Design of a piezo-electric actuator for dynamic testing of rolling element bearings

This paper describes the design of an actuator for a bearing test system to dynamically apply Multiple-Degree-of-Freedom (MDOF) loading, including moment loading to a bearing arrangement under test with sufficient bandwidth to replicate the propellor loading from an EVTOL application. The solution presented uses Piezo Electric Actuators (PEA), which provide very high force density and fast response time. However, significant challenges are also present, including the phenomenon of self-heating due to cyclic loading, and the limitation on actuator stroke due to their very high stiffness. Under consideration are the dynamic response of the system, including the stiffness of mechanical mounting hardware and the inherent damping of the PEA, which is modelled as a Kelvin -Voigt material.