The goal of this thesis is to improve the predictive capability of Finite element (FE) by gathering data from experimental test and implement the characteristics into the material model that is used. FE is a commonly used method to predict the mechanical behavior of materials and components during applied forces. Therefore, it’s an important part of product development since it gives an opportunity to lower the costs as well as saving resources since it reduces the number of experimental tests. The method for this thesis was to first simulate tensile tests in Abaqus and then to analyze its results. Once all the simulations were done, we replicated the simulation with experimental tests. This was done with DIC (Digital Image Correlation) to help gather data. Since the goal of this thesis is to see how the predictive capability of the FEM-simulation can be improved the results are compared and discussed to see what from the FEM-simulation matches the DIC results and what does not. This will help understand what in the material model that needs to be changed to better match the testing. DIC is a non-contact method that is used to measure deformations and strain locally over an area which results in a more detailed view of the mechanical behavior of the material. The idea of using DIC during this thesis is to sample enough valuable data and apply it to the original material model of the FE-simulations to increase the predictive capability. After the results from the experimental tests were analyzed it was clear that there were both resemblances and differences in the results, for example the Young’s modulus in the FEM-calculations was higher than it was for the experimental tests, Yield strength was lower in the FEM-calculations compared to the experimental tests, maximum load at fracture was lower in the FEM-calculations compared to the experimental tests and elongation was lower in the FEM-calculations compared to the experimental tests. The FEM-calculations were based of the assumptions that the material was homogenous but that wasn’t the case for the experimental tests. Due to the strain varying over the tests the material model could be improved by adding a statistical variation, to all the elements to give them varying mechanical properties simulate how the strain vary more correctly over the specimen.

This thesis documents research done for a transient hot wire system that will be used in future thermal conductivity measurements of molten salts. Research done with molten salts have been limited because of erroneous measurement capabilities, but the current research strives to introduce a new technique to accurately record thermal conductivity over a wide range of temperatures. This work follows up on past transient hot wire researchers whose designs and tests produced an instrument that can measure the thermal conductivity of molten metals up to 750 K. The transient hot wire (THW) technique has been selected to be used in molten salt to derive thermal conductivity values. While running a THW test in molten salts is outside the scope of this thesis, a modular system has been created for the use of running transient hot wire test that allows for a robust and repeatable testing. A PEGDA/galinstan sensor is used for the validation of the system. A robust GUI has been created to automate the experimental procedure in a glovebox environment. The inverse finite element method has been paired with a non linear fit script to optimize calculations and reduce run times. Test have been done to determine the thermal conductivity of PEGDA. The overall uncertainty of the thermal conductivity measured with the PEGDA sensor is estimated to be ±5% at a 95% confidence level. With a THW system implemented and validated a sensor has been designed to work in molten salts. A model has been created in two separate FEA programs to validate design changes and material properties. The sensor is made up of a chemical vapor deposition (CVD) diamond substrate and tungsten wires to overcome corrosion and heat challenges introduced when measuring molten salts. New manufacturing processes have been designed to allow the technique to use these materials in the THW sensor design. The selected material properties of the sensor and extensive finite element work have laid down the ground work for future experimentation and understanding of the thermal properties of molten salts. It is predicted that the CVD diamond (carbide) apparatus design will use the THW techniques to operate with an estimated accuracy of ±3% over a wide range of temperatures, from ambient up to 1200 K. Manufacturing of the diamond-tungsten sensor have proven the viability of depositing tungsten wire onto CVD diamond and growing a secondary layer of CVD diamond over the tungsten wire.

