Yu B, Katafiasz T J, Nguyen S, Allegri G, Finlayson J, Greenhalgh E S, Pinho S T, Pimenta S
Department of Aeronautics, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
Philos Trans A Math Phys Eng Sci. 2023 Jan 9;381(2240):20210220. doi: 10.1098/rsta.2021.0220. Epub 2022 Nov 21.
The translaminar fracture toughness reflects the damage tolerance of a fibre-reinforced composite under longitudinal tension, which often governs the final failure of structures. One of the main energy-dissipation mechanisms that contributes to the translaminar toughness of composites is the fibre pull-out process. The present study aims to quantify and model the statistical distribution of fibre pull-out lengths formed on the translaminar fracture surface of composites, for the first time in the literature; this is done under different temperatures, so that the relationship between pull-out length distributions, micromechanical properties and the translaminar fracture toughness can be established. The fracture surfaces of cross-ply compact tension specimens tested under three different temperatures have been scanned through X-ray computed tomography to quantify the extent of fibre pull-out on the fracture surfaces; the distribution of pull-out lengths showed alarger average and larger variability with an increase in temperature, which also lead to an increase in translaminar fracture toughness. A similar trend has been captured by the proposed analytical model, which predicts the pull-out length distribution based on the analysis of quasi-fractal idealizations of the fracture surface, yielding an overall accuracy of more than 85%. This article is part of the theme issue 'Ageing and durability of composite materials'.
层间断裂韧性反映了纤维增强复合材料在纵向拉伸下的损伤容限，而纵向拉伸往往决定着结构的最终失效。对复合材料层间韧性有贡献的主要能量耗散机制之一是纤维拔出过程。本研究旨在首次在文献中量化并模拟复合材料层间断裂表面上形成的纤维拔出长度的统计分布；这是在不同温度下进行的，以便能够建立拔出长度分布、细观力学性能与层间断裂韧性之间的关系。通过X射线计算机断层扫描对在三种不同温度下测试的正交铺层紧凑拉伸试样的断裂表面进行了扫描，以量化断裂表面上纤维拔出的程度；拔出长度的分布显示，随着温度的升高，平均拔出长度更大且变异性更大，这也导致层间断裂韧性增加。所提出的分析模型捕捉到了类似的趋势，该模型基于对断裂表面的准分形理想化分析来预测拔出长度分布，总体准确率超过85%。本文是“复合材料的老化与耐久性”主题特刊的一部分。
