This paper presents a numerical study on cracking of granitic rock by high frequency-high voltage-alternating current actuation (HF-HV-AC) of piezoelectric properties of Quartz mineral. For this end, a numerical method based on 3D embedded discontinuity finite elements for rock fracture and an explicit time stepping scheme to solve the coupled piezoelectro-mechanical problem is developed. Rock heterogeneity and anisotropy are accounted for at the mineral mesotructure level. Novel numerical simulations demonstrate that disc-shaped and cylindrical granitic rock specimens (with the tensile strength of about 8 MPa) can be cracked by a sinusoidal excitation with an amplitude of ∼10 kV at a frequency matching one of the resonance frequencies of the specimen (e.g. 125 kHz in the present case of 30 mm radius and 10 mm height). The effects of specimen shape and electrode locations are tested. Various Quartz grain alignment schemes are tested and even the worst case of having a 50%:50% mixture of right- and left-handed Quartz crystals without any preferred orientation show stresses of about 1 MPa at the resonance frequency. The simulation results suggest that HF-HV-AC piezoelectric excitation of Quartz bearing rocks could be a potential pre-treatment technique in comminution.

本文介绍了石英矿物压电特性的高频-高压-交流驱动(HF-HV-AC)对花岗岩开裂的数值研究。为此，开发了一种基于 3D 嵌入式不连续性有限元的岩石断裂数值方法和显式时间步长方案来解决压电-机械耦合问题。岩石的非均质性和各向异性是在矿物细观结构水平上考虑的。新的数值模拟表明，圆盘形和圆柱形花岗岩样品（抗拉强度约为 8 MPa）可以通过振幅为 10 kV 的正弦激励在与样品共振频率之一匹配的频率下破裂（例如，在当前半径为 30 毫米、高度为 10 毫米的情况下为 125 kHz）。测试样品形状和电极位置的影响。测试了各种石英晶粒排列方案，即使是具有 50%:50% 的右旋和左旋石英晶体混合物而没有任何优选取向的最坏情况，在共振频率下也显示出约 1 MPa 的应力。模拟结果表明，含石英岩石的 HF-HV-AC 压电激发可能是一种潜在的粉碎预处理技术。