<p>Nefab Plypak AB i Habo bedriver produktion och försäljning av lådor och väskor för långvarigt produktskydd. De har identifierat behovet av att rationalisera montering av beslag på sina produkter. Idag monteras beslagen genom nitning vilket är en väl beprövad metod som använts under lång tid. Behovet av mer rationell montering skapade underlag för detta examensarbete innefattande vidareutveckling av monteringsmetoder.</p><p>Kravet på möjligheter till automatiserad montering har påverkat utvecklingsprocessen mot att utveckla fästen som inte kräver ytterligare komponenter eller arbetsmoment i monteringen. De nya koncepten måste uppfylla samma krav avseende belastning och robusthet som dagens komponenter.</p><p>Resultatet av utvecklingsarbetet är ett koncept där befintlig handtagsdel används tillsammans med en nyutvecklad fästdel. Den nya fästdelen är utformad för att ersätta de tre komponenterna på den befintliga lösningen. Genom att fästet försetts med så kallade nabbar* som pressas fast i plywooden behövs inte längre någon nit eller annat fästelement. Nabbarna är försedda med flikar** vilket ger en stark och tillförlitlig lösning. Konceptet bygger på rationell montering med ett pressverktyg och kan med fördel ingå i automatiserad monteringsprocess.</p> / <p>Nefab Plypak AB is a producer of plywood boxes and cages used for long-term product protection. They are also a supplier of all types of long term packaging boxes. Nefab have identified the need of cut costs through rationalization of their mounting process of the fittings. The current method Nefab uses for mounting their fittings is rivet, which is a method that has been used for a long period of time. Rivet is a well known method for its reliability, though not easy to rationalize to a further level. This fact has made a good background to investigate possibilities to find new mounting methods.</p><p>Nefab have a strategy to implement an automatized production, which have influenced the development process to develop something that would not need any additional components or extra steps in the mounting process. The new concepts need to fulfill the present requirements considering the force of load as well as the strength.</p><p>The result of the development process is a concept that uses current handle part with a brand new solution for the fitting part. The new part is developed to replace the current three parts, rivet, plastic cover and fitting. The new fitting is designed with a sort of hooks that will be pressed through the plywood and lock the construction, which allow a design without a rivet. The hooks are designed with a barb that will lock the fitting, which provides a secure and strong solution. The concept is based on a rational mounting process and can be a part of an automatized mounting process.</p>

<p>At every joint there is a redundant set of muscle activated during movement or loading of the system. Optimization techniques are needed to evaluate individual forces in every muscle. The objective in this thesis was to use static optimization techniques to calculate individual muscle forces in the human extremities.</p><p>A cost function based on a performance criterion of the involved muscular forces was set to be minimized together with constraints on the muscle forces, restraining negative and excessive values. Load-sharing, load capacity and optimal forces of a system can be evaluated, based on a description of the muscle architectural properties, such as moment arm, physiological cross-sectional area, and peak isometric force.</p><p>The upper and lower extremities were modelled in two separate studies. The upper extremity was modelled as a two link-segment with fixed configurations. Load-sharing properties in a simplified model were analyzed. In a more complex model of the elbow and shoulder joint system of muscular forces, the overall total loading capacity was evaluated.</p><p>A lower limb model was then used and optimal forces during gait were evaluated. Gait analysis was performed with simultaneous electromyography (EMG). Gait kinematics and kinetics were used in the static optimization to evaluate of optimal individual muscle forces. EMG recordings measure muscle activation. The raw EMG data was processed and a linear envelope of the signal was used to view the activation profile. A method described as the EMG-to-force method which scales and transforms subject specific EMG data is used to compare the evaluated optimal forces.</p><p>Reasonably good correlation between calculated muscle forces from static optimization and EMG profiles was shown. Also, the possibility to view load-sharing properties of a musculoskeletal system demonstrate a promising complement to traditional motion analysis techniques. However, validation of the accurate muscular forces are needed but not possible.</p><p>Future work is focused on adding more accurate settings in the muscle architectural properties such as moment arms and physiological cross-sectional areas. Further perspectives with this mathematic modelling technique include analyzing pathological movement, such as cerebral palsy and rheumatoid arthritis where muscular weakness, pain and joint deformities are common. In these, better understanding of muscular action and function are needed for better treatment.</p>

