Simulated Road Profiles According to ISO 8608 in Vibration Analysis

Abstract

Nowadays, synthetic longitudinal road profiles based on an ISO 8608 road classification are used for simulation purposes to solve various tasks in vibration analysis of mechanical and civil structures and road-vehicle-driver interaction system. Standard ISO 8608 specifies road classification of longitudinal road profiles based on vertical displacement power spectral density (PSD). PSD represented on logarithmic scales is characterized by two parameters of a straight line, an unevenness index and waviness. The aim of this study was to compare spectrum parameters of real roads with ISO 8608 road classes used in scientific papers. Road classes that were used in a sample of 27 current scientific papers were analyzed. Results often indicated marked differences among road classes used for simulation purposes in comparison to the spectrum properties of real roads. For simulation purposes, road Class A may be recommended as representative of typical good or average quality road (motorway, expressway, and first class road). Classes B and C may be appropriate to simulate low-quality paved surfaces (2nd and 3rd class roads or local highways).

Design and Potential Power Recovery of Two Types of Energy Harvesting Shock Absorbers

“…Neither the curves, nor the cant on the roads, nor the accelerations or decelerations of the vehicle are taken into account, all these conditions would only increase the power generated by the EHSA. Using the same approach as Múčka et al [42], it can be deduced that the power that would be generated circulating at 120 km/h with the Ford Focus in the case of German roads (G q (n 0 ) = 100•10 −6 m 3 ) would be between 350-500 W, for Chinese roads (G q (n 0 ) = 270•10 −6 m 3 ) it would increase to 400-700 W, and for roads in Eastern Europe (G q (n 0 ) = 400•10 −6 m 3 ) it would be between 700-1200 W. Keep in mind that in all these results, the vehicle is driving in a straight line at a constant speed. Neither the curves, nor the cant on the roads, nor the accelerations or decelerations of the vehicle are taken into account, all these conditions would only increase the power generated by the EHSA.…”

Assessment of the Road Surface Condition with Longitudinal Acceleration Signal of the Car Body

“…In order to determine the periodic vibrations of the body, the correlation function was proposed. These functions belong to the classic methods of analysis of deterministic signals disturbed by random noise [ 9 , 31 ]. To determine the periodicity of the analyzed signal in relation to time t , the autocorrelation function R xx ( τ ), described by Equation (2), is used to identify the periodicities hidden in the noise of the analyzed acceleration of the body.…”

“…To determine the periodicity of the analyzed signal in relation to time t , the autocorrelation function R xx ( τ ), described by Equation (2), is used to identify the periodicities hidden in the noise of the analyzed acceleration of the body. It allows to determine the time consistency between adjacent fragments of the analyzed process (signal), shifted by different time values ( t ) and ( t + τ ) [ 9 ]. By measuring the amplitude in two moments, separated by a delay ( τ ), and multiplying the obtained values and averaging them after the recording time, statistical information about the signal periodicity was obtained.…”

“…As a result, the linear acceleration components of the body are generated. Due to the shape of the profile of the road surface roughness, differences in the determined (e.g., sinusoidal) and random profiles occur [ 9 ]. For their geometric analysis and identification, the power spectral density function, the amplitude spectrum and statistical parameters are used.…”

Assessment of adjustable damping in the ride comfort of a baja SAE vehicle

“…The vehicle will be excited by a random signal added to a harmonic input function that will simulate a road roughness for a poor unpaved road and the oscillations present in the baja SAE track. The use of random signal is a common approach for suspension optimization [25], leading to a better understanding of shock absorber performance [15] and is widely used in vibration evaluation [20]. Finally, results will be compared to [26] to evaluate the level of vibration for different shocks configurations and understand how these affect vehicle ride.…”