Author: blackledge.3

>> “Magnetostrictive materials for tunable fluid pumps” published in Proceedings of SPIE Smart Structures and Materials + NDE 2024

Abstract

This paper compares the magnetostrictive properties of Metglas and Galfenol and investigates their potential as substrate materials for diaphragms to tune the performance of piezoelectric diaphragm pumps. These pumps are found in medical, automotive, and aerospace applications. Conventional diaphragm pumps consist of a vibrating diaphragm actuated by a piezoelectric wafer affixed to a rigid substrate; operating in bending mode, the diaphragm propels a specific volume of fluid across a defined space. Pump designs generally represent a trade-off between maximum output pressure and maximum flow rate. In this paper, we propose two well-established magnetostrictive materials, Metglas and Galfenol, as alternatives to conventional passive substrates to actively modulate pump characteristics such as pressure and flow rate. We experimentally characterize the Delta-E effects of Metglas and Galfenol to verify their stiffness tunability in response to magnetic fields. We develop COMSOL finite element models to simulate the performance of a commercial piezoelectric pump with and without the addition of active substrate materials. Finally, we investigate the potential for tuning the performance of diaphragm pumps with magnetostrictive substrates. This concept can enhance the efficiency of pumping mechanisms, allowing for adaptable performance across a range of specifications.
M. M. KHATTAK, A. W. Dolph, L. M. Headings, and M. J. Dapino “Magnetostrictive materials for tunable fluid pumps”, Proc. SPIE 12947, Behavior and Mechanics of Multifunctional Materials XVIII, 129470G (9 May 2024); https://doi.org/10.1117/12.3014281

>> Dapino appointed to ASME Committee on Honors

Prof. Marcelo Dapino was appointed to serve as a member-at-large on the Committee on Honors of the American Society of Mechanical Engineers (ASME).  The appointment, announced by ASME President Thomas R. Kurfess, extends from January 2024 to June 2027.

Each year, the ASME Committee on Honors confers awards to over 65 individuals, recognizing meritorious contributions to mechanical engineering. The Committee consists of nine Members or Fellows, which typically includes a past president and two honorary members or ASME medalists.

In addition to this appointment, Dapino’s most recent recognition is receiving the ASME Dedicated Service Award formally presented at the ASME Smart Materials, Adaptive Structures, and Intelligent Systems (SMASIS) Conference held in Austin, Texas on September 11-13, 2023. Prof. Dapino is a Fellow of ASME.

>> “Improvements in bonding through ultrasonic additive manufacturing of titanium by stabilizing displacive phase transformations,” published in Materialia

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Abstract

The development of advanced materials to operate in extreme environments (temperature, pressure, strain rate, irradiation, etc.) is essential to meet future energy challenges. In addition to being an advanced solid-state bonding technique, ultrasonic additive manufacturing (UAM) can be considered as a type of extreme environment due to the high strain and high strain rate deformation that is created. Understanding the physical processes that occur in this extreme environment can be valuable to creating new desirable microstructures and/or phase changes. Although UAM has demonstrated great success in bonding a variety of materials, the underlying science mechanisms controlling the bonding are not well quantified. We observed crystal structure changes from hexagonal closed packed (HCP) to body centered cubic (BCC) in Ti and Ti alloy specimens occurring within ∼0.5 seconds following UAM bonding with an estimated peak temperature of ∼400°C. Extensive interdiffusion of elements (0.2 µm – 2 µm depending on location) occurred that does not conform to thermal equilibrium bulk or grain boundary diffusion. We present evidence that a significant concentration of deformation-induced vacancies Xv (between 10−4 – 10−6 atomic fraction) was created during UAM, approximately ten orders of magnitude higher than the Xv value of ∼10−15 expected for thermal equilibrium conditions. This caused pronounced metallurgical changes including rapid elemental diffusion, strain-induced phase transformation, and bonding. We examined this UAM-induced severe plastic deformation on a variety of materials and performed uncertainty calculations from the measurements.

M. Pagan, N. ZHAO, L.M. Headings, M.J. Dapino, S. Vijayan, J.R. Jinschek, S.J. Zinkle, and S. S. Babu, “Improvements in bonding through ultrasonic additive manufacturing of titanium by stabilizing displacive phase transformations,” Materialia. https://doi.org/10.1016/j.mtla.2023.101979

>> “Dynamic Response of a Polyvinylidene Fluoride (PVDF) Sensor Embedded in a Metal Structure Using Ultrasonic Additive Manufacturing” published in Actuators

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Abstract
This study aims to examine the dynamic response of a polyvinylidene fluoride (PVDF) piezoelectric sensor which is embedded into an aluminum coupon using ultrasonic additive manufacturing (UAM). Traditional manufacturing techniques used to attach smart materials to metals on the surface have drawbacks, including the potential of exposing the sensor to adverse environments or physical degradation during manufacture. UAM can avoid these issues by integrating solid-state metal joining with subtractive processes to enable the fabrication of smart structures. A commercial PVDF sensor is embedded in aluminum with a compression technique to provide frictional coupling between the sensor and the metallic matrix. The PVDF sensor’s frequency bandwidth and impact detection performance are evaluated by conducting cantilever and axial impact tests, as well as harmonic excitation tests with an electrodynamic shaker. Under axial loading, the embedded sensor displays high linearity with a sensitivity of 43.7 mV/N, whereas impact tests in the cantilever configuration exhibit a steady decay rate of 0.13%. Finally, bending tests show good agreement between theoretical and experimental natural frequencies with percentage errors under 6% in two different clamping positions, and correspond to the maximum voltage output obtained from the embedded VDF sensor at resonance.

 

M.M. KHATTAK, L.M. Headings, and M.J. Dapino, “Dynamic response of a polyvinylidene fluoride (PVDF) sensor embedded in a metal structure using ultrasonic additive manufacturing,” Actuators 12(11), 428, 2023. https://doi.org/10.3390/act12110428