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Vibration analysis of 28 kHz horn transducer for ultrasonic cleaning based on harmonic response analysis
(2022-01-01)
Phophayu, Suchada
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Thongsri, Jatuporn
The Horn Transducer (HT) is one of the key components in ultrasonic applications, consisting of a front mass, piezoelectric, and back mass parts. Previously, most of the research focused on vibration study of the front mass part based on modal analysis, but the other parts were ignored; therefore, the research results have limitations to actual usage. This research presents the vibration analysis of HT included all parts, based on harmonic response analysis (HRA). First, a conventional HT of 28 kHz, 50 W, 220 V, front mass-radius (R) of 29 mm, and height (H) of 5 mm was investigated for the vibration analysis. Next, proposed designs were also investigated by varying the R as 27 mm - 32 mm, and H as 4 mm - 8 mm. All results were analyzed to find a suitable shape and investigated the designs that affected the vibration. The simulation results revealed that the longitudinal amplitude depends on R and H. In addition, the simulation results were consistent with an experiment and previous work. Finally, the suitable design with R of 29 mm and H of 7 mm provided the optimum vibration at 27,250 Hz. The outcomes of this research were applied to develop a high-performance ultrasonic cleaner.
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A proper shape of the trailing edge modification to solve a housing damage problem in a gas turbine power plant
(2021-04-01)
Jansaengsuk, Thodsaphon
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Kaewbumrung, Mongkol
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Busayaporn, Wutthikrai
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Thongsri, Jatuporn
To solve the housing damage problem of a fractured compressor blade (CB) caused by an impact on the inner casing of a gas turbine in the seventh stage (from 15 stages), modifications of the trailing edge (TE) of the CB have been proposed, namely 6.5 mm curved cutting and a combination of 4 mm straight cutting with 6.5 mm curved cutting. The simulation results of the modifications in both aerodynamics variables C<inf>l</inf> and C<inf>d</inf> and the pressure ratio, including structural dynamics such as a normalized power spectrum, frequency, total deformation, equivalent stress, and the safety factor, found that 6.5 mm curved cutting could deliver the aerodynamics and structural dynamics similar to the original CB. This result also overcomes the previous work that proposed 5.0 mm straight cutting. This work also indicates that the operation of a CB gives uneven pressure and temperature, which get higher in the TE area. The slightly modified CB can present the difference in the properties of both the aerodynamics and the structural dynamics. Therefore, any modifications of the TE should be investigated for both properties simultaneously. Finally, the results from this work can be very useful information for the modification of the CB in the housing damage problem of the other rotating types of machinery in a gas turbine power plant.
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Robot arm structure design using polyamide evaluated by finite element analysis
(2020-01-01)
Kaitwanidvilai, Somyot
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Buthgate, Siwawong
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Aoyama, Hisayuki
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Konghuayrob, Poom
Robots have increasingly replaced humans for many jobs, including 24 h work, routine tasks, and dangerous jobs. However, the robot operating system has high power consumption in many processes. This has led to energy efficiency being the main focus. We have opted to build a robot with high strength, light weight, and low power consumption by reducing the weight of its components. Presently, we know that the structure of most robots in the world is made of metals, plastics, and composite materials. In this research, we designed the mechanical structure of robot arms with three different materials (cast iron, polyamide, and aluminum) using the finite element method to analyze and evaluate the possibilities of these materials. The dynamic load, power consumption, and mechanical characteristics were compared. It was found that polyamide could help lighten the weight by 40% and increase energy efficiency along with cost effectiveness by 41%. Although polyamide is particularly easy to find, cast iron is stronger than polyamide.
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A test bench for characterization of piezoelectric frequency up-converting energy harvesters
(2018-07-02)
Panthongsy, Phosy
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Isarakorn, Don
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Hamamoto, Kazuhiko
This work focuses on the design and realization of a test bench used to characterize the performances of the piezoelectric cantilever for frequency up-converting energy harvesters. A test bench is completed by combining a frequency up-converter with an oscilloscope (Tektronix TD 3032B). The frequency up-conversion mechanism achieves the excitation on a piezoelectric cantilever through an interaction between a permanent magnet and an iron bar. In the mechanism design, the air gap between a permanent magnet and an iron bar is analyzed by Finite Element Method (FEM). After the design is verified, a test bench is fabricated and then validated with experimental study by testing the performances of a PZT-5H bimorph (T220-H4-503X, Piezo Systems, Inc.); the considered performances are resonant frequency, average output power, total output energy and energy conversion efficiency. The experimental results demonstrate that a fabricated test bench is satisfactory.
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The optimum design of micro gripper for lifetime improvement based on fatigue analysis and six sigma analysis
(2017-01-01)
Boonkaew, Pisut
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Thongsri, Jatuporn
This article reports a problem in hard disk drive manufacturing (HDD) process and a practical solution. A traditional micro gripper of stainless steel 304, practically used in an HDD factory, has a low life expectancy. Therefore, the fatigue analysis was employed to solve this problem. Firstly, 27 cases of possible designs of micro gripper were proposed according to the full factorial design of six sigma (6σ) analysis. Each case is different regarding the micro grippers shapes which are degree, radius, and length. Secondly, 3D models of the micro gripper for all cases were created and transferred to the finite element analysis to simulate the equivalent stress and the compressive force. After the simulation completed, we found that the optimum design of micro gripper has 457.9 MPa of the equivalent stress and 0.991 N of the compressive force, which was less than those of the traditional design. Finally, the optimum design was brought to analyze in more details by using the fatigue analysis. The comparing results of simulation showed that the maximum equivalent stress and the compressive force of the optimum design compared to the traditional design were reduced 14.5% and 19.4%, respectively. These make approximately extending 136.5% of the life cycle and increasing 17.5% of the safety factor. This improvement was expected that it could be able to extend the lifetime of the micro gripper and save up to 60 million dollars annually.
