1.1 本试验方法包括测定环向抗拉强度，包括连续纤维增强高级陶瓷管在环境温度下承受单调单轴载荷的弹性嵌件膨胀产生的内部压力下的应力应变响应。这种类型的测试配置有时被称为悬臂管。该测试方法针对管道几何形状，因为与平板相比，复合管中的缺陷数量、纤维结构和试样几何形状因素通常明显不同。 1.2 在试验方法中，通过弹性嵌件（位于管道中间）的径向膨胀产生的内部加压来加载具有规定计量截面和已知壁厚的复合管/圆柱体，弹性嵌件由推杆从任一端纵向压缩。弹性嵌件在推杆的单轴压缩载荷下膨胀，并在管内施加均匀的径向压力。记录复合管产生的环向应力应变响应，直到管发生故障。环向抗拉强度和环向断裂强度分别由产生的最大压力和断裂压力确定。 环向拉伸应变、环向比例极限应力和环向弹性模量由应力-应变数据确定。注意，本试验方法中使用的环向抗拉强度是指从单调、单轴加载的弹性嵌件的诱导压力开始的环向抗拉强度，其中“单调”是指从试验开始到最终断裂没有反转的连续、不间断的试验速率。 1.3 本试验方法主要适用于具有连续纤维增强的高级陶瓷基复合管: 单向（1D，纤维缠绕和胶带缠绕）、双向（2D，织物/胶带缠绕和编织）和三向（3D，编织和编织）。这些类型的陶瓷基复合材料可以由多种晶体和非晶陶瓷基成分（氧化物、碳化物、氮化物、碳、石墨和其他成分）中的多种陶瓷纤维组成。 1.4 本试验方法不直接涉及不连续纤维增强、晶须增强或颗粒增强陶瓷，尽管此处详述的试验方法可能同样适用于这些复合材料。 1.5 该试验方法适用于基于非尺寸参数的一系列试样管几何形状，该参数包括复合材料特性和管半径。复合管、推杆和弹性嵌件的长度由该无量纲参数确定，以提供具有均匀内部径向压力的标距。材料特性、管半径、壁厚、管长度和插入长度的广泛组合是可能的。 1.5.1 本试验方法适用于环境温度试验。高温测试要求高- 带有温度控制和测量系统的温度炉和加热装置，以及具有温度能力的夹具和加载夹具，本测试标准中未涉及这些内容。 1.6 本试验方法涉及以下章节中的管状试样几何形状、试样方法、试验速率（力速率、诱导压力速率、位移速率或应变率）以及数据收集和报告程序。 部分 范围 1. 参考文件 2. 术语 3. 试验方法总结 4. 意义和用途 5. 干扰 6. 仪器 7. 危害 8. 试样 9 试验程序 10 计算结果 11 汇报 12 精度和偏差 13 关键词 14 附录 验证载重列车定位 附录X1 计算最大环向应力的应力系数 附录X2 轴向力对内压 附录X3 1.7 本试验方法中表示的数值符合国际单位制（SI）( IEEE/ASTM SI 10 ). 1.8 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 第节给出了具体的危险说明 8. 和 注1 . 1.9 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 该试验方法（也称为悬管法）可用于材料开发、材料比较、材料筛选、材料下料选择和质量保证。 不建议将本试验方法用于材料表征、设计数据生成、材料模型验证/确认或其组合。 5.2 连续纤维增强陶瓷复合材料（CFCC）由细晶粒（<50%）中的连续陶瓷纤维定向（1D、2D和3D）增强体组成 µm）具有受控孔隙度的陶瓷基质。这些复合材料通常在纤维上有一层工程化的薄（0.1至10µm）界面涂层，以产生裂纹偏转和纤维拉拔。 5.3 CFCC组件具有材料特性、界面涂层、孔隙率控制、复合结构（1D、2D和3D）和几何形状的独特协同组合，这些通常是不可分割的。 通过将CFCC平板的测量特性应用于管的设计，无法预测CFCC管（尤其是具有编织和3D编织结构）的机械性能。特别是，由CMCs材料组成的管状组件形成了材料和几何形状的独特协同组合，通常是不可分割的。换句话说，CMC管的机械性能通常无法通过使用平板测量的性能进行预测。内压CMC管的强度测试提供了有关多轴应力材料的机械行为和强度的信息。 5.4 与从单一主要缺陷灾难性断裂的单片高级陶瓷不同，CMC通常在累积损伤过程中经历“优雅”断裂。因此，虽然在单个均匀加压管试验中承受均匀环向拉伸应力的材料体积可能是确定基体开裂应力的重要因素，但相同体积可能不是确定CMC极限强度的重要因素。然而，复合材料脆性基体强度分布的概率性质要求统计分析和设计的试样数量具有统计学意义。 确定试样体积对复合材料强度分布的确切影响的研究尚未完成。应注意的是，由于这些体积效应，使用不同推荐试样获得的环向抗拉强度可能会有所不同，该试样在计量截面中具有不同的材料体积。 5.5 环向抗拉强度试验提供了材料在管道内部加压引起的双轴应力下的强度和变形信息。非均匀应力状态在这些类型的测试和任何非线性应力的后续评估中都是固有的- 应变行为必须考虑CMC在双轴应力下的不对称行为。这种非线性行为可能是累积损伤过程（例如，基体开裂、基体/纤维脱粘、纤维断裂、分层等）的结果，其可能受到测试模式、测试速率、加工或合金化效应或环境影响的影响。其中一些影响可能是应力腐蚀或亚临界（缓慢）裂纹扩展的后果，可以通过本试验方法中概述的足够快的速度进行试验来最小化。 5. 6. 从特定材料或零件的选定部分或两者制作成标准尺寸的试样的环向抗拉强度试验结果可能不能完全代表整个全尺寸最终产品的强度和变形特性或其在不同环境中的使用行为。 5.7 出于质量控制目的，鉴于主要加工条件和加工后热处理，从标准管状环向抗拉强度试样得出的结果可被视为指示材料的响应。 5.8 CMC的环向拉应力行为和强度取决于其固有的抗断裂能力、缺陷的存在或损伤累积过程，或两者兼而有之。强烈建议对断裂面和断口进行分析，尽管这超出了本试验方法的范围。

1.1 This test method covers the determination of the hoop tensile strength including stress-strain response of continuous fiber-reinforced advanced ceramic tubes subjected to an internal pressure produced by the expansion of an elastomeric insert undergoing monotonic uniaxial loading at ambient temperature. This type of test configuration is sometimes referred to as an overhung tube. This test method is specific to tube geometries because flaw populations, fiber architecture, and specimen geometry factors are often distinctly different in composite tubes, as compared to flat plates. 1.2 In the test method a composite tube/cylinder with a defined gage section and a known wall thickness is loaded via internal pressurization from the radial expansion of an elastomeric insert (located midway inside the tube) that is longitudinally compressed from either end by pushrods. The elastomeric insert expands under the uniaxial compressive loading of the pushrods and exerts a uniform radial pressure on the inside of the tube. The resulting hoop stress-strain response of the composite tube is recorded until failure of the tube. The hoop tensile strength and the hoop fracture strength are determined from the resulting maximum pressure and the pressure at fracture, respectively. The hoop tensile strains, the hoop proportional limit stress, and the modulus of elasticity in the hoop direction are determined from the stress-strain data. Note that hoop tensile strength as used in this test method refers to the tensile strength in the hoop direction from the induced pressure of a monotonic, uniaxially loaded elastomeric insert, where “monotonic” refers to a continuous, nonstop test rate without reversals from test initiation to final fracture. 