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Author: search.filters.author.Punsawat, Woratat

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    Development and fatigue testing of a PZT assembly with PE housing for harvesting mechanical energy
    (2019-01-01)
    Punsawat, Woratat
    ;
    Khaosa-Ard, Krittanat
    ;
    Makcharoen, Worawut
    This paper presents the results of simulation of design and a real fatigue test of a protected PZT assembly for energy harvesting application. The protection was from a new encapsulation design. Based on a previous unpublished research, simulation runs with ANSYS program to simulate the effect of stress on Polyethylene (PE) protective layers of various shapes were performed and the results demonstrated that PE layers of rectangular shape were able to distribute an external pressure at a suitable amount to the PZT sheet and withstand repeated pressings from an external pressure in the range of 5-20 MPa. These results enabled us to choose the best shape of PZT sheet and PE housing assembly. The fatigue parameter of the assembly was determined by subjecting the assembly to a repeated external force. And the voltage cycle of the encapsulated PZT assembly was measured with an oscilloscope. The voltage cycle test results show similarly-shaped cycles with a mean voltage of 3.76 V both before and after the assembly was subjected repeatedly to an external force. The fatigue parameter was defined as a minimum voltage that the assembly could deliver after a large number of repeated pressings by an external pressure in the range of 5-20 MPa. Our criterion of successful protection was a minimum of 3.5 V after 4,500 pressings. Therefore, we concluded that the constructed assembly was able to withstand an external operating pressure satisfactorily.
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    Development of a Ternary Composite of PU Resin/Carbon Black/PZT for Mechanical Energy Harvesting Application
    (2018-01-01)
    Punsawat, Woratat
    ;
    Makcharoen, Worawut
    Today, rapid depletion of energy sources forces us to discover alternative sustainable electrical energy sources quickly. The aim of this work was to develop a ternary composite of PU resin/carbon black/PZT to be an efficient mechanical energy harvester. Specifically, this present work attempted to find the optimum weight ratio of a PU resin/carbon black/PZT composite that could provide the highest mechanical-to-electrical conversion efficiency. The PU resin was the main matrix. Carbon black (CB) was added to improve conductivity while still maintaining good casting property. Then, PZT was added to generate electricity. Testing several weight ratios of this composite, it was found that the samples ratio of 60:20:20 was optimum and able to generate an average voltage of 0.357 V/in2. This ternary composite material has a candidate to into a practical and efficient electrical energy harvester source.
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    Dielectric Relaxation and Microstructures of SnO2 Doped CaCu3Ti4O12 Electroceramics Prepared Via Vibro-milling Method
    (2017-01-01)
    Makcharoen, Worawut
    ;
    Punsawat, Woratat
    High dielectric constant CaCu<inf>3</inf>Ti<inf>4</inf>O<inf>12</inf> (CCTO) is a compound with a high dielectric constant, but it has a high loss tangent at room temperature. This research aims to study on the dielectric properties and loss tangent of SnO<inf>2</inf> doped CaCu<inf>3</inf>Ti<inf>4</inf>O<inf>12</inf> (CCTO) ceramics were investigated. The ceramic samples of SnO<inf>2</inf> doping CCTO were prepared by a solid-state reaction method. The characterization of the samples was carried out using scanning electron microscopy (SEM) and x-ray diffraction (XRD). The conventional solid-state reaction was employed. The metal oxide powders were mixed using a vibratory milling for 6 hour and sintered at 1000°C for 4 hour. The phase formation of the calcined powders and sintered ceramics was examined by X-ray diffraction technique (XRD). Microstructure was examined by scanning electron microscopy (SEM). SnO<inf>2</inf> doping produced a notable decrease in grain size. Average values of grain size, as measured by the linear intercept method. The dielectric measurements at room temperature to 130°C, in the frequency range 100 Hz- 500 kHz. The XRD result a CCTO structure does not changes on Sn doped samples. The results show the loss tangent at room temperature and at 100 kHz decreased from 0.14 for the 0 mol% Sn doped CCTO sample to 0.04 for the 2.0 mol% Sn doped sample while at 500 kHz, it was decreased from 0.2 for the undoped CCTO sample to 0.04 for the 2.0 mol% Sn doped sample. However, the lowest loss tangent was 0.02 at 500 kHz and at 65°C and show a stable loss tangent in temperature range 25 - 130°C.