Investigation on the dynamic fracture property of oblique open-joints under bunch-hole explosion

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Journal of Vibration and Shock ›› 2019, Vol. 38 ›› Issue (6) : 151-158.

LI Qing, GUO Yang, XU Wenlong,PENG Yang, LV Chen, MA Rundong

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Abstract

The dynamic caustic method and ABAQUS numerical simulation were used to study the fracture mechanics characteristics of oblique open-joints in the column area and at the end region under bunch-hole explosion in oblique open-joints medium. The transmitted wave and diffracted wave generated by the initial explosion stress wave in the oblique open joints are superimposed on the initial explosion stress wave and the wing crack in the column area of the borehole propagates perpendicularly to the oblique open-joints surface due to the tensile-shear stress. Compared with the wing crack at the near-end of oblique open-joints, the propagation speed, crack length and stress intensity factor of the wing crack at the far-end of oblique open-joints are bigger. The reflected tensile wave generated by the explosion stress wave at the boundary of the specimen and the oblique open-joints interact with each other so as to induce the happening of secondary crack, which initiates and propagates similarly along the horizontal direction due to the tensile stress. The initial toughness of the secondary cracks at the far-end of oblique open-joints is about 0.5 times that of the wing crack. The secondary crack length is shorter than the wing crack because the intensity of the reflected wave is weaker. The wing crack and secondary crack at the end area of borehole occur due to the interaction of the oblique open-joints with the reflected tensile wave and diffracted wave in the oblique open-joints. The wing crack tends to initiate in the borehole direction, and propagates in the opposite direction, while the secondary crack initiates and propagates gradually along the direction of explosion stress waves.

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Dynamic caustic method / ABAQUS numerical simulation / bunch-holes / explosive stress wave / oblique open-joints

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LI Qing, GUO Yang, XU Wenlong,PENG Yang, LV Chen, MA Rundong. Investigation on the dynamic fracture property of oblique open-joints under bunch-hole explosion[J]. Journal of Vibration and Shock, 2019, 38(6): 151-158

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