Changes in the mechanical performance of an ortho-planar spring after aging tests

Abstract

This paper analyzed an ortho-planar spring (OPS) compliant mechanism and evaluated its mechanical performance after hygrothermal and ultraviolet radiation aging tests. The aging analysis performed here addresses the performance of compliant mechanisms after aging processes which can help inform the design of future compliant mechanisms. ASTM D638 tensile test type I samples were also submitted to aging to serve as a comparison for OPS samples. The samples were submitted to three different kinds of aging conditions, namely water immersion, oil immersion and ultraviolet radiation. In conclusion, tensile samples showed significant statistical changes in Young's modulus and elongation at break, whereas OPS samples did not show significant statistical changes in any aging condition, indicating that aging processes at the time interval analyzed in this work did not affect the mechanical properties and elastic capabilities of the samples. Although tests using the specific materials, environment and exposure time would be needed to verify the use in a specific application, the results of this study suggest that compliant mechanisms show promise for implementation in applications where aging is a concern and their life is expected to be within the bounds of this aging study. Ortho-planar spring compliant mechanism samples were analyzed in this work to understand how aging conditions such as ultraviolet radiation, water immersion and oil immersion would affect their mechanical properties and elastic capabilities. Even after six months of harsh aging conditions, no significant changes were detected in the mechanisms, which is an interesting result.