Nowadays vehicle design paradigm influences not only the effectiveness of the different means of transport, but also the environment and economy in a critical way. The assessment of the consequences that design choices have on society at large are necessary to understand the limits of the methods and techniques currently employed. One of the mechanisms set in motion is the planned obsolescence of products and services. This has affected vehicle design paradigm in such a way that the variety in the market has shadowed the primary function of vehicle systems: the transport of persons and goods. Amongst the consequences of the expansion of such market is the exponential rise on combustion emissions to the atmosphere, which has become a great hindrance for humans health and survival of ecosystems. The development of evaluation tools for such consequences and their piloting mechanisms is needed so as to implement an ECO2  (Ecological and Economical) vehicle design paradigm. Moreover, the multifunctional design paradigm that drives aeronautical and vehicle engineering is an ever-growing demand of smart materials and structures, able to fulfil multiple requirements in an effective way. The understanding of certain phenomena intrinsic to the introduction of novel materials has found certain limits due to the complexity of the models needed. This work presents as a first step an assessment of the causes and consequences of the vehicle exponential market growth based on the analysis of the planned obsolescence within. Furthermore, a method for the acoustic response analysis of multilayered structures including anisotropic poroelastic materials is introduced. The methodology consists in a plane wave approach as a base for introducing the complex mechanic and acoustic equations governing anisotropic homogeneous media, e.g. open-celled foams, into an alternative mathematical tool manipulating physical wave amplitudes propagation within the studied media. In addition, this method is coupled to a power partitioning and energetic assessment tool so as to understand the phenomena present in complex multilayered designs. / <p>QC 20150323</p>

The brake system is critical for ensuring safe driving and has been the focus of development for many years. Pneumatic braking technology is commonly used in heavy vehicles,but it results in energy wastage and high service costs. Some countries mandate auxiliarybraking systems to assist in stopping the vehicle in addition to service brakes. One suchsystem is the regenerative braking system, which captures kinetic energy from braking andconverts it into electrical energy. Retarders are another commonly used auxiliary brakingsystem. These systems are essential due to heavy vehicle weight, which can weaken servicebrake performance.This thesis focuses on estimating net forces on the truck’s driven axle to understandhow auxiliary braking systems and vehicle traction affect the normal force on the drivenwheel axle. The expected result can assist in maintaining the slip ratio and increasing thelife span and performance of brakes.Scania uses a function to estimate forces on the driven axle and drive wheel slip. Theyneed to determine the normal force on the axle to improve performance of auxiliary brakingsystems, but tests showed that for the same specified slip ratio, the auxiliary braking forcerequired was smaller than that in an acceleration state. Scania believe that dynamic axleload transfer may be the cause, so a 6x2 electrified truck will be investigated in this thesis.The obtained results show the driven wheel axle’s behavior during different dynamicalscenarios.This research aimed to develop a model that can accurately simulate a truck’s movement and estimate the ground reaction force in response to variations in the scenario of thecontrol signal. By studying the quarter car model, bounce-pitch and half car model, theresearchers were able to obtain a model represented by 5 ODEs, which predicts the wheelaxle normal force. To verify the model, data from the CAN bus and measurements using ascale were collected and compared with the model’s output. The Mean Squared Error canbe used to evaluate and compare the model’s performance, and the results showed that themodel provides a reasonable estimate of the normal force on all axles. The study also analyzed the factors that contributed to the errors in the results. The behavior of the normalforce for each wheel axle during acceleration and braking was illustrated, explaining howthe normal force distribution becomes mirrored compared to the acceleration state duringbraking. The study’s discussions enhance the validity of the observed behavior and thereliability of the results.

