EXPERIMENTAL COMPARISON OF LIMIT CYCLE METHOD WITH PHASE RESONANCE AND PHASE SEPARATION METHODS FOR DETERMINING MODAL CHARACTERISTICS OF AIRCRAFT STRUCTURES

摘要

Classical phase resonance method (PRM) with multipoint excitation was successfully utilized in ground vibration tests (GVT) from 60-th up to 90-th years of the 20th Century. The appearance of highly productive computers resulted in replacement of this method in majority of tests by phase separation method (PSM), which requires less testing structure occupation time but needs more data evaluation and analysis time. Due to relatively complicated data processing algorithms that are required by PSM, the final results reliability is lower than in PRM. In this paper short overview of TsAGI experience in aerospace structures GVT is presented, and possible improvements of phase resonance method are discussed. The main issue is how to decrease test duration time without loss of accuracy and reliability. Under discussion is one of the possible ways, i.e. the application of feedback control of excitation force using modern data acquisition and signal generation equipment. A few examples are presented to demonstrate effectiveness and restrictions.