Parametric Study of Circular Micro Flexure Hinge Design

Compliant mechanism is a monolithic device that utilizes flexible elements, instead of pins, to transform the input to a useful output position, and flexure hinge is an integral part of a compliant mechanism. Flexure hinge design is important because it provides a means for motion actuation in a mechanism. An ideal design of a flexure hinge for a displacement output mechanism is that it provides maximum displacement output with minimum input. The objective of this study is to establish a design guide based on stiffness, displacement, and stresses for a generalized circular micro flexure hinge model using finite element method. Parametric study of a circular flexure hinge was performed using ABAQUS finite element code. The finite element results were compared with relevant analytical model from literature. Micro flexure hinge finite element models with selected range of dimensions for study were evaluated, and the optimal dimensions for flexure hinge design for maximum output displacement and minimum stresses were identified. From this study, the following parameters were established as design guide for a circular micro flexure hinge. With the width (w) of a circular flexure from 300 to 500μm range, our recommended flexure hinge height (h) is twice of the width, and the flexure hinge thickness ratio (b/t) is about 10.