Spännhjulen på den av BAE Systems Hägglunds tillverkade midjestyrda bandvagn BvS10 har nått sin belastningsgräns, eftersom vagnens vikt numera uppgår till 16 000 kg. I det här arbetet undersöks om det skulle vara möjligt att tillverka ett hjul dimensionerat för 17 000 kg, utan att ändra hjulets diameter, lagring eller bandstyrning. Eftersom hjulet även borde gå att använda som bärhjul tas viss hänsyn till att vikten bör hållas nere. Huvudspåret för undersökningen är att hjulen ska gjutas i aluminium och därför görs försök att utforma geometrin för att utnyttja gjutmetodens fördelar till fullo. Relevanta lastfall tas fram för hjulen som sedan beräknas med hjälp av finita element-metoden för att undersöka om de besitter tillräckliga hållfasthetsegenskaper. Undersökningen visar att det borde gå att tillverka aluminiumhjul som kombinerar tillräcklig hållfasthet med de geometriska kraven, som dessutom inte behöver väga mer än nuvarande hjul. Hjulens slutgiltiga design är relativt simpel vilket öppnar upp för möjligheten att svarva fram hjulen istället för att gjuta dem. / The tension wheel on the BAE Systems Hägglunds BvS10 has reached its load carrying limit. The cause of this is the current vehicle weight now reaching 16 000 kg. This report examines the possibility to increase the load carrying capability of the tension wheel so that it will withstand the forces applied from a vehicle weighing 17 000 kg. No changes are to be made regarding the wheels outer diameter, bearing or track guide. The wheel should also be able to see use as a road wheel, which means that the weight of the wheel should be held at a minimum. The primary approach is to make the wheel out of cast aluminium. This dictates that efforts should be made to take full advantage of the benefits of different casting methods, when designing the wheel geometry. Finite element analysis for relevant load cases is performed on the wheels to see if they possess the required mechanical properties. The results indicate that it is possible to produce aluminium wheels that combine sufficient mechanical strength with the geometrical requirements. The study also shows that the weight of these wheels would be comparable or only slightly higher than the weight of the current wheels. The final design of the wheels suggested is relatively simple, which provides the possibility to produce it using lathe machining instead of casting.

Indiana University-Purdue University Indianapolis (IUPUI) / One of the most common concern among patients who need orthodontic treatment is treatment duration. The ability to accelerate orthodontic tooth movements would be bene cial to reduce the undesired side-effects of prolonged treatment. Methods have been used in conjugate with common orthodontic appliances to shorten the treatment. One of them is to use vibrational force (VF), which is non-invasive. The VF stimulates bone modeling and remodeling, which is essential to tooth movement. However, commercial devices used in the clinic failed to deliver consistent outcomes. The effects of the VF highly depend on its intensity the tooth receives. There must be a range of stimulation that optimizes the ffeects. The stimulation outside the range either have no effects or creates damages, which adversely affects the orthodontic treatment. Since these devices have generic mouthpiece and teeth are in di erent heights, hence some teeth cannot get force stimulation and others may be overloaded. The current designs also do not have ability to adjust the level of VF intensity that individual tooth needs, as in some cases orthodontists are required to move a tooth faster than others or even slower, which needs the device to be personalized. There- fore, the primary cause of inconsistent clinical outcomes is the inadequate design of the mouthpiece of the current device. The goal of this study is to design a better vibratory device that not only guarantees VF delivery but also enables orthodontists to control the level of VF on the individual tooth, which meets the patient's treat- ment needs. This is a preliminary study to understand the effects of different design parameters affecting the VF distribution on teeth. A nite element model, which consists of human upper and lower jaws in their occlusal positions and a mouthpiece, was created. The VF was from a vibratory source with a peak load of 0.3N and speci ed frequencies (30 and 120 Hz). The element size was determined through a convergence test and the model was validated experimentally. Results showed that the VF distribution among the teeth relies on the material property of the mouthpiece. The distribution is uneven, meaning some teeth bearing much more load than others. This means, with the current device design, teeth would be a ected with di erent level of force stimulation, which results in di erent clinical outcomes consequently. Dynamic load (VF) changes the force distribution on the teeth comparing to the dis- tribution from a static load. Frequency does not affect the peak load. Finally, the study demonstrated that the level of VF stimulation can be adjusted by introducing clearance or interference between the teeth and mouthpiece. It is feasible to control the level of the VF intensity for individual tooth based on treatment requirement.

