วารสารวิชาการเทคโนโลยีอุตสาหกรรม (J. Ind. Tech.) อยู่ในฐานข้อมูล TCI กลุ่ม 2 (2563) มีค่า JIF = 0.094 | The Journal of Industrial Technology (J. Ind. Tech.) is indexed in TCI Tier 2 (2020) with impact factor, JTIF 0.094

Articles

Effect of Thickness and Loading Rate on Mode I Fracture Toughness of Epoxy Resin

Machanical Engineering

Nowadays, polymer materials have begun to play a greater role in human life. Epoxy resin is one of the most widely used polymer materials because of its relatively high mechanical properties and can be easily molded due to its presence in the liquid state before forming. Epoxy resin has various used in many sections of industries due to its easily forming and making. A wide variety of applications result in different load characteristics or dimension of parts made from epoxy resin. In the use of parts made from epoxy resin or containing epoxy resin, it is found that the parts are mostly damaged under the lower load designed. Due to the design of those complex parts, it does not take into account the crack occur on the part. If the parts are complex, the important factor to consider is the fracture toughness of the material used to make the parts. Therefore, this research aims to study the fracture toughness of epoxy resin under mode I loading, which simulates a variety of applications by changing the range of variables, loading rates, and thickness of the specimen. For calculating the fracture toughness of epoxy resin, it is calculated using the finite element method. From the result, it was found that the loading rate and thickness of the specimen clearly affected the fracture toughness and fracture behavior of the epoxy resin under mode I loading.

Mathematic Model by Response Surface Methodology and Artificial Neural Network for Predict Result of Tensile Shear and Nugget Size of Zinc Coated Steel JIS G3313 Welded by Resistance Spot Welding

Machanical Engineering

This research described to the determine an optimization mathematic model using response surface methodology in central composite design method and artificial neural network (ANN) for predicting the of tensile shear and nugget size in the zinc coated steel JIS G3313. The following resistance spot welding (RSW) parameters were studied: the welding current, welding time, and electrode force. The resulting materials were examined using tensile shear tests which were observed nugget size and microstructure with scanning electron microscopy (SEM). The microstructure phenomenon could be explained by the welding optimum condition that fine pearlite and intensity in heat affected zone. The research results reveal that an optimum RSW parameters were welding current of 12 kilo amperes, welding time of 9 cycle and 1.5 kilo newton electrode force. The fine acicular ferrite occurred in the nugget size, which results in increased welding material high mechanical property. The ANN model with the proposed mathematical model, which tensile shear represents 3 neurons for the input 10 neurons for 1 hidden layer and 1 output neurons (3-10-1). The ANN model was developed to establish of the nugget predict represents 3 neurons for the input 5 neurons for 1 hidden layer and 1 output neurons (3-5-1). The mean square error (MSE) and coefficient of determination (R2) for tensile shear predict was showed that of 0.0026 and 0.956 respectively, which nugget size predicted MSE of 0.0004 and R2 of 0.958. This research, the related manufacturing sector can use research data and mathematical models was used to predict and quality control of the RSW processes to obtain tensile shear and the nugget size according to the acceptance criteria.

Blade Element Momentum Theory for Estimating Efficiency of Thai Sail Windmill

Machanical Engineering

Thai sail windmill (TSW) is a local machine of Thailand now using for pumping brine to the salt farms. TSW is a horizontal axis wind turbine that the blade is a triangular shape made of canvas. Traditional TSW efficiency is typically about 10-17%. However, it has been now developed and augmented its efficiency until 30-35%. Therefore, due to a low construction cost, an uncomplicated structure and a higher efficiency, these things encourage TSW more interesting for research. By the way, the wind turbine simulation is one significant research topic because the accurate simulation can bring about the evaluation of torque, power and efficiency correctly in another condition without the experiment. So, the simulation is very helpful to design the blade of the wind turbine. The purpose of this article is to perform the TSW simulation based on the blade element momentum theory to appraise the efficiency and to validate results with the experiment data. The efficiency evaluation would be regarded by 4 manners of the tip pitch angle as follows: 5, 10, 15 and 20 degrees. The results show that the TSW efficiencies estimated by the simulation are accurate at the tip pitch angle of 10, 15 and 20 degrees in the range of tip speed ratio of 2.0-3.5 whose average percentage error is about 7.0%.

