摘要
为了研究PBX炸药裂纹起裂扩展全过程的断裂行为规律,基于三点弯曲断裂试验载荷-裂缝口张开位移(P-CMOD)曲线的测试技术,结合双K断裂准则,对HMX基PBX炸药在20~60℃下的断裂行为和断裂参数进行定量表征。结果表明,在位移控制下的准静态线性加载断裂过程中,裂缝口张开位移(CMOD)随着时间演变先近似线性平稳增加,之后发生短暂急速增加,而后继续近似线性快速增加;急速增加的跃升段随温度升高而趋势有所减缓,且60℃下CMOD无急速跃升段;P-CMOD曲线上载荷在初期线性上升时,裂纹不起裂扩展,当达到起裂载荷后转为非线性上升裂纹开始稳定扩展,达到峰值载荷后裂纹处于失稳扩展状态;整体上起裂断裂韧度K_(IC)^(ini)和失稳断裂韧度K_(IC)^(un)均随温度的升高而降低,但起裂断裂韧度相较于失稳断裂韧度随温度变化更剧烈,黏聚断裂韧度随温度升高而增大,临界裂缝扩展长度随温度的升高显著增长。表明本试验方法可实现对PBX三点弯曲试样P-CMOD曲线的精确测量并计算其断裂过程参数。
To investigate the fracture behavior patterns of PBX explosive cracks throughout the entire cracking and propagation process,the fracture behavior and fracture parameters of HMX-based PBX explosives at temperatures ranging from 20℃to 60℃were quantitatively characterized through a testing technique based on the load-crack mouth opening displacement(P—CMOD)curve from three-point bending fracture tests,combined with the dual-K fracture criterion.The results indicate that during quasi-static linear loading fracture under displacement control,the crack mouth opening displacement(CMOD)first increases approximately linearly and steadily over time,followed by a brief rapid increase,and then continues to increase approximately linearly at a rapid rate.The trend of the rapid increase segment slows down with increasing temperature,and at 60℃,there is no rapid increase segment in CMOD.On the P—CMOD curve,during the initial linear increase in load,the crack does not initiate propagation.After reaching the initiation load,the load increases non-linearly,and the crack begins to propagate stably.After reaching the peak load,the crack shows an unstable propagation state.Overall,both the initial fracture toughness K_(IC)^(ini) and the unstable fracture toughness K_(IC)^(un) decrease with increasing temperature.However,the initial fracture toughness exhibits a more pronounced temperature-dependent variation compared to the unstable fracture toughness.The cohesive fracture toughness increases with rising temperature,and the critical crack propagation length shows a significant increase with temperature.This study indicates that the experimental method can accurately measure the P—CMOD curve of PBX three-point bending specimens and calculate the fracture process parameters.
作者
刘振晓
王丽君
唐维
董天宝
文乾乾
单骏鹏
LIU Zhen-xiao;WANG Li-jun;TANG Wei;DONG Tian-bao;WEN Qian-qian;SHAN Jun-peng(Institute of Chemical Materials,China Academy of Engineering Physics,Mianyang Sichuan 621900,China)
出处
《火炸药学报》
北大核心
2025年第8期698-705,I0001,共9页
Chinese Journal of Explosives & Propellants
基金
国家自然科学基金(No.12002322)。
