As the autonomous vehicles are getting clo-ser to commercial roll out, the challenges for the developersof the software are getting more complex. One challenge thedevelopers are facing is the interaction between humans andautonomous vehicles in traffic.Such situation requires a hugeamount of data to in order to design and proof test autonomoussystem than can handle complex interactions with humans.Such data can not be collected in real traffic situations withoutcompromising the safety of the human counterparts, thereforesimulations will be necessary. Since human driving behavior ishard to predict, these simulations need human interaction inorder to get valid data of human behaviour.The purpose of thisproject is to develop a driving interface and then evaluate theusers experience in an experiment. To do this we have designedand implemented steering,braking and acceleration on a userinterface for a simulator used in autonomous driving researchcalled Car Learning to Act (CARLA) at the Smart Mobility Lab(SML) at KTH. We have implemented two driving simulatoruser interfaces, with different levels of information feedbackto the user. To evaluate the developed user interface, a surveywas designed to measure how intuitive the driving experiencewas while also comparing it to the original setup at SML. Thesurvey showed that the driving experience was more intuitivewith the two developed user interfaces and that 60% would feelcomfortable using the new systems on a real vehicle in traffic. / Allteftersom autonoma bilar kommer närmare kommersiell lansering blir utmaningarna för utvecklarna av mjukvaran mer komplexa. En utmaning som utvecklarna står inför är interaktionen mellan autonoma bilar och människor i och utanför trafiken. Dessa situationer kommer kräva en stor mängd data för att säkerhetställa att autonoma bilar kommer kunna agera optimalt. För att inhämta sådan data utan att riskera säkerheten för alla ute i trafiken kommer simulatorer behövas. Eftersom vi inte kan förutspå mänskligt beteende kommer industrin behöva använda mänskliga förare i dessa simulatorer för att få realistiska resultat. Syftet med detta projekt är att utveckla ett förargränssnitt för människor och sedan utvärdera autenticiten av upplevelsen från ett mänskligt perspektiv. Genom att implementera olika bilmekanismer så som styrning, inbromsning, accelerationen och retardation i en simulator för autonom bil forskning, Car Learning To Act(CARLA) i Smart Mobility Lab(SML) på KTH. Vi implementerade två användargränssnitt med olika nivåer av informations återkoppling till användaren. För att utvärdera användargränssnitten utformades ett frågeformulär för att mäta hur intuitivt körupplevelsen var och samtidigt jämföra med det originella användargränssnittet i SML. Undersökningen visade att körupplevelsen var mer intuitiv med det två utvecklade användargränssnitten och att 60% skulle vara bekväma med att använda ett utav dessa system för att styra ett riktigt fordon i trafik. / Kandidatexjobb i elektroteknik 2020, KTH, Stockholm

<p>Masonry is one of the most commonly used materials in building construction throughout the world. Unreinforced masonry (URM) walls typically have very low flexural capacities and tend to posses brittle failure modes. Due to brittle nature of URM walls, it is critical to predict the behaviour of the wall when exposed to extreme out of plane loadings such as blast loads. An effective way to enhance the ability of unreinforced masonry walls to withstand blast loads and consequently to limit the amount of wall damage is imposing arching mechanism on the wall. Since carrying out physical experiments to study the response of URM walls subjected to blast load is both dangerous and expensive, finite element modeling has become more attractive to researchers. In this research, an unreinforced one-way arching wall is simulated using the finite element program LS-DYNA and its behaviour subjected blast loading is studied. The model is constructed based on the data recorded earlier during a physical blast experiment. Close agreement was observed between the numerical and experimental results which validated the developed model. A sensitivity study is then performed where the influence of variation of some input parameters such as mortar strength, coefficients of friction, scaled distance, boundary condition, wall height and the effect of two-way arching action on the wall’s response is evaluated. The most influential parameters in this study found to be the scaled distance, wall height and two-way arching action. Smaller scaled distances result in high deflection and as the scaled distance increases the maximum deflection decreases. The wall height also significantly affect the wall’s response to blast loads, i.e. the taller the wall the larger the maximum displacement. It is also concluded that two-way arching action can significantly reduce the wall’s maximum deflection.</p> / Master of Applied Science (MASc)

