Frequency response and strength analysis of the elbow orthosis planetary gearbox shaft using FEA

Abstract

Shafts of various sizes are used in various fields of mechanical engineering, automotive, marine and aerospace industries to transmit torque according to requirements. In this paper, we simulate and analyse the modal and harmonic response of a shaft on which a satellite of a planetary gearbox for an elbow orthosis is mounted. The orthoses are used during the rehabilitation of patients in the postoperative period or during the regeneration of lost limb functions. Steel 45 and PLA polylactide were used in the shaft modelling. The planetary gearbox shaft was analysed for modal and harmonic characteristics at three different torque values, i. e. 1732 N·mm, 3464 N·mm, 5196 N·mm, using ANSYS Workbench. The modal and harmonic analysis of the shaft stress-strain state is calculated, completed comparative analysis, and the vibration characteristics are discussed: shown natural frequencies, mode shapes, and harmonic response. Calculations for shaft durability under a complex stress state were performed, and safety factors were calculated for shafts made of steel 45 and PLA polylactide.