机械振动和冲击.机械机动性的试验测定.第5部分:用未连接到结构上的激励器进行冲击激励的测量

[中文适用范围]： 本文件规定了测量结构的机械活动性和其他频率响应函数的程序，这些结构是通过未连接到被测结构的激励器产生的脉冲力来激励的。 它适用于使用冲击激励测量移动性、加速度或动态柔量，作为驱动点测量或转移测量。 其他激励方法，例如阶跃松弛和瞬态随机，导致信号处理要求与冲击数据的要求类似。 然而，此类方法超出了本文档的范围，因为它们涉及使用连接到结构的激励器。 所涵盖的信号分析方法均基于离散傅里叶变换（DFT），其主要通过快速傅里叶变换（FFT）算法来执行。 这种范围限制仅基于实施这些方法的设备的广泛可用性以及使用这些方法的大量经验基础。 它并不旨在排除使用当前正在开发的其他方法。 冲击激励还广泛用于获取未校准的频率响应信息。 例如，获得近似固有频率和模态形状的快速冲击测试对于规划随机或正弦测试以实现精确的移动性测量非常有帮助。 使用冲击激励来获得定性结果可以是迁移率测量的第一阶段。 本文件仅限于使用冲击激励技术来进行精确的迁移率测量。 [外文原描述]： This document specifies procedures for measuring mechanical mobility and other frequency-response functions of structures excited by means of an impulsive force generated by an exciter which is not attached to the structure under test. It is applicable to the measurement of mobility, accelerance or dynamic compliance, either as a driving point measurement or as a transfer measurement, using impact excitation. Other excitation methods, such as step relaxation and transient random, lead to signal-processing requirements similar to those of impact data. However, such methods are outside the scope of this document because they involve the use of an exciter which is attached to the structure. The signal analysis methods covered are all based on the discrete Fourier transform (DFT), which is performed mostly by a fast Fourier transform (FFT) algorithm. This restriction in scope is based solely on the wide availability of equipment which implements these methods and on the large base of experience in using these methods. It is not intended to exclude the use of other methods currently under development. Impact excitation is also widely used to obtain uncalibrated frequency-response information. For example, a quick impact test which obtains approximate natural frequencies and mode shapes can be quite helpful in planning a random or sinusoidal test for accurate mobility measurements. These uses of impact excitation to obtain qualitative results can be a first stage for mobility measurements. This document is limited to the use of impact excitation techniques for making accurate mobility measurements.