<p>The link suspension is the most prevailing suspension system for freight wagons in central and western Europe. The system design is simple and has existed for more than 100 years. However, still its characteristics are not fully understood. This thesis emphasizes freight wagon dynamics and comprises three parts:</p><p>In the first part a review of freight wagon running gear is made. The different suspension systems are described and their advantages and disadvantages are discussed. The review covers the running gear standardized by UIC and the conventional so-called three-piece bogie. Additionally five improved three-piece bogies and twelve novel running gear designs are presented.</p><p>The second part focuses on the lateral force-displacement characteristics in the link suspension. Results from stationary measurements on freight wagons and laboratory tests of the link suspension characteristics are presented. To improve understanding of the various mechanisms and phenomena in link suspension systems a simulation model is developed. Link suspension systems have strongly nonlinear characteristics including a hysteresis loop. The loop exhibits usually three characteristic sections with different tangential stiffnesses. The actual contact geometry of the links and end bearings has a significant influence on the characteristics. By wear in ordinary service - as well as by geometric tolerances on new components - the contact geometry may deviate considerably from nominal geometry. Further, it seems that elastic deformation in the contact surfaces has considerable effects on the suspension characteristics, in particular on the initial rolling stiffness for small displacements. Also, flexibilities in links and end bearings influence the characteristics. It is also observed that new components after a short period of dynamic testing can exhibit a very low amount of energy dissipation, a phenomenon that is also indicated in some stationary measurements on wagons.</p><p>To summarize the second part, it appears that the link suspension characteristics are very sensitive to several factors being hard to control in the real world of freight wagon operations. The various stiffnesses and hysteresis loops have a considerable variation and may have a strong influence on the ride qualities of vehicles. As long as the characteristics can not be controlled within closer limits than found in this study, there is a strong need for sensitivity analysis to be made, both in predictive multibody simulations of vehicle dynamics, as well as in verification and acceptance tests.</p><p>In the third part a study on the possibility to improve ride qualities of freight wagons with link suspensions is presented. Parametric studies with multibody dynamic simulations on freight wagons equipped with link-suspension bogies are performed. The effect of supplementary friction and hydraulic damping is investigated under various running conditions: speed, loading, tangent and curved track, wheel-rail contact geometry, track gauge and track irregularities. Substantial improvements of the lateral running behaviour of wagons with link suspension bogies can be achieved - both at ordinary speeds and at increased speeds - by using a proper combination of supplementary hydraulic dampers. Speeds up to 160 km/h could be realistic.</p>

<p>Powder compaction is a production method commonly used in the manufacturing industry today. In order to minimize costly experiments and to optimize serial production of details several methods to analyze the powder compaction process are developed and used. One method is to use micromechanical analysis where the local description of contact between two individual particles is of great importance. In this dissertation a visco-plastic contact law has been used and further developed in order to understand the powder compaction process at packing, low relative density compaction up to high relative density compaction.</p><p>In order to relax some assumptions from previous theoretical studies simulation with the discrete element method (DEM) was performed. Up to 10.000 spherical particles were used in packing and early compaction simulation. It was found that rearrangement of particles is one of the major densification mechanisms in the early phases of compaction. At die compaction this effect of rearrangement was shown to be more pronounced than predicted from theoretical analyses. It was also found that the size ratio of particles is of importance when the number fraction of small particles in the compound is high.</p><p>The finite element method has been used for numerical analyses to investigate the local contact problem between two particles when self-similarity no longer prevail. Based on the numerical results a suggestion for an approximate compliance relation was made. With this approximate formula the local compliance behaviour between two dissimilar particles was analysed. These findings are directly applicable to simulations with the discrete element method. Finally, an investigation using the finite element method to evaluate the range of the accuracy for theoretical and approximate compliance formula has been done with compounds of different regular lattices. It was found that the range of accuracy is much dependent on the number of contacts within the lattices, specially new forming contacts during the compaction.</p>

<p>This report describes how an aircraft creates and flies its User Preferred Trajectory from take-off to landing, based on the objectives and constraints the aircraft is subjected to from a technological and operational viewpoint.</p><p>A basic description of commercial aircraft operation is given, with an emphasis on identifying the different stakeholders (Air Navigation Service Providers, Airline Operation Center, Pilot/Aircraft, Airport and Civil Aviation Authority). A general description of Instrument Flight Rules operations is also given, together with an explanation of the capabilities of modern flight management systems.</p><p>The objectives and constraints of the trajectory building process from an aircraft and air traffic management viewpoint are described in Chapter 4. Those are instrumental in understanding how the user preferred trajectory is built. The initial and detail route planning process is then described.</p><p>The initial route planning is performed long before the flight and usually by the airline operating center, while detail flight planning, including take-off, runway and departure procedure is performed later by the crew. This process is re-performed minutes before take-off, and usually iterated during the flight when the details of approach and landing are communicated to the aircraft crew.</p><p>The implementation of this user preferred trajectory is explained in terms of the options that the pilots have in the aircraft avionics to perform the mission. The implementation explained in this report is based on the avionics suite of a Boeing 737NG aircraft equipped with the most advanced flight management systems.</p><p>An implementation of a user preferred trajectory, where the aircraft crew is able to best fulfill their objectives is composed of an idle or near idle descent from the cruise altitude. This type of descent, called an advanced continuous descent approach has been implemented by some air navigation service providers, airlines and airports, based on advanced technology that will be further described in this paper. Those procedures are called Green Approaches.</p><p>In the last part of this report, the benefits of flying Green Approach procedures are analyzed by means of aircraft simulations. The analysis describes in detail the lateral and vertical trajectories of the Green Approaches at Stockholm’s Arlanda Airport and Brisbane Airport (Australia), together with the calculated advantages in term of fuel consumption, noise and gas emissions.</p>

