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M-DOF dynamic model for load sharing behavior analysis of PGT
Huimin Dong,Yangyang Wu,Delun Wang,Shaoping Bai 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.3
A Multi-degree-of-freedom (M-DOF) nonlinear dynamic model for n-pinion Planetary gear train (PGT) is presented in this paper to investigate load sharing behavior of planet gears. In this dynamic model, manufacturing and assembly errors, elastic deformation and time-varying mesh stiffness are considered. Two sets of elastic compatibility equations are proposed to describe compatibility relationship between displacements, errors and elastic deformations. By means of Ishikawa formula, time-varying mesh stiffness of the gear pair is determined. The dynamic motion equations are solved with Runge-Kutta numerical integral method, which yields the displacements and deformations of each component. With the model, dynamic load sharing behavior of planet gears is evaluated. An example of 3-pinion PGT dynamic modeling is included, for which the influence of floating sun gear and adding flexible planet pin on the load sharing characteristics is analyzed.
Modeling dynamic behavior of MDOF systems with multiple bilinear springs
Yali Ma,Shudong Yu,Delun Wang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.9
A computational scheme is presented in this paper to simulate dynamical behavior of multiple degrees of freedom (MDOF) systems with multiple bilinear springs. In the proposed scheme, a bilinear spring is modeled using by two parallel springs - a primary spring and a secondary spring. The primary spring is an ordinary linear spring having identical stiffness in tension and compression, and is active for tension and compression. The secondary spring, whose stiffness characterizes the bilinearity, is active only during compression. It is employed in connection with the Newmark integration method and the linear complementarity problem (LCP) formulation to obtain time-domain responses of dynamical systems with bilinear springs due to initial disturbances and harmonic excitations. The scheme described in this paper is effective in dealing with the sudden transition from tension to compression and vice versa simultaneously for all bilinear springs. Numerical results for bilinear oscillators with finite bilinearity ratios and impact oscillators with an infinite bilinearity ratio show that the proposed bilinear spring model is accurate, generic and valid for bilinearity ratios ranging from zero to infinity. Orderly and chaotic behavior of viscously damped 3-DOF system under harmonic excitation is studied for a wide range of excitation frequencies and bilinear ratios to demonstrate the effectiveness and applicability of the proposed model for MDOF bilinear systems.
Huimin Dong,Chu Zhang,Shaoping Bai,Delun Wang 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.8
A discrete model to study the load distribution behavior of helical planetary gear trains (PGTs) is developed, in which 3D planet position errors, induced by carrier pinhole position errors and tooth modifications, are duly considered. The model adopts a discrete approach with which the planetary gear train is discretized into a series of slice-units in order to ease the problem of gear meshing in 3D cases. In the modelling, compatibility conditions and discrete equilibrium are developed for the coupling among 3D planet position errors, tooth modifications, instantaneous meshing situations, elastic deformations and rigid body spatial motions. Upon the discrete model, a method for analysis of the load distribution is further developed. The influence of 3D planet position errors and tooth modifications on the load distribution was simulated for a helical PGT having three and four planets. Tests on the actual wind turbine PGTs were conducted with results agreed with the simulations obtained, which validate the proposed method.