Simulation, measurement, and asymmetric buckling of thermal microactuators

Predicting the force capabilities of thermal microactuators is a key issue when designing to meet specific size and power requirements. This paper uses simulation and experimental measurements to characterize the force capabilities of chevron-shaped thermal in-plane microactuators. Force measurements are obtained using a novel dual stage in situ force gauge that performs the functions of both a fixed load spring and a movable force gauge. Results show that a significant decrease in performance can occur for some designs due to higher-order asymmetric buckling, which may be caused by an offset load or process variations. Nonlinear finite element models are used to simulate the behavior, provide predictions of the force output capability, and develop design rules for mitigating the effect of asymmetric buckling.