I skolämnet matematik och centralt innehåll problemlösning har en kvalitativ observation har genomförts i en årskurs fem. Syftet med studien har varit att utöka kunskaper om hur undervisningen kan synliggöra elevernas förståelse för matematiken i problemlösningsuppgifter med hjälp av muntlig kommunikation i mindre grupper. Datainsamlingen har skett genom ljudinspelning av elevsamtalen. Denna studie syftar identifiera en instrumentell eller relationell förståelse hos eleverna som synliggör vid en muntlig kommunikation. Detta har gjort genom att granska de argument som eleverna delger i sina samtal med varandra. Analysen har visat att elevernas förståelse synliggörs när undervisningen erbjuder de förutsättningar som krävs för att muntlig kommunikation ska vara givande. / <p>Matematik</p>

Den här rapporten handlar om ett maskintekniskt konstruktionsprojekt som framtagits av Christian Wikman och Oliver Öhman. Det är ett uppdrag som givits av EcoistVehicleTM för att slutföra högskoleingenjörsexamen inom maskinteknik vid Högskolan i Halmstad. Princip- och Primärkonstruktion (Olsson, 1995), Fundamentals of Vehicle Dynamics (Gillespie, 1992) och en stor mängd egen sökning har använts som grund till metoden som använts under projektets gång.   EcoistVehicleTM är ett fordonsprojekt som startats av Thomas Koch. Det är en eldriven, singelsits och trehjulig bil med ett drivande bakhjul. Idén bakom bilen är att transportera föraren till sin destination på ett miljövänligt sätt. Bilen är lämpad till landsbygd och pendling med en räckvidd på 40-50km. Syftet med uppdraget som gavs våren 2017 var att hitta snabbare metoder att konstruera och tillverka en svingarm till fordonet.   Uppdraget som gavs var att konstruera och möjligtvis tillverka en svingarm för det drivande bakhjulet som skall passa in på bilens dimensioner samt ha en relativt snabb tillverkningsprocess för en produktionsserie på 10-20 bilar. Uppdragsgivarens önskemål var att 3D-printa ut de större delarna av svingarmen och sedan efterbearbeta monteringsdelar och passytor med fräsning. Flera tillverkningsprocesser som används inom fordonsindustrin för framtagning av motorcykelsvingarmar har setts över och jämföras för att få fram den metod som passar detta projekt.   Det som författarna bidragit med till projeketet är en högre kunskap om 3D-printning av metall, då specifikt aluminium, olika koncept för tillverkning samt analyser av konstruktionen för att testa hållfasthet till den slutgiltiga produkten. / This report will be about a mechanical design project that has been developed by Christian Wikman and Oliver Öhman. The assignment was given by EcoistVehicleTM to complete a bachelor’s degree in mechanical engineering at Halmstad University. Princip- och Primärkonstruktion (Olsson, 1995), Fundamentals of Vehicle Dynamics (Gillespie, 1992) and a large amount of research on the web has been used as the foundation for the method that’s been used all through this project.   EcoistVehicleTM is a vehicle project started by Thomas Koch. It is an electrically powered, single seat, three wheeled vehicle that's driven by a single rear wheel. The idea behind the car is to transport the driver to his destination in an environmentally friendly way. The car is suited for commuting in the countryside with a range of 40-50km. The purpose of the assignment that was given in the spring of 2017 was to look into faster methods of designing and manufacturing a swingarm for the vehicle.   Our assignment was to design and possibly manufacture a swingarm for the driving rear wheel that should fit the specifications of the car and have a relatively fast manufacturing process for a series of 10-20 cars. Our mentor and taskmaster has a request to 3D-print the larger parts of the swingarm then after work the mounting surfaces and mating surfaces with milling. Several manufacturing processes used in the automotive industry for the production of motorcycle swingarms will be screened and compared to get the method that will fit this project.   The authors have contributed with a higher knowledge of 3D-printing, specifically aluminum, different design concepts together with analysis of the design to test the solidity of the final product.