Assessment of Wind Energy Potential in Thailand Based on Using the Multiple-Weibull Distribution

Machanical Engineering

Wind energy potential analysis is a design key to maximize wind turbine efficiency and annual energy output. Typically, the annual wind speed frequency is represented by a Single-Weibull distribution curve in spite of strong and calm wind patterns could occur through a year in many regions in the world, Thailand for instance. For this reason, wind energy potential should be analyzed by Multiple-Weibull distribution curves which are the representative of the meteorological seasons due to the monsoon’s effect. Therefore the objective of this study is to compare the accuracy of the Single-Weibull distribution and the Multiple-Weibull distribution in assessment of wind energy potential. The comparison was made between these two statistical distribution functions and the actual wind speed distribution (measured wind speed frequency) in order to determine the level of credibility of these two distribution functions. The wind speed data employed in this study was measured at Lamtakhong dam site in Nakhon Ratchasima province, Thailand. As the results, the error between the Single-Weibull distribution was 16.46% where the error between the Multiple-Weibull distribution was 14.82%, it was revealed that the smaller error, the higher reliability. Two of the most widely used wind turbines (Enercon E-30 and Windspot) were selected to verify the Multiple-Weibull concept. Approximately 40% increase in annual energy yield by using this method. So, the results confirmed that the Multiple-Weibull distribution is valid for the assessment of the annual energy production of wind turbines. Therefore, this will be a practical method for achieving the optimal design of stall-regulated wind turbine in the further work.

A Study on Knowledge and Skills Essential for Work Safety in Automotive Factories

Machanical Engineering

The objectives of this study were to study the factors that affect the work safety of employees in the automotive parts manufacturing industry according to the supervisor opinion and study the knowledge and skills necessary to manage the safety in the operation of employees in the automotive parts production line. The samples were the supervisor of the production department of the automotive parts manufacturing industry in the areas of Rayong, Chonburi and Chachoengsao. Questionnaires and statistics used in the analysis were frequency, percentage, mean and standard deviation. The results showed that the factors that affect the safety of the employees in the automotive parts manufacturing industry as a whole were at a high level. (x􀴤 = 4.08) Including factors on each side, with an average of all levels, The most average aspect is the working environment. (x􀴤 = 4.23) The person with the lowest. (x􀴤 = 3.94) The knowledge and skills necessary for the supervisor to manage safely in the overall picture were at a high average. (x􀴤 = 4.00) Especially the knowledge of the operation is the highest average. (x􀴤 = 4.08) Which the skills of good leaders that the supervisor or the senior management must use a lot of technical skills including knowledge and expertise in the operations of that department to resolve problems with subordinates.

