This master’s thesis deals with the construction of parts of a bucket-wheel stacker/reclaimer designed to operate lignite stockyard at coal power plant. First the basic parameters of machine and loads applied in service are defined. The work also includes the design of steel structure of bucket-wheel boom, bucket-wheel, buckets, bucket-wheel drive, shaft, bearings and other parts of bucket-wheel boom. These parts are verified by analytical or finite element analysis.

The main content of the diploma thesis is the strength calculation of the heat exchanger according to ASME Code. The introduction is a summary of issues within the design of this equipments. In the practical part there are a strength calculation of the main parts of heat exchanger and the FEM analys with their evaluation. In the last part there is the calculation of cumulative damage.

Diploma thesis deals with creating of computational model of welded frame to perform strain-stress analysis. Thesis aims at verification of welded joints and their possible changes. The next goal is to compare stresses obtained from calculation with respect to welding standard and FEM analysis.

Master´s thesis deals with design of four cylinder race engine for rally application with requirement of small construction weight, by using specific Super 2000 regulations. Calculation analysis is mainly focused on crankshaft stress analysis and torsion vibration.

When developing drivetrain cooling modules for commercial vehicles, the top priority is the strength of the products. The reason lays within the structural change that companies are undergoing where the warehouses are minimized and the companies are relying on the transportation of commercial vehicles. If a drivetrain cooling module would fail to maintain a targeted temperature range of the drivetrain, there is not long until the vehicle is forced to a stop. At worst, the downtime of commercial vehicles can cause companies to come to a halt as well. Therefore, developing verified FE simulation methods together with strength verification tests, are some of the core activities to ensure the strength of the cooling modules before implementation in vehicles. One of the methods that have not been sufficiently verified regards how to perform structural FEA on a crimp joint with a gasket. A crimp joint is established through a hemming process, where the aluminium header tabs are crimped over the polyamide tank, creating a watertight seal together with a gasket. The objective of this master’s thesis is to verify the existing simulation methods of the crimp joint and determine the margin of error with respect to strains. The objective of this thesis is also to develop a verified FE simulation method with a lower margin of error compared to the existing methods. The verification of the methods has been conducted through a comparison between numerical results and an experimental stress analysis, where the strain located on the header is measured with strain gauges in a pressure pulsation rig. The average margin of error found on the three existing methods of simulating the crimp joint was 39,7%, 13,4%, and 11,5% located on the outer bottom dimensioning radius of the crimp joint at a pressure of 100 kPa. However, the method used to determine the margin of error was found to be invalid, but the margin of error is only slightly affected by the verification method where the existing methods still are insufficiently representing the crimp joint. The method of determining the margin of error was then corrected for the development of the new method to represent the crimp joint in the FE model. The developed method in this thesis has an average margin of error of 6,9% at 100, 160, 220, and 260 kPa. / Vid utveckling av kylarmoduler för drivlinor som appliceras i kommersiella fordon, är högsta prioritet att säkerhetsställa hållfastheten hos produkterna. Anledningen ligger kring den strukturomvandling som företag genomgår där storleken på lagerlokaler minskar och företagen väljer att förlita sig på transporterna som utförs av kommersiella fordon istället. Ifall en kylarmodul inte skulle klara av att bibehålla ett bestämt temperaturintervall hos drivlinan så dröjer det inte länge förens fordonet tvingas att stanna. I värsta fall kan fordonets stillestånd påverka ett företag att tvingas stanna i väntan. Därför är utveckling av FE simuleringsmetoder tillsammans med utmattningstest, några av de kärnaktiviteter som utförs för att säkerhetsställa hållfastheten av kylarmodulerna innan de implementeras i fordon. En av de metoder som ännu inte blivit tillräckligt verifierat gäller hur man utför FEA på ett falsförband med packning. Falsförbandet skapas genom en falsningsprocess där ändplåten av aluminium falsas över polyamidtanken, vilket skapar ett vattentätt förband med hjälp av packningen. Omfattningen av detta examensarbete gäller att verifiera de existerande simuleringsmetoderna av falsförbandet och bestämma felmarginalen med avseende på töjningar. Omfattningen av examensarbetet innefattar även ett utvecklingsarbete av en ny FE simuleringsmetod med en lägre felmarginal jämfört med de existerande metoderna. Verifieringen av metoderna sker genom en jämförelse mellan de numeriska resultaten och en experimentell spänningsanalys där töjningen på ändplåten är uppmätt med hjälp av trådtöjningsgivare i en tryckpulsationsrigg. Den genomsnittliga felmarginalen av de tre existerande metoderna för att simulera falsförbandet var 37,9%, 13,4%, och 11,5% vid den nedre dimensionerande yttre radien på falsförbandet vid ett tryck på 100 kPa. Den använda metoden för att bestämma felmarginalen upptäcktes senare vara felaktig, men det resulterar endast i små förändringar av den bestämda felmarginalen, de existerande simuleringsmetoderna är fortfarande sedda som otillräckliga. Metoden för att bestämma felmarginalen korrigerades sedan inför utvecklandet av den nya FE simuleringsmetoden av falsförbandet. Den utvecklade metoden i detta examensarbete har en genomsnittlig felmarginal på 6,9% vid 100, 160, 220 och 260 kPa.

