Railway track stiffness (vertical track load divided by track deflection) is a basic parameter oftrack design which influences the bearing capacity, the dynamic behaviour of passing vehiclesand, in particular, track geometry quality and the life of track components. Track stiffness is abroad topic and in this thesis some aspects are treated comprehensively. In the introductionpart of the thesis, track stiffness and track stiffness measurements are put in their propercontext of track maintenance and condition assessment. The first aspect is measurement of track stiffness. During the course of this project, Banverkethas developed a new device for measurement of dynamic track stiffness called RSMV(Rolling Stiffness Measurement Vehicle). The RSMV is capable of exciting the trackdynamically through two oscillating masses above one wheelset. The dynamic stiffness is acomplex-valued quantity where magnitude is the direct relation between applied load anddeflection (kN/mm) and phase is a measure of deflection-delay by comparison with force. Thephase has partial relationship with damping properties and ground vibration. The RSMVrepeatability is convincing and both overall measurements at higher speeds (up to 50 km/h)and detailed investigations (below 10 km/h) can be performed. The measurement systemdevelopment is described in Paper A and B. The second aspect is evaluation of track stiffness measurements along the track from a trackengineering perspective. Actual values of stiffness as well as variations along the track areimportant, but cannot always answer maintenance and design related questions alone. InPaper D track stiffness is studied in combination with measurements of track geometryquality (longitudinal level) and ground penetrating radar (GPR). The different measurementsare complementary and a more reliable condition assessment is possible by the combinedanalysis. The relation between soft soils and dynamic track stiffness measurements is studiedin Paper C. Soft soils are easily found and quantified by stiffness measurements, in particularif the soft layer is in the upper part of the substructure. There are also possibilities to directlyrelate substructure properties to track stiffness measurements. Environmental vibrations areoften related to soft soils and partly covered in Paper C. One explanation of the excitationmechanism of train induced environmental vibrations is short waved irregular supportconditions. This is described in Paper E, where track stiffness was evinced to have normalvariations of 2 – 10 % between adjacent sleepers and variations up to 30 % were found. Anindicative way of finding irregular support conditions is by means of filtering longitudinallevel, which is also described in the paper. Train-track interaction simulation is used in PaperH to study track stiffness influence on track performance. Various parameters of trackperformance are considered, e.g. rail sectional moment, rail displacement, forces at wheel-railinterface and on sleepers, and vehicle accelerations. Determining optimal track stiffness froman engineering perspective is an important task as it impacts all listed parameters. The third aspect, efficient maintenance, is only partially covered. As track stiffness relates toother condition data when studied from a maintenance perspective, vertical geometricaldefects (longitudinal level and corrugation/roughness) are studied in paper F. The generalmagnitude dependency of wavelength is revealed and ways of handling this in conditionassessment are proposed. Also a methodology for automated analysis of a large set ofcondition data is proposed in Paper G. A case study where dynamic track stiffness,longitudinal level and ground penetrating radar are considered manifests the importance oftrack stiffness measurements, particularly for soil/embankment related issues. / QC 20100623

This thesis covers the field of vortex-flow dominated external aerodynamics. As part of the contribution to the AVT-113 task group it was possible to prove the feasibility of high Reynolds number CFD computations to resolve and thus better understand the peculiar dual vortex system encountered on the VFE-2 blunt leading edge delta wing at low to moderate incidences. Initial investigations into this phenomenon seemed to undermine the hypothesis, that the formation of the inner vortex system depends on the laminar/turbulent state of the boundary layer at separation onset. As a result of this research, the initial hypothesis had to be expanded to account also for high Reynolds number cases, where a laminar boundary layer at separation onset can be excluded. In addition, unsteady transonic computations are used to shed light on a highly non-linear phenomenon encountered at high angles of incidence. At certain conditions, the increase of the incidence by a single degree leads to a sudden movement of the vortex breakdown location from the trailing edge to mid-chord. The lessons learned from the contribution to the VFE-2 facet are furthermore used to prove the technology readiness level of the tools within the second facet of AVT-113, the Cranked Arrow Wing Aerodynamics Project International (CAWAPI). The platform for this investigation, the F-16XL aircraft, experiences at high transonic speeds and low incidence a complex interaction between the leading edge vortex and a strong, mid-chord shock wave. A synergetic effect of VFE-2 with a further project, the Environmentally friendly High Speed Aircraft (HISAC), is also presented in this thesis. Reynolds number dependence is documented in respect to leading edge vortex formation of the wing planform for a reference HISAC configuration. Furthermore, proof is found for a similar dual vortex system as for the VFE-2 blunt leading edge configuration. / QC 20100713