At present, the usage of FEM-programs becomes wider for loads effect calculation of bridges. Even though the calculation in all FEM-programs works following the same procedure, it differs when it comes to moving loads where we can identify two different approaches, ILM and ISM (influence line and influence surface method). ISM is used in FEM-programs that are most adapted for bridges where moving loads have great influence, while ILM is used in FEM-programs where moving loads are less important as house constructions. The aim is to evaluate the use of ILM programs (eg FEM-Design) when managing of moving loads in bridge and facilities contexts. This is achieved by comparing the results obtained from ILM programs with the results obtained from IYM programs. In addition, it will be checked how FEM-Design envelops the max and min values regarding (most adverse, conditional summation and unconditional summation). The comparison between those two methods was carried out using two different FEM programs based on different methods. Work carried out using FEM-Design (ILM program) and Brigade/Standard (ISM program). A platform bridge has been modeled and analyzed in both programs and a comparison between the results of both models has been performed. This comparison aims to investigate how ILM and ISM works when calculating moving loads and its influence in a bridge plate and in what way these two methods differ. to achieve comparable results between the programs, we examined different parameters and conditions. The thesis has shown which factors influenced the difference av results between FEM-Design and Brigade, and which summation methods that FEM-Design uses. / I dagsläget blir användning av FEM-program ännu bredare för lasteffektsberäkning och analys av brokonstruktioner. Trots att beräkningen sker i princip enligt samma process i alla FEM-program skiljer den sig när det handlar om rörliga laster. När det gäller beräkning av rörliga laster identifieras två olika metoder: ILM och IYM (influenslinje- och influensytametod). Influensytametod används i de FEM-program som är anpassade framförallt för brokonstruktioner där rörliga laster har stor påverkan, medan influenslinjemetod används i FEM-program där rörliga laster har mindre betydelse t.ex. huskonstruktioner. Målet är att utvärdera användning av ILM-program (t.ex. FEM-Design) vid hantering av rörliga laster i bro- och anläggningssammanhang. Detta uppnås genom att jämföra resultaten man får från ILM-program med resultaten som fås från IYM-program. Dessutom skall det kontrolleras hur FEM-Design utvärdera max- och minvärdena med hänsyn till mest ogynsamma, vilkorlig summering och ovilkoriga summering. Jämförelsen mellan de två metoderna har utförts med hjälp av två olika FEM-program som är baserade på de olika metoderna: FEM-Design 18 (ILM-program) och Brigade/standard 4.3 (IYM-program). En plattbro (en enkel bro) har modellerats och analyserats i båda programmen och en jämförelse mellan resultaten från båda modellerna har utförts. Denna jämförelse ämnar undersöka hur influenslinje- och influensytametoden fungerar vid beräkning av rörliga laster och dess påverkan i en brobaneplatta, och på vilket sätt dessa två metoder skiljer sig åt. För att uppnå jämförbara resultat mellan programmen undersöktes/studerades olika parametrar och förutsättningar. Examensarbetet har visat vilka faktorer som påverkat skillnaden av resultat mellan FEM-Design och Brigade, och vilka summeringsmetoder som FEM-Design använder.

