Open AccessStrain Rate Effect on Acoustic Emission Characteristics and Energy Mechanisms of Karst Limestone under Uniaxial Compression
Author(s) -
Qingsong Wang,
Jianxun Chen,
Jiaqi Guo,
Yanbin Luo,
Yao Li,
Hongyu Wang,
Qin Liu
Publication year - 2020
Publication title -
advances in materials science and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 42
eISSN - 1687-8442
pISSN - 1687-8434
DOI - 10.1155/2020/6871902
Subject(s) - materials science , acoustic emission , coalescence (physics) , strain (injury) , strain rate , logarithm , composite material , slow strain rate testing , elastic modulus , strain energy , compression (physics) , structural engineering , mathematics , medicine , mathematical analysis , physics , alloy , finite element method , astrobiology , stress corrosion cracking , engineering
In this paper, the strain rate effect on mechanical properties, failure modes, acoustic emission (AE) characteristics, and energy mechanism of the karst limestone was analyzed based on uniaxial compression tests with different strain rates (5 × 10 −6 –5 × 10 −4 /s). The results showed that the peak strength increased linearly and peak strain increased quadratically with the logarithm value of the strain rate. Moreover, the strain rate effect on elastic modulus was not significant. Under low strain rates, the rock was damaged seriously, AE signals appeared continuously, and the cumulative number of AE signals was high. Under high strain rates, the total quantity of the macroscopic cracks decreased, but the crack length extended with better coalescence. The AE peak significantly increased under high strain rates, while the cumulative AE activity significantly reduced. The energy evolution of the karst limestone failure process had significant stage characteristics, and the strain energy ratio presented an S-shape. The maximum value of the elastic strain energy at peak stress showed a linear relationship with the logarithm value of the strain rate.