Indiana University-Purdue University Indianapolis (IUPUI) / Statement of problem: Yttria-partially stabilized tetragonal zirconia polycrystal (Y-TZP) all-ceramic restorations have been reported to suffer from chipping or cracking of the veneering porcelain (VP) as the most common complication. There is little information in the literature regarding the influence of surface treatment on VP shear bond strength to Y-TZP after cyclic loading. Purpose of this study: The goals of this study were (1) to investigate the influence of zirconia surface treatments on veneering porcelain shear bond strength and (2) to investigate the influence of cyclic loading on the shear bond strength between VP and Y-TZP. Materials and Methods: 48 cylinder–shaped specimens (6mm in diameter and 4mm in height) were divided into 4 groups containing 12 specimens each according to the surface treatment. As a control group (C), no further treatment was applied to the specimens after grinding. Group H was heat-treated as a pretreatment according to the manufacturer’s recommendations. Group S was airborne-particle abraded with 50 µm alumina (Al2O3) particles under a pressure of 0.4 MPa for 10 seconds. In the group SH, the heat-treatment was performed after the airborne-particle abrasion. A VP cylinder (2.4 mm in diameter and 2 mm in height) was applied and fired on the prepared Y-TZP specimens. The shear bond strength was tested using a universal testing machine. Six specimens from each group were subjected to fatigue (10,000cycles, 1.5Hz, 10N load) before testing. Results: The 3-way ANOVA showed no statistically significant effect of surface treatment and cyclic loading on shear bond strength. The highest mean shear bond strength was recorded for the air-particle abrasion group without cyclic loading (34.1 + 10 MPa). The lowest mean shear bond strength was the air-particle abrasion group with cyclic loading (10.7 ± 15.4 MPa). Sidak multiple comparisons procedure demonstrated cyclic loading specimens had significantly lower shear bond strength than non-cyclic loading specimens after air-particle abrasion without heat treatment (p=0.0126) Conclusion: Within the limitations of this study, (1) Shear bond strength between Y-TZP and VP is not affected statistically by surface treatment using heat treatment, airborne-particle abrasion, and heat treatment after airborne-particle abrasion. (2) There is significant difference in shear bond strength with air-particle abrasion between with and without cyclic loading groups. This difference suggested that air-particle abrasion should be avoided in clinical situations as a surface treatment without heat treatment.

Indiana University-Purdue University Indianapolis (IUPUI) / The objectives: 1. To compare the flexural strength, flexural modulus, and fracture toughness of specimens fabricated from recently marketed translucent full-contour zirconia, traditional zirconia, and lithium disilicate glass ceramic. 2. To compare the load-to-failure of crowns fabricated from recently marketed translucent full-contour zirconia, traditional zirconia, and lithium disilicate glass ceramic at their recommended tooth-reduction thickness. Methodology: Four groups of translucent zirconia (BruxZir, KDZ Bruxer, CAP FZ, Suntech zirconia), one group of traditional zirconia (CAP QZ) and IPS e.maxCAD) were tested. Twelve bars of each material were made and tested for flexural strength, and fracture toughness. Fracture patterns were imaged under SEM. Forty-eight crowns (8 from each group) were fabricated with CAD/CAM technique following manufacturers’ recommendations for the amount of tooth reduction. All the crowns were cemented to prepared epoxy resin dies with RelyX Unicem and tested for static load to failure in a universal machine. Result: In bar-shape samples, CAP QZ (traditional zirconia) showed the highest flexural strength (788.12 MPa), fracture toughness (6.85 MPa.m1/2), and fracture resistance (2489.8 N). All translucent zirconia groups show lower mechanical properties than QZ. However, there were no differences between translucent and traditional zirconia in the fracture resistance of the crown-shape samples. There was no significant difference in fracture resistance between IPS e.max crowns at recommended thickness and other zirconia crowns at recommended thickness. Conclusion: With less reduction of tooth structure, a high inherent strength and chip resistance make full-zirconia crowns a good alternative to porcelain-fused-to-metal crowns and all other ceramic crowns.