<p>Research in the field of human injury biomechanics with respect to athletes has indicated that head acceleration events (HAEs) suffered during participation in a contact sport can cause long-term neurological changes that present asymptomatically. This concept has been referred to as “mild” traumatic brain injury (mTBI). This mirrors results found in soldiers, where it is also now thought that traumatic brain injury, coupled with psychological trauma can lead to posttraumatic stress disorder (PTSD). Current consensus amongst the neurotrauma research community is that all HAEs matter, whether caused by blast, blunt force, or directed energy weapons.</p> <p><br></p> <p>Previous research has focused on the long-term changes that have been demonstrated and quantified, however very little research has been done to quantify the effects of a single insult to the brain. Several studies have had participants perform head motions while in a magnetic resonance imaging (MRI) scanner. Digital twins may be used to simulate the effects of an insult, be it blast, blunt force, or directed energy to an object. Finite element models of the human head and brain have a long history of development from the earliest models in the 1970s to today. Currently, numerous software packages allow for the regularization and comparison of MRI datasets. Some software packages offer additionally the ability to create subject specific finite element meshes interactively from a single MRI image. Previous research in the HIRRT Lab reduced the time to generate simulation geometry to approximately 48 hours to generate a patient specific finite element mesh. This represented a substantial reduction in the processing time for a single scan, which to the knowledge of the authors required on the time scale of weeks to process a single geometry including the skull robustly or required costly software licenses, and still required user interactive processes. The architecture and deployment of the HIRRT Lab Cluster, a high-performance computing system that is a cost-optimized research tool to enable rapid processing of scans to simulation geometry using batch processes on a Slurm cluster. There are software optimizations, operating system optimizations, and Linux kernel-level optimization (and selections) utilized that enable the hardware selected to perform optimally. </p> <p><br></p> <p>To the knowledge of the author, no single pipeline enables the automated generation of robust, patient specific finite element meshes from raw datasets fresh from an MRI. This package addresses those limitations with a design heavily tilted towards Linux cluster implementations. The author has created a pipeline of code designed to run on a Linux-based compute cluster that is capable of processing 1700 scans from raw T1-weighted MRI scans to a finite element mesh with regions of interest (ROIs) identified as element sets, and white matter fiber orientation determined from diffusion tensor imaging (DTI) scans in under 7 days using the current hardware available in the HIRRT Lab Cluster with appropriate software licensing. This represents a speed up of over 1200x compared to the original program overall at just mesh processing, and a speed up of 22x for a single scan being processed, with additional features and detail not captured by the original code. </p> <p><br></p> <p>Accurate representative models for subpopulations via their immutable traits (e.g. size, biological sex, ethnicity/ancestry, or age) can further reduce the number of simulations that are required to accurately assist in the improvement of finite element models that may be used to improve the design of personal protective equipment, create new techniques, or aid in the design of new vehicles capable of reducing the exposure of individuals to potentially traumatic damage. The use of subpopulation groupings rather than the simulation of each unique individual, even models consisting of bounding cases, such as the largest or smallest representative members of a subpopulation can reduce the amount of data that needs to be processed to generate useful design feedback for engineers. </p> <p><br></p> <p>Subject-specific models allow for greater variation in strain due to geometric differences between individuals brains and should be used where possible to describe a given individual’s strain history more accurately, which can be used to assess the formation of damage as indicated by biomarkers. To understand the long-term effects of blast overpressures on brain structure, function, and chemistry, and subsequently develop appropriate mitigation strategies, computational models of individual soldiers must be developed. These models must integrate blast physics and neuroimaging of actual tissue damage to the brain. There is a need to develop constitutive equations capable of being used in multi-scale models to relate various insults directly to damage in the brain. These equations should be linked to damage as indicated through various MRI scan types and used to robustly assess individuals over the course of their unique impact histories. Through the development of a digital twin in this manner, unique predictive medicine may be used to proactively identify those athletes and warfighters who may be at higher risk for long term detrimental effects from further exposure to HAEs.</p>

Flerbostadshuset som studeras i rapporten är uppfört och dimensionerat med ett äldre regelverk och benämns BABS. Idag tillämpas Eurokod vid dimensioner av byggnadsverk. Skillnader i dessa regelverk skapar problem som förekommer vid en våningspåbyggnad. Dessa problem är både konstruktionstekniska och byggnadstekniska. Syftet med rapporten är att studera den mest effektiva varianten av våningspåbyggnad med avseende på bärighet, gällande krav, tilläggsåtgärder och effektivitet. Arbetet har utförts i samarbete med Sweco Structures för ett referensobjekt som har blivit modellerat i FEM för att få fram lasten vid den kritiska punkten i tre olika skeden. De tre olika skedena består av grundbyggnad, grundbyggnad med påbyggnad i betong och grundbyggnad med påbyggnad i trä. Erhållna resultat jämförs sedan med handberäkningar i enlighet med Eurokod och till viss del medhandberäkningar för BABS. Alla resultat jämförs sedan med maximal kapacitet på mark från den kritiska punkten för att kontrollera behovet av grundförstärkning. Referensobjektet undersöks även med avseende på de krav som gäller och jämförs med kraven från det äldre regelverket. Därefter analyseras eventuella tilläggsåtgärder som kan göras i samband med våningspåbyggnaden. Resultaten som erhölls var av stor betydelse för bestämmandet av typen av våningspåbyggnad. Detta eftersom resultaten bidrog till förståelse kring lastskillnader vid olika materialval och olika bestämmelser. Vid ett dåligt materialval kan lönsamhet och effektivitet äventyras. Vid oklarheter kring regelverk kan missförståelse förekomma och risk för feldimensionering uppstå. Resultaten påvisade att det mest effektiva valet av påbyggnad var påbyggnaden i trä. Detta eftersom att denna klarade av diverse krav. Påbyggnaden i betong bidrog med för stora krafter vilket skulle kunna äventyra markens stabillitet. Att förstärka marken är kostsamt och därmed drogs slutsatsen att trä var det mest effektiva materialvalet.

