支撑钢棒上材料的组合振动阻尼特性的实验室测量

[中文适用范围]： 本SAE标准描述了一种实验室测试程序，用于测量由阻尼材料粘附在振动悬臂钢条上组成的系统的振动阻尼性能。该钢条通常称为Oberst棒（以H. Oberst博士命名），测试方法通常称为Oberst棒测试方法。阻尼处理材料可能包括均质材料、非均质材料或均质、非均质和/或非弹性（如铝箔）材料的组合。这些材料通常安装在运输系统（如地面车辆、船舶产品和飞机）中，以减少共振时的振动，从而降低振动表面的噪声辐射。本文描述的测试方法是为了对用于汽车钢板上的材料进行排序而开发的，但也可能适用于其他情况或条件。大多数材料和系统的阻尼性能随频率和温度的变化而变化。因此，本测试程序包括测量适用于许多运输系统的频率和温度范围内的阻尼的规定。测量的阻尼性能将以复合损耗因数ηc表示，频率范围约为100至1000 Hz，并在给定应用的有用温度范围内。术语“复合”指的是钢和阻尼材料的组合。因此，复合损耗因数取决于钢和阻尼材料层的厚度、阻尼和模量。本文描述的测试程序基于ASTM E756中描述的方法。然而，本SAE文件与ASTM E756方法的不同之处在于，SAE实践规定了棒材材料、三种棒材尺寸、测试样品的安装条件以及建议的标准插值频率。本文件提供了一种方法，根据代表典型金属板应用的测试样品的复合损耗因数值对阻尼材料进行排序。如果满足附加条件，则可以仅从本文件中指定的测试样品计算阻尼材料的材料特性，包括杨氏模量E和材料损耗因数η。ASTM E756定义了这些附加条件以及用于计算单层（Oberst梁）配置的阻尼材料特性的方程。 [外文原描述]： This SAE Standard describes a laboratory test procedure for measuring the vibration damping performance of a system consisting of a damping material bonded to a vibrating cantilevered steel bar. The bar is often called the Oberst bar (named after Dr. H. Oberst) and the test method is often called the Oberst bar test method. Materials for damping treatments may include homogeneous materials, nonhomogeneous materials, or a combination of homogeneous, nonhomogeneous, and/or inelastic (such as aluminum foil) materials. These materials are commonly installed in transportation systems such as ground vehicles, marine products, and aircraft to reduce vibration at resonance, and thus reduce the noise radiation from the vibrating surface. The test method described herein was developed to rank order materials for application on panels using general automotive steel but also may be applicable to other situations or conditions.Damping performance for most materials and systems varies as a function of both frequency and temperature. Accordingly, this test procedure includes provisions for measuring damping over a range of frequencies and temperatures found applicable to many transportation systems. The measured damping performance will be expressed in terms of composite loss factor, η c , within the frequency range of approximately 100 to 1000 Hz, and over the useful temperature range for the given application. The term composite refers to the steel and damping material combination. The composite loss factor is, therefore, dependent upon the thickness, damping, and modulus of both the steel and damping material layer.The test procedure described here is based on the method described in ASTM E756. However, this SAE document differs from the ASTM E756 method in that the SAE practice specifies the bar material, three bar sizes, the mounting conditions of the test samples, and suggested standard interpolation frequencies. This document provides a means of rank ordering damping materials according to their composite loss factor values from test samples that represent typical sheet metal applications.The material properties of the damping material alone, including Young’s modulus E, and the material loss factor η, may be computed from the test samples specified in this document if additional conditions are met. ASTM E756 defines these additional conditions as well as the equations to be used to compute the damping material properties for the single layer (Oberst beam) configuration.Cross Reference: