PBX材料宏细观断裂行为的数字散斑相关法实验研究

An Experimental Study on the Micro/Macro Fracture Behavior of PBX Using Digital Speckle Correlation Method

采用半圆盘弯曲实验和数字散斑相关方法,对高聚物粘结炸药(PBX)的宏、细观断裂行为进行了实验研究。宏观上,带有预制裂纹的半圆盘试样发生拉伸破坏,利用数字散斑相关技术得到了试样的应变场和位移矢量场分布,定量分析了试样全场的变形特征,并测得了PBX材料的平面应变断裂韧性;细观上,用配有加载装置的扫描电子显微镜对含预制裂纹的半圆盘试样间接拉伸下的损伤演化和破坏过程进行了实时原位观察,借助于数字散斑相关方法,定量分析了试样损伤局部化特征。结果表明,将数字散斑相关方法用于研究PBX材料宏、细观尺度上的变形破坏问题是有效的。

The micro/macro fracture behavior of a polymer bonded explosive（PBX） material was experimentally studied using a semi-circular bend test and digital speckle correlation method（DSCM）.Brittle fracture occurred when a semi-circular disc sample of PBX with a preset crack was compressed.The whole strain field and displacement vector plot were obtained using the DSCM,and the plane strain fracture toughness of PBX material was acquired.In addition,real time microscopic examination was conducted to observe the process of deformation and failure of PBX material under semi-circular bend test using a scanning electron microscope（SEM） equipped with a loading stage.The localized damage and its evolution in PBX were obtained by the DSCM,demonstrating possible fracture route of microcracks.The results indicate that DSCM technique is a valid and effective tool to study the deformation and fracture mechanisms of PBX.