This work presents an effort to scale down the short beam shear (SBS) test for measuring the interlaminar shear strength (ILSS) of polymer matrix composites (PMCs). The scale-down is performed to faciliate testing of new PMC systems with limited availability and high cost. The effect of specimen size on the failure mode and ILSS is investigated using digital image correlation and X-ray computed tomography. For the PMC system used, reduction of specimen size results in failure transitioning from a single dominant delamination in the full-scale specimens to multiple delaminations in the small-scale specimens, along with the specimen stress-strain response transitioning from quasi-brittle to quasi-ductile. Detailed analysis of tests results demonstrates that the observed change in specimen behavior has a negligible effect on the measured ILSS. Results from this study are used to provide guidance for future small-scale SBS testing to ensures accurate measurements of ILSS without introducing undesired failure modes.

这项工作提出了按比例缩小短梁剪切（SBS）测试以测量聚合物基复合材料（PMC）的层间剪切强度（ILSS）的努力。缩小比例是为了以有限的可用性和高成本来方便地测试新的PMC系统。使用数字图像关联和X射线计算机断层扫描技术研究了样本尺寸对破坏模式和ILSS的影响。对于所用的PMC系统，减小试样尺寸会导致失效从全尺寸试样中的单个主要分层过渡到小尺寸试样中的多个分层，以及试样的应力-应变响应从准脆性过渡到准脆性-延性。对测试结果的详细分析表明，观察到的试样行为变化对测量的ILSS的影响可以忽略不计。