The Life Cycle Energy Optimisation (LCEO) methodology aims at finding a design solution that uses a minimum amount of cumulative energy demand over the different phases of the vehicle's life cycle, while complying with a set of functional constraints. This effectively balances trade-offs, and therewith avoids sub-optimal shifting between the energy demand for the cradle-to-production of materials, operation of the vehicle, and end-of-life phases. This work further develops the LCEO methodology and expands its scope through three main methodological contributions which, for illustrative purposes, were applied to a vehicle sub-system design case study. An End-Of-Life (EOL) model, based on the substitution with a correction factor method, is included to estimate the energy credits and burdens that originate from EOL vehicle processing. Multiple recycling scenarios with different levels of assumed induced recyclate material property degradation were built, and their impact on the LCEO methodology's outcomes was compared to that of scenarios based on landfilling and incineration with energy recovery. The results show that the inclusion of EOL modelling in the LCEO methodology can alter material use patterns and significantly effect the life cycle energy of the optimal designs. Furthermore, the previous model is expanded to enable holistic vehicle product system design with the LCEO methodology. The constrained optimisation of a vehicle sub-system, and the design of a subset of the processes which are applied to it during its life cycle, are simultaneously optimised for a minimal product system life cycle energy. In particular, a subset of the EOL processes' parameters are considered as continuous design variables with associated barrier functions that control their feasibility. The results show that the LCEO methodology can be used to find an optimal design along with its associated ideal synthetic EOL scenario. Moreover, the ability of the method to identify the underlying mechanisms enabling the optimal solution's trade-offs is further demonstrated. Finally, the functional scope of the methodology is expanded through the inclusion of shape-related variables and aerodynamic drag estimations. Here, vehicle curvature is taken into account in the LCEO methodology through its impact on the aerodynamic drag and therewith its related operational energy demand. In turn, aerodynamic drag is considered through the estimation of the drag coefficient of a vehicle body shape using computational fluid dynamics simulations. The aforementioned coefficient is further used to estimate the energy required by the vehicle to overcome aerodynamic drag. The results demonstrate the ability of the LCEO methodology to capitalise on the underlying functional alignment of the structural and aerodynamic requirements, as well as the need for an allocation strategy for the aerodynamic drag energy within the context of vehicle sub-system redesign. Overall, these methodological developments contributed to the exploration of the ability of the LCEO methodology to handle life cycle and functional trade-offs to achieve life cycle energy optimal vehicle designs. / Livscykelenergioptimerings-metodologin (LCEO) syftar till att hitta en designlösning som använder en minimal mängd av energi ackumulerat över de olika faserna av en produkts (i detta arbete i formen av ett fordon) livscykel, samtidigt som den uppfyller en förutbestämd uppsättning funktionella begränsningar. Genom detta kan avvägningar balanseras effektivt, och därmed undviks suboptimala förskjutningar mellan energibehovet för vagga-till-produktion av material, fordonets användningsfas samt hantering av det uttjänta fordonet, på engelska kallad End-Of-Life (EOL). Detta arbete vidareutvecklar LCEO-metodologin och utvidgar dess omfattning genom tre huvudsakliga metodologiska bidrag, som, för illustrativa syften, har applicerats på en fallstudie av ett fordons sub-systemdesign. En EOL-modell baserad på substitution med korrigeringsfaktorer, är inkluderad för att uppskatta energikrediter och bördor som härrör från hanteringen av det uttjänta fordonet. Flera olika scenarier som beskriver återvinning med olika nivåer av antagen degradering av egenskaper hos de återvunna materialen har definierats, och deras respektive LCEO utfall har jämförts med motsvarande resultat för scenarier baserade på deponering och förbränning med energiåtervinning. Resultaten visar att införandet av en EOL-modell i LCEO-metodologin kan ändra flöden och mönster kring materialanvändning och har en signifikant påverkan på den totala livscykelenergin i de optimala fordonsdesignen Då valet av EOL-modell har signifikans för LCEO utfallet, har de föregående, statiska modellerna kompletterats med en utvidgning mot en mer holistisk systemstudie utifrån LCEO. I denna utvidgning studeras frågor kring optimerade produktsystem, framförallt avseende en delmängd av EOL processernas parametrar som har inkluderats i form av kontinuerliga designvariabler med antagna barriärfunktioner som modellerar deras genomförbarhet. Resultaten visar att LCEO kan användas för att finna den optimala designen av en fordonskomponent tillsammans med dess associerade, ideala, syntetiska EOL-scenario. Dessutom demonstreras metodens förmåga att identifiera de underliggande mekanismer som möjliggör den optimala lösningens avvägningar. För att utöka komplexiteten i de ansatta funktionella begränsningarna har även form-relaterade variabler och aerodynamiska motståndsberäkningar tagits med. I det här fallet används krökningen på den studerade fordonskomponenten som ytterligare en variabel i LCEO analyser, med dess inverkan på det aerodynamiska motståndet och i och med detta variationer i användningsfasens energibehov. I detta fallet har det aerodynamiska motståndet tagits med i analysen genom uppskattning av motståndskoefficienten av en fordonskomponent framtagen genom strömningsmekaniska beräkningar. Denna uppskattning används sedan för att modellera den energi som krävs av fordonet för att övervinna det aerodynamiska luftmotståndet. I detta sammanhang visas också på behovet av en strategi för allokering av den aerodynamiska motståndsenergin hos en sub-komponent i relation till helheten, när fokus ligger på design av ett sub-system hos ett fordon. Resultaten visar att LCEO beskriver den underliggande funktionella synergin mellan de ansatta strukturella och de aerodynamiska kraven. Detta arbete bidrar till att LCEO utvecklas i flera olika avseenden som utgör väsentliga steg mot en pro-aktiv metod som kan hantera livscykel- och funktionella avvägningar i en optimal fordonsdesign ur ett livscykelenergiperspektiv.

