Strain-induced crystallization around a crack tip in natural rubber under dynamic load
Strain-induced crystallization around a crack tip in natural rubber under dynamic load
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DOI：
10.1016/j.polymer.2013.08.045
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发表时间：
2013-10-18
期刊：
影响因子：
4.6
通讯作者：
Heinrich, Gert
中科院分区：
文献类型：
--
作者：
Bruening, Karsten;Schneider, Konrad;Heinrich, Gert
采用时间分辨扫描广角X射线衍射（WAXD）技术，测定了动态载荷作用下天然橡胶裂纹尖端的局部结晶度。使用高通量同步辐射微束，WAXD图案与小于20 ms的曝光时间被收购，而缺口橡胶样品进行循环动态拉伸的频率为1 Hz，类似于撕裂疲劳实验中的负载条件。通过扫描连续循环的样品，在任何给定的应变相位角获得完整的结晶度图。与静态裂纹尖端扫描相比，裂纹尖端处的结晶度显著降低。进一步的研究揭示了R比和裂纹扩展阻力之间众所周知的关系的潜在结构原因。通过对不断拉伸的橡胶样品进行静态裂纹尖端扫描，研究了裂纹偏转和分支背后的机制。(C)2013爱思唯尔有限公司保留所有权利。
The local degree of crystallinity around a crack tip in natural rubber under dynamic load was measured by time-resolved scanning wide-angle X-ray diffraction (WAXD). Using a high-flux synchrotron micro-beam, WAXD patterns with less than 20 ms exposure time were acquired while the notched rubber sample was subjected to cyclic dynamic stretching at a frequency of 1 Hz, similar to the loading conditions in tear fatigue experiments. By scanning the continuously cycling sample, a complete crystallinity map at any given strain phase angle was obtained. The crystallinity at the crack tip is considerably reduced compared to static crack tip scans. Further investigations revealed the underlying structural reasons for the well-known relation between R-ratio and crack growth resistance. By performing static crack tip scans on increasingly stretched rubber samples, the mechanisms behind crack deflection and branching were studied. (C) 2013 Elsevier Ltd. All rights reserved.