This diploma thesis is concerned with the numerical analysis of welded aluminim structures. In these structures, there are significant decreases in the mechanical properties at the area of the weld and in the heat affected zone as a result of welding. Within this thesis, simulations of quasi-statically loaded welded joints made from EN AW-6082 T6 alloy were performed to investigate the load capacity and ductility of these joints. Computations were performed using a programme system based on an explicit finite element method. To describe material anisotrophy, a nonlinear material model called the Weak texture model was chosen. Material properties of the weld and the heat affected zone were considered to be different from base material. The required material parameters were adopted from available literature, however, material tests and indetification procedure of these parameters were described. In comparison with the experimental data, the results of the numerical simulations showed a relatively good ability of models to capture load capacity of studied welded joints. Nevertheless, due to mesh sensitivity of models caused by localization of deformation, it was not possible to determine ductility of these joints.

Le bois est un matériau cellulaire naturel et excellent absorbeur d’énergie. Employé au sein de structures du type limiteur d’impact, il subit de nombreux phénomènes lors d’un cas de chute. Une large campagne expérimentale est réalisée afin d’analyser les réponses en compression du hêtre et de l’épicéa, en fonction de la direction de sollicitation, de la vitesse de déformation pour la plage [0.001-600] s−1 et de deux types de restrictions latérales qualifiées d’extrêmes. La direction longitudinale se révèle la plus sensible à la vitesse ainsi qu’au type de restrictions latérales et les conséquences sur la capacité d’absorption d’énergie du bois sont alors significatives. Par ailleurs, les protocoles développés ont vocation à être déclinés pour un large panel d’essences aux propriétés mécaniques variées. Un modèle matériau élastoplastique, isotrope transverse et sensible à la vitesse de déformation est élaboré à l’aide des techniques multi-échelles et de la micromécanique. Les propriétés élastiques macroscopiques sont estimées à l’aide du schéma d’homogénéisation de Mori-Tanaka à partir de données issues de la microstructure. Un critère de type Gurson étendu reposant sur l’approche micromécanique de l’endommagement ductile est employé pour retranscrire le comportement non linéaire, la densification et le caractère compressible du bois. Des paramètres de dégradation découplés du critère sont appliqués selon la direction longitudinale. La modélisation proposée repose sur une description simplifiée du bois et les résultats numériques associés illustrent la bonne capacité du modèle à reproduire les différentes réponses observées lors d’un cas de chute. / Wood is a natural cellular material, which is widely and advantageously used as shock absorber for the transport of radioactive materials. Accident situations are evaluated based on the 9 m drop test, which allows us to observe the complex crushing behavior of wood. A compressive experimental study is conducted on spruce and beech wood species over a large range of strain rates (from 0.001 to 600 s−1) to investigate the effect of the loading direction and of two extreme lateral confinements. The longitudinal direction is the most sensitive to the effect of strain rate and of lateral confinements which have significant consequences on the energy absorption. Besides, the experimental investigation can be adapted to various wood species with very different mechanical properties. A strain rate dependent elastoplastic model with transversal isotropy is developed using multi-scale and micromechanics techniques. The elastic macroscopic properties of wood are estimated with a Mori-Tanaka scheme and information extracted from the microstructure. The Gurson type criterion based on the micromechanical approach of the ductile damage is used in order to describe the non linear behavior of wood, its densification regime and its compressibility as well. Additionally, uncoupled degradation parameters are applied to reproduce the failure mechanisms involved in the longitudinal response. A simplified description of wood is used within the modeling and the numerical results exhibit the good ability of the model to reproduce the various wood responses during an accident situation.