1.3 This test method applies primarily to advanced ceramic matrix composite tubes with continuous fiber reinforcement: unidirectional (1D, filament wound and tape lay-up), bidirectional (2D, fabric/tape lay-up and weave), and tridirectional (3D, braid and weave). These types of ceramic matrix composites can be composed of a wide range of ceramic fibers (oxide, graphite, carbide, nitride, and other compositions) in a wide range of crystalline and amorphous ceramic matrix compositions (oxide, carbide, nitride, carbon, graphite, and other compositions). 1.4 This test method does not directly address discontinuous fiber-reinforced, whisker-reinforced, or particulate-reinforced ceramics, although the test methods detailed here may be equally applicable to these composites. 1.5 The test method is applicable to a range of test specimen tube geometries based on a non-dimensional parameter that includes composite material property and tube radius. Lengths of the composite tube, pushrods, and elastomeric insert are determined from this non-dimensional parameter so as to provide a gage length with uniform internal radial pressure. A wide range of combinations of material properties, tube radii, wall thicknesses, tube lengths, and insert lengths are possible. 1.5.1 This test method is specific to ambient temperature testing. Elevated temperature testing requires high-temperature furnaces and heating devices with temperature control and measurement systems and temperature-capable grips and loading fixtures, which are not addressed in this test standard. 1.6 This test method addresses tubular test specimen geometries, test specimen methods, testing rates (force rate, induced pressure rate, displacement rate, or strain rate), and data collection and reporting procedures in the following sections. Section Scope 1 Referenced Documents 2 Terminology 3 Summary of Test Method 4 Significance and Use 5 Interferences 6 Apparatus 7 Hazards 8 Test Specimens 9 Test Procedure 10 Calculation of Results 11 Report 12 Precision and Bias 13 Keywords 14 Appendixes Verification of Load Train Alignment Appendix X1 Stress Factors for Calculation of Maximum Hoop Stress Appendix X2 Axial Force to Internal Pressure Appendix X3 1.7 Values expressed in this test method are in accordance with the International System of Units (SI) ( IEEE/ASTM SI 10 ). 1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 8 and Note 1 . 1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 This test method (also known as overhung tube method) may be used for material development, material comparison, material screening, material down selection, and quality assurance. This test method is not recommended for material characterization, design data generation, material model verification/validation, or combinations thereof. 