电磁加载下7075铝环的膨胀断裂模式转变研究

利用电磁膨胀环实验技术，研究了7075铝环在2700～8700 s?1拉伸加载应变率下的断裂模式转变现象。实验结果表明:在低应变率下，铝环的断裂受最大正应力控制，发生拉伸断裂；在高应变率下，铝环的断裂受最大剪应力控制，发生剪切断裂；在中应变率下，铝环的断裂同时受最大正应力和最大剪应力控制，为拉伸和剪切同时存在的拉剪混合断裂模式；随着应变率的增加，铝环的破片数量呈先增加、再减小、最后增加的趋势，破片数量变化拐点与断裂模式转变点基本吻合。

Expansion fracture mode of 7075 aluminum ring under electromagnetic loading

The transition of fracture mode of 7075 aluminum ring was discovered by using electromagnetic expansion rings technique. The experimental results show that the fracture of the aluminum ring is affected by the maximum normal stress criterion at low strain rate, and tensile fracture easily occurs. Under the high strain rate, the fracture of the aluminum ring is affected by the maximum shear stress criterion and is prone to shear fracture. At the normal strain rate, the fracture of the aluminum ring is affected by both the maximum normal stress and the maximum shear stress criterion, resulting in a mixed fracture mode of tensile and shear fractures. And with the increase of strain rate, the number of fragments in the aluminum ring first increases, then decreases, and then increases again. These inflection points are the transition points of the fracture modes.