การปรับปรุงสายการผลิตชิ้นส่วนรถยนต์ด้วยเครื่องมือทางวิศวกรรมอุตสาหการ

Machanical Engineering

งานวิจัยนี้เป็นการศึกษาและปรับปรุงสายการผลิตชิ้นส่วนรถยนต์กรณีศึกษาสายการผลิต Power main A-Plat No.1 ซึ่งมีปริมาณการค้างส่งร้อยละ 16.50 จากการศึกษาปัญหาเบื้องต้นพบว่า การผลิตใช้เวลานานและมีขั้นตอนในการผลิตที่ยุ่งยากซับซ้อน จึงมีแนวคิดที่มุ่งเน้นเพื่อกำจัดความสูญเปล่าที่เกิดขึ้นในกระบวนการ การดำเนินการปรับปรุงเริ่มจากการศึกษากระบวนการผลิตโดยใช้เครื่องมือการศึกษาวิธีการทำงาน และการศึกษาเวลา ทำการจำแนกความสูญเปล่าที่เกิดขึ้นในกระบวนการทำงานตามหลักการความสูญเปล่า 7 ประการ จากนั้นใช้แผนผังก้างปลาในการวิเคราะห์หาสาเหตุของแต่ละปัญหา เพื่อนำไปใช้ในการปรับปรุงประสิทธิภาพการทำงานด้วยหลักการ ECRS ซึ่งผลที่ได้จากการปรับปรุงพบว่าเวลาในการทำงานสถานีงานที่ 1 ลดลงจากเดิม 17.27 วินาทีต่อชิ้น เหลือ 14.93 วินาทีต่อชิ้น คิดเป็นร้อยละ 13.55 และจากการปรับปรุงในสถานีงานที่ 2 มีเวลาการทำงานก่อนการปรับปรุง 19.21 วินาทีต่อชิ้น ลดลงเหลือ 15.70 วินาทีต่อชิ้น ประสิทธิภาพที่เพิ่มขึ้นร้อยละ 18.27 ส่งผลทำให้จำนวนชิ้นงานเพิ่มขึ้นจากเดิม 187 ชิ้นต่อชั่วโมง เป็น 220 ชิ้นต่อชั่วโมง มีค่าสมดุลการผลิตเพิ่มขึ้นจากเดิมร้อยละ 84.73 เป็น ร้อยละ 90.89 และปริมาณการค้างส่งลดลงจาก ร้อยละ 16.50 เหลือ ร้อยละ 13.22

Optimization of Metal Inert Gas Pulse Brazing Process on Galvanized Steel Sheets Based on Taguchi Method

Machanical Engineering

The purpose of this research was to identify the optimal conditions of the galvanized steel sheets based on the Metal inert gas pulse brazing process (MIGPBP). The study used the Taguchi method to experimentally design the L25 orthogonal array, including five main parameters: 1) wire feed speed, 2) arc voltage, 3) travel speed, 4) peak current, and 5) pulse frequency. Each of these parameters consisted of 5 levels, and thus the experiment runs 25 times with 3 replications (75 experiments in total) to find the characteristics of the MIGPBP that were considered important parameters and were exhibited significantly, including: 1) zinc coated balance of joint (ZB), 2) area for penetration of filler metal into the fit-up (ARP), and 3) tensile shear strength (TSS). The results demonstrated that the optimum conditions of the MIGPBP of galvanized steel sheets for the ARP and TSS were 4 meter/minute wire feed speed, 18 V arc voltages; 0.6 meter/minute travel speed, 450 ampere peak current and 35 Hz pulse frequency. For the ZB, the finding indicated the wire feed speed at 3.25 m/min, the arc voltages at 18 V, the travel speed at 0.9 m/min, the peak current at 425 A, and the pulse frequency at 35 Hz to be such optimal conditions which effected the quality of zinc coated balance of joint.

Physio-geometrical Characterization of Combustion Generated Nano-particle Emissions from a Palm Oil based Biodiesel Fueled Agricultural Engine

Machanical Engineering

A physio-geometry of the particulate matter emitted from the combustion chamber becomes growingly important as it can affect to the exhaust gas after-treatment devices. The surface area of the particles will play a vital role as it is a site for catalytic combustion to be taken place. This work investigates the combustion characteristics and particulate matter related emissions of a single-cylinder agricultural diesel engine fueled with palm oil based biodiesel at constant speed and loads. The experimental results from the combustion analysis using an indicating system reveal that the biodiesel initiates the combustion faster with pronounce premixed combustion regime than that of diesel fuel. The specific fuel consumption of biodiesel was greater that leads to a slight reduction in brake thermal efficiency compared with diesel. Biodiesel combustion reduces smoke opacity that is ultimately in-line with the total particle mass. The nano-particle emissions was characterized by an electrical mobility spectrometer and analyzed in terms of number, surface area, and mass. The particle number size distribution was found to be in the nucleation and accumulation modes, and the total particle number increased with smaller size when fueling with biodiesel. The distributions of the particle surface area and mass are left-screwed in the log-scale of area and mass diameter ranges, respectively, leading to the lesser total particle areas and masses for biodiesel fuel at smaller size.

