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This SAE Standard presents a test procedure for determining the airborne sound insulation performance of materials and composite layers of materials commonly found in mobility, industrial, and commercial products under conditions of representative size and sound incidence so as to allow better correlation with in-use sound insulator performance. The frequency range of interest is typically 100 to 10000 Hz 1/3-octave band center frequencies. This test method is designed for testing flat samples with uniform cross section, although in some applications the methodology can be extended to evaluate formed parts, pass-throughs, or other assemblies to determine their acoustical properties. For non-flat parts or assemblies where transmitted sound varies strongly across the test sample surface, a more appropriate methodology would be ASTM E90 (with a reverberant receiving chamber) or ASTM E2249 (intensity method with an anechoic or hemi-anechoic receiving chamber).

This SAE Recommended Practice describes a laboratory test procedure for measuring the composite loss factor and bending stiffness properties of a system consisting of a damping material bonded to a vibrating bar which is excited at the center. The bar could be a steel, aluminum, glass, or other metal or composite bar that would be used in ground vehicles, marine products, and aircraft. The damping materials could be homogeneous, nonhomogeneous, a combination of homogeneous and nonhomogeneous, used in conjunction without or with an inelastic material (such as aluminum foil) in an extensional layer or a constrained layer configuration. The damping material could be a heat bondable material, adhesive backed sheet material, sprayable coating material, or other kinds of viscoelastic materials. The damping procedure discussed here provides means to measure damping over a range of frequencies and temperatures found applicable and useable for different transportation systems.