In order to comprehensively analyze the adaptability of four-leg hydraulic support with large mining height under impact dynamic load, this paper adopts HyperMesh software to conduct a flexible pretreatment for the top beam, shield beam, and front and rear rods. The numerical simulation model of four-leg hydraulic support is established with ADAMS, where variable stiffness spring is used to replace columns to simulate their elastic characteristics. Building on analysis of the specific parameters of the support, this paper attempts to study the adaptability of the hydraulic support with impact dynamic load acting on the top beam. Additionally, the impact coefficient I and the excitation coefficient E have been introduced to transform the analysis results and optimize the evaluation method of the response degree of the top beam under impact load. Consequently, the response characteristics of the columns and pins at the hinged joints under various coupling states of the surrounding rock are found. Meanwhile, the paper has made a detailed comparison on the stress state of hydraulic support with different impact loads acting on the top beam. The adaptability change rule of the impact dynamic load under various impact conditions has been explored, which is of great significance to the optimization and strength design of four-leg hydraulic support with large mining height.

Hydraulic support is significant in the mining process because it serves as the primary supporting equipment in a coal mine. The roof beam and shield beam of hydraulic support are easily damaged because of the dynamic impact loads it has to bear. To improve its working performance, this study investigated the movement trend, pose, and mechanical response of hydraulic support when its roof beam and shield beam were subjected to impact loads. First, the roof beam, shield beam, and bars were made flexible using Hypermesh software. Then, a numerical simulation model of the hydraulic support was constructed using Adams software. The working resistance of the support was provided by two active external load signals applied vertically to the roof beam and located above the upper column. The impact load was applied along the normal direction of the top beam and the shield beam toward the symmetrical centre. The pose and stress state variations of the support were obtained under different impact conditions through measuring the variations of the rotation angles of the roof beam, deflection angles of the columns, length of the columns and balanced jack, and force of the hinge points. Results indicate that various trends of the hydraulic support under different impact effects are different, and in general, the support is more easily damaged when the impact load acts both on the roof beam and the shield beam compared with the single impact condition. This study is helpful for the stability control and structural design of the hydraulic support.

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