In der Projektierungsphase eines Elektrofahrzeugs entstehen optimale Antriebskonfigurationen erst durch die gezielte Kombination der einzelnen Antriebskomponenten. Um technisch vorteilhafte Auslegungszusammenhänge zu erkennen, ist eine systematische Untersuchung der Auslegungsfreiheitsgrade erforderlich. Diese Freiheitsgrade ergeben sich v. a. aus der Wahl der Auslegungsparameter, der Komponententypen und der Antriebstopologien. In diesem Artikel wird gezeigt, wie bereits in einer frühen Entwicklungsphase energieeffiziente Antriebskonfigurationen für Elektrofahrzeuge durch analytische Methoden identifiziert werden. Diese Methoden basieren grundsätzlich auf physikalischen Modellen und frei zugänglichen Datenblattangaben der Komponenten, die v. a. Energiespeicher, Wechselrichter, Elektromotor und Getriebe umfassen. Mithilfe dieser Methoden lässt sich der energetische Vergleich der zahlreichen Antriebskonfigurationen ohne großen Zeitaufwand durchführen. Die Ergebnisse führen schließlich zu einem informativen Auswahldiagramm, mit welchem aussagekräftige Prognosen zu den energieeffizienten Konfigurationen für beliebige Fahrprofile getroffen werden. / Optimal powertrain configurations develop only through the specific combination of individual powertrain components during the project planning phase of an electric vehicle. In order to identify the technically beneficial design correlations, a systematic investigation of the degrees of freedom in the powertrain design is necessary. The degrees of freedom arise primarily from the selection of design parameters, component types, and drive topologies. This article shows how energy-efficient powertrain configurations of electric vehicles can be identified at an early stage of development using analytical methods. These methods are based on physical models and freely available component data sheets. The components include a battery, inverter, electric motor, and gearbox. With these methods, the energy efficiency of various powertrain configurations can be evaluated quickly. The evaluation leads to an informative selection diagram, which allows forecasting energy-efficient configurations for different driving profiles.

Systeme zum automatisierten Fahren erlauben es, die Fahrzeugführung in einem gewissen Maß vom Fahrer an das Fahrzeug zu übertragen. Da der Fahrer auf diese Weise unterstützt, entlastet oder sogar ersetzt werden kann, werden Systeme zum automatisierten Fahren mit einem großen Potential für Verbesserungen hinsichtlich Straßenverkehrssicherheit, Fahrkomfort und Effizienz verbunden - vorausgesetzt, dass diese Systeme angemessen benutzt werden. Systeme zum hochautomatisierten Fahren stellen in diesem Zusammenhang eine besondere Herausforderung für die Mensch-Maschine-Interaktion dar: So wird es dem Fahrer bei diesem Automatisierungsgrad zwar zum ersten mal ermöglicht, das System nicht mehr permanent überwachen zu müssen und somit die Fahrtzeit potentiell für fahrfremde Tätigkeiten zu nutzen. Es wird jedoch immer noch erwartet, dass der Fahrer nach einer vorherigen angemessenen Übernahmeaufforderung die Fahrzeugführung im Bedarfsfall gewährleisten kann. Angemessenes Automatisierungsvertrauen stellt daher eine zentrale Komponente für die erfolgreiche Kooperation zwischen Fahrern und Systemen zum hochautomatisierten Fahren dar und sollte bei der Gestaltung derartiger Systeme berücksichtigt werden. Frühere Befunde weisen beispielsweise bereits darauf hin, dass unterschiedliche Informationen über automatisierte Systeme ein möglicher Ansatz sein könnten um das Automatisierungsvertrauen des Fahrers aktiv zu gestalten. Automatisierungsvertrauen als Variable in der Gestaltung von Fahrzeugtechnologie zu berücksichtigen erfordert jedoch zunächst auch in der Lage zu sein, Automatisierungsvertrauen adäquat messen zu können. In diesem Sinne war die Zielsetzung dieser Arbeit einerseits die Untersuchung verschiedener Methoden zur Messung des Automatisierungsvertrauens des Fahrers sowie andererseits die Identifikation, prototypische Umsetzung und Bewertung potentieller Ansätze zur Gestaltung von Automatisierungsvertrauen im Kontext von Systemen zum hochautomatisierten Fahren. Zu diesem Zweck wurden drei Fahrsimulatorstudien mit insgesamt N = 280 Probanden durchgeführt. Die vorliegenden Ergebnisse weisen darauf hin, dass (i) sowohl Selbstberichtsverfahren als