Autonomous modal analysis - A method for experimental Modal Analysis using self-generated excitation

A method is presented to extend the well-known techniques and procedures used for Experimental Modal Analysis (EMA) to cases where the excitation forces are generated autonomously by the system under investigation. This method is referred to as Autonomous Modal Analysis (AMA). In some practical cases, it can be difficult to implement the EMA approach because the excitation system may interfere with the test structure and alter its boundary conditions. In order to overcome these limitations, the AMA method presented here is based on the use of dynamic exciting forces generated by an actuator mounted internally in the system, as a part of it. A new type of response function is introduced (the Reactive Response Function, RRF) and the AMA theory is developed in full. The AMA methodology is demonstrated using an extensive numerical simulation study, addressing a full range of damped structures, with universally good results which closely match those obtained applying EMA to the same test cases.