In the Jet-Circulating electrodeposition, selective electrodeposition is done using the local circulation of the electrolyte. The Scale of fabricated patterns using the Jet-Circulating electrodeposition is dependent on the contact area between the nozzle and the workpiece surface through the electrolyte circulation. The shape of the electrolyte meniscus determines the contact area. The factors that influence the shape of the meniscus include the electrolyte jetting parameter and the characteristics of the workpiece surface. The jet distances are analyzed based on the shape of the electrolyte meniscus and contact area which is dependent on the jetting pressure and the suction pressure. In order to investigate the effect of contact area on the workpiece surface, the surface is treated using Hexamethyldisilazane spin coating, self-assembled monolayer formation, and Neverwet ® spray coating. The contact angle and the contact area based on the surface treatment methods are analyzed. The width of the copper patterns fabricated through Jet-Circulating electrodeposition are compared. The copper pattern width of the self-assembled monolayer formation surface had reduction of 30% in comparison to the untreated surface.

Picosecond ultrasonic evaluation on the Young’s modulus of a ceramic thin-film was performed in the present study. A 100nm thick silicon nitride thin-film was deposited on a silicon wafer using the plasma enhanced chemical vapor deposition technique and gigahertz-frequency longitudinal bulk waves were excited in the film using a femtosecond laser setup. A thermoelastic equation was numerically solved using the finite difference method and compared to the experimental data to estimate the elastic property of the film. Results show that the present measurement technique can effectively evaluate the film’s Young’s modulus and it is recognized that the modulus is 60-70% lower than that of its bulk status. This study is expected to provide a way to characterize nanoscale ceramics with very high spatial and temporal resolutions for the design and analysis of microelectromechanical systems and thin-film based devices.

Patients with complete paralysis that only walk with the assistance of exoskeleton robots because they lost their ability to walk. However, robots do not allow the exoskeleton robot to grasp the current state before walking and change the walking pattern. A "Stability Circle Region" was proposed to determine the current state of the exoskeleton robot. The Stability Circle is an area that can determine the possibility of a fall situation before the next walk using the link parameters of the robot and the current center of gravity of the patients. This study verified the validity of "stability circle" by simulating the change in the center of mass. Simulation results can be used to determine the stability of walking depending on whether the position of the center of mass before the walking is included in the circle area.

The objective of this study was to address the parameter estimation of the line-of-sight stabilization system on temperature variation, which is a significant element in regulating the control performance of mobile platform with visual targeting system. To this end, the LuGre friction model in this study was used both to represent the characteristic of the friction behavior and to design a control algorithm for the friction compensation. Results from both simulation and experimental tests helps to identify the friction parameters on LuGre friction model. Based on LuGre with parameter estimation, PI-LEAD control algorithm is designed to compensate nonlinear characteristic of the line-of-sight stabilization system on the variation of temperature. Finally, through simulation, the good control performance of line-of-sight stabilization system was evaluated according to the temperature variation.

The blade cylinder root is a key component connecting the blade and pitch bearing of a wind turbine and is 20% of the blade’s manufacturing cost. Blade cylinder roots are manufactured using the open die forging method with steel alloy. However the blade cylinder root for 750 KW class wind turbine is manufactured using AA5083 cast material to reduce weight. The purpose of this study is to develop a hot open die forging method, through experiment and FEA, using AA5083 material manufactured by continuous casting. The forging process was designed using the mandrel forging method. Hot compression tests were conducted to obtain flow stress of cast microstructure at different temperatures and strain rates. Control parameters of each forging process were analyzed/compared to predict adaptability of the mandrel forging process. High productivity, good internal quality, shapes, and dimension were verified by prototypes manufactured by the proposed forging process.

