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冲击荷载作用下单元式吸能防冲液压支架响应特性

Response characteristics of unit type energy-absorbing and anti-impact hydraulic support under impact load

  • 摘要: 在冲击地压矿井中,掌握超前液压支架的力学特性及其模态响应特性是巷道超前液压支架选型与优化设计的基础和前提。针对如何提升单元式液压支架吸能防冲性能问题,开展冲击荷载作用下单元式吸能防冲支架响应特性研究。采用非线性有限元分析软件ABAQUS/Explicit显式求解器,建立单元式吸能防冲液压支架数值计算模型,通过数值模拟对吸能防冲支架进行竖向冲击试验,分析吸能防冲支架的力学响应特性与模态响应特性,探究单元式吸能防冲液压支架的吸能特性、固有频率与易变形部件。结果表明:力学响应特性方面,冲击荷载作用下,单元式吸能防冲支架表现出了良好的“让压降阻、减震降幅、吸能止冲”的综合效能;整个冲击过程中,吸能防冲支架共计吸收2.30 MJ的能量,吸能器塑性变形耗能占40%~50%。模态响应特性方面,单元式吸能防冲液压支架整机固有频率为665.37~3 280.5 Hz,频率较高。该吸能支架对近场顶板脆性断裂或煤体压缩失稳等中高频类型冲击地压显现具有良好的避频适应性。由数值模拟计算结果可知,液压支架的2根立柱和立柱护板是最容易发生振动变形的部件。立柱设计时要重点考虑避免第1、2、4、5、6和9阶振动频率处的振动变形,尤其主振型的避频设计;立柱护板设计时要重点考虑避免第1、2和9阶振动频率处的振动变形及其变形趋势。研究结果能够为巷道吸能防冲液压支架的合理选型与后续优化设计提供技术支撑。

     

    Abstract: In the rock burst mines, mastering both the mechanical and modal response characteristics of advanced hydraulic supports is the basis and premise for the selection and optimization of roadway advanced hydraulic supports. Research was conducted on the response characteristics of unit-type energy-absorbing and anti-impact hydraulic supports under impact loads to address the issue of enhancing anti-impact performance. Using the nonlinear finite element analysis software ABAQUS/Explicit, the numerical calculation model of the unit type energy-absorbing and anti-impact hydraulic support was established. The vertical impact test was carried out on the energy-absorbing and anti-impact supports by numerical simulation, both the mechanical and modal response characteristics of the energy-absorbing and anti-impact supports were analyzed, and the energy-absorbing characteristics, natural frequency, and easily deformable components of the unit type energy-absorbing and anti-impact hydraulic support were explored. The results show that in terms of mechanical response characteristics, under the impact load, the unit type energy-absorbing and anti-impact support exhibits a good comprehensive efficiency of “reducing pressure to drop resistance, damping to mitigate amplitude, and absorbing energy to stop impact”. During the entire impact process, the energy-absorbing and anti-impact support absorbed a total of 2.30 MJ of energy, and the plastic deformation energy consumption of the energy absorber accounted for 40% to 50%. In terms of modal response characteristics, the natural frequency of the unit type energy-absorbing and anti-impact hydraulic support is 665.37−3280.5 Hz, which is relatively high. The support has good frequency avoidance adaptability for medium-high frequency types of rock burst, such as brittle fracture of the near-field roof or instability of coal compression. Through numerical simulation calculations, it is found that the two pillars of the hydraulic support and the pillar guard plate are the most susceptible components to vibration deformation. When designing pillars, it is important to avoid vibration deformation at the 1st, 2nd, 4th, 5th, 6th, and 9th order vibration frequencies, especially in the frequency avoidance design of the main vibration mode; When designing pillar guard plates, it is important to avoid vibration deformation and its deformation trend at the 1st, 2nd, and 9th order vibration frequencies. The research results can provide technical support for the rational selection and subsequent optimization of energy-absorbing and anti-impact hydraulic supports in roadways.

     

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