A 3D nonlinear finite element analysis was developed for simulating the behavior of skewed concrete slabs and to identify the response of the slab with different angles and element sizes. The purpose of this research is helping the engineering and construction industry to utilize the FEM study and results more in different structural applications.Simulations performed in ABAQUS for skewed slabs are also compared to straight and skewed slabs according to the analytical formulation by Timoshenko.The result showed that when the distance increases, the load capacity measured by reaction forces decreases for all different skew angles except angle 0° and 15° which show a stable reaction force along the entire path. .The study reveals that depending on the skew angle and the element size, the stress distribution and vertical displacements in the slab vary significantly from those in a straight slab. It is shown that the displacement decreases with the increase of the skew angle while the stresses increase with the decrease of the skew angle.There are small differences in the vertical displacements and stress distribution between the results obtained by this study and the results obtained by Timoshenko regarding the plates with skews of 0°, 30° and 45°.

I skolämnet matematik och centralt innehåll problemlösning har en kvalitativ observation har genomförts i en årskurs fem. Syftet med studien har varit att utöka kunskaper om hur undervisningen kan synliggöra elevernas förståelse för matematiken i problemlösningsuppgifter med hjälp av muntlig kommunikation i mindre grupper. Datainsamlingen har skett genom ljudinspelning av elevsamtalen. Denna studie syftar identifiera en instrumentell eller relationell förståelse hos eleverna som synliggör vid en muntlig kommunikation. Detta har gjort genom att granska de argument som eleverna delger i sina samtal med varandra. Analysen har visat att elevernas förståelse synliggörs när undervisningen erbjuder de förutsättningar som krävs för att muntlig kommunikation ska vara givande. / <p>matematik</p>

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En av dagens vanligaste maskiner för att underlätta hanteringen av tungt gods är gaffeltrucken. Denna tillverkas i industriell produktion där konkurrensen är hård. Den hårda konkurrensen bland tillverkningsföretagen på den globala marknaden ökar strävan att tillverka produkter till ett så kostnadseffektivt pris som möjligt. Syftet med det här arbetet är att utreda huruvida det går att optimera en befintlig drivlinsupphängning med avseende på tillverkningskostnad och vikt. Genom en produktutveckling skall ett koncept för en optimerad lösning tas fram gällande konstruktion, materialval och tillverkningsmetod. För att skapa ett underlag till denna produktutvecklingsprocess har väsentliga teorier tagits fram och presenterats i arbetet. Produktutvecklingen kommer generera ett nytt koncept. I produktutvecklingen utförs även materialval, val av tillverkningsmetod, beräkningar, FEM-simuleringar, designoptimering och utvärdering angående kostnaderna. Detta resulterade slutligen i en möjlig kostnadsreducering. Vikten kan dessutom reduceras utan att försämra hållfastheten.

Alumina is one of the most commonly used engineering ceramics for a variety of applications ranging from microelectronics to prosthetics due to its desirable properties. Unfortunately, conventional machining techniques generally lead to fracture, tool failure, low surface integrity, high energy consumption, low material removal rate, and high tool wear during machining due to high hardness and brittleness of the ceramic material. Laser machining offers an alternative for rapid processing of brittle and hard engineering ceramics. However, the material properties, especially the high thermal expansion coefficient and low thermal conductivity, may cause ceramic fracture due to thermal damage. Striation formation is another defect in laser cutting. These drawbacks limit advanced ceramics in engineering applications. In this work, various lasers and machining techniques are investigated to explore the feasibility of high-quality laser machining different thicknesses of alumina. The main contributions include: (i) Fibre laser crack-free cutting of thick-section alumina (up to 6-mm-thickness). A three-dimensional numerical model considering the material removal was developed to study the effects of process parameters on temperature, thermal-stress distribution, fracture initiation and propagation in laser cutting. A rapid parameters optimisation procedure for crack-free cutting of thick-section ceramics was proposed. (ii) Low power CW CO2 laser underwater machining of closed cavities (up to 2-mm depth) in alumina was demonstrated with high-quality in terms of surface finish and integrity. A three-dimensional thermal-stress model and a two-dimensional fluid smooth particle hydrodynamic model (SPH) were developed to investigate the physical processes during CO2 laser underwater machining. SPH modelling has been applied for the first time to studying laser processing of ceramics. (iii) Striation-free cutting of alumina sheets (1-mm thickness) is realised using a nano-second pulsed DPSS Nd: YAG laser, which demonstrates the capability of high average power short pulsed lasers in high-quality macro-machining. A mechanism of pulsed laser striation-free cutting was also proposed. The present work opens up new opportunities for applying lasers for high-quality machining of engineering ceramics.

