Evaluation of Flexure Modulus and Energy Dissipation in Intact Rocks Using Resonant Column Testing and Numerical Simulations

Design and analysis of rock structures subjected to earthquakes, machine vibrations, blasts, and other cyclic loads require reliable knowledge of their dynamic mechanical properties, particularly Young’s modulus. This study evaluates the flexural dynamic behavior of rocks using the resonant column (RC) apparatus in flexure mode, where the flexure modulus is related to Young’s modulus through beam theory. Four rock types—Gypsum plaster, Kota sandstone, Jodhpur sandstone, and Makrana marble—were tested across varying strain amplitudes. The RC apparatus was calibrated for flexure to ensure accuracy, and damping ratios were obtained using both free vibration decay and bandwidth methods. Numerical simulations with 3DEC replicated the RC setup, validating experimental results through comparison of peak displacements. Findings show that flexure modulus and damping ratio vary significantly with strain amplitude, highlighting nonlinear dynamic response. This research advances understanding of rock behavior under flexural loading, aiding seismic analysis, foundation design, and rock-support systems.