Hu Junfeng, Zhang Xutong, Chen Zhou, Guo Wenkang, Li Hang, Deng Xi
School of Mechanical and Power Engineering, Nanjing Tech University, No. 30 Pu Zhu South Road, Nanjing 211816, China.
College of Civil Engineering, Hunan University, Yuelu Mountain, Changsha 410082, China.
Polymers (Basel). 2020 Jul 21;12(7):1622. doi: 10.3390/polym12071622.
Laminates with unidirectionally arrayed chopped strands (UACS) are one of the advanced short fiber reinforced polymer composites (SFRP) with significant application prospect, which greatly improves mechanical properties compared to the traditional SFRP, meanwhile ensuring excellent flowability. In practice, composite laminate with an open hole is one of the typical connective components, and it is necessary to clarify the allowable load and damage tolerance performance of notched structures. In the present study, UACS laminates were fabricated using the continuous carbon fiber reinforced polymer (CFRP) prepreg, on which regularly arrayed bi-angled slits were introduced by a commercial numerical control cutter. The tensile strength and strain distribution around the open hole of the notched UACS laminate were experimentally investigated, while the damage progression near the open hole of the notched UACS laminate was analyzed by the finite element method (FEM). The tensile strength of the notched UACS laminate was measured at 298 MPa, which is about 60% of the strength of the unnotched UACS laminate. The simulation results match well with the experimental results, although there is a little overestimate on strength, by about 5% and 7%, for unnotched and notched UACS laminates, respectively. The final critical failure mode for the notched UACS laminate is mainly dominated by the delamination instead of the fiber breakage in the unnotched UACS laminate.
具有单向排列短切纤维（UACS）的层压板是一种具有重要应用前景的先进短纤维增强聚合物复合材料（SFRP），与传统的SFRP相比，它极大地提高了力学性能，同时确保了优异的流动性。在实际应用中，带有开孔的复合材料层压板是典型的连接部件之一，因此有必要明确带缺口结构的许用载荷和损伤容限性能。在本研究中，采用连续碳纤维增强聚合物（CFRP）预浸料制备了UACS层压板，并使用商用数控刀具在其上引入了规则排列的双角切口。通过实验研究了带缺口UACS层压板开孔周围的拉伸强度和应变分布，同时采用有限元方法（FEM）分析了带缺口UACS层压板开孔附近的损伤扩展情况。带缺口UACS层压板的拉伸强度测量值为298MPa，约为无缺口UACS层压板强度的60%。模拟结果与实验结果吻合良好，尽管对强度有一定程度的高估，无缺口和带缺口UACS层压板的强度分别高估了约5%和7%。带缺口UACS层压板最终的临界失效模式主要由分层主导，而非无缺口UACS层压板中的纤维断裂。
