Identification of dynamic rock properties using a genetic algorithm

In the present study, a genetic algorithm is implemented to identify the dynamic property of hard rocks in the Split Hopkinson Pressure Bar (SHPB) test. Numerical simulation of the SHPB test based on one-dimensional wave propagation theory and finite difference method is developed. To demonstrate the efficiency of the parameter identification by using genetic algorithm, a stress-strain curve for granite is predefined. The measured signals are obtained from the numerical SHPB test and they are subsequently applied to reconstitute the stress-strain curve by using genetic algorithm. It is shown that the reconstituted curve can match the given curve very well, no matter one signal or two signals of the measured strains are adopted. The results show that the present method has the ability to identify the dynamic stress-strain curve of hard rock by cementing the strain gauges at any point on the incident bar and the transmitted bar. The parameter identification method proposed in the present study has been further developed to modify the conventional SHPB configurations by using short pressure bars.