Interfacial mechanics of push-out tests: theory and experiments
Interfacial mechanics of push-out tests: theory and experiments
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DOI：
10.1016/s1359-835x(00)00051-8
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发表时间：
2001-01-01
影响因子：
8.7
通讯作者：
Ghonem, H
中科院分区：
文献类型：
--
作者：
Chandra, N;Ghonem, H
复合材料体系（PMC/MMC/IMC/CMC）界面的热-力学特性是复合材料力学与工程中的一个挑战性问题。每个系统都有自己的特点;然而，在金属基复合材料和金属间化合物的研究呈现出更复杂的，由于不断变化的化学物种（时间和空间），和多轴状态的残余应力。在金属基复合材料或金属基复合材料可以用于实际应用之前，界面不仅在增强机制中而且在增韧机制中的作用需要被清楚地理解。为了评价界面的界面力学性能，薄片推出试验已成为事实上的标准。虽然从概念上说，测试程序很简单，但对测试结果的解释却不简单。必须进行非常仔细的实验，进行精确的细观和宏观化学/结构/力学观察，并进行彻底的理论/数值模拟，然后才能以定量的方式使用测试数据。本文根据作者小组几年来的理论、数值和实验研究工作，对push-our试验进行了全面的分析。在这项工作中，薄片推出试验主要是在不同的测试温度（室温和高温）和不同的加工条件（温度和时间）的钛基复合材料进行。具有钛基基体的不同复合材料系统（Ti-6Al-4V.钛合金21 S、Ti-15 Nb-3Al）用碳化硅纤维（SCS-6）单轴增强。研究了界面化学和结构（基体、涂层和反应区）的演变对剪切强度τ（s）和摩擦强度τ（1）的影响。基于非线性有限元方法，实现了一种新的有限元分析方法，不仅模拟了界面裂纹的萌生，而且模拟了裂纹的扩展。在分析中，剪切应力和断裂能为基础的标准被用来模拟（闭合）裂纹的萌生。然后基于实验数据和数值模拟提取τ（s）、τ（f）、G（I）和G（II）的定量值。对基于应力和能量的界面建模方法及其对各种边值问题的适用性进行了严格的审查。(C)2001年由Elsevier Science Ltd.出版
The thermo-mechanical characterization of interfaces in composite systems (PMC/MMC/IMC/CMC) is one of the challenging problems in composite mechanics and engineering. Each system has its own distinguishing features; however, in MMCs and IMCs the study is rendered more complex due to the evolving chemical species (both temporally and spatially), and the multi-axial state of residual stresses. Before MMCs or IMCs can be used in actual applications, the role of interfaces in not only the strengthening but also toughening mechanisms needs to be clearly understood. For evaluating the interfacial mechanical properties of interfaces, thin slice push-out test has emerged as the de-facto standard. Though, conceptually the testing procedure is simple, interpretation of the test results is not. It is essential to conduct very careful experiments, make precise meso- and macroscopic chemical/structural/mechanical observations and perform a thorough theoretical/numerical simulation before the test data can be used in a quantitative manner. In this paper, a comprehensive analysis of the push-our test is presented based on the theoretical/numerical and experimental research work of the authors' group during the past few years. In this work, thin slice push-out tests were conducted primarily on Titanium Matrix Composites at various test temperatures (room and elevated) with different processing conditions (temperature and time). Different composite systems with Titanium based matrices (Ti-6Al-4V. Timetal 21S, Ti-15Nb-3Al) uniaxially reinforced with Silicon Carbide fibers (SCS-6) were chosen for the study. Effect of the evolution of interfacial chemistry and architecture (in matrix, coating and reaction zone) on both shear strength tau (s) and frictional strength tau (1) were studied. A novel finite element analysis based on nonlinear finite element method was implemented, in which not only the initiation but propagation of interfacial cracks ale simulated. In the analysis, both shear stress and fracture energy based criteria are used to model the initiation of (closed) cracks. Quantitative values of tau (s), tau (f), G(I) and G(II) are then extracted based on the experimental data and the numerical simulation. A critical review of stress and energy based interface-modeling approaches and their applicability to various boundary value problems are made. (C) 2001 Published by Elsevier Science Ltd.