On-the-road Measurements to Establish the Dynamic Characteristics of Transport Vehicles

Abstract

This paper deals with a proposed approach to estimate the dynamic characteristics of road vehicles using only on-the-road response data. Previous work undertaken by the authors was ultimately unable to be validated as the actual pavement elevation profile traversed by the single-wheeled, idealized vehicle was unknown. In order to address this, the single-wheeled vehicle used by the authors was instrumented to operate as an inertial profilometer in order to measure the actual longitudinal pavement elevation profile to establish the transmissibility frequency response function of the vehicle during operation. The on-theroad transmissibility frequency response functions were compared with those established in the laboratory (using a large-scale vibration table) and found to significantly differ, particularly in the level of damping of the sprung mass mode (body) of the vehicle. The unsprung mass mode (axle-hop) resonant frequency is also consistently observed to shift to a lower frequency during operation (on-the-road). Two approaches are outlined to estimate the spectral exponent of the assumed pavement elevation spectral model but were found to yield inaccurate results because of the variation in the pavement profiles travelled by the vehicle during each experimental run. The in-built profilometer revealed that it is incorrect to use an assumed spectral model for the excitation as it is unable to accurately represent the actual pavement spectrum travelled over by the vehicle.

Paper as an alternative for collation shrink film

“…Two additional bands of paper with the same circumference are produced to repeat the test. An increasing horizontal inertia forces test: Bundles are almost always stacked in several layers on a pallet for transport by road and possibly rail. During this transport, inertia forces occur in the direction of travel due to acceleration and deceleration of the vehicle and in the transverse direction due to changes in direction 33–41 . In practice, the accelerations and decelerations almost always remain under 2 m/s 2 and occur with intervals of several minutes.…”

Estimation of road transport vehicle dynamic characteristics using random decrement analysis and on-the-road vibration data

“…To address this, a practical method using only a relatively short record of the vertical vibration response of a vehicle's sprung mass mode travelling at a nominally constant operating speed was developed. The method, based on the random decrement technique, was initially developed and validated using a custom-design single-wheeled experimental vehicle (Ainalis et al, 2015b;Ainalis et al, 2016). The analysis technique is described in further detail in the following section.…”

Practical Considerations for Estimating Road Vehicle Frequency Response Functions from Response Data

“…Typical example of the estimated spectral exponent (as a function of frequency) for various nominally constant speed ratios for the SWEV‐A (50 kg) travelling over route BG, from …”

“…A complete description of the development and evaluation of this approach can be found in. 19,20 Random Decrement-based Approach A second analytical approach was developed based on the use of the random decrement technique to analyse the on-the-road vibration response data. The random decrement technique is designed to estimate the dynamic characteristics of a system using only response data and was first proposed by Henry Cole in the late 1960s to detect the failure of aerospace components.…”