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The paper presents a method of simultaneously measuring the normal and shear stresses in the tire-road contact patch. For this purpose a tri-axial road transducer was designed to work under real rolling conditions. Its design allows the real contact surface to remain unaltered. The tests were performed using passenger car and truck tires, in braking, traction and free rolling conditions. The resulting stress distributions on the contact patch length are displayed as contour or relief maps. The rolling conditions are strongly influencing the longitudinal stress distribution.

The paper presents some aspects of the experimental investigation of shear stresses in the tire-road contact patch. The rolling process is achieved by loading a freely rotating tire against a movable table. The rig structure, measuring stages, and special developed programs are mentioned. A comparison between treadless and pattern tread band design, pertaining to shear stress distribution, is presented. The influence of inflation pressure and normal force values on the shape and magnitude of the shear stresses is also shown.

The interaction tire-road at high speeds of rolling is a principal source of noise and vibration and influences the passenger comfort and safety. The paper presents the experimental and theoretical research on radial vibrations of tire tread-band at different rolling speeds. The experimental research involves the measurement of tread-band vibrations at 100 km/h, 140 km/h and 180 km/h rolling speeds. Also, the radial natural frequencies and corresponding mode shapes were measured. A two-dimensional finite element model was created for modal analysis and for study of tread-band radial vibrations at the mentioned rolling speeds. Likewise, the model enables the study of tire standing wave phenomenon. In order to correlate the model natural frequencies with the real tire ones, a model updating procedure was applied. The results offer useful information on the magnitude, on the circumferential distribution, and on the periodicity of tread-band radial vibrations.

The paper presents the theoretical and experimental research on radial vibrations of rotating passenger car tire at high speed of rolling, in contact with the road. A three-dimensional and a two-dimensional finite element tire models were created for modal analysis and for study of tire circumference deformed shapes at critical velocity of rolling. The experimental research involves the measurement of treadband accelerations of tire running on a drum at different speeds. The models make possible the prediction of the tire vibration behavior, even in projecting stage.

The paper presents a study of the preheating process of a diesel engine functioning at very low ambiental temperatures. A general preheating of the engine was used. The study consists of a mathematical modeling for the unsteady heat transfer in the cylinder and in the oil sump. Two versions of oil preheating equipament are analised. The numerical results are compared with the experimental ones.