The main objective of this work is to develop a quasi three-dimensional numerical model to simulate stony debris flows, considering a continuum fluid phase, composed by water and fine sediments, and a non-continuum phase including large particles, such as pebbles and boulders. Large particles are treated in a Lagrangian frame of reference using the Discrete Element Method, the fluid phase is based on the Eulerian approach, using the Finite Element Method to solve the depth-averaged Navier–Stokes equations in two horizontal dimensions. The particle’s equations of motion are in three dimensions. The model simulates particle-particle collisions and wall-particle collisions, taking into account that particles are immersed in a fluid. Bingham and Cross rheological models are used for the continuum phase. Both formulations provide very stable results, even in the range of very low shear rates. Bingham formulation is better able to simulate the stopping stage of the fluid when applied shear stresses are low. Results of numerical simulations have been compared with data from laboratory experiments on a flume-fan prototype. Results show that the model is capable of simulating the motion of big particles moving in the fluid flow, handling dense particulate flows and avoiding overlap among particles. An application to simulate debris flow events that occurred in Northern Venezuela in 1999 shows that the model could replicate the main boulder accumulation areas that were surveyed by the USGS. Uniqueness of this research is the integration of mud flow and stony debris movement in a single modeling tool that can be used for planning and management of debris flow prone areas.

Fackverksmodellering (eng. strut-tie modeling) är en accepterad och rationell beräkningsmetod för betongkonstruktioner där vanlig balkteori inte kan appliceras. Det gäller områden för s.k. diskontinuitetsregioner (D-regioner). Den komplexa spännings- och kraftfördelningen som uppstår i D-regioner substitueras till fackverkskomponenter i form av trycksträvor, dragstag och noder. Lastfallen omvandlas, under förenklade villkor, med andra ord till ett lösbart fackverksfall. Metodiken för tillgångasättet har länge ansetts som iterativ och långdragen process, där ett fackverk antas samt optimeras tills ett godtyckligt och rimligt fackverk har uppnåtts. Erfarenhet har betydelse för hur fackverksutformningen kommer att se ut. Oerfarna ingenjörer kan till en början ha svårt att se hur spännings- och kraftfördelningen i en betongkonstruktion sprider ut sig. Med hjälp av FEM kan fackverksmodelleringens process effektiviseras. Spänningsoch kraftfördelningen kan tas fram i belastande betongkonstruktioner i form av finita elementmodeller. Därmed kan konstruktörerna visuellt utforma fackverket efter fördelningen. I studien har ett verkligt fall tillhandahållits från företaget WSP. Konstruktionsdelen som ska dimensioneras är en väggskiva från ett flerbostadshus i Stockholm. Med FEM-design har väggskivan rekonstruerats till en finita elementmodell med en framtagen spännings- och kraftfördelning. Fördelningen har använts som ett underlag för vidare dimensionering för hand efter Svenska Standard, Eurokod 2. Resultaten visar att det är möjligt att utforma ett fackverk med FEM-design som underlag. Även framtagna stångkrafter och upplagskrafter har jämförts mellan handberäkning och FEM, som visar att skillnader mellan beräkningsmetoderna är mellan ungefär 5,1-7,7 %, dock bara för studiens fall. Rapporten visar att en påskyndning i processen kan göras om man använder FEM. Metoden möjliggör en förenkling i processen som kan nyttjas av oerfarna konstruktörer. Detta kan bidra till en bättre slutprodukt och gynna utvecklingen för byggbranschen i slutändan. / Strut-tie modeling is an accepted and rational calculation method for regions in concrete structures where Berouille-theorem can’t be applied. These regions are so called discontinuity regions (D.regions). The stress and force distribution is substituted for strut, ties and nodes much like the members of a truss. Complex load-bearing cases can be transformed, under simplified conditions, to solvable cases. The strut-tie modeling can be seen as an iterative process. At the start of the process the form of the truss is assumed and optimized through trial and error. Experience in the field is therefore of big significance, where unexperienced designers can have a hard time to visualize the stress and force distribution through the concrete structure. The purpose of the study is to use the strut-tie method on a concrete structure. The study will investigate if the strut-tie method can be simplified and if the assumed truss is reasonable. The stress and force distribution is going to be visualized through a finite element model, and hence try to eliminate the iterative modelling phase. In the study, a real load-bearing case will be examined. The concrete structure is a deep beam in an apartment block in Stockholm, Sweden. The designs of the apartment have been provided from the multinational company WSP. The deep beam have been reconstructed to a finite element model through the program FEMdesign 17 3D Structure. The visualized results from the stress and force distribution have been used as a base for further calculations, with the strut-tie method, in accordance to Eurocode 2. The result from the study shows that it’s possible to create a truss from FEM-designs visualized stress- and force distribution. In the study a comparison have also been made between truss member forces calculated by strut-tie and the forces calculated by FEM-design. It shows a difference between 5,1-7,7%. The study shows through the program FEM-design 17 that strut-tie method can be improved, and help unexperienced designers during the truss modeling phase.

