An experimental-numerical method for the prediction of on-road comfort of city bicycles

Abstract

A low-cost experimental-numerical method for the prediction of on-road comfort of city bicycles is presented. Experimental tests are performed by exciting the wheels of the bicycle with impulsive vibrations and measuring the frequency response functions (FRFs) between different sensitive points of the bicycle (i.e. seatpost and steerer tube) and the wheels. Laboratory tests are carried out with the rider on the bicycle, and the posture is carefully checked. A mathematical model is employed to predict the accelerations experienced by the rider on the road, considering tyre and wheelbase filtering. As a verification of the proposed methodology, comfort predictions obtained with the experimental-numerical method are compared with reference data obtained from road tests. A general agreement in terms of the root mean square values and power spectral densities is found.

Energy Harvesting From Bicycle Vibrations

“…Most of the vibration energy is concentrated in the range from 0 to 40 Hz. This typical phenomenon happens because in bicycles the high-frequency excitation from the road is filtered by the tire enveloping effect [16]. Therefore, many high-frequency modes of vibration of the bicycle, that are related to the structural deformation of frame and forks, are not significantly excited.…”

Energy Harvesting from Bicycle Vibrations by Means of Tuned Piezoelectric Generators

“…Another evident feature of these acceleration PSDs is that almost all the power is contained in the range 0-40 Hz, as a consequence of the tyre filtering effect [9]. The pneumatic tyre acts like a low-pass filter on the road profile, filtering low-wavelength perturbations thanks to its geometry and compliance.…”

“…The bicycle is very popular sport equipment and also an efficient means of transport that strongly contributes to eco-friendly mobility in urban and sub-urban areas. The rolling motion of the wheels on a rough road generates significant vibration levels in many parts of the bicycle and some researches have been carried out to improve riding comfort [8,9]. Vibration levels are low only in very particular conditions, as in racing bicycles in indoor tracks or in top-level city bicycles equipped with shock absorbers and running in good quality bicycle lanes.…”