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In diesem Beitrag werden neben der detaillierten Betrachtung der Wandervorgänge von Lagerringen primär die Simulationsmethodik bezüglich elastischer Zwischenschichten sowie die Ergebnisse einer FE-Parameterstudie präsentiert. Der Fokus liegt dabei auf Wälzlageraußenringen von Radiallagern unter Punktlast.

The research describes possible reasons why the flaking tendency during cold rolling can vary between different austenitic stainless steels. The flaking phenomenon was observed after a rolling process in Granlund Tools AB’s roll reducing mill “KOR-8”. A literature review was conducted with the purpose of finding a connection between rolling process, austenitic stainless steels and flaking. The laboratory work aimed at revealing possible differences between the flaked material and materials that is known to be cold rolled with high surface finish in the particular machine. In order to come to a conclusion regarding the flaking appearance, scanning electron microscopy (SEM), Vickers hardness test and light optical microscopy (LOM) were performed. The literature review along with the laboratory results made it possible to determine the two major factors affecting the flaking behavior. Two independent analyses revealed what came to be the most important discovery in this study. LOM showed the appearance of a thick oxide scale on the surface of the flaked steel which was further confirmed by SEM-Energy-Dispersive X-ray Spectroscopy that indicated the existence of oxides on the steel’s surface. These observations along with the knowledge that oxide scales grow only during high-temperature processing led to the conclusion that the steel is not appropriate for the cold rolling process due to the earlier steel manufacturing.

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Simulation can play an important role when aiming to streamline extensive and time-consuming tests. It has the potential to save time, money and energy. One of the testing methods used to test shock absorbers (SA), is accelerated life testing using a rolling road, CamDrum. It is therefore of great interest to examine the possibilities to streamline this testing method. This master thesis is conducted in co-operation with Öhlins Racing AB and the Machine Design department at KTH. The thesis project aims to look into the following: How can the use of simulation software aid in streamlining the test sequence used for shock absorbers in CamDrum? What limitations is there when simulating the CamDrum method using the selected simulation software? The goal was to develop an adequate model according to specified requirements, to facilitate early testing of new ideas and parameter changes. The delimitations includes, that the project only focuses the test-rig for MTB shock absorbers, the parts of the test-rig are assumed to be rigid and the simulation of the shock absorber is out of scope, since the aim of this thesis is to simulate the test-rig. To succeed with the project, a background research was conducted to gain knowledge about shock absorbers, test method and equipment, dynamics and useful software. The simulation model was verified against data obtained from tests. The tests were performed using the CamDrum with two different MTB shock absorbers and a stiff rod. The aim was to log and verify the change in position for the test-rig, shock absorbers and wheel. In addition the forces acting on the shock absorbers was investigated using strain gauges attached to the test-rig. The mean deviation in % for configuration 70-30-30 [mm] bump: SA MTBM1899, A4: 11.6% - 23.2%. SA MTB1691, A4: 15.8% - 28.1%. Stiff rod, A3: 0.9% - 4.9%, A5: 2.0% - 5.1%. SA Force, 16.1% - 24.0%. The deviation between the simulation and the test environment increases with the velocity. The use of stiff rod verifies the model against the CamDrum regarding the displacement. The resulting force from the use of strain gauges verifies the simulation models force regarding the shape. The Amesim model has the potential to be of great aid when designing tests. / Simulering kan vara en väg till att effektivisera tidskrävande och omfattande tester. Det finns potential att spara såväl energi som tid och pengar. En av metoderna för att testa stötdämpare är rullande landsväg, CamDrum. Det är därför intressant att undersöka hur den processen kan effektiviseras. Examensarbetet utförs i samarbete mellan Öhlins Racing AB och institutionen för Maskinkonstruktion på KTH. Det här examensarbetet avser att undersöka följande: Hur kan användandet av simuleringsprogram underlätta effektivisering av testmetoden som används för stötdämpare i CamDrum? Vilka avgränsningar finns vid användande av simulering för CamDrum-metoden med valt simuleringsprogram? Målet var att utveckla en modell som uppfyller givna krav och underlättar vid initieringsfasen för utveckling av tester för CamDrum. Projektets avgränsningar innebär att enbart riggen för MTBstötdämpare undersöks, alla ingående komponenter i testriggen antas styva och dämparmodellen som utvecklats är förenklad då målet är att simulera riggen för dämparen. För att lyckas med uppgiften har en förstudie genomförts för att samla nödvändig kunskap om stötdämpare, dynamik, testmetoden och lämplig mjukvara. Simuleringsmodellen verifieras mot data hämtat från utförda tester. Testerna utfördes i CamDrum med två olika MTB-stötdämpare och en rundstång med mål att logga och verifiera rörelser för riggen, stötdämpare och hjulet. Vidare har krafterna på stötdämparen undersökts med hjälp av trådtöjningsgivare monterade på testriggen. Medelavvikelsen i % för guppkonfigurationen 70-30-30 [mm]: SA MTBM1899, A4: 11.6% - 23.2%. SA MTB1691, A4: 15.8% - 28.1%. Rundstång, A3: 0.9% - 4.9%, A5: 2.0% - 5.1%. SA Force, 16.1% - 24.0%. Avvikelsen mellan simuleringen och testerna ökar med hastigheten. Användandet av rundstången verifierar modellen gentemot CamDrum med avseende på positionsförändring. Den resulterande kraften från användandet av trådtöjningsgivare verifierar simuleringsmodellen med avseende på form.  Amesim-modellen har en möjlighet att underlätta vid framtagning av tester.

