Improving Weather Simulations Through Increased Generality

By adding support for spatially variable velocity fields and anisotropy, the CoSMoS simulation package can more accurately reproduce physical phenomena.

Passive shape shifting: A compliant design approach for full film bearings

In tribotronic bearing design active components are used to adapt bearing performance to operating conditions. The principle of self-adaptive bearings has also been presented in literature in which a passive modification of geometry was used for a variation in conditions. This work presents an alternative design approach for self-adaptive bearings. This approach is focused on the shift between two known bearing geometries, where each of them is the preferred solution in a part of the operating regime. Using compliant elements in the bearing design allows for passive shape shifting. Four examples are presented which present this behavior for variable velocity and load conditions. The design approach could possibly provide a cheaper alternative for simple active bearing designs, or could be combined with active components in a tribotronics design to improve existing performance.

An Electrostatic Self-Excited Resonator with Pre-Tension/Pre-Compression Constraint for Active Rotation Control

We report a novel electrostatic self-excited resonator driven by DC voltage that achieves variable velocity-position characteristics via applying the pre-tension/pre-compression constraint. The resonator consists of a simply supported micro-beam, two plate electrodes, and two adjustable constraint bases, and it can be under pre-compression or pre-tension constraint by adjusting the distance L between two constraint bases (when beam length l > L, the resonator is under pre-compression and when l < L, it is under pre-tension). The oscillating velocity of the beam reaches the maximum value in the position around electrodes under the pre-compression constraint and reaches the maximum value in the middle position between two electrodes under the pre-tension condition. By changing the constraint of the microbeam, the position of the maximum velocity output of the oscillating beam can be controlled. The electrostatic self-excited resonator with a simple constraint structure under DC voltage has great potential in the field of propulsion of micro-robots, such as active rotation control of flapping wings.