Three-dimensional deformation mapping of Mode I interlaminar crack extension in particle-toughened interlayers
Three-dimensional deformation mapping of Mode I interlaminar crack extension in particle-toughened interlayers
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DOI：
10.1016/j.actamat.2015.09.059
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发表时间：
2016-01-15
期刊：
影响因子：
9.4
通讯作者：
Spearing, S. M.
中科院分区：
文献类型：
--
作者：
Borstnar, G.;Gillard, F.;Spearing, S. M.
本文介绍了第一次使用数字体积相关（DVC）的碳纤维增强塑料（CFRPs），以量化的应变场之前的模式I分层。DVC是一种相对新颖的工具，可用于测量载荷下材料内部发生的位移和应变。与计算机断层扫描（CT）结合，该技术已应用于多孔材料，结果为验证有限元（FE）模型提供了应变数据。然而，该技术在层压材料中的应用受到限制，研究通常需要体积相关所需的基准标记。在这项工作中，裂纹扩展步骤被捕获在325 nm的体素分辨率使用同步辐射计算机断层扫描（SRCT）。调查的材料系统具有不同的裂纹桥接机制，如颗粒桥，树脂韧带，和纤维桥。对应变测量的噪声和子体积大小的评估确定最佳子体积大小为150个体素，具有50%重叠。这为应变提供了48.8 μ m的空间分辨率，并且为重复的参考扫描提供了范围在220和690 μ m之间的相应应变分辨率。刚体平移研究证实，垂直于纤维方向的试样运动支持“真实的”物理位移。然而，沿着纤维方向，相关性差，只有在颗粒增韧夹层内才能检测到正确的位移。该研究表明，应变测量可以垂直于整个夹层的纤维方向，这可用于验证这些知之甚少的颗粒增韧夹层的未来有限元模型。(c)2015 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
This paper presents the first use of Digital Volume Correlation (DVC) on Carbon Fibre Reinforced Plastics (CFRPs) to quantify the strain fields ahead of a Mode I delamination. DVC is a relatively novel tool that can be used to measure displacements and strains occurring inside materials under load. In conjunction with Computed Tomography (CT), the technique has been applied to porous materials, with results providing strain data for validation of Finite Element (FE) models. However, the application of the technique to laminated materials has been limited, with studies often requiring fiducial markings required for volume correlation. In this work, crack propagation steps were captured at a 325 nm voxel resolution using Synchrotron Radiation Computed Tomography (SRCT). The material systems investigated featured different crack bridging mechanisms such as; particle-bridges, resin ligaments, and fibre-bridges. An assessment of noise and sub-volume size on the strain measurement determined that the optimal sub-volume size was 150 voxels with 50% overlap. This provided a spatial resolution of 48.8 mu m for strain and a corresponding strain resolution ranging between 220 and 690 mu epsilon for the repeated reference scans. A rigid body translation study confirmed that specimen movements perpendicular to the fibre orientation support the 'real' physical displacements. However, along the fibre direction, the correlation was poor, with correct displacements being detected only within the particle-toughened interlayers. The study demonstrates that strain measurements can be made perpendicular to the fibre direction across the interlayer, which could be used to validate future FE models of these poorly understood particletoughened interlayers. (c) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.