Structural response to low‐frequency acoustic excitation

Abstract

Many noise sources at Army installations are of a low‐frequency (25 to 125 Hz) impulsive nature (e.g., artillery and explosives training, or helicopters). Mitigation of the impacts due to these sources, both on‐ and off‐post, require an understanding of the response of a structure to low‐frequency excitation. Little information is available in the literature for response below about 63 Hz. In order to study the response below this band, a structure of typical residential construction has been erected inside the CERL Bi‐Axial Shock Test Machine (BSTM) building, and extensively instrumented for vibrational and acoustic response. The BSTM has been utilized to produce impulsive acoustic excitation (114 to 130 dB, 25‐ to 40‐ms duration) of the structure. A set of specially designed speakers has been utilized to produce nearly pure tone excitation (90–100 dB, 20 to 125 Hz). Production of the excitation signals and preliminary structural response results are presented.