Alshahrani Hassan, Sebaey Tamer A
Department of Mechanical Engineering, College of Engineering, Najran University, Najran 11001, Saudi Arabia.
Engineering Management Department, College of Engineering, Prince Sultan University, Riyadh 12435, Saudi Arabia.
Polymers (Basel). 2022 May 19;14(10):2076. doi: 10.3390/polym14102076.
With the development of spread-tow, thin-ply technology, ultra-thin composite laminates could be produced. Composite bolted joints are commonly used on aircraft's load-bearing structures and are considered the main cause of stress concentration. The aim of this research is to investigate the bolted joint behavior of composite laminates that combine thin-plies and conventional thick-plies in a predetermined stacking sequence. The impact of thin-ply placement within the stack on bearing strength, including the onset of damages, is examined. The work involves mechanical tests and fractographic activities to understand the damage mechanisms of the plies and their interactions, and its reflections on the bearing load capacity of the joint for double-lap bolted joints. The results showed an improvement in the bearing strength of up to 19% by inserting the thin-plies inside the laminate. The visual examination of the specimens showed a bearing damage mode for all the tested specimens. The computed tomography scans showed damage mechanisms that mostly occurred with the normal plies, rather than breaking the thin-plies. For the specimens of traditional plies, delaminations were noticed at most of the interfaces. For the one with a block of thin-plies in the middle, all the delaminations were forced to the surface layers with an extra large size. Forspecimens with distributed thin-plies, a higher number of smaller delaminations was recognized.
随着铺展丝束薄铺层技术的发展，可以生产出超薄复合材料层压板。复合材料螺栓连接常用于飞机的承载结构，并且被认为是应力集中的主要原因。本研究的目的是研究以预定堆叠顺序将薄铺层和传统厚铺层相结合的复合材料层压板的螺栓连接行为。研究了堆叠中薄铺层的放置对承载强度的影响，包括损伤的起始情况。这项工作涉及力学测试和断口分析活动，以了解铺层的损伤机制及其相互作用，以及其对双搭接螺栓连接接头承载能力的影响。结果表明，通过在层压板内部插入薄铺层，承载强度提高了19%。对试样的目视检查显示，所有测试试样均呈现出一种承载损伤模式。计算机断层扫描显示，损伤机制大多发生在普通铺层，而非薄铺层断裂。对于传统铺层的试样，在大多数界面处都发现了分层现象。对于中间有一块薄铺层的试样，所有分层都被挤到了表层，且尺寸格外大。对于有分布薄铺层的试样，则发现了较多数量的较小分层。