auch Verhaltensmaße prinzipiell dazu verwendet werden können um das Automatisierungsvertrauen des Fahrers in Systeme zum hochautomatisierten Fahren zu operationalisieren, (ii) eine vorherige Auseinandersetzung mit funktionalen Grenzen von Systemen zum hochautomatisierten Fahren einen nachhaltigen Effekt auf das Automatisierungsvertrauen des Fahrers in das System haben kann und (iii) insbesondere Informationen über die Funktionsweise von Systemen zum hochautomatisierten Fahren das Automatisierungsvertrauen des Fahrers in derartige Systeme verbessern können. Damit liefert die vorliegende Arbeit sowohl wertvolle Ansatze zur Messbarmachung als auch Hinweise für die Gestaltung von Automatisierungsvertrauen im Kontext des hochautomatisierten Fahrens. Darüber hinaus können die Befunde dieser Arbeit in gewissem Maße auch auf andere Arten von Fahrzeugautomatisierung sowie unterschiedliche Domänen und Anwendungen von Automatisierung übertragen werden. / Automated driving systems allow to transfer a certain degree of vehicle control from the driver to a vehicle. By assisting, augmenting or even supplementing the driver, automated driving systems have been associated with enormous potential for improving driving safety, comfort, and efficiency - provided that they are used appropriately. Among those systems, conditional automated driving systems are particularly challenging for human-automation interaction: While the driver is no longer required to permanently monitor conditional automated driving systems, he / she is still expected to provide fallback performance of the dynamic driving task after adequate prior notification. Therefore, facilitating appropriate automation trust is a key component for enabling successful cooperation between drivers and conditional automated driving systems. Earlier work indicates that providing drivers with proper information about conditional automated driving systems might be one promising approach to do this. Considering the role of automation trust as a variable in the design of vehicle technology, however, also requires that drivers` automation trust can be viably measured in the first place. Accordingly, the objectives of this thesis were to explore difffferent methods for measuring drivers` automation trust in the context of conditional automated driving as well as the identification, implementation and evaluation of possible approaches for designing drivers` automation trust in conditional automated driving systems. For these purposes, three driving simulator studies with N = 280 participants were conducted. The results indicate that (i) both self-report measures and behavioral measures can be used to assess drivers` automation trust in conditional automated driving systems, (ii) prior familiarization with system limitations can have a lasting effffect on drivers` automation trust in conditional automated driving systems and (iii) particularly information about the processes of conditional automated driving systems might promote drivers` automation trust in these systems. Thus, the present research contributes much needed approaches to both measuring and designing automation trust in the context of conditional automated driving. In addition, the current findings might also be transferred to higher levels of driving automation as well as other domains and applications of automation.

The design and manufacture of lightweight electric vehicles is becoming increasingly important with the rising cost of petrol, and the effects emissions from petrol powered vehicles are having on our environment. The University of Waikato and HybridAuto's Ultracommuter electric vehicle was designed, manufactured, and tested. The vehicle has been driven over 1800km with only a small reliability issue, indicating that the Ultracommuter was well designed and could potentially be manufactured as a solution to ongoing transportation issues. The use of titanium aluminide components in the automotive industry was researched. While it only has half the density of alloy steel, titanium aluminides have the same strength and stiffness as steel, along with good corrosion resistance, making them suitable as a lightweight replacement for steel components. Automotive applications identified that could benefit from the use of TiAl include brake callipers, brake rotors and electric motor components.

