Materials Engineering Symposium on Innovation for Industry

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Browsing Materials Engineering Symposium on Innovation for Industry by Author "Adikary, SU"

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    item: Conference-Abstract
    Design and development of ultrasonic wave generator using piezoelectric ceramics
    (Department of Materials Science and Engineering, 2020-02) Sivanujan, S; Adikary, SU; Abeygunawardane, AAGA
    Ultrasonic transducers using piezoelectric materials are popular among researchers because of the efficiency, ease handling, low weight, and small size. In this research, an ultrasonic wave generator using piezoelectric ceramics was designed using mathematical modelling and finite element analysis. Then a prototype was fabricated to compare the performance. Piezoelectric constitutive equation for converse effect and differential equation of spring- mass system with a forcing function were used for mathematical calculation in thickness mode to determine resonant frequency, dimensions of the design and acoustic impedance of matching layer and backing layer. The matching layer transmits the mechanical vibration as ultrasonic wave. To identify optimum parameters of the design, finite element analysis was done. The design resonant frequency and parameters of layers were calculated from solid mechanics and electrostatics for Eigen frequency and Frequency domain studies using 3D model. Transmitting wave frequency in water and air was calculated from acoustic pressure variation, which was obtained as a results of simulation using 2D axisymmetric model. Arduino software was used to feed controlled electric signals to piezoelectric material. Finally a prototype device was developed using Lead Zirconate Titanate (d33 = 400 ×10-12 m/V) as piezoelectric ceramics, Aluminum as matching material and Steel as backing material. Thickness of them are respectively 1.5 mm, 3 mm, and 10 mm. Terminal wires were soldered and all three were merged together using glue gun with polymer binder. Prototype testing was performed with Oscilloscope. The resonance was observed at 75 kHz, 182 kHz, and 232 kHz. Resonance was also confirmed by Impedance - Frequency and Phase - Frequency analysis using LCR measurements.
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    Design and optimization of linear actuator for biomedical applications
    (Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Chandrasiri, WAD; Rashmika, WAD; Adikary, SU; Abeygunawardana, AAGA
    Microelectromechanical system (MEMS) actuators are a promising innovation that is essential to the development of a wide variety of biomedical devices. The invention of smaller fluid pumps has been valued with increasing interest, these miniaturized micro pumps are designed to handle a very small, precise, and controllable amount of fluid normally in the range of μl/min to ml/min. Thyroid hormone imbalance is a highly increasing, common, genetically or non-genetically disease, which is conducted to Hypothyroidism (an underactive thyroid gland) and Myxedema Coma. So, levothyroxine should be injected frequently into the human body to maintain the metabolic system. This research was carried out to design a linear actuator for a micro pump that injects a certain dose of levothyroxine hormone into the human body accurately. Lead Zirconate Titanate (PZT) gives a high piezoelectric charge coefficient value with high frequency and stiffness that is required for the micro pump. Theoretical mathematical calculations of the piezoelectric stack configuration were carried out to get the displacement of the actuator and maximum displacement. Considering water as the fluid, an equation for flow rate was derived theoretically with supposing fluid behave as a laminar flow. Finite Element Analysis (FEA) was performed to identify the suitable dimensions of the micro pump which is compatible with the flow rate of the fluid.
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    Development of a vibration and shock sensor using piezoelectric ceramics
    (Department of Materials Science and Engineering, 2019-01) De Silva, HTTM; Dayananda, RKAS; Adikary, SU; Sivahar, V; Sitinamaluwa, HS
    When buildings are exposed to vibration or shock, those buildings can be damaged partially or fully depending on the energy of vibration. Hence, quantitative analysis of building vibration has become popular among researchers. In this research, a vibration sensor was developed using a piezoelectric ceramic cantilever beam and a tip mass to confirm that the vibration frequency of the building does not exceed the cosmetic damage range. As the first step, a mathematical model was developed to calculate the resonance frequency of the cantilever beam with a tip mass. At the resonance frequency, maximum amplitude could be achieved resulting in a higher output voltage of the piezoelectric sensor. The developed mathematical model and finite element analysis were used to determine the accurate dimensions of the cantilever beam based piezoelectric sensor. According to the calculations, width, length and thickness of the piezoelectric material, copper beam and tip mass are 10x20x1, 10x100x0.3 and 10x30x3 mm respectively. Hence, the piezoelectric sensor output voltage was calculated using finite element analysis at the vibration frequency range that corresponds to the cosmetic damage. According to the calculations, threshold voltage level and frequency of the sensor to activate the alarm were 4.35 mv and 9.5 Hz respectively. Arduino software was used to analyze the output signal of the sensor. Vibration source was used to verify the calculation steps. Finally, liquid crystal display and small buzzer were added to show the frequency and give a warning when vibration frequency exceeds the required level.
