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The mathematical thermal design of the vehicle brakes will lead to success if all influence parameters such as friction (fading effect), car geometry and inertia, brake amplifier, tire, convective heat flow, heat conductance and heat radiation are taken into consideration. In addition to a lot of design criteria, the thermal stability of the vehicle brake is becoming more and more important because of permanently increasing engine powers and weight of the vehicles. This requires both stable friction behavior in the contact zone between brake lining and brake disk and a sufficient transfer of the friction energy by means of convective heat flow. In order to accomplish these two tasks, considerable expense on a brake test bed and innumerable brake trials are necessary. It must be guarantied at the end of the brake design process that the vehicle reaches the required braking distance and the thermal stability of the brake, e.g. after several freeway braking sequences.

The present technical article deals with the modeling of dynamic tire forces, which are relevant during interactions of safety relevant Advanced Driver Assistance Systems (ADAS). Special attention has been paid on simple but effective tire modeling of semi-physical type. In previous investigations, experimental validation showed that the well-known first-order Kelvin-Voigt model, described by a spring and damper element, describes good suitability around fixed operation points, but is limited for a wide working range. When aiming to run vehicle dynamics models within a frequency band of excitation up to 8 Hz, these models deliver remarkable deviations from measured tire characteristics. To overcome this limitation, a nonlinear Maxwell spring-damper element was introduced which is qualified to model the dynamic hardening of the elastomer materials of the tire.

Modern small capacity motor scooters make high demands on a trendy vehicle design in combination with a customer friendly handling and multifarious storage space. In addition, increasing engine performance characteristics and high requirements on the vehicle weight call for the development of new vehicle frame concepts. Considering lightweight construction and strength durability, the new concepts are also due to fulfill the boundaries of a low cost production. The driving behavior of a scooter is directly influenced by the interaction of the suspension components, the mounting system of the drive unit and the stiffness of the frame. The present publication treats an assessment of different frame types in the 50cc scooter class by tests and simulation with the target to formulate key data regarding the solidness and stiffness characteristics. Based on these data collection a complete new frame concept has been designed and revised by calculation.