Stability is an important criterion in the design and performance of launch vehicles. Present day launch vehicles have become more and more flexible due to the constraints of weight reduction, necessarily imposed for enhanced performance of the vehicle. Due to higher flexibility, the launch vehicle stability becomes a concern. Instability in the launch vehicles has been noticed due to three major sources: thrust, aerodynamic forces and combustion induced instabilities. Instability in the launch vehicles may pose problem to the structural integrity leading to structural failure or it may lead to the deviation in the trajectory of the vehicle. Several structural failures of launch vehicles due to instabilities have been reported in the literature. The prediction of the structural response due to various excitations such as thrust and aerodynamic loading is essential to identify any failure scenarios and to limit the vibrations transmitted to the payload. Therefore, determination of dynamic and stability characteristics of a launch vehicle under the influence of different parameters, is of vital importance. Disciplines such as, flight mechanics (dynamics), structural dynamics, aerodynamics, propulsion, guidance and control are closely related in the design and analysis of launch vehicles. Typically, flight mechanics, guidance and control problems consider a rigid vehicle for modeling and simulation purposes. The disciplines of structural dynamics and aeroelasticity consider a flexible vehicle. In order to bring in the effect of flexibility on the flight dynamics of the launch vehicle, structural dynamics and aeroelasticity aspects need to be effected. The preliminary design of a new launch vehicle requires inputs from different disciplines and parametric studies are required to finalise the vehicle configuration. The study of the effect of different parameters on the dynamics and stability of launch vehicles is required. In this context, there is a need to develop an integrated approach that provides tools for the design and analysis of a launch vehicle. The availability of integrated modeling and simulation tools will reduce the requirement of costly prototype development and testing. In the present thesis, an attempt has been made to develop a numerical tool to conduct parametric studies for launch vehicle dynamics and stability. The developed tool is suitable for prediction of onset of instabilities under the influence of different parameters. The approach developed in this thesis is also well suited for specialized analysis of problems involving vertical launch, stage separation, engine shutdown and internal stress wave propagation related to structural integrity. Stability problems due to thrust and the aerodynamic forces (aeroelastic stability) in the launch vehicles/ missiles have been reported in the literature. Most of these works have modeled the vehicle as a beam or by using discrete degrees of freedom. In these works, the effect of thrust or aerodynamic forces on the flexible body modes is investigated and it is shown that the instability may occur in one of the bending modes due to change in the parameters such as thrust or aerodynamic forces. Traditionally, the dynamic characteristics are obtained in a body-fixed coordinate system, whereas the prediction of trajectory (rigid body dynamics) is carried out in an inertial frame of reference. Only few works have addressed the coupling of the rigid body motion and the flexible body dynamics of a vehicle. But these works also, do not consider the total derivative of displacements with respect to an inertial frame of reference. When the integrated equations of motion are derived in an inertial frame of reference, the rigid body motion and the elastic displacements are highly coupled. In this thesis, the rigid body motion and the flexible body dynamics is studied in an inertial frame of reference. The flexible body dynamics of the moving vehicle is studied in an inertial frame of reference, including velocity induced curvature effects, which have not been considered so far in the published literature. A detailed mechanics based model is developed to analyze the problem of structural instabilities in launch vehicles. Coupling among the rigid-body modes, the longitudinal vibrational modes and the transverse vibrational modes due to asymmetric lifting-body cross-section are considered. The model also incorporates the effects of aerodynamic forces and the propulsive thrust of the vehicle. The propulsive thrust is considered as a follower force. The model is one-dimensional, and it can be employed to idealized slender vehicles with complex shapes. The governing differential equations along with the boundary conditions are derived using Extended Hamilton’s principle. Subsequently, the modeling of the propulsive thrust and the aerodynamic forces are included in the formulation. In the literature, the propulsive thrust has generally been modeled as a follower force applied at the nozzle end. Few of the works in the literature have modeled the combustion process in the solid rocket motor and the liquid propellant engine in detail. This is required to understand the combustion induced instabilities. In the present thesis, the propulsive thrust is considered as a follower force and few of the combustion parameters affecting the thrust are considered. In the literature, the modeling of the aerodynamic forces acting on a launch vehicle has been carried out using general purpose computational fluid dynamics (CFD) codes or by using empirical methods. CFD codes are used to obtain the pressure and the shear stress distribution on the vehicle surface by the solution of Navier Stokes/ Euler equations. The empirical methods have been used to obtain the distributed aerodynamic forces acting on the vehicle. The aerodynamic forces are expressed in terms of distributed aerodynamic coefficients. In the present work, the modeling of the aerodynamic forces has been carried out in two different ways: using a CFD package and by using empirical methods. The stability of a system can be studied by determining the system response with time. Eigenvalue analysis is another tool to investigate the stability of a linear system. To study the stability characteristics of the system using eigenvalue analysis, a computational framework has been developed. For this purpose, the finite element discretization of the system is carried