Evaluation of Material Damping Properties in Bituminous Coal: A Comparative Analysis of Numerical and Experimental Approaches

The study employed novel non-destructive testing techniques for coal sample such as resonant column testing, cyclic torsional technique, and ultra-sonic pulse velocity analysis.

The study confirms the coal in the present study as bituminous coal by analyzing the microstructure and composition of coal using scanning electron microscope and energy-dispersive X-ray spectroscopy method.

The damping characteristics (resonant frequency, damping ratio) and dynamic shear modulus of the coal are determined using the resonant column test and the ultrasonic pulse velocity test. Further, numerical simulations using the finite-element method (FEM) in ABAQUS software are performed to obtain resonant frequencies for intact coal samples under torsional and flexural vibrations, and the results of the experimental and numerical studies are found to be in good agreement.

The study has established a critical damping factor range based on the input frequency that can help ensure sustainable design of underground and surface mines.