Collision avoidance systems have become an integrated part of modern vehicles and aim to avoid accidents or mitigate the crash severity for the occupant. For example, the autonomous emergency braking system influences the pre-crash state of the occupant in sitting posture, stress state, or velocity. The occupant might try to retain its posture by activating muscles, which induce muscle bracing and could counteract the movement of the occupant in the pre-crash phase.  Therefore, it is essential to study the influence of active musculature on occupant response in pre-crash and crash events. A finite element human body model (HBM) with and without closed-loop muscle activation control was used to simulate the occupant response during those events. Comparing the HBM responses &amp; head kinematics reveal an influence of muscle bracing in the evasive braking manoeuvre. Simulating the pre-crash and in-crash phase in two stages can provide multiple benefits. However, the correlation between a single-stage simulation (baseline) and a two-stage simulation needs to be investigated. The baseline simulation uses an active HBM to model an occupant during an evasive braking manoeuvre and the muscles are deactivated when entering the frontal impact phase. The parameters of the final pre-crash state, which are needed to mimic the baseline’s response when transitioning from the pre-crash to the in-crash event are investigated in this study. For that reason, sitting position, stress state and velocity are transferred respectively to the initial passive in-crash HBM state. The simulations enabled the comparison of occupant response and calculation of cross-correlation. Each retainment strategy gave a good cross-correlation with the baseline simulation. / Kollisionsundvikande system har blivit en viktig del i moderna fordon där syftet är att undvika olyckor samt att minska allvarhetsgraden av olyckor för de åkande. Ett exempel är nödbromssystem som kan påverka den åkandes initiala tillstånd direkt före en krock som, till exempel, sittposition, spänningstillstånd, eller initial hastighet inför krock. Den åkande kan försöka att bibehålla sin hållning genom att aktivera sina muskler vilket påverkar rörelsen av dess kropp under för-krocks fasen. Det är därför viktigt att studera hur aktiva muskler påverkar rörelsen av kroppen hos den åkande under både före krocksfasen och själva krockfasen. En finit element humanmodell (HBM) med och utan reglerad muskelaktivitet används för att prediktera responsen hos den åkande i båda faserna. En jämförelse mellan simuleringarna visar att aktiva muskler kan påverka åkandekinematiken under bromsningsförloppet. Att simulera fasen före krock och fasen under krock i två steg kan medföra flera fördelar. Korrelationen mellan en enkelstegssimulering (originalsimulering) och en tvåstegssimulering måste dock studeras. Som originalsimulering används en aktiv HBM för att modellera den åkande under för-krocksfasen där den reglerade muskelaktiviteten inaktiveras under krockfasen. I denna studie undersöks den åkandes initiala tillstånd före krocken som behövs för att efterlikna originalsimulerings respons vid övergången från för-krocksfasen till krockfasen. Av den anledningen mappas det passiva HBM-tillståndet till det slutliga tillståndet av före krocksfasen för sittposition, spänningstillstånd respektive hastighet. Simuleringarna möjliggjorde en jämförelse av åkande respons och beräkning av korskorrelation. Varje mappningsstrategi gav en bra korskorrelation med originalsimuleringen.