With the growth of wireless communications, comes the need for engineers knowledgeable in 3D electromagnetic (EM) simulation of high-frequency circuits. To give electrical engineering students a better understanding of the behavior of electromagnetic fields, experiments including the use of 3D EM simulation software were proposed. Most students get lost in differential equations, curls, and divergences; this thesis aims to remedy that by exposing them to 3D EM simulation, which may motivate them toward further study in electromagnetics. Also, experience using EMPro is very beneficial for future RF/microwave/antenna engineers, as use of 3D EM simulation is becoming a requirement for this field. 3D EM simulators solve problems where using classical analysis techniques is impractical. Classical EM solutions to simple objects such as boxes, cylinders, and spheres, are widely known; but when the object is more complex, numerical approaches are preferred for their speed. Currently, Cal Poly does not use 3D electromagnetic simulation in any of its courses. Targeted relevant courses include EE 335/375: EM Fields & Transmission Lines, EE 402: EM Waves, EE 405/445: High-Frequency Amplifier Design, EE 425/455: Analog Filter Design, EE 502: Microwave Engineering, and EE 533: Antennas. As a starting point, EE 425/455 was targeted. In choosing which filters to investigate, simplicity and cost were the most important factors. For simplicity, transverse electromagnetic (TEM) mode filters were chosen; also, using a trough design for these filters would allow for simple construction and access. Also, a circular waveguide filter was chosen as an alternative to the TEM filters, as the modes are either transverse electric or transverse magnetic. To lower costs, printed circuit board was used to construct the filters, along with brass tubing, semi-rigid coaxial cable, and copper plumbing caps. From these guidelines, three electronic bandpass filter experiments were investigated: a 1 GHz half-wave coaxial resonator filter, a 2 GHz copper end cap filter, and a tunable 1 GHz quarter-wave coaxial resonator filter. Electric and magnetic field coupling was used to excite the filters. They were then simulated using finite difference time domain (FDTD) simulations in Agilent EMPro. From the simulations, tradeoffs between insertion loss and bandwidth were observed. After, the filters were built and measured using a network analyzer. The quarter-wave filter was incorporated in Cal Poly’s EE 455 course during spring 2012. Students completed an EMPro tutorial, simulated the filters, and measured them using network analyzers. Student feedback was mixed, and modifications were made for future implementations.

Skicket på den nuvarande lösningen ”materialfickorna” är så pass dåligt att en ombyggnation i närtid är nödvändig. Traversen som används för att lyfta granulatlådorna är gammal och kommer behöva bytas ut inom ett år och då omfattande renoveringsbehov ändå krävs vill Tarkett se en annan lösning. Materialfickorna användes från början endast till lagring av spillmaterial, utan några krav på rengöring och är därför inte idealt utformade för att hantera granulat till tillverkning av högkvalitativa varor. Nuvarande lösning analyserades och observerades vid användning. Genom brainstorming utvecklades fem koncept som alla på ett liknande eller effektivare sätt kunde användas till att uppfylla det syfte som materialfickorna har i produktionen. De fem koncepten jämfördes med materialfickorna på sju olika kriterier i en konceptsållningsmatris där kriterierna viktades utefter de krav företaget ställde på lösningen. Konceptet ”lådvändaren” erhöll 4 poäng av maximalt 5 poäng och bedömdes vara den bästa lösningen. Visuell analys av lådvändaren utfördes och diverse förbättringsåtgärder togs fram. Lådvändarens hållfasthet analyserades också dels i Inventor Nastran och dels genom analytiska beräkningar för att undersöka vilka krafter den utsattes för under drift. För att klara av en från Tarketts sida önskad ökning av maxkapacitet från nuvarande 5000 kg/h till 8000 kg/h beräknades att två lådvändare krävs för att klara av det förändrade kapacitetskravet.

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