out. Further to that, two different methods are utilized for finite element discretization of the vehicle structure: Fourier Transform based Spectral Finite Element method (SFEM) and an hp Finite Element method (FEM). The conventional FEM is a versatile tool for modeling complicated structures and to obtain the solution of the system of equations for a variety of forcing functions. The SFEM is more suitable for obtaining the solution for simple 1D and 2D structures subjected to shock and transient loads, having high frequency content. In this thesis, the spectral finite element model is developed for a vehicle subjected to the propulsive thrust and the aerodynamic forces. Prediction of instability using SFEM, means solving a nonlinear eigenvalue problem. Standard computer codes or routines are not available for solving a nonlinear eigenvalue problem. A computer code has been written to solve the nonlinear eigenvalue problem using one of the algorithms available in the literature. An hp finite element model is also developed for launch vehicle. The finite element stiffness and damping matrices due to the thrust, the aerodynamic forces and the rigid body velocity and acceleration are derived using Lagrange’s equations of motion. A standard linear eigenvalue problem and a polynomial eigenvalue problem is formulated for determination of instability regimes of the vehicle. It is important to understand the influence of different parameters such as thrust, velocity, angle of attack etc. on the stability of a launch vehicle. Parametric studies are important during the preliminary design phase of a vehicle to identify the instability regimes. The design parameters can be changed to reduce the possibility of instabilities. Numerical simulations are carried out to determine the unstable regimes of a slender launch vehicle for propulsive thrust and velocity as the parameters, neglecting the aerodynamic forces. Comparison between the results based on a Fourier spectral finite element model and a hp finite element model are carried out. Phenomenon of static instability (divergence) and dynamic instability (flutter) are observed. Determination of mode shapes of the vehicle is important for deciding the placement of sensors and actuators on the vehicle. In this context, eigenvectors (mode shapes) for different end thrust and speed are analyzed. Further, numerical simulations are also carried out to determine the instabilities in a slender launch vehicle considering the combined effects of propulsive thrust, aerodynamic forces and mass variation. The finite element model simulation results for aeroelastic effects are compared with the published literature. Stability of a vehicle is analysed for velocity (free stream Mach number) as a parameter, at maximum propulsive thrust, including the effect of aerodynamic forces and mass variation. Phenomenon of static instability (divergence) and dynamic instability (flutter) are observed. With the increase in the Mach number, branching (splitting) and merging of the modes is observed. At higher Mach numbers, divergence and flutter are observed in different modes simultaneously. Numerical simulations are carried out for a typical nosecone launch vehicle configuration to analyse the aeroelastic stability at two different Mach numbers using empirical aerodynamic data. The phenomenon of flow separation and reattachment is observed at the cone-cylinder junction. The stability of a typical vehicle under propulsive thrust and aerodynamic forces is investigated using CFD derived aerodynamic data. The aerodynamic pressure and shear stress distribution for a launch vehicle are obtained from the CFD analysis. The effect of different parameters such as combustion chamber pressure, tip mass and slenderness ratio on the stability of a vehicle is studied. In the later part of the thesis, solution methodology for the time domain response for a coupled axial and transverse motion of a vehicle is developed. The axial responses (displacements and velocities) of a typical vehicle subjected to axial thrust are determined using direct integration of the equations of motion. The axial displacements due to two different thrust histories are compared. The axial velocities with time at different locations are determined. The time domain and the frequency domain responses for a representative vehicle subjected to a transverse shock force are determined using Spectral Finite Element method (SFEM). The system of equations for a coupled axial and transverse motion of a vehicle is developed. Numerical simulations are carried out to determine the coupled axial and transverse response of a vehicle subjected to axial and transverse forces. The coupling of rigid body motion with the elastic displacements is illustrated. The thesis is comprised of seven chapters. The first chapter gives a detailed introduction to launch vehicles and covers literature survey of launch vehicle dynamics and stability. The dynamics and stability related aspects of flexible structures are also discussed. In chapter 2, a detailed mathematical model of a slender launch vehicle is developed to analyze the problem of structural instabilities. Chapter 3 deals with the finite element discretization of the vehicle structure using two different methods: Fourier spectral finite element method and an hp finite element method. In chapters 4 and 5, numerical simulations are carried out to determine the instabilities in a slender launch vehicle considering the effects of propulsive thrust, aerodynamic forces and mass variation. In chapter 6, solution methodology for the time domain response for a coupled axial and transverse motion of a vehicle is developed. The last chapter gives the conclusions and the future scope of work. To summarize, this thesis is a comprehensive document, that not only describes some detailed mathematical models for launch vehicle stability studies, but also presents the effect of aerodynamic, propulsion and structural loads on the launch vehicle stability. Linear stability analysis of a representative vehicle is carried out for prediction of onset of the instabilities under the influence of different parameters such as velocity, thrust, combustion factors etc. The correlation between the stability analysis and the time domain response is established. In short, the matter presented in this thesis can serve as a useful design aide for those working in the launch vehicle design.