5.2 Continuous fiber-reinforced ceramic composites (CFCCs) are composed of continuous ceramic-fiber directional (1D, 2D, and 3D) reinforcements in a fine-grain-sized (<50 µm) ceramic matrix with controlled porosity. Often these composites have an engineered thin (0.1 to 10 µm) interface coating on the fibers to produce crack deflection and fiber pull-out. 5.3 CFCC components have a distinctive and synergistic combination of material properties, interface coatings, porosity control, composite architecture (1D, 2D, and 3D), and geometric shape that are generally inseparable. Prediction of the mechanical performance of CFCC tubes (particularly with braid and 3D weave architectures) cannot be made by applying measured properties from flat CFCC plates to the design of tubes. In particular, tubular components comprised of CMCs material form a unique synergistic combination of material and geometric shape that are generally inseparable. In other words, prediction of mechanical performance of CMC tubes generally cannot be made by using properties measured from flat plates. Strength tests of internally pressurized CMC tubes provide information on mechanical behavior and strength for a multiaxially stressed material. 5.4 Unlike monolithic advanced ceramics which fracture catastrophically from a single dominant flaw, CMCs generally experience “graceful” fracture from a cumulative damage process. Therefore, while the volume of material subjected to a uniform hoop tensile stress for a single uniformly pressurized tube test may be a significant factor for determining matrix cracking stress, this same volume may not be as significant a factor in determining the ultimate strength of a CMC. However, the probabilistic nature of the strength distributions of the brittle matrices of CMCs requires a statistically significant number of test specimens for statistical analysis and design. Studies to determine the exact influence of test specimen volume on strength distributions for CMCs have not been completed. It should be noted that hoop tensile strengths obtained using different recommended test specimens with different volumes of material in the gage sections may be different due to these volume effects. 5.5 Hoop tensile strength tests provide information on the strength and deformation of materials under biaxial stresses induced from internal pressurization of tubes. Nonuniform stress states are inherent in these types of tests and subsequent evaluation of any nonlinear stress-strain behavior must take into account the unsymmetric behavior of the CMC under biaxial stressing. This nonlinear behavior may develop as the result of cumulative damage processes (for example, matrix cracking, matrix/fiber debonding, fiber fracture, delamination, etc.) which may be influenced by testing mode, testing rate, processing or alloying effects, or environmental influences. Some of these effects may be consequences of stress corrosion or subcritical (slow) crack growth that can be minimized by testing at sufficiently rapid rates as outlined in this test method. 5.6 The results of hoop tensile strength tests of test specimens fabricated to standardized dimensions from a particular material or selected portions of a part, or both, may not totally represent the strength and deformation properties of the entire, full-size end product or its in-service behavior in different environments. 5.7 For quality control purposes, results derived from standardized tubular hoop tensile strength test specimens may be considered indicative of the response of the material from which they were taken for, given primary processing conditions and post-processing heat treatments. 5.8 The hoop tensile stress behavior and strength of a CMC are dependent on its inherent resistance to fracture, the presence of flaws, or damage accumulation processes, or both. Analysis of fracture surfaces and fractography, though beyond the scope of this test method, is highly recommended.