<p>The use of composite materials in vehicle structures could reduce the weight and thereby the fuel consumption of vehicles.</p><p>As the road safety of the vehicles must be ensured, it is vital that the energy absorbing capability of the composite materials are similar to or better than the commonly used steel structures. The high specific bending stiffness of sandwich structures can with advantage be used in vehicles, provided that the structural behaviour during a crash situation is well understood and possible to predict. The purpose of this thesis is to identify and if possible to describe the failure initiation and progression in in-plane compression loaded sandwich panels.</p><p>An experimental study on in-plane compression loaded sandwich panels with two different material concepts was conducted. Digital speckle photography (DSP) was used to record the displacement field of one outer face-sheet surface during compression. The sandwich panels with glass fibre preimpregnated face-sheets and a polymer foam core failed due to disintegration of the face-sheets from the core, whereas the sandwich panels with sheet molding compound face-sheets and a balsa core failed in progressive end-crushing. A simple semi-empirical model was developed to describe the structural response before and after initial failure.</p><p>The postfailure behaviour of in-plane compression loaded sandwich panels was studied by considering the structural behaviour of sandwich panels with edge debonds. A parametrical finite element model was used to determine the influence of different material and geometrical properties on the buckling and postbuckling failure loads. The postbuckling failure modes studied were debond crack propagation and face-sheet failure. It could be concluded that the postbuckling failure modes were mainly determined by the ratio between the fracture toughness of the face-core interface and the bending stiffness of the face-sheets.</p>

<p>The development of advanced embedded systems requires a systematic approach as well as advanced tool support in dealing with their increasing complexity. This complexity is due to the increasing functionality that is implemented in embedded systems and stringent (and conflicting) requirements placed upon such systems from various stakeholders. The corresponding system development involves several specialists employing different modeling languages and tools. Integrating their work and the results thereof then becomes a challenge. In order to facilitate system architecting and design integration of different models, an approach that provides dedicated workspaces/views supported by structured information management and information exchange between domain models and tools is required.</p><p>This work is delimited to the context of embedded systems design and taking a model based approach. The goal of the work is to study possible technical solutions for integrating different models and tools, and to develop knowledge, support methods and a prototype tool platform.</p><p>To this end, this thesis examines a number of approaches that focus on the integration of multiple models and tools. Selected approaches are compared and characterized, and the basic mechanisms for integration are identified. Several scenarios are identified and further investigated in case studies. Two case studies have been performed with model transformations as focus. In the first one, integration of Matlab/Simulink® and UML2 are discussed with respect to the motivations, technical possibilities, and challenges. A preliminary mapping strategy, connecting a subset of concepts and constructs of Matlab/Simulink® and UML2, is presented together with a prototype implementation in the Eclipse environment. The second case study aims to enable safety analysis based on system design models in a UML description. A safety analysis tool, HiP-HOPS (Hierarchically Performed Hazard Origin and Propagation Studies), is partially integrated with a UML tool where an EAST-ADL2 based architecture model is developed. The experience and lessons learned from the experiments are reported in this thesis.</p><p>Multiple specific views are involved in the development of embedded systems. This thesis has studied the integration between system architecture design, function development and safety analysis through using UML tools, Matlab/Simulink, and HiP-HOPS. The results indicate that model transformations provide a feasible and promising solution for integrating multiple models and tools. The contributions are believed to be valid for a large class of advanced embedded systems. However, the developed transformations so far are not really scalable. A systematic approach for efficient development of model transformations is desired to standardize the design process and reuse developed transformations. To this end, future studies will be carried out to develop guidelines for model and tool integration and to provide support for structured information at both meta level and instance level.</p>

