Fatigue lifespan of a planetary roller-screw mechanism

Electro-mechanical actuators including planetary roller screw (PRS) support cyclic loads in aeronautical conditions. PRS multiple thread contacts between screw, rollers and nut allow the mechanism to large loads. However, accreditation requires fine prediction of fatigue lifespan. In this paper, a design strategy for mechanisms is proposed combining Hertz contact model multi-axial criterion. The method applied on two examples, one standard inverted PRS. lifespan depends maximal Dang Van stress. sliding angle (Hertz main direction/sliding velocity) was introduced analyze performances. For both maximum stress at were located bulk material but not surface. mainly depended curvature ratio, Based analysis, criterion implemented derive loading domain infinite mechanism. Critical always roller-screw side.