Cyclic Micro-Bending and Plasticity Length Scales in LIGA Nickel MEMS Structures

摘要

This paper presents the results of recent studies of cyclic micro-bending and plasticity length scales in LIGA Ni micro-electro-mechanical systems (MEMS). First, size effects due to single micro-bends are analyzed within the context of the phenomenological strain gradient plasticity theory of Fleck and Hutchmson. The evolution of cyclic deformation is then studied by performing fully reversed cyclic micro-bend experiments that provide insights into cyclic stress/strain evolution, back stress effects and cyclic failure phenomena. The implications of the results are then discussed for the analysis of plasticity and cyclic deformation in micro-scale systems.