<p>Linear and nonlinear optimal control have been investigated in transitional channel and boundary layer .ows. The flow phenomena that we study are governed by the incompressible Navier–Stokes equations and the main aim with the control is to prevent transition from laminar to turbulent flows. A linear model-based feedback control approach, that minimizes an objective function which measures the perturbation energy, can be formulated where the Orr– Sommerfeld/Squire equations model the flow dynamics. A limitation with the formulation is that it requires complete state information. However, the control problem can be combined with a state estimator to relax this requirement. The estimator requires only wall measurements to reconstruct the flow in an optimal manner. </p><p>Physically relevant stochastic models are suggested for the estimation problem which turns out to be crucial for fast convergence. Based on these models the estimator is shown to work for both in.nitesimal as well as finite amplitude perturbations in direct numerical simulations of a channel flow at Recl = 3000. </p><p>A stochastic model for external disturbances is also constructed based on statistical data from a turbulent channel flow at ReT = 100. The model is successfully applied to estimate a turbulent channel flow at the same Reynolds number. </p><p>The combined control and estimation problem, also known as a compensator, is applied to spatially developing boundary layers. The compensator is shown to successfully reduce the perturbation energy for Tollmien–Schlichting waves and optimal perturbations in the Blasius boundary layer. In a Falkner– Skan–Cooke boundary layer the perturbation energy of traveling and stationary cross-flow disturbances are also reduced. </p><p>A nonlinear control approach using the Navier–Stokes equations and the associated adjoint equations are derived and implemented in the context of direct numerical simulations of spatially-developing three-dimensional boundary layer .ows and the gradient computation is veri.ed with .nite-di.erences. The nonlinear optimal control is shown to be more e.cient in reducing the disturbance energy than feedback control when nonlinear interactions are becoming signi.cant in the boundary layer. For weaker disturbances the two methods are almost indistinguishable. </p>

<p>Energy supply security is a hot topic today. It highly influences energy market, national security and also residents’ daily lives. However, due to different aims and study strategies, definitions of energy supply security are different. In this report, it is defined as stable energy supply processes that result from good infrastructure, delivery of energy sources, carriers and services, which are sturdily controlled by effective energy policies. Prices of energy supply system</p><p>are also maintained on a reasonable level over a continuous period thanks to the efficient crises assessment and management.</p><p>In order to make a comprehensive research, energy situation has been deeply investigated on worldwide, EU and Swedish levels, respectively. Results from these investments obviously certify that due to the big amount of populations, there are significant imbalances between energy supply and demands in developing countries. To make things better, these imbalances don’t exist in developed world, like EU Members including Sweden because of applications of advanced technologies and wide utilizations of renewable energy carriers. Oppositely, greenhouse gases emission is a severe problem in the world, which gives rise to temperature increasing year by year! Besides the global warming, some other factors also bring about uncertainties to energy supply security, so that efficient policies are necessary in order improve the recent</p><p>situations and to create a secure atmosphere for energy supply, such as</p><p>Directive 98/30/EC for natural gas supply security, Directive 2003/55/EC for integration and compatibility of the energy regulation and Directive 2003/54/EC, the first policy that regulates EU electricity market as well as IEM Directive, which is the improvement of Directive 2003/54/EC, etc.</p><p>Although several policies aiming at creation of competitive energy markets and achieving energy supply security, vulnerabilities still exist in EU energy supply system, such as limited primary energy sources and high dependence on nuclear powers, energy network capacity inadequacy, high voltage electricity transmission, etc. Concerning Swedish energy supply system, extreme low temperatures in winter, drilling technologies and high economic budgets for heat sources from underground, hurricanes, thunderstorms to wind turbines and man-made disruptions are all potential vulnerabilities. Regarding these negative aspects, recommendations are given on four different levels, which are global, EU, Swedish and individual perspectives. Specific suggestions to achieve energy supply security include independence of different energy supplies, to enhance international cooperation, periodic assessments and inspections for energy facilities, population control, to keep original energy policies updated, to enhance abilities to resist abnormal weather conditions, to develop heat pump technologies and try to use energy in efficient ways, etc.</p>

<p>In this thesis structural optimization of castings and thermomechanical analysis of castings are studied.</p><p>In paper I an optimization algorithm is created by using Matlab. The algorithm is linked to the commercial FE solver Abaqus by using Python script. The optimization algorithm uses the successive response surfaces methodology (SRSM) to create global response surfaces. It is shown that including residual stresses in structural optimization of castings yields an optimal shape that differs significantly from the one obtained when residual stresses are excluded.</p><p>In paper II the optimization algorithm is expanded to using neural networks. It is tested on some typical bench mark problems and shows very promising results. Combining paper I and II the response surfaces can be either analytical functions, both linear and non-linear, or neural networks. The optimization is then performed by using sequential linear programming or by using a zero-order method called Complex. This is all gathered in a package called StuG-OPT.</p><p>In paper III and IV focus is on the thermomechanical problem when residual stresses are calculated. In paper III a literature review is performed and some numerical simulations are performed to see where numerical simulations can be used in the industry today. In paper IV simulations are compared to real tests. Several stress lattices are casted and the residual stresses are measured. Simulations are performed by using Magmasoft and Abaqus. In Magmasoft a J2-plasticity model is used and in Abaqus two simulations are performed using either J2-plasticity or the ”Cast Iron Plasticity” available in Abaqus that takes into account the different behavior in tension and compression for grey cast iron.</p> / Report code: LIU-TEK-LIC-2007:34.