Systeme zum automatisierten Fahren erlauben es, die Fahrzeugführung in einem gewissen Maß vom Fahrer an das Fahrzeug zu übertragen. Da der Fahrer auf diese Weise unterstützt, entlastet oder sogar ersetzt werden kann, werden Systeme zum automatisierten Fahren mit einem großen Potential für Verbesserungen hinsichtlich Straßenverkehrssicherheit, Fahrkomfort und Effizienz verbunden - vorausgesetzt, dass diese Systeme angemessen benutzt werden. Systeme zum hochautomatisierten Fahren stellen in diesem Zusammenhang eine besondere Herausforderung für die Mensch-Maschine-Interaktion dar: So wird es dem Fahrer bei diesem Automatisierungsgrad zwar zum ersten mal ermöglicht, das System nicht mehr permanent überwachen zu müssen und somit die Fahrtzeit potentiell für fahrfremde Tätigkeiten zu nutzen. Es wird jedoch immer noch erwartet, dass der Fahrer nach einer vorherigen angemessenen Übernahmeaufforderung die Fahrzeugführung im Bedarfsfall gewährleisten kann. Angemessenes Automatisierungsvertrauen stellt daher eine zentrale Komponente für die erfolgreiche Kooperation zwischen Fahrern und Systemen zum hochautomatisierten Fahren dar und sollte bei der Gestaltung derartiger Systeme berücksichtigt werden. Frühere Befunde weisen beispielsweise bereits darauf hin, dass unterschiedliche Informationen über automatisierte Systeme ein möglicher Ansatz sein könnten um das Automatisierungsvertrauen des Fahrers aktiv zu gestalten. Automatisierungsvertrauen als Variable in der Gestaltung von Fahrzeugtechnologie zu berücksichtigen erfordert jedoch zunächst auch in der Lage zu sein, Automatisierungsvertrauen adäquat messen zu können. In diesem Sinne war die Zielsetzung dieser Arbeit einerseits die Untersuchung verschiedener Methoden zur Messung des Automatisierungsvertrauens des Fahrers sowie andererseits die Identifikation, prototypische Umsetzung und Bewertung potentieller Ansätze zur Gestaltung von Automatisierungsvertrauen im Kontext von Systemen zum hochautomatisierten Fahren. Zu diesem Zweck wurden drei Fahrsimulatorstudien mit insgesamt N = 280 Probanden durchgeführt. Die vorliegenden Ergebnisse weisen darauf hin, dass (i) sowohl Selbstberichtsverfahren als auch Verhaltensmaße prinzipiell dazu verwendet werden können um das Automatisierungsvertrauen des Fahrers in Systeme zum hochautomatisierten Fahren zu operationalisieren, (ii) eine vorherige Auseinandersetzung mit funktionalen Grenzen von Systemen zum hochautomatisierten Fahren einen nachhaltigen Effekt auf das Automatisierungsvertrauen des Fahrers in das System haben kann und (iii) insbesondere Informationen über die Funktionsweise von Systemen zum hochautomatisierten Fahren das Automatisierungsvertrauen des Fahrers in derartige Systeme verbessern können. Damit liefert die vorliegende Arbeit sowohl wertvolle Ansatze zur Messbarmachung als auch Hinweise für die Gestaltung von Automatisierungsvertrauen im Kontext des hochautomatisierten Fahrens. Darüber hinaus können die Befunde dieser Arbeit in gewissem Maße auch auf andere Arten von Fahrzeugautomatisierung sowie unterschiedliche Domänen und Anwendungen von Automatisierung übertragen werden. / Automated driving systems allow to transfer a certain degree of vehicle control from the driver to a vehicle. By assisting, augmenting or even supplementing the driver, automated driving systems have been associated with enormous potential for improving driving safety, comfort, and efficiency - provided that they are used appropriately. Among those systems, conditional automated driving systems are particularly challenging for human-automation interaction: While the driver is no longer required to permanently monitor conditional automated driving systems, he / she is still expected to provide fallback performance of the dynamic driving task after adequate prior notification. Therefore, facilitating appropriate automation trust is a key component for enabling successful cooperation between drivers and conditional automated driving systems. Earlier work indicates that providing drivers with proper information about conditional automated driving systems might be one promising approach to do this. Considering the role of automation trust as a variable in the design of vehicle technology, however, also requires that drivers` automation trust can be viably measured in the first place. Accordingly, the objectives of this thesis were to explore difffferent methods for measuring drivers` automation trust in the context of conditional automated driving as well as the identification, implementation and evaluation of possible approaches for designing drivers` automation trust in conditional automated driving systems. For these purposes, three driving simulator studies with N = 280 participants were conducted. The results indicate that (i) both self-report measures and behavioral measures can be used to assess drivers` automation trust in conditional automated driving systems, (ii) prior familiarization with system limitations can have a lasting effffect on drivers` automation trust in conditional automated driving systems and (iii) particularly information about the processes of conditional automated driving systems might promote drivers` automation trust in these systems. Thus, the present research contributes much needed approaches to both measuring and designing automation trust in the context of conditional automated driving. In addition, the current findings might also be transferred to higher levels of driving automation as well as other domains and applications of automation.

