Advanced FRF Based Determination of Structural Inertia Properties

Experimental identification of rigid body inertia properties using single-rotor unbalance excitation

“…Moreover, depending on the platform's number of degrees of freedom (DOFs), the structure must be mounted successively in several different orientations, which is a difficult and time-consuming task if the structure is heavy, odd-shaped, or fragile. The method proposed in this article is related to another group of methods that derive all ten rigid body parameters from measurements of frequency response functions (FRFs) [8][9][10][11][12][13][14][15][16][17][18][19]. These methods require only standard vibration testing equipment: the structure is excited successively at several points, typically by means of a shaker or an impulse hammer, and several response measurements are made, usually with accelerometers.…”

“…Fig. 1 Example for the FRF of a softly suspended elastic structure A widely adopted FRF method, known as the massline method, derives the rigid body properties from massline values extracted from range (c) by means of modal analysis [9][10][11][12]. Accurate modal curve fitting, however, is difficult if the modal density is high or if the structure shows non-linear vibration behaviour.…”

“…It should be noted that the linear inertia model M was obtained from the full non-linear equations of motion of the rigid body after a number of simplifications had been made based on the assumption of small angular displacements and velocities (Appendix 3). The same linear inertia model is used in all FRF-based identification methods [8][9][10][11][12][13][14][15][16][17][18][19].…”

Identification of Engine Inertia Parameters and System Dynamic Stiffness via In Situ Method

“…e conventional techniques for parameters identification of the rigid body can be divided into two categories, i.e., time domain methods [2][3][4][5][6][7] and frequency domain methods. e frequency domain methods may be further subdivided into three categories: modal model method [8][9][10], residual inertia method [11][12][13][14][15], and direct system identification method [16,17]. e classical domain pendulum method is often timeconsuming due to repetitive configuration adjustments of a heavy target and complicated body such as an automotive powertrain.…”