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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Development of vehicle dynamics tools for motorsports

Patton, Chris 07 February 2013 (has links)
In this dissertation, a group of vehicle dynamics simulation tools is developed with two primary goals: to accurately represent vehicle behavior and to provide insight that improves the understanding of vehicle performance. Three tools are developed that focus on tire modeling, vehicle modeling and lap time simulation. Tire modeling is based on Nondimensional Tire Theory, which is extended to provide a flexible model structure that allows arbitrary inputs to be included. For example, rim width is incorporated as a continuous variable in addition to vertical load, inclination angle and inflation pressure. Model order is determined statistically and only significant effects are included. The fitting process is shown to provide satisfactory fits while fit parameters clearly demonstrate characteristic behavior of the tire. To represent the behavior of a complete vehicle, a Nondimensional Tire Model is used, along with a three degree of freedom vehicle model, to create Milliken Moment Diagrams (MMD) at different speeds, longitudinal accelerations, and under various yaw rate conditions. In addition to the normal utility of MMDs for understanding vehicle performance, they are used to develop Limit Acceleration Surfaces that represent the longitudinal, lateral and yaw acceleration limits of the vehicle. Quasi-transient lap time simulation is developed that simulates the performance of a vehicle on a predetermined path based on the Limit Acceleration Surfaces described above. The method improves on the quasi-static simulation method by representing yaw dynamics and indicating the vehicle's stability and controllability over the lap. These improvements are accomplished while maintaining the simplicity and computational efficiency of the two degree of freedom method. / Graduation date: 2013
22

Měření sil působících za jízdy mezi kolem a vozovkou / Measuring the forces acting between the wheel and the road

Gellner, Pavel January 2020 (has links)
The diploma thesis is focused on the measurement of forces acting between the tire and the road. There is an outline of tire and tire models problematic in the opening part. In the following part, the rear right suspension of the formula student car was mounted with strain gauges and the data logging system was described. There is also a multi-body model of the rear axle created in Adams/Car and SAMS software, that is able to calculate forces acting between the tire and the road, taking the measured forces in the suspension, rocker position, and throttle position into consideration. After a series of calibrations and verification measurements, the measurement on the test track was made, with data analysis focused on forces acting between the tire and the road.
23

Physical understanding of tire transient handling behavior

Sarkisov, Pavel 05 July 2019 (has links)
Increasing vehicle performance requirements and virtualization of its development process require more understanding of physical background of tire behavior, especially in transient rolling conditions with combined slip. The focus of this research is physical description of transient generation of tire lateral force and aligning torque. Using acceleration measurement on the tire inner liner it was observed that the contact patch shape of the rolling tire changes nonlinearly with slip angle and becomes asymmetric. Optical measurement outside and inside the tire has clarified that carcass lateral bending features both shear and rotation angle of its cross-sections. A physical simulation model was developed, which considers the observed effects. A special iterative computing algorithm was proposed. The model was qualitatively validated using not only tire force and torque responses, but also deformation of the tire carcass. The model-based analysis explained which tire structural parameters are responsible for which criteria of tire performance. Contact patch shape change had a low impact on lateral force and aligning torque. Variation of carcass bending behavior perceptibly influenced aligning torque generation. As an example, the gained understanding was applied for feasibility analysis of a novel method to estimate the utilized friction potential rate of a rolling tire.:1 Introduction 1.1 Thesis structure 1.2 Motivation 1.3 State of the art 1.4 Mission statement 1.5 Main terms and hypotheses 1.6 Summary of chapter 1 2 Experimental investigation of tire deformation 2.1 Introduction to experimental research 2.2 Test samples 2.3 Experimental equipment 2.4 Contact patch pressure distribution 2.5 Contact patch geometry of the rolling tire 2.6 Tire carcass deformation 2.7 Tread block properties 2.8 Summary of chapter 2 3 Simulation method of tire deformation behavior 3.1 Concept development 3.2 Physical representation of the model 3.3 Model computing method 3.4 Model parameterization routine 3.5 Model validation 3.6 Summary of chapter 3 4 Model-based analysis 4.1 Understanding of the physical background 4.2 An example of application 4.3 Summary of chapter 4 5 Investigation summary and discussion 5.1 Key results 5.2 Discussion, critique and outlook References List of abbreviations List of symbols List of tables List of figures Appendix
24

Däckmodellering och prestandaanalys för Formula Student

Olsson, Hugo January 2024 (has links)
Arbetets syfte var att göra ett motiverat val av däck till bilen som KTH Formula Student planerar att utveckla till 2025. Detta gjordes genom att använda däckdata från FSAE TTC och utifrån den modellera alla däck med däckmodellen Magic Formula TNO MFTyre/MF-Swift 6.1. Denna modell innehåller variationer i däcktryck, camber och vertikal last. Därefter simulerades varvtid vid olika grenar som skidpad, autocross och endurance för att jämföra alla däcks prestanda. Dessutom kunde flera andra värden värda att jämföras beräknas utifrån däckmodellen och datan från FSAE TTC. Dessa var hållbarhet, däcktemperatur, däckens massa, sidkraftskoefficient, camberkänslighet och däckens fjäderkonstant. Alla dessa värden jämfördes till sist där varvtid och hållbarhet prioriterades. Tre däck fanns kvar i slutet vilka rekommenderades.
25

Návrh zavěšení kol Formule Student / Design of Formula Student Wheel Suspensions

Urban, Marek January 2020 (has links)
Tato práce se se zabývá návrhem kinematiky zavěšení kol obou náprav. Na základě analýz jízdních dat, multi-body simulací v softwaru Adams Car, simulací v Matlabu a analytických kalkulací v Mathcadu, je navržena řada změn s cílem zlepšit jízdní vlastnosti vozu Formule student, tyto změny jsou následně implementovány do CAD modelu vozu. Jednotlivé změny kinematiky náprav jsou provedeny na základě analýzy konkrétního problému, který se snaží řešit. Jednou z problematik je zástavbová náročnost systému odpružení a zavěšení zadních kol, zde je cílem snížit hmotnost, výšku těžiště a moment setrvačnosti. Další problematikou je geometrie předního kola, kde je cílem zlepšit využití pneumatik a snížit síly v řízení. Dále se práce zabývá simulacemi elastokinematiky zadní nápravy, součástí je také návrh měřícího zařízení. V poslední části je zkoumán vliv provedených změn i elastokinematiky na jízdní dynamiku vozu v ustálených stavech za pomocí MM metody simulované s modelem celého vozu v Adams Car a zpracované v Matlabu.

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