1.1本规程涵盖了在轴向疲劳试验系统中进行恒定振幅试验期间，对循环力振幅控制或测量精度进行动态验证的程序。其前提是可以使用应变测量弹性元件进行力验证。使用本规程可确保在任何用户应用校正系数后，测试时机器施加的力或测试机器的动态力读数的精度在第9节建议的范围内。它没有解决静态精度问题，而静态精度必须首先通过实践解决 E4类 或同等产品。 1.2验证针对特定的试验机配置和样本。建议将本标准用于试验机和试样的每种配置。如果将动态校正系数应用于试验机力读数，以满足第9节中建议的精度，则验证也针对所用的校正过程。 最后，如果纠正过程是由一个人触发或执行的，或者两者都触发或执行，那么验证也针对该个人。 1.3众所周知，对每种试验机配置和试样配置进行全面验证可能会耗费大量时间和/或成本高昂。附录A1提供了估算试验机和试样配置变化对动态精度影响的方法，这些变化可能在完全验证之间发生。如果试验机的动态精度受到一个人的影响，建议估计校正过程中涉及的所有个人的动态精度影响。由于对试验机所有者/操作员的强烈依赖，本规程未规定如何进行评估。 1.4本规程旨在定期使用。预期验证结果一致。 使用相同机器配置的验证之间未能获得一致的结果意味着在此期间执行的动态测试的准确性不确定。 1.5与测功机的指示动态力相比，本规程规定了试验机力控制或指示力或两者的精度。力控制验证仅适用于具有某种形式的指示力峰值/峰值监测或振幅控制的测试系统。出于验证目的，测功机的指示动态力将被视为真实力。测功机和力传感器指示力之间的相位滞后不在本规程的范围内。 1.6必须根据本标准第10节报告附录A1计算或完整实验验证的结果。 1.7本规程不保证实际波形的形状在任何规定公差内符合预期波形。 1.8本标准主要针对室温操作。据信，在高温下测试时，还必须解决其他问题。目前，必须将本标准实践视为高温试验的部分解决方案。 1.9以英寸-磅为单位的数值应视为标准值。本标准不包括其他计量单位。 1.10 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和健康实践，并确定监管限制的适用性。 ====意义和用途====== 众所周知，如何在静态条件下测量施加在试样上的力。实践 E4类 详细说明了验证试验机静态力测量能力所需的过程。 然而，在动态操作期间，额外的错误可能会在测试机中表现出来。需要进一步验证以确认试验机的动态力测量能力。 笔记 1-通过实践完成静态机器验证 E4类 简单地建立引用。将测力传感器测得的指示力与测功机调节力进行静态比较以进行确认，然后动态比较以动态验证疲劳测试系统的力输出。 笔记 2-测力传感器输出的动态精度在没有校正的情况下并不总是满足本标准的精度要求。只要在应用校正后进行验证，就可以对测力传感器输出进行动态校正。 笔记 3-整体测试精度是测量精度和控制精度的组合。 本实践提供了评估其中一种或两者的方法。由于控制精度取决于比测量精度更多的变量，因此测试操作员必须使用适当的测量工具来确认测试机器 ’ 验证活动和实际测试活动之间的控制行为是一致的。 动态误差主要取决于跨度，而不是水平。也就是说，动态操作期间特定力端水平的误差取决于前一个力端水平。对于相同的力端水平，跨度越大意味着绝对误差越大。 由于影响动态力精度的试验机因素很多，建议对每种潜在误差产生因素的新组合进行验证。主要因素是样本设计、机器配置、测试频率和加载跨度。 显然，对每个配置执行完全验证通常是不切实际的。为了解决这个问题，动态验证分为两部分。 首先，至少每年进行一次或多次全面验证。本实践的主体部分描述了该程序。这提供了最准确的动态误差估计，因为它将考虑电子和加速度引起的误差源。 附件A1中描述的第二部分是简化的验证程序。它仅提供了估计加速度引起的误差的简化方法。该程序用于常见的配置变化（即试样/夹持器/十字头高度变化）。 建议在整个力和频率范围内对疲劳系统进行动态验证，在该范围内执行计划的疲劳试验系列。当按照实践进行测试时，末端水平仅限于由当前静态力验证定义的机器验证静态力 E4类 . 笔记 4-当在压缩状态下操作而不是在拉伸状态下操作时，框架中的振动是否会有所不同，这是不确定的。因此，本规程建议在最大张力和最大压缩端水平下进行验证。总跨度不需要介于这两个水平之间，但可以作为两个测试进行。 笔记 5-影响动态测量精度的主要电子特性是噪声和带宽。在最小测试频率下，过度噪声通常是主要影响。带宽不足引起的误差通常在最大测试频率下最为显著。

1.1 This practice covers procedures for the dynamic verification of cyclic force amplitude control or measurement accuracy during constant amplitude testing in an axial fatigue testing system. It is based on the premise that force verification can be done with the use of a strain gaged elastic element. Use of this practice gives assurance that the accuracies of forces applied by the machine or dynamic force readings from the test machine, at the time of the test, after any user applied correction factors, fall within the limits recommended in Section 9. It does not address static accuracy which must first be addressed using Practices E4 or equivalent. 1.2 Verification is specific to a particular test machine configuration and specimen. This standard is recommended to be used for each configuration of testing machine and specimen. Where dynamic correction factors are to be applied to test machine force readings in order to meet the accuracy recommended in Section 9, the verification is also specific to the correction process used. Finally, if the correction process is triggered or performed by a person, or both, then the verification is specific to that individual as well. 1.3 It is recognized that performance of a full verification for each configuration of testing machine and specimen configuration could be prohibitively time consuming and/or expensive. Annex A1 provides methods for estimating the dynamic accuracy impact of test machine and specimen configuration changes that may occur between full verifications. Where test machine dynamic accuracy is influenced by a person, estimating the dynamic accuracy impact of all individuals involved in the correction process is recommended. This practice does not specify how that assessment will be done due to the strong dependence on owner/operators of the test machine. 1.4 This practice is intended to be used periodically. Consistent results between verifications is expected. Failure to obtain consistent results between verifications using the same machine configuration implies uncertain accuracy for dynamic tests performed during that time period. 1.5 This practice addresses the accuracy of the testing machine's force control or indicated forces, or both, as compared to a dynamometer's indicated dynamic forces. Force control verification is only applicable for test systems that have some form of indicated force peak/valley monitoring or amplitude control. For the purposes of this verification, the dynamometer's indicated dynamic forces will be considered the true forces. Phase lag between dynamometer and force transducer indicated forces is not within the scope of this practice. 