Bourne N K, Garcea S C, Eastwood D S, Parry S, Rau C, Withers P J, McDonald S A, Brown E N
School of Materials , University of Manchester , Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA , UK.
School of Materials, University of Manchester, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, UK; Defence Science and Technology Organisation, Adelaide, Australia.
Proc Math Phys Eng Sci. 2017 Jan;473(2197):20160495. doi: 10.1098/rspa.2016.0495.
The well-known Taylor cylinder impact test, which follows the impact of a flat-ended cylindrical rod onto a rigid stationary anvil, is conducted over a range of impact speeds for two polymers, polytetrafluoroethylene (PTFE) and polyetheretherketone (PEEK). In previous work, experiments and a model were developed to capture the deformation behaviour of the cylinder after impact. These works showed a region in which spatial and temporal variation of both longitudinal and radial deformation provided evidence of changes in phase within the material. In this further series of experiments, this region is imaged in a range of impacted targets at the Diamond synchrotron. Further techniques were fielded to resolve compressed regions within the recovered polymer cylinders that showed a fracture zone in the impact region. The combination of macroscopic high-speed photography and three-dimensional X-ray imaging has identified the development of failure with these polymers and shown that there is no abrupt transition in behaviours but rather a continuous range of responses to competing operating mechanisms. The behaviours noted in PEEK in these polymers show critical gaps in understanding of polymer high strain-rate response.
著名的泰勒圆柱体冲击试验是将平头圆柱形杆撞击到刚性固定砧座上，针对两种聚合物——聚四氟乙烯（PTFE）和聚醚醚酮（PEEK），在一系列冲击速度下进行的。在之前的工作中，开展了实验并建立了一个模型来捕捉圆柱体在冲击后的变形行为。这些工作表明，在一个区域内，纵向和径向变形的空间和时间变化为材料内部相的变化提供了证据。在这一系列进一步的实验中，在钻石同步加速器对一系列受冲击目标中的这个区域进行了成像。还采用了其他技术来解析回收的聚合物圆柱体内的压缩区域，这些区域在冲击区域显示出一个断裂带。宏观高速摄影和三维X射线成像相结合，确定了这些聚合物的失效发展情况，并表明行为没有突然转变，而是对相互竞争的运行机制有一系列连续的响应。在这些聚合物中观察到的聚醚醚酮行为表明，在理解聚合物高应变率响应方面存在关键差距。