This thesis is on the fatigue assessment of cast components with special attention to defects. The primary material in view is nodular cast iron, but also cast steel is considered. However, the fatigue behaviour is in principle valid for general use on other cast metals.The first two papers is about general cast material behaviour in fatigue loading. The materials considered are a high strength alloyed cast steel and a medium strength nodular cast iron. It is concluded that cast defects is the main fatigue initiation cause and it is only in exception that the fatigue life is not ruled by fracture mechanics. The third paper is a fracture mechanics evaluation of a nodular iron cast sleeve. The analysis of the component is based on crack initiation from cast defects and low-cycle fatigue. Fracture mechanics material parameters for Paris law, c and m, are extracted for the materials considered. In paper D design quality rules for nodular cast iron based on the Swedish standard SS 11 40 60 is presented. The quality rules regard cast defects in fatigue assessments and facilitate defect-based component design. In paper E, a finite element tool that is capable to predict and calculate 3D crack propagation for embedded cracks and defects is presented. The tool is an add-on for ANSYS finite element program. In paper F, closure equations for nodular cast iron are proposed in parallel to refined fracture mechanics material data. The paper includes crack propagation at different load ratios and in different microstructures.Summarized, the thesis composes a further development of the fatigue assessment of cast components. The central role of defects in fatigue is clarified and tools are provided for fracture mechanics evaluations of defects as well as for defect based design. The quality rules are also fit for application in manufacturing and for acceptance tests, hence covering the span from design to complete product. / QC 20100712 / Gjutdesign

When driving a vehicle on the road, the driver has to compensate continuously for small directional deviations from the desired course due to disturbances such as crosswinds, road irregularities and unintended driver inputs. These types of deviations have a tiring effect on the driver and should therefore be minimised. When the magnitude of these disturbances increases, especially with crosswind, the directional deviation might become so large that the driver will have difficulties in compensating for it, and will thereby affect the traffic safety. The objective of this research work is to increase the understanding of the crosswind sensitivity of buses and to find solutions to the problem of improving the safety of buses with respect to crosswind performance. The work presented in this thesis contributes to increased knowledge about the directional stability of buses under the influence of crosswind gusts through parameter studies using detailed vehicle simulation models, through full-scale experiments and through studies of the effect of steering feel on the subjective and objective evaluation of crosswind performance. A natural crosswind gust model has been derived from wind tunnel measurements and implemented in a multi-body dynamics simulation tool. The aerodynamic loads of the crosswind gust model have been applied on a detailed vehicle model and the behaviour of the vehicle model has been studied for various vehicle configurations in both open- and closed-loop manoeuvres. The vehicle model, with parameters corresponding to real vehicle data, has been validated and the agreement with measurements is good. A method for estimating the aerodynamic loads on a bus due to crosswind on a road section is also presented. Aerodynamic loads under real conditions were estimated using this method and these data were thereafter used in a study where the effect of steering feel on the subjective and objective evaluation of crosswind performance was investigated using a moving-base driving simulator, with the aim of finding a relationship between steering feel and crosswind sensitivity. The thesis covers the influence of changing chassis-related parameters and aerodynamics-related parameters on the crosswind sensitivity, as well as the influence of the setting of the steering system on the crosswind performance of the driver-vehicle system. The results identify areas of high potential for improving the crosswind sensitivity of buses, such as the centre of gravity location and the yaw moment overshoot at gust entry. Furthermore, the study shows the importance of having a vehicle that facilitates prompt driver corrections for reducing the lateral deviation under crosswind excitation; i.e. it is shown that a steering system with the possibility of changing the yaw rate gradient referencing the steering-wheel input when the vehicle is subjected to a sudden crosswind has a good potential for improving the crosswind performance of the driver-vehicle system. / QC 20100722