This thesis is concerned with design of pedal box for Formula Student vehicle. Summary of design solutions is presented in introductory chapter, especially those used in Formula Student competition. Designed assembly is divided into parts of single pedals and base plate. The proposed design is supported by stress analysis of loaded parts in pedal box. In conclusion, design is reviewed in terms of the results, as well as compared with current pedal box.

Indiana University-Purdue University Indianapolis (IUPUI) / Background: A silorane based resin composite, Filtek LS restorative, has been introduced to overcome the polymerization shrinkage of the methacrylate based resin composite. The repair of resin composite may hold clinical advantages. Currently, there is no available information regarding the repair potential of silorane resin composite with either silorane or methacrylate based resin composite. Objectives: The purpose of this study was to compare the repaired microtensile bond strength of aged silorane resin composite using different surface treatments and either silorane or methacrylate based resin composite. Methods: One hundred and eight silorane resin composite blocks (Filtek LS) were fabricated and aged by thermocycling between 8oC and 48oC (5000 cycles). A control (solid resin composite) and four surface treatment groups (no treatment, acid treatment, aluminum oxide sandblasting and diamond bur abrasion) were tested. Each treatment group was randomly divided in half and repaired with either silorane resin composite (LS adhesive) or methacrylate based resin composite (Filtek Z250/Single Bond Plus). Specimens were 12 blocks and 108 beams per group. After 24 hours in 37oC distilled water, microtensile bond strength testing was performed using a non-trimming technique. Fracture surfaces were examined using an optical microscopy (20X) to determine failure mode. Data was analyzed using Weibull-distribution survival analysis. Results: Aluminum oxide sandblasting followed by silorane or methacrylate based resin composite and acid treatment with methacrylate based resin composite provided insignificant differences from the control (p>0.05). All other groups were significantly lower than the control. Failure was primarily adhesive in all groups. Conclusion: Aluminum oxide sandblasting produced comparable microtensile bond strength compared to the cohesive strength of silorane resin composite. After aluminum oxide sandblasting, aged silorane resin composite can be repaired with either silorane resin composite with LS system adhesive or methacrylate based resin composite with methacrylate based dentin adhesive.

Indiana University-Purdue University Indianapolis (IUPUI) / Background: Since the introduction of glass ionomer cements (GICs) in the 1970s, many attempts have been made to improve them and expand their application in restorative dentistry. Recently, GC America introduced a new glass ionomer restorative system called EQUIA. The manufacturer claims that this material has improved wear resistance by coating the surface of high-strength GIC with a nano-filled resin coating. Objective: The objective of this study was to measure the wear resistance and hardness of EQUIA and to compare it to other current restorative materials. Materials and Methods: Four different materials were used in this study: EQUIA, Fuji IX GP Extra, Fuji II LC and Z-100. Six specimens of each material were made and then tested in a toothbrush abrasion machine for 20,400 cycles, after which the amount of volume loss was calculated. Eight specimens of each material were made and tested in a three-body Alabama wear testing machine under a load of 75 N for 400,000 cycles. Four surface profiles were obtained from each specimen and volume loss was calculated using computer software. Five specimens of each material were made and Knoop microhardness was determined by using the mean of the three values from the top surface of the specimen. Results of each test were collected and compared with the other materials using one-way analysis of variance (ANOVA) at a significance level of 0.05. Results: Wear-resistance results showed that EQUIA has wear-resistance values comparable to composite resin and higher values than those for the high-strength GIC. The results also showed that Fuji II LC had the highest wear among all tested materials. Microhardness results showed that EQUIA has significantly lower microhardness than Fuji IX GP Extra and Z-100. Conclusion: Based on the results of the present study, it can be concluded that coating the surface of glass ionomer restorations with a nano-filled resin coat results in increasing the wear resistance and decreasing the microhardness of the material. Within the limitations of this study, EQUIA has comparable wear resistance to composite resin.