1.1 本规程描述了通过扫频正弦输入法使用过程补偿谐振测试（PCRT）对新制造和在用零件总体进行异常值筛选的一般程序。PCRT使用设定频率范围内的扫频正弦波输入激励金属和非金属测试组件的共振频率。PCRT检测和分析部件共振频率模式，并使用可接受和不可接受部件之间共振模式的差异来执行无损检测。PCRT频率分析将组件的共振模式与同一组件的已知参考总体的模式进行比较，并根据测试组件与这些总体的相似性得出通过或失败的结果。 对于具有已知缺陷或相关材料状态或两者的无损检测应用，实践 E2534 介绍PCRT排序模块的开发和应用，该模块将测试组件与已知的可接受和不可接受组件总体进行比较。然而，一些应用程序没有具有已知缺陷或材料状态的组件的物理示例。其他应用程序会遇到未知原因的孤立组件故障，或由于超出当前所需检查灵敏度的缺陷传播的原因，或两者兼而有之。在这些情况下，PCRT应用于异常值筛选模式，该模式仅使用假定可接受生产组件的总体开发排序模块，然后比较测试组件与假定可接受总体的相似性。 共振差异可用于区分具有正常过程变化的可接受部件和可能具有材料状态或缺陷（或两者兼有）的异常部件，这将导致性能缺陷。这些材料状态和缺陷包括但不限于裂纹、空洞、孔隙度、收缩、夹杂物、不连续性、晶粒和晶体结构差异、密度相关异常、热处理变化、材料弹性性能差异、残余应力和尺寸变化。本规程适用于能够在声学或超声波频率范围内或两者中激励、测量、记录和分析多个全身机械振动共振频率的仪器。 1.2 单位- 以英寸表示的值- 磅单位应视为标准单位。括号中给出的值是到国际单位制的数学转换，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====== 5.1 PCRT应用程序和功能- PCRT已成功应用于金属和非金属零件制造和维护中的各种异常筛选应用。中讨论了检测到的异常示例 1.1 . PCRT已被证明在许多行业（包括汽车、航空航天和发电）提供了经济高效和准确的异常值筛选解决方案。目前用于商业用途的成功应用示例包括但不限于: (1) 氮化硅轴承元件， (2) 钢、铁和铝摇臂和控制臂， (3) 飞机和工业燃气涡轮发动机部件（叶片、叶片、盘）， (4) 铸造缸盖和缸体， (5) 烧结粉末金属齿轮和离合器片， (6) 机加工锻钢转向和传动部件（齿轮、轴、齿条）， (7) 陶瓷氧传感器， (8) 硅片， (9) 齿轮，包括具有感应淬火或渗碳齿的齿轮， (10) 陶瓷基复合材料样品和组件， (11) 表面喷丸的部件， (12) 机加工或轧制成型钢紧固件，或两者， (13) 使用添加剂制造的部件， (14) 飞机起落架、机轮和刹车组件，以及 (15) 采用金属注射成型的部件。 5.2 通过扫频正弦输入进行PCRT的一般方法和设备要求: 5.2.1 PCRT系统由硬件和软件组成，能够诱导扫频正弦振动，记录部件对诱导振动的响应，并对收集的数据进行分析。 将扫频正弦波输入零件已被证明是引入机械振动的有效方法，并且可以通过与零件物理接触的适当有源传感器耦合的高质量信号发生器来实现。通过记录由适当的被动振动传感器产生的信号，可以实现零件频率响应的收集。分析可用数据所需的软件可能包括各种合适的统计分析和模式识别工具。测量精度和重复性对PCRT的应用至关重要。 5.2.2 硬件要求- 要求扫描正弦波信号发生器和响应测量系统在测试零件的期望频率范围内工作，精度高于0。 002 %. 信号发生器应按照适用的行业标准进行校准。传感器必须在相同的频率范围内工作。通常使用三个传感器；一个“驱动”传感器和两个“接收”传感器。传感器通常在干燥环境中工作，为被检零件提供直接接触耦合。然而，当零件潮湿或涂有油时，非接触响应方法可以适用。除了夹具和传感器接触之外，不允许与零件有其他接触，因为这些机械力会抑制某些振动。为了进行最佳检查，应将零件精确放置在传感器上（通常，每个轴上±0.062 in.（1.6 mm）可提供可接受的结果）。检查槽和电缆应将驱动器与接收信号和接地回路隔离，以避免通道之间产生（机械或电气）串扰。 过大的外部振动或可听见的噪音或两者都会影响测量。 5.3 约束和限制: 5.3.1 PCRT不能基于不影响零件结构完整性的视觉可检测异常来分离零件。可能需要对零件进行额外的目视检查，以识别这些迹象。 5.3.2 零件的过度工艺变化可能会限制PCRT异常值筛选的灵敏度。 5.3.3 不太可能识别特定异常。PCRT是一种全身测量，因此通常不可能在同一位置区分裂纹和空洞。通过使用多种模式和教学集，可以区分一些异常。使用基于物理的建模和仿真来预测部件的共振频谱也可以建立共振频率和缺陷位置/特征之间的关系。 5.3.4 PCRT仅适用于提供峰值质量因子（Q）值大于500的共振的刚性物体。非刚性材料或极薄壁零件可能不会产生令人满意的Q值。 5.3.5 虽然PCRT在许多情况下可以应用于涂漆和涂层零件，但一些表面涂层（如吸振材料和重油层）的存在可能会限制或排除PCRT的应用。 5.3.6 虽然PCRT可应用于温度范围广泛的零件，但不应应用于温度快速变化的零件。在收集共振数据之前，应稳定零件温度。 5.3.7 教学集中的错误分类部分，以及教学集中存在的未知异常，可以显著降低PCRT的准确性和灵敏度。

1.1 This practice describes a general procedure for using the process compensated resonance testing (PCRT) via swept sine input method to perform outlier screening on populations of newly manufactured and in-service parts. PCRT excites the resonance frequencies of metallic and non-metallic test components using a swept sine wave input over a set frequency range. PCRT detects and analyzes component resonance frequency patterns and uses the differences in resonance patterns between acceptable and unacceptable components to perform non-destructive testing. PCRT frequency analysis compares the resonance pattern of a component to the patterns of known reference populations of the same component and renders a pass or fail result based on the similarity of the tested component to those populations. For non-destructive testing applications with known defects or material states of interest, or both, Practice E2534 covers the development and application of PCRT sorting modules that compare test components to known acceptable and unacceptable component