Studiens syfte är att undersöka undervisande matematiklärares, på mellanstadiet, uppfattning om formativa bedömningsstrategier och vilka möjligheter och begränsningar som de medför. Metoden för detta var semistrukturerade intervjuer. Antal intevjuade lärare var sex stycken och samtliga undervisade matematik på mellanstadiet. Resultatet analyserades utifrån den sociokulturella teorin och utifrån formativ bedömnings fem nyckelstrategier. Huvudresultatet för studien är att lärarna använder sig av de fem nyckelstratgeierna för formativ bedömning på olika sätt. Framför allt observerar lärarna eleverna under lektionen och interagerar med dem. Lärarna anpassar undervisningen och bedömner eleverna därefter. Att ge feedback är också en högt förekommande formativ bedömningsstrategi i matematikundervisningen. Den största möjligheten är att eleverna kan utveckla sina kunskaper men begränsingen är tidbrist. Att använda formativ bedömnig i undervisningen anses ta mycket tid från lärarna som redan har ett pressat schema. Formativ bedömning anses trots det vara positivt i undervisingen av många lärare.

Syftet med denna studie var att få djupare kunskap om hur lärare beskriver och resonerar kring sitt användande av formativ bedömning i kemiundervisningen på högstadiet. Utifrån denna bakgrund har ett problemområde formulerats och avgränsats i följande frågeställning: Hur beskriver och resonerar lärare kring sitt användande av formativ bedömning i kemiundervisningen? Denna kvalitativa studie genomfördes med intervjuer av sex lärare som alla undervisar i kemi för årskurs 7–9. För att uppnå syftet och besvara frågeställningarna användes semistrukturerade intervjuer. Detta för att både uppnå syftet och besvara frågeställningen så utförligt och välutvecklat som möjligt. Studiens resultat visar att lärare upplever att formativ bedömning är gynnsamt för elevens lärande i kemiämnet om det används på rätt sätt. Det som framkommer i studien är att det finns flera faktorer som påverkar användandet av formativ bedömning i kemiundervisningen, bland annat spelar lärarens kompetens och användning av olika strategier en avgörande roll. Studien visar även att lärarens egenutbildning, kunskaper i ämnet och ämnesdidaktiska kompetens, har betydelse för hur formativ bedömning används i praktiken. Studien visar också att elevernas upplevelser av formativ bedömning kan påverka användandet av olika former av formativ bedömning i kemiundervisningen, speciellt kamratbedömning.

Cell modulus and prestress are important determinants of cell behavior. This study creates new software tools to compute the modulus and prestress distribution within a living cell. As input, we have a sequence of images of a cell plated on a substrate with fluorescently labeled fibronectin dots. The cell generates focal adhesions with the dots and thus deforms the substrate. A sequence of images of the cell and the fibronectin dots shows their deformation. We tested three different ways to track the movement of the fluorescent fibronectin dots. We demonstrated the accuracy and the adaptability of each method on a sequence of test images with a rigid movement. We found the best method for dot tracking is a combination of successive dot identification and digital image correlation. The dot deformation provides a measure of traction forces acting on the cell. From traction forces thus inferred, we use FEM to compute the stress distribution within a cell. We consider two approaches. The first is based on the assumption that the cell has homogeneous elastic properties. This is straightforward and requires only the cell being meshed and the linear elasticity problem solved on that mesh. Second, we relaxed the homogeneity assumption. We used previously published correlations between prestress and modulus to iteratively update the modulus and prestress distributions within the cell. A novel feature of this work is the implicit reconstruction of the modulus distribution without a measured displacement field, and the reconstruction of the prestress distribution accounting for intracellular inhomogeneity.

In 1952 Alan Turing published his paper "The Chemical Basis of Morphogenesis", which described a model for how naturally occurring patterns, such as the stripes of a zebra and the spots of a leopard, can arise from a spatially homogeneous steady state through diffusion. Turing suggested that the concentration of the substances producing the patterns is determined by the reaction kinetics, how the substances interact, and diffusion.  In this project Turing's model with linear reactions kinetics was studied. The model was first solved using two different numerical methods; the finite difference method (FDM) and the finite element method (FEM) with different boundary conditions. A parameter study was then conducted, investigating the effect on the patterns of changing the parameters of the model. Lastly the controllability of the model and the least energy control was considered. The simulations were found to produce patterns provided the right parameters, as expected. From the investigation of the parameters it could be concluded that the size/tightness of the pattern and similarity of the substance concentration distributions depended on the choice of parameters. As for the controllability, a desired final state could be produced thorough simulations using control of the boundary and the energy cost of producing the pattern increased when decreasing the number of controls.

