SAE J2883:2020 pdf free

SAE J2883:2020 pdf free.Laboratory Measurement of Random Incidence Sound Absorption Tests Using a Small Reverberation Room
The edges of the samples shall be shielded from the impinging sound. The edge shields, used to seal the edges, are often called frames and could be made of steel or aluminum angles or wood frames. These must not be significantly sound absorbing themselves – i.e., including them in the bare room measurement should have no measureable effect. In addition, they must be of significant mass as to block sound energy within the measurement range. The frame must extend at least to the top surface of the test sample being measured; but not extend more than 3 mm above the absorber top surface4. The edge shields must lie flush to the floor of the test chamber within 0.5 mm or less. Any gap between the edge shields and the edges of the flat test samples when viewed from above must be 1.0 mm or less. However, gaps between the edge shields and the floor; and between the edge shields and the edges of the sample exceeding the above values, shall be sealed with tape, caulking compound, or a similar product.
Sample Mounting Conditions: The sample shall be mounted such that it simulates the actual application as close as possible and it shall be documented in the report. More information on the mounting specific to this test method is provided in Appendix E. This test method is suitable for:
– When testing parts and/or objects that are used in an application (i.e., non flat and non rectangular test samples or molded parts), tests shall be conducted in the same manner as is used in the application. For example, when testing a hoodliner or a package tray, the body panel (the hood and the package tray panel) on which these parts rest on in the application shall be used in the study. The part shall be istalled to the body panel similar to the way it is done in the application. The body panel shall be resting on the floor. Any openings or cutouts on the part shall be covered with parts that are intended to be there. The bare room test shall be done with the body panel in the room
– Provided the body panel is not available for measuring the performance of the part, the perimeter of the part shall be sealed to the floor. However for parts like seats that are normally bolted to the floor and do not have a body panel otherwise, they shall be tested as is as it is shown in Appendix E-4.SAE J2883 pdf free download.