populations. However, some applications do not have physical examples of components with known defects or material states. Other applications experience isolated component failures with unknown causes or causes that propagate from defects that are beyond the sensitivity of the current required inspections, or both. In these cases, PCRT is applied in an outlier screening mode that develops a sorting module using only a population of presumed acceptable production components, and then compares test components for similarity to that presumed acceptable population. The resonance differences can be used to distinguish acceptable components with normal process variation from outlier components that may have material states or defects, or both, that will cause performance deficiencies. These material states and defects include, but are not limited to, cracks, voids, porosity, shrink, inclusions, discontinuities, grain and crystalline structure differences, density-related anomalies, heat treatment variations, material elastic property differences, residual stress, and dimensional variations. This practice is intended for use with instruments capable of exciting, measuring, recording, and analyzing multiple, whole body, mechanical vibration resonance frequencies in acoustic or ultrasonic frequency ranges, or both. 1.2 Units— The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that 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 ====== 5.1 PCRT Applications and Capabilities— PCRT has been applied successfully to a wide range of outlier screening applications in the manufacture and maintenance of metallic and non-metallic parts. Examples of anomalies detected are discussed in 1.1 . PCRT has been shown to provide cost effective and accurate outlier screening solutions in many industries including automotive, aerospace, and power generation. Examples of successful applications currently employed in commercial use include, but are not limited to: (1) Silicon nitride bearing elements, (2) Steel, iron, and aluminum rocker and control arms, (3) Aircraft and industrial gas turbine engine components (blades, vanes, disks), (4) Cast cylinder heads and cylinder blocks, (5) Sintered powder metal gears and clutch plates, (6) Machined forged steel steering and transmission components (gears, shafts, racks), (7) Ceramic oxygen sensors, (8) Silicon wafers, (9) Gears, including those with induction hardened or carburized teeth, (10) Ceramic matrix composite (CMC) material samples and components, (11) Components with shot peened surfaces, (12) Machined or rolled-formed steel fasteners, or both, (13) Components made with additive manufacturing, (14) Aircraft landing gear, wheel and brake components, and (15) Components made with metal injection molding. 5.2 General Approach and Equipment Requirements for PCRT via Swept Sine Input: 5.2.1 PCRT systems are comprised of hardware and software capable of inducing swept sine vibrations, recording the component response to the induced vibrations, and executing analysis of the data collected. Inputting a swept sine wave into the part has proven to be an effective means of introducing mechanical vibration and can be achieved with a high quality signal generator coupled with an appropriate active transducer in physical