Modeling and validation of wear and fatigue life of a lead screw driven actuator
Abstract
The wear and fatigue life of lead-screw actuators is a topic of great interest in the field of Industrial Automation. The friction, wear and resulting fatigue life behaviors in this type of actuators closely relates to many factors such as load, velocity, lubrication, material properties, surface properties, pressure, and temperature. Therefore, the wear and fatigue life of lead screw actuators cannot be modeled without a simultaneous consideration of solid mechanics, fluid dynamics, contact mechanics, and thermal dynamics. A great deal of research has been conducted in the past fifty years in the estimation of sliding wear involving metal and polymer interfaces. In this thesis, the wear and fatigue life of a lead screw actuator are modeled and validated. First, the asperity contact theory and Archard's model of sliding wear are applied to estimate the amount of wear under given conditions. Then, a test platform is developed based on a standard ASTM test protocol and the wear in ball-on-flat sliding is measured to validate the developed wear model. Simultaneously, fatigue life testing of the lead screw actuators is performed in order to verify the experimental life against the theoretical life. Next, finite element analysis is carried out using Nei-Nastran Software in order to assess the contact stresses in the lead screw and nut assembly model. Finally, the data generated from the three sources is merged to formulate a mathematical model that can predict the wear and fatigue life of a lead-screw actuator.
Degree
M.S.E.
Advisors
Bi, Purdue University.
Subject Area
Mechanical engineering
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