1.6 The results of either the Annex A1 calculation or the full experimental verification must be reported per Section 10 of this standard. 1.7 This practice provides no assurance that the shape of the actual waveform conforms to the intended waveform within any specified tolerance. 1.8 This standard is principally focused at room temperature operation. It is believed there are additional issues that must be addressed when testing at high temperatures. At the present time, this standard practice must be viewed as only a partial solution for high temperature testing. 1.9 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard. 1.10 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 and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== It is well understood how to measure the forces applied to a specimen under static conditions. Practices E4 details the required process for verifying the static force measurement capabilities of testing machines. During dynamic operation however, additional errors may manifest themselves in a testing machine. Further verification is necessary to confirm the dynamic force measurement capabilities of testing machines. Note 1—The static machine verification accomplished by Practices E4 simply establishes the reference. Indicated forces measured from the force cell are compared with the dynamometer conditioned forces statically for confirmation and then dynamically for dynamic verification of the fatigue testing system's force output. Note 2—The dynamic accuracy of the force cell's output will not always meet the accuracy requirement of this standard without correction. Dynamic correction to the force cell output can be applied provided that verification is performed after the correction has been applied. Note 3—Overall test accuracy is a combination of measurement accuracy and control accuracy. This practice provides methods to evaluate either or both. As control accuracy is dependent on many more variables than measurement accuracy it is imperative that the test operator utilize appropriate measurement tools to confirm that the testing machine ’ s control behavior is consistent between verification activities and actual testing activities. Dynamic errors are primarily span dependent, not level dependent. That is, the error for a particular force endlevel during dynamic operation is dependent on the immediately preceding force endlevel. Larger spans imply larger absolute errors for the same force endlevel. Due to the many test machine factors that influence dynamic force accuracy, verification is recommended for every new combination of potential error producing factors. Primary factors are specimen design, machine configuration, test frequency, and loading span. Clearly, performing a full verification for each configuration is often impractical. To address this problem, dynamic verification is taken in two parts. First, one or more full verifications are performed at least annually. The main body of this practice describes that procedure. This provides the most accurate estimate of dynamic errors, as it will account for electronic as well as acceleration-induced sources of error. The second part, described in Annex A1, is a simplified verification procedure. It provides a simplified method of estimating acceleration-induced errors only. This procedure is to be used for common configuration changes (that is, specimen/grip/crosshead height changes). Dynamic verification of the fatigue system is recommended over the entire range of force and frequency over which the planned fatigue test series is to be performed. Endlevels are limited to the machine's verified static force as defined by the current static force verification when tested in accordance with Practices E4 . Note 4—There is uncertainty as to whether or not the vibration in a frame will be different when operating in compression as opposed to tension. As a consequence, this practice recommends performing verifications at maximum tension and maximum compression endlevels. The total span does not need to be between those two levels, but can be performed as two tests. Note 5—Primary electronic characteristics affecting dynamic measurement accuracy are noise and bandwidth. Excessive noise is generally the dominant effect at the minimum test frequency. Insufficient bandwidth-induced errors are generally most significant at the maximum test frequency.