数字图像相关方法分析PBX带孔板拉伸应变场

Strain Analysis for PBX Plate with Hole under Tension Based on Digital Image Correlation Method

为研究孔结构对高聚物粘结炸药(PBX)的拉伸力学行为的影响,设计了一种带中心圆孔的平板试样进行实验,基于数字图像相关方法(DICM)对实验进行应变场分析。试样在圆孔处发生脆性断裂,应变分量εyy作为主特征破坏参数在圆孔左右边缘先达到临界值,继而裂纹起裂并扩展至破坏。实验所得应变场除有显著的不均匀性和非对称性,基本与理论预测相一致。分析认为材料的不均匀性和微观缺陷是应变场分布不均匀的重要原因,小孔处的应变集中是试样破坏的主要原因,但是缺陷也会劣化结构抵抗破坏的能力。

To study the effect of hole structure on tensile behavior of polymer-bonded explosive（ PBX）, a plate specimen with-hole was designed and digital image correlation method （DICM） was applied for strain analysis. The quasi-static tension results show that brittle fracture occurs at the edge of hole. Moreover, as the main characteristic failure parameter, the strain component εyy, reaches the critical value at the horizontal edge of the hole, and then cracks initiates and propagates to failure. Except for the sig- nificant heterogeneity and asymmetry, the strain distribution agrees well with the theoretical analysis. The inhomogeneity and mi- croscopic defects of the materials may take a major responsibility for the imperfect distribution of the strain field. The defects near the hole may remarkably deteriorate the strength of the structure, even though the strain concentration around the hole is the criti- cal reason of specimen failure.