Road Surface Irregularities Research Articles

Messungen von Fahrbahn-Unebenheiten paralleler Fahrspuren und Anwendung der Ergebnisse

SUMMARY Measurement of two track road inputs and theoretical application of the results The calculation of vehicle response to road-surface irregularity inputs requires the spectral densities of the left and right longitudinal track and their statistical dependence This paper presents some resluts of parallel profile measurements, three typical german roads have been chosen Random vibration of two vehicle types are digital-simulated. The dynamic tire load shows that independent suspension systems are more advantageous than beam axles, because by wheel tramp this type increases the dynamic tire load.

The Riding Qualities of Wheeled Vehicles

A wheeled vehicle traversing an irregular road surface is subjected to forced vibration. This vibration is analysed into heaving, pitching, and rolling modes, and means are described to compute or simulate the response of the vehicle both to continuous excitation at definite frequencies, and to isolated obstacles affecting one wheel at a time. It is shown that a simple model, comprising only rigid masses, linear springs, and velocity damping, suffices to represent the riding quality of the vehicle, and a procedure by which the model may be matched to the vehicle as closely as possible is described. The theory is illustrated by computation of the impact loads imposed on the wheels of a six-wheeled lorry when surmounting artificial obstacles, allowance being made for the effects both of the wheels leaving the road, and of interaction between the four wheels in the rear truck. Good agreement with experimental records of wheel load is shown, and it is suggested that similar computation or simulation applied to passenger-carrying vehicles would prove of value in the improvement of riding quality.