The application of thermoplastics as load-carrying components in furniture applications is an attractive prospect at IKEA. Thermoplastics can be used instead of metal where advanced geometries and aesthetics are considered. In this thesis work in solid mechanics, it is of interest to investigate different test setups proposed in the literature for compression testing of thermoplastics while taking into account the complex stress fields induced in the test samples during the compression test.  The simulations have showed that the main cause of complex stress fields in compression test specimens is the presence of friction between the specimen and the machine heads. Friction prevents perfect Poisson contractions during the test which shifts the orientation of the local stress tensors from the direction of loading. Out of the shapes investigated in this thesis, it has been concluded that cube-shaped specimens were the most suitable to utilize in compression tests. The results were based on exploiting measures that pertain to accuracy and robustness parameters within stress and strain. Furthermore, manufacturing impact and ease of test measurements were considered. / Användningen av termoplaster som lastbärande komponenter i möbelapplikationer har ökat under de senaste åren inom IKEA. Då det förutom att vara estetiskt tilltalande för hela möbler är främsta användningen i komponenter som har mer komplicerade geometrier. I detta examensarbete i hållfasthetslära är det av intresse att undersöka olika provkroppar vilket föreslås i litteratur för kompressionsprovning av termoplaster med hänsyn till de komplexa spänningstillstånden som orsakas under provning.  Simuleringarna har påvisat de komplexa spänningstillstånd i kompressionsprov som uppkommer på grund av friktion mellan provstaven och grepen. Friktion förhindrar perfekt tvärkontraktion, vilket förändrar orienteringen av de lokala spänningstensorerna från belastningsriktningen, vilket är enaxlig. Utifrån de former som undersöktes i detta examensarbete blev slutsatsen att kubformade provkroppar var de mest lämpliga att använda i kompressionsprovning. Resultaten baserades på att utnyttja åtgärder som avser noggrannhetsparametrar inom spänning och töjning men även tillverknings och provmätningens lätthet.

Comparison of Dyna-CLUE and Land Change Modeler software for predictive modelling in the suburban area of Prague Abstract The objective of this work was to predict the development of the suburban area of Prague, using Dyna- CLUE and Land Change Modeler (LCM) software, and based on the results compare the capabilities of both these software tools. In this work I used time series of land cover data obtained by the department of applied geoinformatics and cartography, local plans of the municipalities, and information about soil protection provided by the Research Institute for Soil and Water Conservation. Based on these data, a predicted land cover map for 2020 was created in both software tools. The results were then compared and showed that the models respect the restriction of development in predetermined areas. In accordance with local plans, new residential development was properly allocated. For commercial development, the requirements were not completely fulfilled. It is evident that both models are able to create a correct map of future land cover based on specified requirements. However, the instability of LCM and the necessity of using other software while working with Dyna- CLUE somewhat complicated the work. Keywords: Dyna-CLUE, Land Change Modeler, predictive modelling, land cover, residential...

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.

Cross median crashes have become a serious problem in recent years. Most of the median cross sections used for divided highways have terrains with steep slopes. Traffic barriers, frequently used on slopes, are generally designed based on the findings obtained from crash tests performed on flat terrain. For barriers placed on roadside and median slopes, vehicle impact height varies depending on the trajectory of the vehicle along the ditch section and lateral offset of the barrier. Thus depending on the placement location on a relatively steep slope, a barrier can be impacted by an errant vehicle at height and orientation more critical compared to those considered during its design. Hence, detailed study of performance of barriers on roadside and median slopes is needed to achieve acceptable safety performance. In this study, performances of modified G4(1S) W-beam, Midwest Guardrail System (MGS), modified Thrie-beam, modified weak post W-beam, and box-beam guardrail systems on sloped terrains are investigated using numerical simulations. A procedure is developed that provide guidance for their placement on roadside and median slopes. The research approach consists of nonlinear finite element analyses and multi-rigid-body dynamic analyses approach. Detailed finite element representation for each of the barriers is developed using LS-DYNA. Model fidelity is assessed through comparison of simulated and measured responses reported in full scale crash test studies conducted on flat terrain. LS-DYNA simulations of vehicle impacts on barriers placed on flat terrain at different impact heights are performed to identify performance limits of the barriers in terms of acceptable vehicle impact heights. The performances of the barriers are evaluated following the guidelines provided in NCHRP Report 350. Multi-rigid-body dynamic analysis code, CARSIM, is used to identify trajectories of the vehicles traversing various roadside and median cross-slopes. After analyzing vehicle trajectories and barrier performance limits, a guideline has been prepared with recommendations for the placement of barriers along roadside and median slopes. This guideline is then verified and refined using the responses obtained from full-scale LS-DYNA simulations. These simulations capture the full encroachment event from departure of the vehicle off the traveled way through impact with the barrier.

<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>