Fluid load augmented micro balance

Abstract

Micro-cantilever based micro weighing balance was studied using polydimethylsiloxane micro-cantilever beam and water droplet. In this system, micro-cantilever beam acts as spring balance while the droplet acts as weight. Initially, tip defection of cantilever beam under the body load provided by water droplets of sizes 4, 5, 6 and 7 μl were found experimentally. For this study, droplets were placed at dimensionless length ξ = 0.8 from the clamped end. Fluid load augmentation was studied by studying the tip deflection of the beam with droplet under flow velocities between 0.75 and 1.5 m/s. A mini wind tunnel is used to provide fluid load with wind flow occurring along the length of the beam. Experimental results show an increase in tip deflection with flow velocity, suggesting the phenomena of fluid load augmentation. In addition to experimental results, this paper presents details on modelling of natural frequency of the micro-cantilever beam with added mass using Rayleigh’s energy method.