厚径比对高阻尼橡胶材料的缓冲吸能特性实验

Experimental study on buffering and energy absorption characteristics of high damping rubber material with thickness-diameter ratio

摘要:

为减少深部强扰动诱发的岩石冒落、岩爆等动力灾害,将具有良好防冲和吸能特性的高阻尼橡胶材料应用于拟研发的新型小应变吸能锚杆中.为系统评价厚径比对高阻尼橡胶材料缓冲吸能的影响,采用落锤冲击系统和分离式霍普金森压杆(SHPB)装置,对不同厚径比的高阻尼橡胶试样和“橡胶-花岗岩”组合试样进行冲击实验.落锤实验结果表明,相同冲击条件下,随着厚径比增大材料的动力响应呈幂函数趋势递减,且当厚径比大于0.6时材料动力响应变化幅度趋于平稳.同时,在同落距的6次单独重复冲击中,材料每次动力响应峰值与第一次动力响应相比其改变幅值均在15%以内；SHPB冲击结果表明,材料在厚径比0.3处取得最大吸能率为0.336.在相同气压冲击下,“橡胶-花岗岩”组合试样的花岗岩分形维数（D）随着厚径比增大呈幂函数递减,在厚径比大于0.3时D值趋于平稳,变化幅值较小.

Abstract:

Aiming at reducing the dynamic disasters such as rock fall and rock burst caused by deep strong disturbance, high damping rubber material with good anti-scouring and energy absorbing characteristics was applied to a new type of small strain energy absorbing bolt. To systematically evaluate the influence of geometric dimensions on the buffering and energy absorption properties of high damping rubber materials, the drop hammer impact system and SHPB device were used to carry out impact tests on high damping rubber samples and “rubber-granite” composite samples with different thickness-diameter ratios. Results of drop hammer impact system test show that under the same impact condition, the dynamic response of the material decreased with the increase of the thickness-diameter ratio and it tended to be stable when the thickness-diameter ratio was greater than 0.6. In addition, the peak value of each dynamic response of the material was less than 15% compared with the first dynamic response in six repeated impacts with the same drop distance. SHPB impact test results show that the maximum energy absorption rate was 0.336 at the thickness-diameter ratio of 0.3. Under the same pressure impact, the fractal dimension (D) of granite decreased with the increase of thickness-diameter ratio. When the thickness-diameter ratio was greater than 0.3, the D value tended to change steadily with smaller amplitude.