QC 20110118

This thesis deals with the development of a Conceptual Design Tool for unmanned helicopters, so called VTOL UAVs. The goal of the Design Tool is: • Quick results • Good accuracy • Easy to use The two first points of the goal are actually more or less dependent on each other. In almost all cases a high accuracy gives a slow calculator and vice versa. In order to fulfill the goal a compromise between calculation accuracy and calculation time needs to be done. To make the Design Tool an easy to use program a graphical user interface is used. The graphical user interface allows the user to systematically work his way thru the program from a fictive mission to a complete design of a helicopter. The pre-requirements on the user have been eliminated to a minimum, but for the advanced user the possibilities to create more specific and complex helicopters are good. In order to develop a Conceptual Design Tool the entire helicopter needs to be seen as a complete system. To see the helicopter as a system all of the sub parts of a helicopter need to be studied. The sub parts will be compared against each other and some will be higher prioritized than other. The outline of this thesis is that it is possible to make a user friendly Conceptual Design Tool for VTOL UAVs. The design procedure in the Design Tool is relatively simple and the time from start to a complete concept is relatively short. It will also be shown that the calculation results have a good agreement with real world flight test data.

The thesis consists of the design of an electric bike. Based on the analysis of the needs arising from urban transport in Sweden and its people.We wanted to develop a bicycle that could be manufactured in the coming years and be widely accepted by the Swedish population and later also in Europe.

The objective of this thesis work was to construct and implement an algorithm into the programADAPDT to calculate the zero-lift drag profile for defined aircraft geometries. ADAPDT, shortfor AeroDynamic Analysis and Preliminary Design Tool, is a program that calculates forces andmoments about a flat plate geometry based on potential flow theory. Zero-lift drag will becalculated by means of different hand-book methods found suitable for the objective andapplicable to the geometry definition that ADAPDT utilizes. Drag has two main sources of origin: friction and pressure distribution, all drag acting on theaircraft can be traced back to one of these two physical phenomena. In aviation drag is dividedinto induced drag that depends on the lift produced and zero-lift drag that depends on the geometry of the aircraft. How reliable and accurate the zero-lift drag computations are depends on the geometry data thatcan be extracted and used. ADAPDT‟s geometry definition is limited to flat plate geometrieshowever although simple it has the potential to provide a huge amount of data and also delivergood results for the intended use. The flat plate representation of the geometry proved to beleast sufficient for the body while wing elements could be described with much more accuracy. Different empirical hand-book methods were used to create the zero-lift drag algorithm. Whenchoosing equations and formulas, great care had to be taken as to what input was required sothat ADAPDT could provide the corresponding output. At the same time the equations shouldnot be so basic that level of accuracy would be compromised beyond what should be expectedfrom the intended use. Finally, four well known aircraft configurations, with available zero-lift drag data, weremodeled with ADAPDT‟s flat plate geometry in order to validate, verify and evaluate the zeroliftdrag algorithm‟s magnitude of reliability. The results for conventional aircraft geometriesprovided a relative error within 0-15 % of the reference data given in the speed range of zero toMach 1.2. While for an aircraft with more complicated body geometry the error could go up to40 % in the same speed regime. But even though the limited geometry is grounds foruncertainties the final product provides ADAPDT with very good zero-lift drag estimationcapability earlier not available. A capability that overtime as ADAPDT continues to evolve hasthe potential to further develop in terms of improved accuracy. / Målet med detta examensarbete var att skapa och implementera en algoritm som införmöjligheten att beräkna nollmotstånd för givna flygplansgeometrier i programmet ADAPDT.ADAPDT, kort för AeroDynamic Analysis and Preliminary Design Tool, är ett program som,baserat på potential strömnings teori, beräknar krafter och moment på en geometri uppbyggd avplana plattor. Nollmotståndet kommer att baseras en kombination av handboksmetoder somfunnits lämpliga och applicerbara på geometridefinitionen given i ADAPDT. Motstånd har sitt ursprung i två fysikaliska fenomen: friktion och tryckfördelning, ur vilka alltmotstånd som agerar på ett flygplan härrör. Inom flyget delar man in motståndet ilyftkraftsberoende inducerat motstånd samt geometriberoende nollmotstånd. Hur pålitliga och noggranna motståndsberäkningarna kan förväntas vara beror på mängdengeometriska data som finns att tillgå. ADAPDT:s geometridefinition är begränsad till planaplattor men trots detta finns potential att leverera stora mängder data och resultat med rimlignoggrannhet. Plan plattgeometrin visade sig, för kroppsgeometrin, väldigt begränsad ochotillräcklig medan ving element kunde beskrivas med större noggrannhet. En rad olika empiriska handboksmetoder användes för att skapa nollmotståndsalgoritmen. Vidvalet av formler och ekvationer var det viktigt att välja sådana som ADAPDT kunde försetillräckligt med data till. Samtidigt fick formlerna inte vara alltför simpla så att måttet avnoggrannhet i resultaten vart alltför låg mot för vad som, för ändamålet, är förväntat. Slutligen valdes fyra kända flygplan, med nollmotståndsdata tillgängligt, att modeleras medADAPDT:s plan plattgeometri för att validera, verifiera och utvärdera algoritmens mått avtillförlitlighet. Resultaten för mer konventionella flygplanskonfigurationer visade på ett relativtfel mellan 0-15 % mot de givna referensflygplanens nollmotståndsdata inom hastigheterna 0 tillMach 1,2. För mer komplicerade konfigurationer steg det relativa felet omedelbart upp mot 40% inom samma hastighetsregim. Men även om den begränsade geometridefinitionen iADAPDT är grunden för mycket osäkerheter förser den slutliga produkten ändå programmetmed en väldigt god möjlighet till skattning av nollmotståndet som inte tidigare fanns. Enmöjlighet som över tid, allteftersom ADAPDT forstätter att utvecklas, har all potential till attförbättras med avseende på noggrannhet och tillförlitlighet.

