness of the current knife model can be reduced. Analysis were done also on a knife model assembly with a double sided cutting edge knife to see if the knife model can be used to its full extent. The simulation models and analysis results were given to the company to develop a more economical knife model.