Tire characteristics and behavior are of great importance in vehicle dynamics since the forces transmitted in the tire-road contact are the main contributors to global vehicle performance. Several research groups have focused on the study and modeling of tires. Some of the most important factors that need to be known are tread characteristics and pressure distribution in the tire-ground contact patch. In this work, a test bench has been used to adequately determine the aforementioned factors. The measurement principle of the test bench is the frustration of total internal reflection (FTIR) of light. It makes use of a laterally illuminated glass on which the tire leans. An interposed plastic interface between them causes the reflection of light. Finally, a video camera captures the bright image formed through the glass. The brightness level in each pixel of the image is related to existing normal pressure. A study of the parameters that affect the test bench calibration such as type of interface material used, diffuse light, hysteresis, creep and transverse light absorption is performed. Experimental tests are conducted to relate tire inflation pressure and camber angle to the pressure distribution. Furthermore, the test bench is used to detect and evaluate the influence of defects in the tire on the contact pressures.

This paper presents results from experiments on soft impact testing of glass plates. In the experiments, a 50-kg twin-tire pendulum was used to strike different glass plates at speeds of up to 4.85 m/s. The impact parameters that were defined and measured include the micro-strain in the glass plates, pendulum acceleration, duration of contact, pendulum height, and maximum tire track values. A total of 240 impacts on 17 specimens were carried out for different glass thicknesses (5, 6, 8, and 10 mm) and boundary conditions (four sides, two sides and four pin points supported). Tempered monolithic and toughened bi-layered laminated plates were tested. To find out if the selected parameters represent the phenomena, multiple regression analysis was carried out.

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