Experimental and numerical testing of prototypical under ballast mats (UBMs) produced from deconstructed tires – The effect of mat thickness
Cezary Kraśkiewicz, Artur Zbiciak, Jan Pełczyński, Anna Al Sabouni-Zawadzka
Abstract
In this study, the authors analyse performance of prototypical under ballast mats (UBMs) made of recycled rubber granulate and fibres, produced from end-of-life tires. First, a series of experimental tests is performed, in order to identify static and dynamic elastic characteristics (static bedding modulus, low- and high-frequency dynamic bedding modulus) of four UBMs with the same density and different thicknesses. Additionally, fatigue strength of the mat with a thickness of 20 mm is analysed. Then, the values of static and dynamic bedding moduli are used as an input in the finite element model of the ballasted track structure with UBM. The main aim of the numerical simulations is to compare mechanical behaviour of the reference system and systems with four different mats. It is proved that the thickness of UBMs has a significant effect on the values of static and dynamic bedding moduli, and on the effectiveness of vibration isolation. The insertion loss values vary between 62 % for the thickness 15 mm and 75 % for the thickness 30 mm (at the frequency 31.5 Hz, that is vibration), and between 37 % for the thickness 15 mm and 54 % for the thickness 30 mm (at the frequency 125 Hz, that is structure-borne noise).