Behovet av att minska klimatpåverkan genom optimering av armerade betongkonstruktioner har på senaste årtiondet väckt stort intresse. I traditionell dimensionering av betongkonstruktioner övervägs endast ett fåtal utformningar. På senare tid har en metod där flera möjliga lösningar genereras och som möjliggör sena förändringar växt fram, metoden är en så kallad set-based design (SBD). För att utvärdera implementeringen av denna typ av designprocedur utvecklades ett beräkningsskript.  Det primära syftet med denna studie är att med hjälp av ett beräkningsscript, baserat på SBD och parametrisk optimering kunna identifiera den bästa utformningen för ett påldäck med hänsyn taget till kriterierna klimatpåverkan och viljan att standardisera konstruktionen och underlätta produktionen. En del av syftet i studien kommer också vara att på en detaljerad nivå undersöka hur man kan implementera armeringsutformningen i beräkningsscriptet och vilken effekt det ger på optimeringen mot det undersökta kriteriet. På grund av att beräkningsskriptet begränsas av ofullständiga funktioner hos programutvecklaren resulterade det i att en del av datagenereringen fick ske manuellt för att uppnå önskat resultat. Resultatet genererades genom en manuellt genomförd parametrisk studie där utvalda modeller med olika kombinationer av variabler analyserades. Parametrar av betydelse för konstruktionens armeringsutformning och utvärderingskriterier identifierades genom jämförelse av data för olika beräkningsfall. Dessutom jämfördes resultat från flera olika kombinationer av variabler för att se vilka som var av betydelse. De genomförda undersökningarna visade att god armeringsutformning uppnås genom att tillåta parametrar variera fritt. Att erbjuda en lösning där valmöjligheter på ingående parametrar definieras för varje studerad riktning och tillåta variationer i armeringsutformningen för konstruktion leder till en mer noggrann armeringsutformning utifrån önskat resultat. Med parametrisk optimering och dataanalys kan olika lösningar identifieras för effektiv användning av material och bidra till god byggbarhet. Genom studien har det konstaterats att det finns ett stort intresse hos programutvecklare att hjälpa dess användare med att ta fram de funktioner som efterfrågas, och ta åt sig av den input som kommer från dess användare. Detta tyder på en vilja att implementera nya funktioner i dimensioneringsprocessen och en vilja att föra utvecklingen av automatiserade beräkningar vidare.

This work is about wind stabilization of a SIPS building in Sweden where the focus is onhow joints take place between the foundation plate and the walls. SIPS (Structural insulatedpanels) is a load-bearing insulation element used to build the entire building envelope. It is anewly arrived building technology in Sweden that is used for passive houses in order toreduce energy use. The elements are prefabricated and bonded together with fiberglassbeams, which are also used to reinforce openings in the building. The method that will beused in this work is the finite element method using a computer program FEM-design by thecompany Strusoft. In the programme the model was rebuilt and calculated according to theEurocode. In collaboration with SIP's company Avis Building technology, the building andthe joint were modeled according to one of their buildings, which was then analyzed. Thisresulted in the joint consisting of screws attached to a profile of aluminum. The result gavethe shear and normal forces that affect the screw and plat. In this way, the question of how anattachment of a SIPs building can take place has been answered. The results in FEM-designshow that a SIPS building can be wind-stabilized in Sweden with the exception of certainparts that can be supplemented with a load-bearing inner wall to achieve full stabilization.But this question cannot be answered with complete certainty without more data and researchon the element being. Too many parameters about the properties of the elements wereunknown, which led to uncertainty. In the program, the building was stabilized but had toolarge deformations in some places. This does not mean that such a building cannot bestabilised, but more research must be carried out before the conclusion can be drawn. In thework, no tests were made of the element, which contributed to this uncertainty. With moremeasurements and trials, a SIPS building can definitely become a future building technologyin Sweden.