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    Influence of particle size and crystallite size on hydroxyapatite nanoparticle degradation in pbs
    (Department of Materials Science and Engineering, University of Moratuwa., 2023-07-28) Anjana, JY; Arachchi, DHR; Adikary, SU; Sivahar, V
    In this study, we investigate the influence of particle size and crystallite size of Hydroxyapatite nanoparticles, synthesized using the wet chemical precipitation technique on degradation in Phosphate Buffer Saline (PBS). Different concentrations of calcium hydroxide and orthophosphoric acid were used for the synthesis process to achieve different supersaturations. The Ca/P molar ratio was kept at 1.67 while changing the supersaturation. The synthesized nanoparticles were characterized using a laser particle analyzer, Scanning Electron Microscope (SEM), X-ray diffractometer (XRD), Energy Dispersive X-Ray Analysis (EDAX), and Fourier- Transform infrared (FT-IR) spectroscopy to study their size, morphology, structure, and composition. The study demonstrated that controlling the precursor concentrations to induce varying supersaturation levels allows for the modulation of particle size and crystallite size of Hydroxyapatite nanoparticles, subsequently affecting the degradation behavior of HA, which is dependent on the particle size.
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    Modelling and simulation of nanogenerator using vertically integrated zinc oxide nanowire array
    (Department of Materials Science and Engineering, University of Moratuwa., 2023-07) Samaraweera, RLU; Buddhima, LHP; Adikary, SU; Sivahar, V
    Recent developments in nano-level energy harvesting are mainly focused on using piezoelectric power generators from compression and vibration modes. In this work, a vertically integrated zinc oxide piezoelectric nanowire array was modeled to scavenge energy from low-frequency compression force. COMSOL Multiphysics 5.4 software was used to simulate and model nanowire array structures to ensure the potential distribution and overall electric energy generator of the piezoelectric structure under compression displacement. Piezoelectric constitutive equations were used to develop mathematical equations in terms of comparing and confirming induced piezoelectric outputs. The simulation results confirmed that the voltage output of the nanowire array does not depend on the number of nanowires. Total electric energy harvested by the array depends on the number of nanowires and nanowire density.
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    Modelling and simulation of piezoelectric nanogenerator using zinc oxide for wearable electronics
    (Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Vithusan, T; Nashira, MNF; Adikary, SU; Abeygunawardana, AAGA
    A vertically integrated Zinc Oxide nanowire (NW) based piezoelectric nanogenerator (NG) was modelled for energy harvesting applications. Nanogenerators were modelled on unit element based and arrays based and were simulated using COMSOL Multiphysics 5.3 and the mathematical equations were derived considering the coupled piezoelectric and mechanical behaviour. Moreover, the voltage output of the single NW under a constant lateral force was analysed varying with the NW dimensions in terms of aspect ratio. The results showed that the compression of ZnO NW gives more output voltage compared to the bending of the NW for the same NG. The stress variation was analysed for the range of nanowire dimensions (aspect ratio) using the software. The influence of aspect ratio, length, and diameter on the output electrical potential of the ZnO nano wire-based NG was investigated using simulated results. It was observed that when the diameter is increasing along with the aspect ratio decreasing for constant length, electrical potentials at the output decrease. The aspect ratio was analysed by maintaining a constant dimeter and with variable length. When the length is increasing along with the aspect ratio, the voltage output shows lesser deviation. The theoretical and simulation results also proved that the length of the NW does not influence the piezoelectric potential in a lateral bent NW. The unit element and then the integrated array design with PMMA filler and insulator were modelled by assembling such 9x9 (81) unit elements with the inter wire distance of 40nm and the results were analysed.
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    Modelling of micro size ultrasonic generator and receiver characteristics of lead zirconate titanate and polyvinylidene fluoride using finite element analysis
    (Department of Materials Science and Engineering, University of Moratuwa., 2021-12) Thasankithan, VS; Gamage, UV; Adikary, SU; Abeygunawardana, AAGA
    Ultrasonic devices (sensors, generators and transducers) using piezoelectric materials are more prominent due to its accuracy, efficiency and ease handling. In this research, modelling and simulation of ultrasonic generator and receiver characteristics were performed using finite element analysis (FEA). PZT is the most popular piezoelectric ceramic in ultrasonic applications due to its higher coupling factors, which is the main reason why PZT-5H was chosen for FEA analysis over other piezoceramic materials. PVDF was chosen for FEA analysis over other piezopolymer materials, due to its high piezoelectric voltage coefficient. Then piezoelectric constitutive equations for direct effect and indirect were used for mathematical calculation in thickness mode to determine the generated voltage and displacement along the z direction. The dimensions of the design were selected in micro scale. Using the FEA simulation, disc shape ultrasonic generator and receiver were designed. To identify the resonant frequency of the model wizard, 3D model was created using COMSOL Multiphysics software. The FEA simulation was implemented via 4 different cases, for instance using PZT-5H as generator material with PVDF and PZT-5H as two separate ultrasonic receiver materials and PVDF as generator material with PVDF and PZT-5H as two separate ultrasonic receiver materials. Initially the resonant frequency of the piezoelectric disc was determined as 13 MHz from the simulation and electric potential of 10V with 13MHz was used to generate the ultrasound wave. This ultrasonic wave was then directed to hit the ultrasonic receiver to generate electric potential. When PVDF worked as receiver it generated higher electric potential than PZT. On the other hand, when PZT worked as an ultrasonic generator the high amount of ultrasonic pressure was generated.