An experimental study on the failure characteristics of magnetite ore based on dynamic load

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Journal of Vibration and Shock ›› 2019, Vol. 38 ›› Issue (12) : 231-238.

LI Zhanjin1, HAO Jiawang1, 2, GAN Deqing1, LIU Zhiyi1

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Abstract

The impact experiments of magnetite ore under different strain rates were carried out by a splitting Hopkinson pressure bar (SHPB) equipment.The mechanical properties and the crack propagation of the magnetite ore under dynamic load were analyzed to evaluate the distribution pattern of the fragmentation of the magnetite ore.Experiment results indicate that the strain rate effect of the dynamic elastic modulus and strength of the magnetite ore is obvious.The unloading rates and unloading modes in the post-peak of stress-strain curve are different under different strain rates.With strain rate increasing, the softening factor (K) of the magnetite ore decreases and the softening degree increases.Both the relations between the strength scale factor (λ) of the magnetite ore and ε?1/3, and the specific energy absorption of the magnetite ore and ε? are linear distribution.The broken form of the magnetite ore is of distinct self-similarity that the mean fragment size of the magnetite ore decreases, fractal dimension increases and the magnetite ore is broken strongly with strain rate.The fractal dimension increases linearly both with the strain rate and the specific energy absorption of the magnetite ore.The distribution pattern of the fragmentation of the magnetite ore, which is clearly revealed by means of the total logarithmic curve of the cumulative particle size, combined with the block distribution coefficient (C), the reasonable range of the strain rate of the magnetite ore crushing is obtained.The study results provide significant references for the analysis of the crushing mechanism of magnetite ore under dynamic load, the distribution of the fragmentation and the energy consumption.

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magnetite ore / SHPB / mechanical properties / strain rate / failure mode / the fractal dimension

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LI Zhanjin1, HAO Jiawang1, 2, GAN Deqing1, LIU Zhiyi1. An experimental study on the failure characteristics of magnetite ore based on dynamic load[J]. Journal of Vibration and Shock, 2019, 38(12): 231-238

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