The thesis focuses on investigating and optimizing a bushing script implemented as a tool in MSC ADAMS/Car. The study provides an insight on the representation of a rubber bushing and identify parameters which can be used to define the properties of a bushing in a simulation environment such as ADAMS/Car. The tool being studied here can be used to implement different kind of bushings such as a hydro bushing and a general rubber bushing, but optimization was implemented for the rubber bushing only. With an increasing reliance on Computer Aided Engineering (CAE) tools in the designing process, it is necessary that the vehicle behaviour can be predicted without relying on physical testing. CAE tools reduces the need of prototypes and provides a faster approach to designing vehicles. MSC ADAMS/Car is one such tool, which has been used here to predict the vehicle dynamic behaviour, which will influence the ride, handling and comfort characteristics of the vehicle. Rubber bushings, which have been studied here, have a significant contribution to the overall stiffness of the vehicle and as such, it is imperative that the tool being used here, is accurate and makes the designing process easy. The rubber bushing can be imagined to be a combination of a non-linear elastic spring, a frequency dependent Maxwell component and an amplitude dependent frictional element. In order to ease the design of the bushing properties, a reduced number of input properties are used to calculate the bushing properties internally. While trying to validate the force hysteresis loop obtained through the model with the measured data, it was seen that the accuracy was quite poor for the model when loading it with dynamic loads corresponding to amplitudes of0.2 mm and lower. The quasi-static loading and dynamic loading above 0.2 mm is shown to have a satisfactory accuracy when compared to the measured data.

In today’s competitive automotive industry, most companies are trying to make their new designs and features implemented in their products to be ahead of their competitors. However, in the preliminary design stage of CEVT vehicles, dynamic simulation consumes excessive amount of time depending on the complexity of the dynamic model and simulation settings. It is beneficial and possible to shorten the simulation time. This thesis focuses on reducing the dynamic simulation time in ADAMS/Car in engine suspensions’ early development stage. Five simulation time reducing methods, i.e., reducing end time in driver control maneuver, stopping similar simulations, converting specific flexible parts to rigid parts, properly increasing the step size and performing simulation for engine suspension subsystem instead of the full vehicle system, were proposed and investigated separately to study their effects on the simulation time and the accuracy of the fatigue damage results of the engine suspension. With the proper combination of the five methods, total dynamic simulation time was effectively reduced to 61% and the variation of fatigue damage results of each engine suspension component was controlled within 30%. Dynamic modelling of an exhaust system is also included in this thesis and it provides referential data for the packaging design of exhaust system. / I dagens konkurrensutsatta bilindustri försöker de flesta företag att göra sina nya mönster och funktioner implementerbara i sina produkter för att vara före sina konkurrenter. I det preliminära konstruktionsstadiet av CEVT-fordon förbrukar dynamisk simulering dock en stor tid beroende på komplexiteten hos den dynamiska modellen och simuleringsinställningarna. Det är fördelaktigt och möjligt att förkorta simuleringstiden. Denna avhandling fokuserar på att minska den dynamiska simuleringstiden i ADAMS / Car i motorupphängningens tidiga utvecklingsstadium. Med hjälp av bakgrundsstudier och erfarenheter från CEVT’s personal provades fem olika sätt att minska simuleringstiden, samtidigt som simuleringsresultatens noggrannhet kontrollerades. Varje metod användes separat i simuleringen för att studera effekten på resultatens noggrannhet. I slutet kombineras alla metoder i simuleringen för att få bästa möjliga simuleringstid utan att förlora noggrannhet. Genom att kombinera de fem metoderna reducerades den totala dynamiska simuleringstiden till 61% och variationen i utmattningsskadans resultat av varje motorupphängningskomponent kontrollerades inom 30%. Dynamisk modellering av ett avgassystem ingår också i denna avhandling, vilket ger referensdata för framtida förpackningsdesign av avgassysteme

The object of this master thesis is testing of vehicle using four post rig. The main goal is to make a research about testing and tuning vehicle characteristics on four post rig in order to implement them for testing of TU Brno Racing’s Formula Student racecar. The main method of testing, input signals and measurement description are presented in this thesis. The different methods of analysis of testing data to find best tuning of damper and spring stiffness for different race disciplines are described. In the last part of this work, quarter car model and multibody model in MSC Adams Car is created. Input parameters of model are based on measurements from real car/ component testing, including damper characteristics and static tire radial stiffness for best fit with the characteristics of real vehicle. The measurements themselves were also described in separate chapter of this thesis. The last but not the least goal was to compare these simulations with measurements, made od real four post rig in order to decide whether car model is suitable for racecar development.