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Rapid and high-sensitivity detections of biological analytes are critically important to ensure timely diagnosis of disease and effective monitoring of public health. Although various new biosensing platforms have been established as alternatives to conventional laboratory methods, most of these biosensing platforms suffer from insufficient sensitivities that severely limit their wide applications. To improve the detection sensitivities of these biosensors, surface modifications based on poly(amidoamine) (PAMAM) dendrimers and rolling circle amplification (RCA) have been proven to be effective methods. In this thesis, surface modification strategies based on PAMAM dendrimers and RCA have been applied on three biosensing platforms, including enzyme-linked immunosorbent assay (ELISA), localized surface plasmon resonance (LSPR) sensor chip, and affinity membrane, to improve their detection sensitivities. For the ELISA platform, glass-bottom and poly(styrene) 96-well plates are surface modified by dendrimer-aptamer conjugates to improve detection performances of human platelet-derived growth factor-BB using ELISA. The results show that the ELISA performed using the modified 96-well plates presents a much broader linear detection range and a significantly lower limit of detection (LOD) than conventional ELISA plates. For the LSPR platform, the dendrimer and aptamer modification strategy is employed to surface modify LSPR sensor chips for sensitive detection of the SARS-CoV-2 virus, and an RCA-AuNPs complex is developed to amplify the detection signals. The results show that the modified chip can sensitively detect the SARS-CoV-2 virus with a LOD of 148 vp/mL, suggesting that the modified LSPR chip and signal amplification method can be used for early diagnosis of Covid-19. For the affinity membrane platform, nylon membranes with dendrimer and dual-RCA surface modifications are developed to detect Escherichia coli O157:H7 in food samples. The surface-modified membranes significantly reduce the detection time of the target bacteria to two hours instead of several days using traditional bacterial detection methods. In addition, the new membranes achieve higher sample throughputs (around 4-5 mL/s) with a lower LOD (10 cells/ 250 mL) in processing real-world food samples compared to other similar detection platforms. The excellent properties of our surface modification approaches may provide further advantages when employed in other platforms, such as target separation and enrichment, antifouling and antibacterial, and drug delivery applications.

