Abstract
The dual-rotor system has been widely used in aero-engines and has the characteristics of large axial size, the interaction between the high-pressure rotor and low-pressure rotor, and stiffness nonlinearity of bolted joints. However, the testing of a full-scale dual-rotor system is expensive and time-consuming. In this paper, the scaling relationships for the dual-rotor system with bolted joints are proposed for predicting the responses of full-scale structure, which are developed by generalized and fundamental equations of substructures (shaft, disk, and bolted joints). Different materials between prototype and model are considered in the derived scaling relationships. Moreover, the effects of bolted joints on the dual-rotor system are analyzed to demonstrate the necessity for considering bolted joints in the similitude procedure. Furthermore, the dynamic characteristics for different working conditions (low-pressure rotor excitation, high-pressure rotor excitation, two frequency excitations, and counter-rotation) are predicted by the scaled model made of a relatively cheap material. The results show that the critical speeds, vibration responses, and frequency components can be predicted with good accuracy, even though the scaled model is made of different materials.
Highlights
Similitude studies of dual-rotor systems considering the nonlinearity of bolted joints are not found
Many meaningful works on similitude have been completed, the following issues still exist: (i) most similitude studies focused on the linear systems or simple structures, but similitude studies of dual-rotor systems considering the nonlinearity of bolted joints are not found; (ii) Similitude Theory Applied to Governing Equations (STAGE) and energy method (EM) need the governing equation and a lot of work of derivation
This paper presents the scaling relationships for predicting the dynamic characteristics of a dual-rotor system with bolted joints, where different materials between the prototype and models are taken into account
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Similitude studies of dual-rotor systems considering the nonlinearity of bolted joints are not found. Energy method (EM) was presented by Ungbhakorn and Singhatanadgid [33], which considered the scaling laws of boundary conditions, but the work of derivation was required. Many meaningful works on similitude have been completed, the following issues still exist: (i) most similitude studies focused on the linear systems or simple structures, but similitude studies of dual-rotor systems considering the nonlinearity of bolted joints are not found; (ii) STAGE and EM need the governing equation and a lot of work of derivation.
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