1.1 本试验方法涵盖了在环境温度下测定应变计疲劳寿命的统一程序。包括建议的测试设备设计。 1.2 本试验方法不适用于使用金属粘结电阻应变计作为传感元件的力传感器或引伸计。 1.3 应变计是一个复杂系统的一部分，该系统包括结构、粘合剂、应变计、引线、仪器和（通常）环境保护。因此，许多因素会影响应变计的性能，包括用户技术。更复杂的是，应变计一旦安装，通常无法重新安装在其他位置。因此，不可能校准单个应变计；性能特征通常以统计为基础。 1.4 本试验方法仅包括完全反转的染色循环。 1.5 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。 1.6 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 应变计是测量应变和评估结构应力最广泛使用的设备。在许多应用中，经常存在可能导致应变计失效的循环载荷。 应变计的性能特性受其制造材料及其几何设计的影响。 4.2 大多数应变计性能特征的确定需要破坏性的机械测试。由于疲劳寿命测试的应变计不能再次使用，因此有必要对数据进行统计处理。一般来说，电阻较低的更长、更宽的应变计将具有更大的疲劳寿命。应变计的可选附加装置（例如整体引线）通常会降低疲劳寿命。 4.3 要使用应变计，必须将其粘接到结构上。良好的结果，尤其是在疲劳环境中，在很大程度上取决于用于清洁粘合表面、粘合应变计和提供保护涂层的材料。安装人员的技能是成功的另一个主要因素。 最后，应仔细选择和校准仪表系统，以确保其不会过度降低应变计的性能。 4.4 疲劳 失败 对应变计的测量通常不涉及应变计的可见裂纹或断裂，而仅仅是足够的零位移，以损害静态应变分量的应变计输出精度。

1.1 This test method covers a uniform procedure for the determination of strain gage fatigue life at ambient temperature. A suggested testing equipment design is included. 1.2 This test method does not apply to force transducers or extensometers that use metallic bonded resistance strain gages as sensing elements. 1.3 Strain gages are part of a complex system that includes structure, adhesive, strain gage, lead wires, instrumentation, and (often) environmental protection. As a result, many things affect the performance of strain gages, including user technique. A further complication is that strain gages, once installed, normally cannot be reinstalled in another location. Therefore, it is not possible to calibrate individual strain gages; performance characteristics are normally presented on a statistical basis. 1.4 This test method encompasses only fully reversed stain cycles. 1.5 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. 1.6 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 Strain gages are the most widely used devices for measuring strains and for evaluating stresses in structures. In many applications there are often cyclic loads that can cause strain gage failure. Performance characteristics of strain gages are affected by both the materials from which they are made and their geometric design. 4.2 The determination of most strain gage performance characteristics requires mechanical testing that is destructive. Since strain gages tested for fatigue life cannot be used again, it is necessary to treat data statistically. In general, longer and wider strain gages with lower resistances will have greater fatigue life. Optional additions to strain gages (integral lead wires are an example) will often reduce fatigue life. 4.3 To be used, strain gages must be bonded to a structure. Good results, particularly in a fatigue environment, depend heavily on the materials used to clean the bonding surface, to bond the strain gage, and to provide a protective coating. Skill of the installer is another major factor in success. Finally, instrumentation systems shall be carefully selected and calibrated to ensure that they do not unduly degrade the performance of the strain gages. 4.4 Fatigue failure of a strain gage often does not involve visible cracking or fracture of the strain gage, but merely sufficient zero shift to compromise the accuracy of the strain gage output for static strain components.