Preliminary Study of Hydrous Ethanol as a Fuel for a Spark Ignition Engine on Performance and Combustion

Machanical Engineering

Fuel crisis during the last few decades has encouraged the use of alternative fuels available in Thailand. Recently, the government has issued a renewable energy plan to increase ethanol production. This has emboldened ethanol to be used as a fuel for transportation. Initially, anhydrous ethanol has been blended with gasoline in different amounts for the current spark ignition (SI) engines. However, the anhydrous ethanol production needs water removal at a cost. Therefore, the use of hydrous ethanol in a SI engine is a choice to promote the policy and also save energy for ethanol production. To investigate the engine performance and combustion characteristics, this work studies the effects on an unmodified 4-cylinder port fuel injection Honda engine fuelled with gasohol (E10), anhydrous ethanol (E100) and hydrous ethanol (5% water content, Eh95). The hydrous ethanol fuelled engine can operate on low to mid loads with lower performance than that of gasohol. E100 and Eh95 consume more fuel than E10. Thermal efficiencies from both ethanol combustions are lower than those of gasohol, especially at low load. Hydrous ethanol combustion shows the lowest maximum pressure and heat release rate among the others. It is suggested that the possibility to calibrate for better engine performance and emission can be achieved.

Reformed Exhaust Gas Recirculation Products of Rapeseed-based Biodiesel: A Chemical Equilibrium Simulation

Machanical Engineering

This paper simulates the products from an exhaust gas fuel reforming of rapeseed methyl ester (RME) in comparison with ultra-low sulphur diesel (ULSD). Both types of fuel were also correspondingly used as reformer fuels. In all cases, the reactor inlet temperature was kept constant at 300°C which represents exhaust gas temperature at low load engine condition and is comparable to the actual average exhaust gas temperature. The gas hourly space velocity (GHSV) was set-up at 30,000 h-1 and 45,000 h-1 whereas the latter is a half of typical value for automotive three-way catalytic converters. Different fuel flow rates between 25 and 55 mlh-1 were tested. The reforming products and temperatures were calculated using an equilibrium model. The results have shown that different engine and reforming fuels affect the produced reformed gasses. Reforming of RME produced less hydrogen compared to the ULSD reforming. The results from simulation were compared with those from experiment at the same condition. At the higher GHSV, an offset between the measured experimental results and the predicted results from the equilibrium model has been found for all conditions tested. For the lower GHSV, the equilibrium model enables a good prediction in reforming yields of hydrogen.

Reduction of Work Distortion in the Gas Metal Arc Welding Process

Machanical Engineering

Welding process performed under an improper condition usually causes workpiece deflection due to the different heat energy conducting into each location of workpiece. This results in the different thermal expansion and accordingly introduces the deflection of workpiece after being welded. The manufacturing of leaf spring s holder for automobile also involves the welding process. Based on the welding of such automotive part in a case-studied company, the workpiece obtained after the gas metal arc welding process (GMAW) presented the deflection of greater than 1 mm which is out of the customer s limits. This significant degree of deflection can directly affect the assembling process in the automotive manufacturing and also alters the ability to withstand the mechanical loads to which is not corresponded with the engineer s design and calculation. Therefore, this research aims at decreasing the workpiece deflection after the gas metal arc welding process. The results revealed that the welding current, voltage, speed and welding sequence were the significant factors affecting the work deflection, and the optimum welding parameters for minimizing the deflection were the welding current of 130 A, voltage of 19 V and welding speed of 50 cm/min. This optimum condition can cause the deflection of only 0.83 mm. In addition, the welding sequence associated with the alternating technique can well spread heat evenly in the workpiece, thus decreasing the heat discrepancy of workpiece. By using this welding sequence, the deflection can be minimized and successfully conformed to the customer s requirement.

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