DIAGNOSTIC TECHNIQUE TO IDENTIFY AIRBORNE AND STRUCTUREBORNENOISE COMPONENTS

THERE IS A CRITICAL NEED TO MEASURE STRUCTUREBORNE NOISE TRANSMISSION IN AIRCRAFT, PARTICULARLY THOSE POWERED BY THE ADVANCED TURBOPROP. IT IS PROPOSED THAT A STRUCTUREBORNE INTENSITY MEASUREMENT PROCEDURE BE FORMULATED AND DEVELOPED FOR IN-FLIGHT APPLICATION. THE PROCEDURE WOULD INCLUDE CONSIDERATION OF FLEXURAL, LONGITUDINAL AND ROTATIONAL WAVE COMPONENTS, SINCE THEY ALL CONTRILUTE TO THE TRANSMISSION OFVIBRATIONAL ENERGY. UNDER PHASE I, THE BASIC FORMULATIONS WILL BE DEVELOPED; SIMPLIFICATIONS AND ATTENDANT LIMITATIONSWILL THEN BE EXPLORED IN ORDER TO ACHIEVE FORMULATIONS THAT ARE COMPATIBLE WITH PRACTICAL MEASUREMENT PROCEDURES. THEN THE APPROACH WILL BE EVALUATED BY POSTULATING STUDIES OF TYPICAL AIRCRAFT CONFIGURATIONS. AT THE CONCLUSION OF PHASE I THE NEED FOR ADDICIONAL SIMPLIFICATIONS OF THE ANALYTICAL FORMULATION WILL BE IDENTIFIED; THE SIMPLIFICATIONS WILL BE INCORPORATED DURING PHASE II OF THE PROGRAM. MEASUREMENT PROCEDURES WILL THEN BE SPECIFIED FOR GENERAL USE AND THE METHOD DEMONSTRATED ON A TYPICAL AIRPLANE STRUCTURE.