In Sweden fall-related injuries among the elderly lead to over a thousand deaths and close to 300.0000 hospital visitations annually. Fall related injuries can in many cases lead to serious head injuries along with other fractures. The elderly are more prone to fall and sustain an injury because of conditions such as osteoporosis and weak muscles. Researchers at KTH from the Division of Neuronic Engineering have developed a special floor that absorbs energy from an impact which can reduce the severity of injury when a person falls. There has been research done on the floor focusing on hip fractures which have shown good results. The floor has been set up in an elderly home in Stureby, Stockholm, Sweden, however further testing is needed to fully develop the floor to its maximum capacity. One goal of this master thesis was to investigate certain obstacles with the floor which arose during testing in Stureby. One of the challenges was that the floor had greater rolling resistance since it is softer than a normal concrete floor. The experiment was done by using a dynamo meter to measure the force needed to move a test wagon with a fixed weight and different sizes of wheels. Another goal of this thesis was to investigate head impacts on the KTH floor. That was done in a helmet testing lab at Mips helmet company. There a dummy head was dropped from various heights and the acceleration was measured. The 1st principle strain of the brain was calculated from the collected data. Other companies have created similar floors so it was a part of the thesis to compare the KTH floor with its competitors. The results from the rolling resistance showed that by increasing the width and diameter of the wheels there was less force needed to move the test wagon. Further tests are needed to investigate the problem regarding the indentation issues seen on the floor set up in Stureby. Some research has already begun with different types of linoleum and glue. In the head impact studies, the KTH floor showed the best results of all tested floors when dropped from 60 cm. However, when dropped from 100 cm a competitor floor showed better results in the resultant translational acceleration.

Outokumpu Stainless AB är en global tillverkare av rostfria stål. I Outokumpus stålverk i Avesta har varmbandverket problem med risker för personskador vid hantering av defekta plåtstycken efter steckelvalsning. Denna hantering av defekta plåtar görs i dagsläget manuellt av operatörer i varmbandverket. Lyft med travers av defekta plåtar har fått höga riskpoäng i Outokumpus riskutvärdering vilket innebär risk för olycksfall föreligger och momentet bör ses över.Outokumpu som uppdragsgivare vill därför undersöka möjligheten att ta fram ett konceptuellt förslag för att minska risken för personskador i hanteringen av defekt plåt som ska forslas bort från produktionslinan. Konceptet ska även kunna minska cykeltiden för hanteringen samt kunna anpassas till befintlig konstruktion.Det här arbetet tar fram en kravspecifikation tillsammans med uppdragsgivare samt ett urval av koncept som utvärderas utifrån kravspecifikation och andra kriterier för att jämföra koncepten. Efter utvärderingen har det koncept som fått bäst utvärderingspoäng jobbats vidare med för att dimensionera och analysera.Resultatet av den konceptuella framtagning genererade ett koncept som med ett balkverk lyfter den defekta plåten rakt ovanför utrullbanan med hjälp av fyra hydraulcylindrar. I upplyft läge ligger plåten på balkverket och skjuts av utrullbanan direkt på ett bolster med en linjal som styrs av två hydraulcylindrar. Konceptet uppfyller kraven från kravspecifikationen och minskar risken i Outokumpus riskutvärdering. / Outokumpus Stainless AB is a global manufacturer of stainless steel. In Outokumpus steelwork in Avesta, the heat rolling unit has problems with the risk of personal injury when handling defective pieces of sheet metal after steckel rolling. This handling of defective sheets is currently manually executed by operators, where high-lift risks with defective plates have been given high risk points in Outokumpu's risk assessment.Outokumpu as a client wants to investigate the possibility of developing a conceptual proposal to reduce the risk of personal injury in handling defective sheet to be disposed of from the production line. The concept should also reduce the cycle time of the handling and be adapted to existing construction.This report presents a requirement specification and a selection of concepts evaluated based on requirements specification and soft criterias. After the evaluation, the concept with the best evaluation points has been worked on to set dimensions and analyze the concept.The result of the conceptual development became a concept that, with a beamwork, lifts the defective plate directly above the rolling path using four hydraulic cylinders. In the raised position, the plate is on the beamwork and is pushed off the rolling roller directly onto a bolster with a ruler driven by two hydraulic cylinders. The concept meets the requirements of the requirement specification and reduces the risk in Outokumpu's risk assessment.Keywords: Risk