冲击载荷下不同尺寸煤岩动力学分析及损伤特性研究  

Dynamic analysis and damage characteristics of coal rock with different sizes under impact loading

作　　者：王磊[1] 邹鹏 谢广祥[1] 范浩[1] 焦振华 陈礼鹏 WANG Lei;ZOU Peng;XIE Guangxiang;FAN Hao;JIAO Zhenhua;CHEN Lipeng(State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mine,Anhui University of Science and Technology,Huainan 232001,China)

机构地区：[1]安徽理工大学深部煤矿采动响应与灾害防控国家重点实验室,安徽淮南232001

出　　处：《振动与冲击》2023年第22期322-331,共10页Journal of Vibration and Shock

基　　金：安徽高校协同创新资助项目(GXXT-2020-055);国家自然科学基金青年科学基金(52204083)。

摘　　要：为探究冲击载荷作用下不同尺寸煤岩的动态力学及损伤特性,利用分离式霍普金森压杆系统对直径50 mm长度分别为15 mm,20 mm,25 mm,30 mm,35 mm,40 mm,45 mm和50 mm的煤岩开展了冲击压缩试验,通过分析应力-应变曲线特征得出应变率、峰值应力和动态弹模随尺寸变化的关系,并基于能量耗散规律提出煤岩受载全过程动态损伤指标K,同时与Weibull分布结合D-P准则得出的损伤变量D_(w)进行对比,探究不同尺寸煤岩的动态损伤特性。结果表明:不同尺寸煤岩的动态应力-应变曲线包含弹性、塑性和塑性软化3个阶段。随煤岩尺寸的增加,应变率和峰值应力呈减小趋势,动态模量为线性增加;动态损伤指标K是煤岩弹性阶段结束后的瞬时破碎耗能与完全破坏时对应总破碎耗能的比值;动态损伤指标与损伤变量的曲线形态具有相似性,变化趋势具有一致性,表明了K的合理性。指标K的最大损伤值更稳定、更符合破坏状态假设,说明了其具有一定的适用性。In order to investigate the dynamic mechanics and damage characteristics of coal rock with different sizes under impact loading,impact compression tests of coal rock with 50 mm diameter and length of 15 mm,20 mm,25 mm,30 mm,35 mm,40 mm,45 mm and 50 mm were carried out by using the split Hopkinson pressure bar system.By analyzing the characteristics of the stress-strain curve,the relationship between the rock size and the strain rate,peak stress and dynamic elastic modulus was obtained.Based on the law of energy dissipation,the dynamic damage index K of coal rock in the whole process of loading was proposed,and the dynamic damage characteristics of coal rock with different size were explored by comparing with the damage variable D_(w) derived according to the Weibull distribution combined with D-P criterion.The results show that the dynamic stress-strain curves of coal rock with different sizes include three stages,namely,elastic,plastic and plastic softening.With the increase of coal size,the strain rate and peak stress decrease,and the dynamic modulus increases linearly.The dynamic damage index K is the ratio of instantaneous crushing energy dissipation at the end of elastic stage of coal rock to the corresponding total crushing energy dissipation when it is completely destroyed.The curve shape of the dynamic damage index and damage variable is similar,and the change trend of them is consistent,which shows that K is reasonable.The maximum damage value of index K is more stable and more consistent with the hypothesis of failure state,which shows that it has certain applicability.

关 键 词：霍普金森压杆 煤岩 不同尺寸 力学特性 动态损伤指标 

分 类 号：TH212[机械工程—机械制造及自动化] TH213.3