Ahmad Dilshad, Ajaj Rafic M
Department of Aerospace Engineering, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates.
Advanced Research and Innovation Center (ARIC), Department of Aerospace Engineering, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates.
Polymers (Basel). 2023 Mar 20;15(6):1526. doi: 10.3390/polym15061526.
The use of elastomer-based skins in morphing wings has become increasingly popular due to their remarkable stretchability and mechanical properties. However, the possibility of the skin fracturing during multiaxial stretching remains a significant design challenge. The propagation of cracks originating from flaws or notches in the skin can lead to the specimen breaking into two parts. This paper presents an experimental study aimed at comprehensively evaluating crack propagation direction, stretchability, and fracture toughness of silicone-based elastomeric skin (Ecoflex) for morphing wing applications, using varying Shore hardness values (10, 30, and 50). The findings show that the lower Shore hardness value of 10 exhibits a unique Sideways crack propagation characteristic, which is ideal for morphing skins due to its high stretchability, low actuation load, and high fracture toughness. The study also reveals that the Ecoflex 10 is suitable for use in span morphing, with a fracture toughness of approximately 1.1 kJ/m2 for all thicknesses at a slower strain rate of 0.4 mm/min. Overall, this work highlights the superior properties of Ecoflex 10 and its potential use as a morphing skin material, offering a groundbreaking solution to the challenges faced in this field.
由于其卓越的拉伸性和机械性能，基于弹性体的蒙皮在变形机翼中的应用越来越普遍。然而，在多轴拉伸过程中蒙皮发生破裂的可能性仍然是一个重大的设计挑战。蒙皮中由缺陷或切口引发的裂纹扩展会导致试件断裂成两部分。本文进行了一项实验研究，旨在使用不同的邵氏硬度值（10、30和50）全面评估用于变形机翼应用的硅基弹性蒙皮（Ecoflex）的裂纹扩展方向、拉伸性和断裂韧性。研究结果表明，邵氏硬度值为10时具有独特的侧向裂纹扩展特性，因其高拉伸性、低驱动载荷和高断裂韧性，这对于变形蒙皮而言是理想的。该研究还表明，Ecoflex 10适用于展向变形，在0.4毫米/分钟的较慢应变率下，所有厚度的断裂韧性约为1.1千焦/平方米。总体而言，这项工作突出了Ecoflex 10的优越性能及其作为变形蒙皮材料的潜在用途，为该领域面临的挑战提供了开创性的解决方案。
