Dynamic strength of granite porphyry under freezing-thawing cycles

Abstract

Elastic modulus, Poisson's ratio, uniaxial compressive strength, tensile strength and dynamic stress- strain curves of granite porphyry were obtained under freezing-thawing cycles utilizing the relevant static and dynamic experiments. On the basis of parameter analysis to Holmquist-Johnson-Cook(HJC) model, numerical simulations of the split Hopkinson pressure bar(SHPB) tests were carried out utilizing the finite element software LS-DYNA. According to the results of numerical simulations and experiments, the relationships of the dynamic strength with the strain rate and the freezing-thawing cycles were obtained. The shapes of the stress-strain curves, the reflected and transmitted waves before and after freezing-thawing were different. Samples with the same incident wave under freezing-thawing cycles had the different strain rate. The numerical simulation on the basis of HJC model parameters agreed well with the results of SHPB experiment. The numerical simulation and the laboratory test complemented each other. The strain rate and the freezing-thawing cycles had opposite but interconnected effects on the dynamic strength.