contact with the part. Collection of the part’s frequency response can be achieved by recording the signal generated by an appropriate passive vibration transducer. The software required to analyze the available data may include a variety of suitable statistical analysis and pattern recognition tools. Measurement accuracy and repeatability are extremely important to the application of PCRT. 5.2.2 Hardware Requirements— A swept sine wave signal generator and response measurement system operating over the desired frequency range of the test part are required with accuracy better than 0.002 %. The signal generator should be calibrated to applicable industry standards. Transducers must be operable over same frequency range. Three transducers are typically used; one “drive” transducer and two “receive” transducers. Transducers typically operate in a dry environment, providing direct contact coupling to the part under examination. However, noncontacting response methods can operate suitably when parts are wet or oil-coated. Other than fixturing and transducer contact, no other contact with the part is allowed as these mechanical forces dampen certain vibrations. For optimal examination, parts should be placed precisely on the transducers (generally, ±0.062 in. (1.6 mm) in each axis provides acceptable results). The examination nest and cabling shall isolate the drive from receive signals and ground returns, so as to not produce (mechanical or electrical) cross talk between channels. Excessive external vibration or audible noise, or both, will compromise the measurements. 5.3 Constraints and Limitations: 5.3.1 PCRT cannot separate parts based on visually detectable anomalies that do not affect the structural integrity of the part. It may be necessary to provide additional visual inspection of parts to identify these indications. 5.3.2 Excessive process variation of parts may limit the sensitivity of PCRT outlier screening. 5.3.3 Specific anomaly identification is highly unlikely. PCRT is a whole body measurement, so differentiating between a crack and a void in the same location is generally not possible. It may be possible to differentiate some anomalies by using multiple patterns and teaching sets. The use of physics-based modeling and simulation to predict the resonance frequency spectrum of a component may also allow relationships between resonance frequencies and defect locations/characteristics to be established. 5.3.4 PCRT will only work with stiff objects that provide resonances whose peak quality factor (Q) values are greater than 500. Non-rigid materials or very thin-walled parts may not yield satisfactory Q values. 5.3.5 While PCRT can be applied to painted and coated parts in many cases, the presence of some surface coatings such as vibration absorbing materials and heavy oil layers may limit or preclude the application of PCRT. 5.3.6 While PCRT can be applied to parts over a wide range of temperatures, it should not be applied to parts that are rapidly changing temperature. The part temperature should be stabilized before collecting resonance data. 5.3.7 Misclassified parts in the teaching set, along with the presence of unknown anomalies in the teaching set, can significantly reduce the accuracy and sensitivity of PCRT.