1887

Abstract

Summary

Rock physics experiments based on the stress-strain oscillation method are often conducted to obtain elastic parameters of rocks in the seismic frequency band. However, real experiments sometimes show anomalous amplitudes for the measured strains in some frequency zone. These strain amplitudes, if used for calculation of the elastic moduli, will lead to unreliable results. To investigate the cause and effect of these anomalies, we established a numerical simulation model for a typical setup for the stress-strain oscillation apparatus using the finite element method. We find that the resonance modes of the measurement system cause non-uniform distribution of stress along the sample column in addition to the boundary effect, and thus cause anomalous amplitudes for the strains and the elastic moduli calculated. Comparisons between the simulation results at one resonant frequency and non-resonant frequencies show that the resonance introduce as much as 1455.8% relative to the true value for Young's modulus, and 385.8% for Poisson's ratio. Therefore, the numerical modeling of stress-strain oscillation experiments are helpful in quantitative error analysis and calibration, and thus can be used for guidance such real experiments in the laboratory.

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/content/papers/10.3997/2214-4609.201901032
2019-06-03
2019-12-13
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References

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