1.1 本试验方法包括在标准单搭接接头试样上以及在规定的制备和试验条件下，测定粘接金属用粘合剂的表观剪切强度。 1.2 以国际单位制表示的数值应视为标准值。国际单位制后括号中给出的值仅供参考，不被视为标准值。 1.3 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。 1.4 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====== 4.1 本试验方法主要是比较性的。然而，在确定粘附物表面制备参数和粘合剂环境耐久性的变化时，它确实可以用作鉴别器。该试验方法可用于控制表面处理、底漆和粘合剂系统，以确定测试系统的强度特性。 4.2 将本试验方法获得的强度值误用为结构接头的设计许用应力值可能会导致产品失效、财产损失和人身伤害。从给定的单搭接小试样中获得的粘合剂的表观剪切强度可能不同于从由不同粘附物或不同粘接工艺制成的接头中获得的表观剪切强度。使用环境中温度和湿度的正常变化会导致粘附物和粘合剂膨胀或收缩。粘附物和粘合剂可能具有不同的热膨胀系数和水分膨胀系数。 4.3 即使在小样本中，短期环境变化也可能导致粘合剂中的内应力或化学变化，从而永久影响粘合剂的表观强度和其他机械性能。 如果在较大的结构接缝中使用不同类型的粘附物，而不是在小样本中使用，则在不断变化的环境中预测接缝行为的问题更加困难。 4.4 使用单搭接试样测量的表观剪切强度不适用于确定设计结构接头的设计许用应力，这些结构接头在任何方面都不同于未彻底分析和理解接头和粘合行为的测试接头。 4.5 单搭接试验可用于比较和选择对疲劳和环境变化敏感的粘合剂或粘接工艺，但进行此类比较时必须非常小心，因为不同的粘合剂在不同的接头中可能会有不同的反应。 请参阅指南 D4896 进一步讨论与胶粘剂粘接单搭接接头解释相关的概念。

1.1 This test method covers the determination of the apparent shear strengths of adhesives for bonding metals when tested on a standard single-lap-joint specimen and under specified conditions of preparation and test. 1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard. 1.3 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. 1.4 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 ====== 4.1 This test method is primarily comparative. However, it does have application as a discriminator in determining variations in adherend surface preparation parameters and adhesive environmental durability. The test method has found applications in controlling surface preparations, primer, and adhesive systems for determining strength properties of tested systems. 4.2 The misuse of strength values obtained from this test method as design-allowable stress values for structural joints could lead to product failure, property damage, and human injury. The apparent shear strength of an adhesive obtained from a given small single-lap specimen may differ from that obtained from a joint made with different adherends or by a different bonding process. The normal variation of temperature and moisture in the service environment causes the adherends and the adhesive to swell or shrink. The adherends and adhesive are likely to have different thermal and moisture coefficients of expansion. 4.3 Even in small specimens, short-term environmental changes may induce internal stresses or chemical changes in the adhesive that permanently affect the apparent strength and other mechanical properties of the adhesive. The problem of predicting joint behavior in a changing environment is even more difficult if a different type of adherend is used in a larger structural joint than was used in the small specimen. 4.4 The apparent shear strength measured with a single-lap specimen is not suitable for determining design-allowable stresses for designing structural joints that differ in any manner from the joints tested without thorough analysis and understanding of the joint and adhesive behaviors. 4.5 Single-lap tests may be used for comparing and selecting adhesives or bonding processes for susceptibility to fatigue and environmental changes, but such comparisons must be made with great caution since different adhesives may respond differently in different joints. See Guide D4896 for further discussion of the concepts relative to interpretation of adhesive-bonded single-lap-joints.