Modal Characterization of 3D Printed Compliant Mechanisms for Space Exploration

The moon’s surface is covered with dust (regolith) and microscopic particles created by numerous meteorite impacts (lunar meteoric gardening). The lack of the smoothening actions of hydrological and aeolian process and the interaction with cosmic radiation have made regolith abrasive and electrostatically charged. Due to these characteristics, regolith has been identified as a major issue to lunar (and other planets) exploration, being responsible for clogging and wearing in the exposed hinges of the tools used in extravehicular activities. Compliant mechanisms permit to eliminate the use of hinges and, therefore, of sliding motions between adjacent surfaces, because they use elastic deformation to supply the desired kinematic behavior. Due to their design, these mechanisms present areas that undergo large deformations and alternating stress concentrations and, therefore, fatigue effects. In this work, we examine the dynamic behavior of a compliant mechanism designed for extravehicular space exploration using additive manufacturing. The vibration mode-shapes and the corresponding natural frequencies will be identified, with particular focus on the equivalent structural characteristics and their linearity.