A Study on Estimation of Vertical Road-load Inputs using the Vehicle Frequency Response Function

Vehicle service loads need to be measured under actual driving conditions in order to ascertain the strength and durability requirements for customer usage. However, because road-load data are influenced by the vehicle category and specifications of a vehicle, it takes an enormous amount of time and labor to compare them with existing data and analyze the relationship between service loads and vehicle specifications. This paper presents a study concerning the use of the frequency response function, which differs from one vehicle to another, as a means of predicting the response of a particular target vehicle based on the road-load data, which are input by unevenness of roads, measured for a baseline vehicle. The results predicted in bench tests showed a margin of error of around ±20%, making them sufficiently accurate for practical use. Rice's formula was applied as an index for evaluating the prediction accuracy of the power spectral density. A method is also described for using this formula to predict the frequency even in the case of data which are not normal distributions as a whole.