The characterization of the mechanical behavior of soft living tissues is a big challenge in Biomechanics. The difficulty arises from both the access to the tissues and the manipulation in order to know their physical properties. Currently, the biomechanical characterization of the organs is mainly performed by testing ex-vivo samples or by means of indentation tests. In the first case, the obtained behavior does not represent the real behavior of the organ. In the second case, it is only a representation of the mechanical response of the indented areas. The purpose of the research reported in this thesis is the development of a methodology to in-vivo characterize the biomechanical behavior of two different organs: the breast and the cornea. The proposed methodology avoids invasive measurements to obtain the mechanical response of the organs and is able to completely characterize of the biomechanical behavior of them. The research reported in this thesis describes a methodology to in-vivo characterize the biomechanical behavior of the breast and the cornea. The estimation of the elastic constants of the constitutive equations that define the mechanical behavior of these organs is performed using an iterative search algorithm which optimizes these parameters. The search is based on the iterative variation of the elastic constants of the model in order to increase the similarity between a simulated deformation of the organ and the real one. The similarity is measured by means of a volumetric similarity function which combines overlap-based coefficients and distance-based coefficients. Due to the number of parameters to be characterized as well as the non-convergences that the solution may present in some regions, genetic heuristics were chosen to drive the search algorithm. In the case of the breast, the elastic constants of an anisotropic hyperelastic neo-Hookean model proposed to simulate the compression of the breast during an MRI-guided biopsy were estimated. Results from this analysis showed that the proposed algorithm accurately found the elastic constants of the proposed model, providing an average relative error below 10%. The methodology was validated using breast software phantoms. Nevertheless, this methodology can be easily transferred into its use with real breasts. In the case of the cornea, the elastic constants of a hyperelastic second-order Ogden model were estimated for 24 corneas corresponding to 12 patients. The finite element method was applied in order to simulate the deformation of the human corneas due to non-contact tonometry. The iterative search was applied in order to estimate the elastic constants of the model which approximates the most the simulated deformation to the real one. Results showed that these constants can be estimated with an error of about 5%. After the results obtained for both organs, it can be concluded that the iterative search methodology presented in this thesis allows the \textit{in-vivo} estimation the patient-specific elastic constants of the constitutive biomechanical models that govern the biomechanical behavior of these two organs. / Lago Ángel, MÁ. (2014). A new approach for the in-vivo characterization of the biomechanical behavior of the breast and the cornea [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/44116 / TESIS