Cycloidal Gearbox Model for Transient Analysis Implemented in Fortran with Constant Time Step 2nd Order Integrator

Abstract

In this paper, the transient model of the cycloidal gearbox implemented in Fortran is presented. The constructed model of the gearbox is based on multibody dynamics analysis and guarantees a 10‑times faster kinematical and dynamical solution than the model designed in the engineering software (MSC Adams). The subroutines for contact modelling were implemented with the Kelvin-Voigt model. Opposite to the MSC Adams (constant contact stiffness), the contact in the Fortran model utilizes the curvatures of the contacting parts and their material parameters in each iteration of the analysis. Forces acting on external and internal sleeves have been compared with the MSC Adams model. Both models resulted in similar values of the forces acting on the sleeves. In the Fortran model, the 2­nd order Runge Kutta method in the integration subroutine was used with the constant integration steps. The model in MSC Adams uses the solution method with an adaptive time step. Various dissipative models, which use initial contact velocity and the coefficient of restitution were tested without convergence. The convergence in the Fortran model was obtained only for the constant contact damping coefficient. The Fortran model allows for accurate results and can be further used in the optimization process.