When wind load acts on the Power Transmission Line (PTL) with asymmetric cross section from icing and snowing, the generated vibration is termed ‘galloping phenomenon’. Since galloping phenomenon triggers short circuits or ground faults of the PTL, various galloping studies are being conducted, at home and abroad. However, galloping analysis is performed for single span in most cases, while actual PTL comprises multiple spans. In this study, PTL is modeled as a mass-springdamper system, using a multi-body dynamics analysis program, RecurDyn. To analyze dynamic analysis of the PTL, damping coefficient is derived, by using the free vibration experiment of the PTL and Rayleigh damping theory. Through flow analysis, the galloping occurrence condition was identified, and galloping simulation was performed, by modeling the wind load. The effect of galloping on the stress applied to the pylon, was analyzed by flexible modeling the pylon between spans. As a result, approximately 150% of stress is applied to the pylon, so the galloping phenomenon should be considered when designing the pylon.

Transportation machine manufacturers are putting in efforts on research based on weight reduction. One of the representative materials for weight reduction is Fiber Reinforced Plastic (FRP). Increased used of FRP, glass fiber and carbon fiber could be a way of weight reduction. It is almost unavoidable to generate holes or notches during structural design. Little research have been carried out based on cracks with respect to materials used for design. The utilization of finite element analysis and the reliability of the analysis methods are increasing in order to promptly cope with the damages in materials. In this study, Compact Tension (CT) model based on ASTM E647 was designed using SM45C, steel for structural use, short fiber Glass Fiber Reinforced Plastic (GFRP), and woven type Carbon Fiber Reinforced Plastic (CFRP). In addition, J-Integral, which is a factor for determination of growth of crack that appears in cracks, was applied to general structure analysis. J-Integral is an equation of the body force of the material and strain energy in accordance with the loading force, and illustrates the crack growth using energy release rate. J-Integral values of SM45C, short fiber GFRP and woven type CFRP were found to be approximately 74,978 mJ/mm², 7492.3 mJ/mm² and 6222.4 mJ/mm², respectively.

The precision-guided projectile is a weapon system for precision attacks, and the cannon-launched projectile is guided by a control device. The electrical actuator system is a subsystem of the control device, and the whole projectile undergoes high axial and lateral impact force for 1 to 10mseconds. In this study, a charpy, and a tensile impact analysis were conducted, using specimens made in the materials of SUS630 and Al7075-T6 to understand fracture mechanics and impact property, such as energy change rate. The impact analysis and gas-gun impact test were conducted, to validate the optimized housing model.

This study presents a new balancing method that utilizes the equations of motion associated with the rotor dynamics system. While the conventional balancing method includes calculation of mass unbalance based on so-called as-is and trial-run techniques, the proposed approach computes mass unbalance by only applying the as-is technique and further explains the critical speed and the damping ratio. A simple test rig was employed to validate the efficacy of the proposed method. A non-central rotor system was utilized as the experimental model, the actual value of the rotor system’s mass eccentricity was measured according to ISO 1940/1-1986(E), and with a comparison done using the results obtained by applying the proposed method. The sensitivity of the measurement error was compared with that of the conventional approach which utilizes the influence coefficient method.

Nanoparticle laser sintering is one of the vital technologies in additive manufacturing. Numerous processes such as freeform surfaces or seamless parts have been proposed for the fabrication of complex components, however, the resolution and quality of the processes do not meet the standard necessary for practical applications. Therefore, selective laser sintering is used to fabricate electrode patterns in high-precision manufacturing field. Despite the various advantages, laser sintering process generates defects on the pattern with one of the major contributing factors being the Marangoni flow. In this study, the laser sintering process was used to determine the relationship between the nanoparticle blending conditions and the microstructure of the fabricated electrode pattern through the control of the nanoparticles density and laser characteristics such as power, pulse duration, and scan speed. As a result, the conditions for Marangoni flow were analyzed in relation to the concentration of the nanoparticle solution and laser irradiation parameters. More severe Marangoni flow was produced with the solution having a low weight percent of nanoparticles, while the width of the pattern was uniform when the pulsed laser was applied using a high peak power to achieve the same total amount of energy.