Optical encoders are being widely suggested for precise mobile navigation. Combining such sensor information with Global Positioning System (GPS) is a practical solution for reducing the accumulated errors from encoders and moving the navigational base into global coordinates with high accuracy. This thesis presents integration methods of GPS and optical encoders for a mobile vehicle that is controlled by microcontroller. The system analyzed includes a commercial GPS receiver, dsPIC microcontroller and mobile vehicle with optical encoders. Extended kalman filtering (EKF), real time curve matching, GPS filtering methods are compared and contrasted which are used for integrating sensors data. Moreover, computer interface, encoder interface and motor control module of dsPIC microprocessor have been used and explained. Navigation quality on low speeds highly depends greatly upon the processing of GPS data. Integration of sensor data is simulated for both EKF and real time curve matching technique and different behaviors are observed. Both methods have significantly improved the accuracy of the navigation. However, EKF has more advantages on solving the localization problem where it is also dealing with the uncertainties of the systems.

A discussion regarding the alignment and measuring procedure of propeller shafts has arose due to the competing situation in the industry, and higher standards from the customers. An estimation of the deflection of shafts in different alignment situations has been made with help of FEM-analysis and beam theory. This has been analyzed and compared with the experience from Rolls-Royce AB suppliers of shafts. An evaluation of measuring protocols has been made and the result indicates that there is a correlation between the deflection of the shaft and the run out. Results from a measuring test performed by Balino, Spain, verifies this conclusion. But the main issue is considered to be the type of supports that prevent the shaft from moving in the horizontal plane. The solution to this issue is to use supports along the shaft that only prevents the deflection in the median plane.   A recommendation to the Rolls-Royce AB is to perform changes in their measuring protocols to make them easier to use and to include more information. The sequence of the measuring points in the protocol should be re-arranged and re-named. Information of what type of support that has been used by the supplier and where they been placed should be added to the protocols to increase the traceability when questions arise. To make the measuring protocol unequivocal, the position of the measuring gauge should be marked in the protocol and the point of reference marked on the shaft.   External expertise will participate in a workshop to educate and discuss with Rolls-Royce AB personnel how to change required references in the drawing of the shaft arrangements.