MEMS Sensors for Aeroacoustics

MEMS-Based Biomedical Ultrasound

Shape Memory Alloy MEMS

Shear Stress Sensors for CMP

Cochlear Mechanics

Cochlear Like MEMS

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Pressure and Shear Stress Sensor Arrays for Aeroacoustic Applications

This project aims to develop arrays of MEMS pressure sensors and shear stress sensors that can measure fluctuating pressures and shear stresses in the turbulent boundary layer near the surface of an aircraft in flight. The goal is to characterize the properties of the turbulent boundary layer in order to improve noise control strategies for the aircraft. Project is being conducted with an industry partner. The current array design has 64 elements (8x8 array), arrayed with 1.26 mm center-to-center spacing. Each element is 600 microns in diameter, and expected to achieve a 500 Hz-80 kHz bandwidth with 85-150 dB SPL dynamic range. Student: Joshua Krause, ME Masters of Science student.

Light microscope images of two of the elements in the MEMS sensor array.

Modeling and Characterization of MEMS Based Biomedical Ultrasound Elements

We are working with collaborators to produce and validate computational models of capacitive micromachined ultrasound transducer elements (cMUTs) that are being used as part of a MEMS-based biomedical ultrasound system. This project involves both computational and experimental aspects, as well as close collaboration with industrial and academic partners. Student: Christopher Doody, ME Masters of Science student.

Model results showing a predicted element frequency response in air and water, and a beam pattern in water.

Shape Memory Alloy Composite MEMS Actuators

We are developing MEMS actuators based around shape memory alloy (SMA) microwires in an elastomeric structure. The ultimate goal is to use these soft actuator patches for actuation of an all-soft-material robot under development with collaborators. We are working on fabrication, modeling, design, and testing of these devices. Student: Aaron Gerratt, ME Undergrad, Peter Fallon, ME Undergrad, Brian Keirstead, ME Masters of Science student.

Left: Concept diagram of the device. Right: Microscope pictures of one device before annealing.

Stress Sensors for Chemimechanical Polishing (CMP)

We are developing MEMS stress sensors to measure the interaction forces between the polishing pad and wafer during CMP processing. This will include both fluid shear stresses and direct solid-solid contact between pad asperities and the wafer surface. Floating element sensors and polymer micropost sensors are being pursued. The project is being conducted with industry and academic partners from around the country. Students: Andrew Mueller, ME Masters of Science student, Douglas Gauthier, ME Masters of Science student.

SEM images of PDMS post-in-well sensors developed at Tufts by Andrew Mueller and Robert White.

Computational and Experimental Models of Cochlear Mechanics

Computational and experimental modeling of the active and passive mechanisms present in the mammalian cochlea. This project is evolving, and may take different paths as it progresses. Currently, we are looking at computational models of basilar membrane static load tests and experimental models of cochlear coiling. This project will include collaborations with Prof. Vetter, in Neuroscience at NEMC and Prof. Guyer in Computer Science at Tufts. Students: Shuangqin Liu, ME PhD, Douglas Gauthier, ME MS, Ethan Mandelup, ME Undergraduate.

Left: Photograph of a mechanical experimental setup with a tapered fluid fileld chamber and tapered membrane. Right: Example tuning curves achieved in the mechanical experiment, measured using LDV.

Cochlear-like Biomimetic Acoustic Sensors

Design, modeling, and fabrication of MEMS sensors which mimic some of the mechanics of the mammalian cochlea as an alternative, low-power acoustic transduction and signal analysis mechanism. Ongoing project in collaboration with Karl Grosh and students at Univ. of Michigan. Currently no students at Tufts.

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