Characteristic evaluation of a bristled wing using mechanical models of a thrips wings with MEMS piezoresistive cantilevers

Abstract

This paper discusses similar-scale mechanical models of a thrips wing using microelectromechanical systems (MEMS) piezoresistive cantilevers to quantitatively evaluate bristled wing characteristics. Each cantilever had combs with varying widths and neighboring gaps that were adjusted so that a constant surface area was maintained. The cantilever body was 1,324 × 256 × 5 μm 3 in size. An aerodynamic drag force from the airflow applied to the cantilever surface was measured using the fractional resistance change of the piezoresistor due to the cantilever's deformation. The aerodynamic characteristics of each model were evaluated in a wind tunnel with airflow velocities between 1.2 and 5.6 m/s. The experimental results suggest that at a lower comb-width-based Reynolds number that was approximately equal to that of a bristled wing of a thrips, the comb areas of the cantilever act as an airflow suppression due to boundary layer effects, which results in an increased aerodynamic force.

Micro Water Flow Measurement Using a Temperature-Compensated MEMS Piezoresistive Cantilever

“…Δ R / R was plotted with respect to the x-directional deflection Δ x in Figure 4 c. The cantilever deflection Δ x and Δ R / R presented a clearly linear relationship; the linear relationship was not distorted, even for a deflection as large as 180 μm. S d was calculated to be 1.1 × 10 2 m −1 from the slope of the relationship, which is coherent with a previous report on the same device configuration [ 17 ]. The linearity was newly confirmed to be maintained for larger deflections; in the previous report, the linearity was examined only for deflections as large as 5 μm.…”

“…In the process, a p-type silicon-on-insulator (SOI) wafer (5 μm device Si layer, 2 μm SiO 2 layer, and 300 μm handle Si layer) was used as the starting material. The fabrication process is described in previous studies in detail [ 17 ]. First, an n-type piezoresistor was formed on the surface of the device Si layer by rapid thermal diffusion ( Figure 2 a).…”

“…However, the heat generated on the wire could damage solutions containing biological samples. In contrast, measuring the flow rate based on the drag force of the fluid using a MEMS force sensor is a promising technique because in principle the sensor does not interact with the biological sample [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. For the sensitive flow rate measurement, a MEMS force sensor-type flowmeter involves placing a cantilever in the flow path and detecting its strain caused by the drag force.…”

“…In addition to the simple flow rate measurement, piezoresistive cantilever typed flow sensors were applied for viscosity sensing [ 19 ] or even a bio-logging application of seabirds [ 16 ]. The addition of some structures, such as bristles [ 17 ] and pillars [ 20 ], was performed to improve the sensor performance. Among them, since the piezoresistance also changes according to the temperature conditions around the sensor, temperature compensation is required to precisely measure the flow rate.…”

Enantiomeric switching of chiral metamaterial for terahertz polarization modulation employing vertically deformable MEMS spirals

“…Further improvement of the amplitude of the optical activity will be possible by increasing the central height of the spiral at the deformation. We estimate that narrowing the interspace between the spiral arms and the addition of micro bristle-like structures on the spiral beam edges will increase the deformation force the spiral beam receives from the air flow 31 , enabling greater deformation of the spirals. Combined with a real-time two-dimensional imager (a THz camera) 32 , the proposed metamaterial can be applied for sensitive real-time measurement system of the circular dichroism spectra of chiral molecules such as amino acids with modulation of the video rate speed (for example, 30 Hz) in a future work.…”