基于RPC试件的爆炸应力波作用下I型裂纹扩展行为的研究  

Study of propagation behaviors of mode I cracks under blasting stress wave based on RPC specimens

作　　者：万端莹 朱哲明 刘瑞峰[1,2] 刘邦 李剑飞 WAN Duanying;ZHU Zheming;LIU Ruifeng;LIU Bang;LI Jianfei(MOE Key Laboratory Deep Underground Science and Engineering,Sichuan University,Chengdu,Sichuan 610065,China;College of Architecture and Environments Sichuan University Chengdu,Sichuan 610065,China)

机构地区：[1]四川大学深地科学与工程教育部重点实验室,四川成都610065 [2]四川大学建筑与环境学院,四川成都610065

出　　处：《岩石力学与工程学报》2019年第12期2478-2490,共13页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(11672194);四川省安全监管局安全生产科技项目(aj20170515161307);四川省科技计划项目(2018JZ0036)~~

摘　　要：为了研究爆炸荷载下I型裂纹的扩展行为,提出带预制裂纹的矩形板试件(RPC)。采用均匀且透明性好的有机玻璃制作试件。实验系统由超动态应变仪、示波器、恒压电源、电阻应变片以及裂纹扩展计组成。电阻应变片与裂纹扩展计分别被用于测量爆炸荷载与裂纹扩展速度。采用扫描电镜对裂纹扩展断面进行观察。在AUTODYN中模拟RPC试件中的裂纹动态扩展现象,采用JWL方程描述爆生产物的状态,线性状态方程被用于模拟有机玻璃压力与密度的关系,并采用修改的最大主应力准则预测材料的破坏状态。基于位移外推法,在ABAQUS中建立计算裂纹尖端动态应力强度因子的数值模型。通过实验与数值结果可得:(1)爆炸应力波作用下I型裂纹会形成稳定扩展阶段与不稳定扩展阶段;(2)裂纹稳定扩展阶段会形成粗糙度逐渐降低的断面,裂纹不稳定扩展阶段形成的断面较为光滑;(3)裂纹在稳定扩展阶段的速度是在一定范围内波动变化的。In order to study dynamic propagation of mode I cracks under blast loads,a rectangle plate specimen with a crack,prepared by PMMA with good homogeneity and transparency,was proposed in this paper. The experimental system consists of a high dynamic strain amplifier,an oscilloscope,a constant source,strain gauges and crack propagation gauges. The strain gauges and crack propagation gauges(CPGs) were used to measure the blast load and crack propagation speed respectively,and the scanning electron microscope was applied in studying the property of the fracture surface. AUTODYN was applied in simulating crack dynamic propagation behavior. The JWL equation of state(EOS) and a linear EOS were respectively applied to describe the explosive detonation products and the relationship between the pressure and density of PMMA. A modified principle stress failure criterion was employed to assess the material state. Based on displacement extrapolation method,a numerical model was established in ABAQUS code to acquire dynamic stress intensity factors at the crack tip. The experimental and numerical results show that the propagation of mode-I cracks under blast stress wave can be divided into stable propagation and unstable propagation stages,Fracture surface roughness will decline with crack propagation in the stable propagation stage and fracture surface is relatively smooth in the unstable propagation stage. It is also revealed that crack propagation velocity varies in a certain range in the stage of crack stable propagation.

关 键 词：岩石力学 爆炸应力波 裂纹扩展 断裂韧度 动态应力强度因子 

分 类 号：TU45[建筑科学—岩土工程]