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The clutch actuation system is directly linked to vehicle easy of operation and ergonomics. For passenger cars, a comfortable pedal force is considered light when it is under 100 N and hard if over 130 N. For Commercial vehicles, about 170 N are considered acceptable. This work looks forward to obtain a pedal curve in Excel which simulates the real one and can low down actuation systems developing time. For in such way, it points to cares about master cylinder actuation geometry, stroke and pedal effort variations in the way that it is comfortable for the driver, works on low hydraulic pressure and is able to keep functionality during whole clutch plate and disc life. Some calculations about lever and master cylinder push rod dimensions are realized in the way of keeping actuation angles drawing limits. Empirical evaluations about losses in components (hydraulic and mechanical) for determination of stroke of pedal and pedal effort actuation are also done.

This paper presents the results of an experimental modal analysis performed on a prototype chassis of an off-road competition vehicle. The vehicle was designed by the Mini Baja EESC-USP team for the annual competition promoted by SAE Brasil. The goal of this experimental modal analysis is to validate a finite element model of the chassis, in order to develop a flexible multibody dynamic model of the complete vehicle. A preliminary finite element modal analysis of the test article was carried out in a free-free boundary condition. A random signal was used for FRFs acquisition. A multimode identification algorithm was used to acquire the system's modal parameters. Based on this information a swept sine was employed for mode shapes identification.

This paper describes the methodology adopted at T-Systems do Brasil, for performing handling analysis of commercial vehicles. Its application to an intercity bus with 3 axles is presented. The objective is to improve primary suspension characteristics alone, with respect to both comfort and handling and to study the behavior of the full vehicle with respect to handling and to improve it through the changes of primary suspensions characteristics. The methodology adopted was the development of a complete multibody model of the bus (Figure 4) in ADAMS, considering all the major non-linearities of the actual vehicle, such as air spring and shock absorber curves, suspension bump stops and tire model (Delft). Once having the model, several analyses were carried out including, modal, single lane change, double lane change, steering impulse and sine steering sweep.

The present work carries out static and kinematical studies of front suspensions of a Brazilian medium sized passenger car. The concept of virtual prototyping with the use of multibody system modelling techniques is employed by ADAMS, a package developed by Mechanical Dynamics Inc.. The concept of virtual prototyping allows vehicle development without the need of physical prototype construction. ADAMS uses the description of the geometric suspension, inertia parameters from its parts and how the parts are connected to generate a full model of the system. The type of analysis which can carry out include vertical and steering behaviour (in the case of a front suspension). These analysis are generated in graphical as well as an animation. The results include among others: toe-in angle, camber and caster angle, ride rate, and so forth. The use of the virtual prototyping concept, has made easier the modelling and analysis of this type of mechanism.