Stress Evaluation Through the Layers of a Fibre-Metal Hybrid Composite by IHD: An Experimental Study

IF 2 3区工程技术 Q2 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Experimental Mechanics Pub Date : 2024-03-05 DOI:10.1007/s11340-024-01047-z

J. P. Nobre, T. C. Smit, R. Reid, Q. Qhola, T. Wu, T. Niendorf

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引用次数: 0

Abstract

Background

Incremental hole-drilling (IHD) has shown its importance in the measurement of the residual stress distribution within the layers of composite laminates. However, validation of these results is still an open issue, especially near the interfaces between plies.

Objectives

In this context, this study is focused on experimentally verifying its applicability to fibre metal laminates.

Methods

Tensile loads are applied to cross-ply GFRP-steel [0/90/steel]s samples. Due to the difference in the mechanical properties of each ply, Classical Lamination Theory (CLT) predicts a distribution of the uniform stress within each layer, with pulse gradients between them. The interfaces act as discontinuous regions between the plies. The experimental determination of such stress variation is challenging and is the focus of this research. A horizontal tensile test device was designed and built for this purpose. A differential method is used to eliminate the effect of the existing residual stresses in the samples, providing a procedure to evaluate the ability of the IHD technique to determine the distribution of stress due to the applied tensile loads only. The experimentally measured strain-depth relaxation curves are compared with those determined numerically using the finite element method (FEM) to simulate the hole-drilling. Both are used as input for the IHD stress calculation method (unit pulse integral method). The distribution of stress through the composite laminate, determined by classical lamination theory (CLT), is used as a reference.

Results

Unit pulse integral method results, using the experimental and numerical strain-depth relaxation curves, compare reasonably well with those predicted by CLT, provided that there is no material damage due to high applied loads.

Conclusions

IHD seems to be an important measurement technique to determine the distribution of residual stresses in fibre metal laminates and should be further developed for a better assessment of the residual stresses at the interfaces between plies.

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通过 IHD 评估纤维-金属混合复合材料层间的应力：一项实验研究

摘要背景增量式钻孔（IHD）在测量复合材料层压板层内残余应力分布方面具有重要作用。然而，这些结果的验证仍是一个未决问题，尤其是在层间界面附近。在这种情况下，本研究的重点是通过实验验证其对金属纤维层压板的适用性。方法在交叉层 GFRP-钢 [0/90/steel] 样品上施加拉伸载荷。由于各层的机械性能不同，经典层压理论（CLT）预测了各层内部的均匀应力分布，以及各层之间的脉冲梯度。界面是层间的不连续区域。这种应力变化的实验测定具有挑战性，也是本研究的重点。为此，我们设计并制造了一个水平拉伸试验装置。采用差分法消除样品中现有残余应力的影响，提供了一种程序来评估 IHD 技术仅确定外加拉伸载荷引起的应力分布的能力。实验测得的应变-深度松弛曲线与使用有限元法（FEM）模拟钻孔时数值确定的应变-深度松弛曲线进行了比较。两者都被用作 IHD 应力计算方法（单位脉冲积分法）的输入。通过经典层压理论（CLT）确定的复合材料层压板应力分布用作参考。结果使用实验和数值应变-深度松弛曲线得出的单位脉冲积分法结果与 CLT 预测的结果比较合理，前提是施加的高载荷不会导致材料损坏。结论 IHD 似乎是确定金属纤维层压板残余应力分布的一种重要测量技术，应进一步开发，以更好地评估层间界面的残余应力。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Experimental Mechanics 物理-材料科学：表征与测试

CiteScore

4.40

自引率

16.70%

发文量

111

审稿时长

3 months

期刊介绍： Experimental Mechanics is the official journal of the Society for Experimental Mechanics that publishes papers in all areas of experimentation including its theoretical and computational analysis. The journal covers research in design and implementation of novel or improved experiments to characterize materials, structures and systems. Articles extending the frontiers of experimental mechanics at large and small scales are particularly welcome. Coverage extends from research in solid and fluids mechanics to fields at the intersection of disciplines including physics, chemistry and biology. Development of new devices and technologies for metrology applications in a wide range of industrial sectors (e.g., manufacturing, high-performance materials, aerospace, information technology, medicine, energy and environmental technologies) is also covered.