含预制缺陷PBX模拟材料损伤演变的原位CT研究

In-Situ X-Ray Tomography Observation of Damage Evolution in PBX Mock Materials with Prefabricated Defects

为研究初始损伤对高聚物粘结炸药(PBX)在外力作用下结构变化与损伤行为的影响,采用预制缺陷的方式模拟了初始损伤,制备了不含预制缺陷、含斜45°非贯通缺陷以及含斜45°贯通缺陷的3组PBX模拟材料样品,利用经改进的圆弧压头巴西试验加载方式,在X射线CT系统上开展原位研究。通过数字图像处理技术获得了裂纹及孔隙的三维形态、尺寸及空间分布信息。利用ABAQUS软件对试验进行了有限元模拟。结果表明,预制缺陷与巴西试验加载方向呈45°角时,预制缺陷会破坏其加载方式的对称性,样品的损伤行为也会相应发生改变;非贯通缺陷与贯通缺陷对样品的损伤行为的影响有很大区别;含非贯通缺陷的样品会发生分层现象,即表层缺陷对样品损伤行为的影响范围主要集中在含有缺陷的部分;模拟的结果与试验结果吻合较好,在一定程度上解释了试验现象。

To study the effect of initial damages on the structural change and damage behavior of polymer bonded explosive(PBX)under external force,the initial damages was simulated by the way of prefabricated defects,three groups of simulated material samples of PBX,including the sample without prefabricated defect,sample with oblique45°non-through defect and sample with oblique45°through defect were prepared,in-situ studies were performed on X-ray CT system.using the loading way of improved arc compress head Brazilian test.Information on three dimensional morphology,size and spatial distribution of cracks and pores were obtained by digital image processing techniques.The finite element simulation of the test was carried out by using ABAQUS software.Results show that when the prefabricated defect has a certain angle to the loading direction of Brazilian test,the prefabri-cated defect makes the symmetry of its loadig way destroy and the damage behavior of the sample will also change accordingly.The influence of non-through defects and through defects on the damage behavior of samples is very different,the non-through de-fect may result in stratification phenomenon of the sample.namely the effect of surface defects on the damage behavior of the sam-ples is mainly concentrated in the defective part.The simulation results are in good agreement with the experimental,and explaine the experimental phenomena to some extent.