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In a society where environmental noise is becoming a major health and economical concern, sound emissions are an increasingly critical design factor for vehicle manufacturers. With about a quarter of the European population living close to roads with heavy traffic, traffic noise in urban landscapes has to be addressed first. The current introduction of electric vehicles on the market and the need for sound systems to alert their presence is causing a shift in mentalities requiring engineering methods that will have to treat noise management problems from a broader perspective. That in which noise emissions need not only be considered as a by-product of the design but as an integrated part of it. Developing more sustainable ground transportation will require a better understanding of the sound field emitted in various realistic operating conditions, beyond the current requirements set by the standard pass-by test, which is performed in a free-field. A key aspect to improve this understanding is the development of efficient numerical tools to predict the generation and propagation of sound from moving vehicles. In the present thesis, a methodology is proposed aimed at evaluating the pass-by sound field generated by vehicle acoustic sources in a simplified urban environment, with a focus on flow sound sources. Although it can be argued that the aerodynamic noise is still a minor component of the total emitted noise in urban driving conditions, this share will certainly increase in the near future with the introduction of quiet electric engines and more noise-efficient tyres on the market. This work presents a complete modelling of the problem from sound generation to sound propagation and pass-by analysis in three steps. Firstly, computation of the flow around the geometry of interest; secondly, extraction of the sound sources generated by the flow, and thirdly, propagation of the sound generated by the moving sources to observers including reflections and scattering by nearby surfaces. In the first step, the flow is solved using compressible detached-eddy simulations. The identification of the sound sources in the second step is performed using direct numerical beamforming with linear programming deconvolution, with the phased array pressure data being extracted from the flow simulations. The outcome of this step is a set of uncorrelated monopole sources. Step three uses this set as input to a propagation method based on a point-to-point moving source Green's function and a modified Kirchhoff integral under the Kirchhoff approximation to compute reflections on built surfaces. The methodology is demonstrated on the example of the aeroacoustic noise generated by a NACA air inlet moving in a simplified urban setting. Using this methodology gives insights on the sound generating mechanisms, on the source characteristics and on the sound field generated by the sources when moving in a simplified urban environment. / I ett samhälle där buller håller på att bli ett stort hälsoproblem och en ekonomisk belastning, är ljudutsläpp en allt viktigare aspekt för fordonstillverkare. Då ungefär en fjärdedel av den europeiska befolkningen bor nära vägar med tung trafik, är åtgärder för minskat trafikbuller i stadsmiljö en hög prioritet. Introduktionen av elfordon på marknaden och behovet av ljudsystem för att varna omgivningen kräver också ett nytt synsätt och tekniska angreppssätt som behandlar bullerproblemen ur ett bredare perspektiv. Buller bör inte längre betraktas som en biprodukt av konstruktionen, utan som en integrerad del av den. Att utveckla mer hållbara marktransporter kommer att kräva en bättre förståelse av det utstrålade ljudfältet vid olika realistiska driftsförhållanden, utöver de nuvarande standardiserade kraven för förbifartstest som utförs i ett fritt fält. En viktig aspekt för att förbättra denna förståelse är utvecklingen av effektiva numeriska verktyg för att beräkna ljudalstring och ljudutbredning från fordon i rörelse. I denna avhandling föreslås en metodik som syftar till att utvärdera förbifartsljud som alstras av fordons akustiska källor i en förenklad stadsmiljö, här med fokus på strömningsgenererat ljud. Även om det aerodynamiska bullret är fortfarande en liten del av de totala bullret från vägfordon i urbana miljöer, kommer denna andel säkerligen att öka inom en snar framtid med införandet av tysta elektriska motorer och de bullerreducerande däck som introduceras på marknaden. I detta arbete presenteras en komplett modellering av problemet från ljudalstring till ljudutbredning och förbifartsanalys i tre steg. Utgångspunkten är beräkningar av strömningen kring geometrin av intresse; det andra steget är identifiering av ljudkällorna som genereras av strömningen, och det tredje steget rör ljudutbredning från rörliga källor till observatörer, inklusive effekten av reflektioner och spridning från närliggande ytor. I det första steget löses flödet genom detached-eddy simulation (DES) för kompressibel strömning. Identifiering av ljudkällor i det andra steget görs med direkt numerisk lobformning med avfaltning med hjälp av linjärprogrammering, där källdata extraheras från flödessimuleringarna. Resultatet av detta steg är en uppsättning av okorrelerade akustiska monopolkällor. Steg tre utnyttjar dessa källor som indata till en ljudutbredningsmodel baserad på beräkningar punkt-till-punkt med Greensfunktioner för rörliga källor, och med en modifierad Kirchhoff-integral under Kirchhoffapproximationen för att beräkna reflektioner mot byggda ytor. Metodiken demonstreras med exemplet med det aeroakustiska ljud som genereras av ett NACA-luftintag som rör sig i en förenklad urban miljö. Med hjälp av denna metod kan man få insikter om ljudalstringsmekanismer, om källegenskaper och om ljudfältet som genereras av källor när de rör sig i en förenklad stadsmiljö. / <p>QC 20170425</p>