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Comparative study of piezoelectric energy harvesters based on polycrystalline PZT and single-crystalline PMN-PT materials
(2016-09-06)
Panthongsy, Phosy
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Isarakorn, Don
The piezoelectric energy harvester for supplying power to low-power electronic devices, especially low-power wireless sensor node has been studied and received more attraction over the past decade. In order to simplify installation and obtain the sufficient power for systems, the harvester possessing simple structure with highest output power is highly required. The aim of this study is to design and compare the characteristic and performance of piezoelectric polycrystalline PZT and single-crystalline PMN-PT energy harvesters based on unimorph configuration. By utilizing ANSYS® for finite element analysis (FEA), the numerical model of composite piezoelectric unimorph generators with proof mass exciting at resonant frequency 150 Hz are designed and then fabricated. For the energy harvesting experiment, the prototypes of harvesters are mounted to the electromagnetic shaker and inputted the vibration with vary frequencies and accelerations. As the results, the piezoelectric single-crystalline PMN-PT unimorph energy harvester has the higher energy density which is 352.85 J/gm3, while the piezoelectric polycrystalline PZT unimorph energy harvester has 8.44 J/gm<inf>3</inf>.
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Analysis of heat transfer and specific absorption rate of electromagnetic field in human body at 915 MHz and 2.45 GHz with 3D finite element method
(2012-12-01)
Suwansin, W.
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Phasukkit, P.
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Pintavirooj, C.
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Sanpanich, A.
This paper presents 3D finite element analysis for heat transfer and specific absorption rate of electromagnetic field in human body at 915 MHz and 2.45 GHz. The purpose of this research is to study the effects and harmfulness of leakage electromagnetic field to organ in living tissue. We propose a simulation of microwave radiation by using a finite element method (FEM) to our system for studying heat transfer and specific absorption rate of electromagnetic field in multi-organs living tissue. Electromagnetic wave distribution source in our system was designed as a microstrip type and placed at 5 cm from multi-organs living tissue model. As a preliminary, leakage power was assumed at 100 W and exposure time was 1800 s. The result from finite element method show distribution of electromagnetic field in 3D air space of multi-organs tissue model , specific absorption rate (SAR) and temperature. The SAR value will be followed the standard of ICNIRP (1998) and the results at 915 MHz and 2.45 GHz shown that maximum temperature in organs are different if frequencies different, in 3D model can be obtained every point of view and benefit for development protection system in near future. ©2012 IEEE.
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Optimal monitoring point for temperature and power control in microwave ablation system by using FEM
(2012-12-01)
Pairoch, S.
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Phasukkit, P.
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Sanpanich, A.
This study presents an optimal location of monitoring point for using by PID system to control temperature and output power of hepatic cancer microwave ablation system. We investigated a relation between output power and treatment time in hepatic ablation. A simple simulation model was adapted from COMSOL FEM solver. As a preliminary, monitoring point was supposed to place at 0.5 centimeter besides ablation probe. The simulation results shown that temperature at this monitoring point is linearly related to output power and treatment time. ©2012 IEEE.
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Analysis of heat sink effect in hepatic cancer treatment near arterial for microwave ablation by using finite element method
(2012-12-01)
Yhamyindee, P.
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Phasukkit, P.
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Tungjitkusolmon, S.
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Sanpanich, A.
This paper presents an analysis of heat sink effect in hepatic cancer treatment near arterial vessel for microwave ablation by using finite element method. We analyze the temperature distribution, Specific Absorbtion Rate (SAR) and coagulation area in two models. The first is hepatic tissue without artery and the second is hepatic tissue with artery. In the second model, we specify distance between antenna and artery at 10 mm. The initial condition is set as power at 50 watts, temperature at 37°C and blood perfusion rate is varied at 6.4 × 10-10, 6.4 × 10-3 and 6.4 × 104 l/s. The simulation results by using three-dimensional finite element analysis show that the temperature distribution in case of hepatic tissue with no artery is larger than the case with artery. We also found that blood perfusion rate affects to the temperature distribution in hepatic tissue. Higher blood perfusion rate, higher heat sink effect occur. ©2012 IEEE.
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Finite element analysis for severe asthma therapy at the airway smooth muscle by radiofrequency ablation
(2012-12-01)
Ruxsapong, P.
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Phasukkit, P.
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Tungjitkusolmun, S.
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Sanpanich, A.
This paper presents a three-dimensional finite element analysis for severe asthma therapy by using radiofrequency (RF) ablation. We study a solution for severe asthma treatment by using radiofrequency ablation method. Severe asthma patients have breathlessness symptom, coughing, and wheezing that influence a daily life of patients. In case of severe asthma, patients have breathlessness symptom, coughing, and wheezing all the time. All symptoms cause to die. Severe asthma therapy by using radiofrequency ablation is a new alternative maneuver to the patient and hopefully may extend his lifetime, reduce using of medicines in asthma treatment and also save money on medical care in long run. The research results obtained from our three-dimensional finite element analysis show temperature distribution for airway dilation and increasing airway wall dimension by using radiofrequency ablation technique significantly. These results also guide us to develop an advance asthma treatment in the future. ©2012 IEEE.

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