This thesis utilizes the Immersed Interface Finite Element Method (IIFEM) for shape optimization and material design, while also investigating the modeling and parameterization of lung tissue for Diver Underwater Explosion (UNDEX) simulations. In the first part, a shape optimization scheme utilizing a four-noded rectangular immersed-interface element is presented. This method eliminates the need for interface fitted mesh or mesh morphing, reducing computational costs while maintaining solution accuracy. Analytical design sensitivity analysis is performed to obtain gradients for the optimization formulation, and various parametrization techniques are explored. The effectiveness of the approach is demonstrated through verification and case studies. For material design, the study combines topological shape optimization with IIFEM, providing a computational approach for architecting materials with desired effective properties. Numerical homogenization evaluates effective properties, and level set-based topology optimization evolves boundaries within the unit cell to generate optimal periodic microstructures. The design space is parameterized using radial basis functions, facilitating a gradient-based optimization algorithm for optimal coefficients. The method produces geometries with smooth boundaries and distinct interfaces, demonstrated through numerical examples. The thesis then delves into modeling the mechanical response of lung tissues, particularly focusing on hyperelastic and hyperviscoelastic models. The research adopts a phased approach, emphasizing hyperelastic model parametrization while reserving hyperviscoelastic model parametrization for future studies. Alternative methods are used for parametrization, circumventing direct experimental tests on biological materials. Representative material properties are sourced from literature or refit from existing experimental data, incorporating both empirically derived data and practical values suitable for simulations. Damage parameter quantification relies on asserted quantitative relationships between injury levels and the regions or percentages of affected lung tissue. / Doctor of Philosophy / This research explores the following themes: optimizing shapes, designing materials using repetitive identical building blocks, and understanding how divers' lungs respond to underwater explosions. When computationally analyzing structures with multiple materials, the conventional method involves creating meshes that align with material interfaces, which can be intricate and time-consuming. The Immersed Interface Finite Element Method (IIFEM) is introduced as a computational approach that simplifies this process, utilizing a uniform grid for analysis regardless of interface shape. Consider a plate with a hole or other inclusions. Shape optimization seeks the optimal hole/inclusion shape for withstanding specific loading. Traditional optimization processes necessitate iterative mesh recreation, a step circumvented by employing IIFEM. This technique also extends to creating micro-building blocks of materials, enabling the architectural design of materials with desired qualities. Materials with specific properties, like strength or flexibility can be achieved. This thesis also addresses the challenge of understanding how divers' lungs respond to underwater explosions, a crucial aspect of safety. Advanced computer models are used to mimic the behavior of lung tissue under shock loads. Directly testing materials and tissues can be difficult and restricted. Techniques like gathering data from scientific papers and refitting existing experimental data are utilized to obtain the information needed. Also, it is hard to directly measure how much damage an underwater explosion does to a diver's lungs. Thus, the level of damage was quantified based on assertions about the relationship between different injury severities and how much lung tissue is affected.

The topic of this thesis is the investigation of the local states of stress resulting from the introduction of av-notch in a coaxial circle on the pressurized surface of a circumferentially clamped plate subject to axisymmetric loading. The understanding of the fracture behavior of a component experiencing such a condition is of particular interest to the aerospace and defense industries where circular plate components are often utilized. In such applications, it is imperative that the designer be able to predict the loading conditions facilitating dynamic fracture. As a step towards solving such problems, the quasi-static analogy is studied. Specifically, the purpose of this research is to examine and model the precise effects a stress raiser will have on the fracture behavior and strength reduction of a circular plate machined from Ultem 1000. Parametric FEM simulations were employed to determine the correlation between notch geometry and the resulting maximum stress and stress distribution in the notch root vicinity. Stress concentration factor (SCF) relationships were developed which characterize the effect individual geometric parameters have on the notch root stresses. Mathematical models were developed to provide the elastic stress concentration factor for any combination of geometric parameters within the range studied. Additionally, the stress distributions along the notch root and ahead of the notch were characterized for a variety of geometric configurations. Test coupons were employed to not only characterize the mechanical behavior of the material, but also characterize the correlation between simple and axisymmetric loading, respectively. The development of a predictive approach for designers of such circular components to be able to accurately determine the fracture behavior of these components was the motivating factor of this study.