http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Optimization of Brazing Conditions for OFHC Cu and ASTM A501 Low Carbon Steel by Taguchi Method
Yi Qi Wang,Ali Md. Afsar,송정일 한국정밀공학회 2009 International Journal of Precision Engineering and Vol. No.
This paper concerns the optimization of brazing conditions for joining the two dissimilar materials Oxygen-free high conductivity (OFHC) copper and ASTM A501 low carbon steel usually used for an Oil-Separator of an airconditioner using Ag-based (BAg) alloy as a brazing filler metal (BFM). A mixture of 70% N2 and 30% H2 gases was used to prevent oxidation of the joints during furnace brazing process. Brazing joint clearance, length, temperature, and time were selected as design parameters that have significant effect on the bonding strength of a brazed joint. Taguchi method was used as a statistical technique for design of experiment (DOE) in an attempt to optimize brazing conditions in terms of shear strength. L9 (34) orthogonal array was designed for conducting the experiments. The relative influence of design parameters and their interaction on the response were also discussed. The experimental results verified that the brazing conditions predicted in this study by Taguchi method could produce the brazed joint between OFHC copper and ASTM A501 low carbon steel with maximum shear strength.
Optimization of Brazing Conditions for OFHC Cu and ASTM A501 Low Carbon Steel by Taguchi Method
Wang, Yi Qi,Afsar, Ali Md.,Song, Jung-Il 한국정밀공학회 2009 International Journal of Precision Engineering and Vol.10 No.3
This paper concerns the optimization of brazing conditions for joining the two dissimilar materials Oxygen-free high conductivity (OFHC) copper and ASTM A501 low carbon steel usually used for an Oil-Separator of an air-conditioner using Ag-based(BAg) alloy as a brazing filler metal (BFM). A mixture of 70% $N_2$ and 30% $H_2$ gases was used to prevent oxidation of the joints during furnace brazing process. Brazing joint clearance, length, temperature, and time were selected as design parameters that have significant effect on the bonding strength of a brazed joint. Taguchi method was used as a statistical technique for design of experiment (DOE) in an attempt to optimize brazing conditions in terms of shear strength. $L_9\;(3^4)$ orthogonal array was designed for conducting the experiments. The relative influence of design parameters and their interaction on the response were also discussed. The experimental results verified that the brazing conditions predicted in this study by Taguchi method could produce the brazed joint between OFHC copper and ASTM A501 low carbon steel with maximum shear strength.
Low Velocity Impact Behavior of Aluminum Honeycomb Structures
Yu Shi,Yi-Qi Wang,Ali Md. Afsar,Jung-Il Song,Intaek Lee,Yasuo Ochi 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
Impact behavior of Aluminum Honeycomb Composites (AHC) under the impact loading is checked by using an explicit definition of dynamic ductile failure. Applicable testing followed by drop weight test is also investigated in this study. The specimens with 1/2inches cell size are tested by two impactors with the weight of 5.25Kgf and 11.9Kgf respectively. Dynamic nonlinear transient analysis using finite element method is accomplished for nonlinear contact and elastoplastic behavior described in FE model of AHC. Impact behavior of AHC along with different contact points appeared nearly the same in low impact energy, but it was different in high impact energy. At the centered contact point of honeycomb core cell, resistance peak force shows the highest and at the contact on short-edge of the core cell, its resistance shows the lowest. Comparing fracture mode and time history of resistance force with test, real time deformation from FE results gives the fracture process when the crack initiated and propagated to go further penetration from faced sheet to the honeycomb core.
Yi Qi Wang,Yu Shi,Ali Md. Afsar,Jung-Il Song 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
Wear behavior of Al₂O₃<SUB>f</SUB> and SiC<SUB>p</SUB> hybrid MMCs are investigated with a view to analyzing the effects of fiber orientations and hybrid ratios under room temperature. The MMCs were fabricated with different hybrid ratios by squeeze casting method. The tests were carried out for both the dry and lubricant conditions using a pin-on-disk friction and wear tester. The dry test results showed that the F20P0 MMCs with N-orientation of fibers had better wear behavior than those with PR-orientation. However, for hybrid MMCS, the wear behavior was better for PR-orientation. The lubricant wear behavior showed that the F20P0 MMCs were better with PR-orientation and hybrid MMCs were better with N-orientation of fibers.
Durability Test And Crash Analysis Of Automobile Power Seat
Yu Shi,Yi-Qi Wang,Ali Md. Afsar,Jung-Il Song 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
'Turny type power seat' was developed to have disabled person get on and off a vehicle without troubles. At the same time, it is imperative to ensure the safety and stability of the power seat which necessitates various tests and analysis. In this study, the durability test and crash analysis were performed for the power seat. The durability test was performed by applying a load of 100㎏ to simulate the weight of passenger. Crash analysis was carried out by using the LS-DYNA program. The durability lest ensured a longer life cycle of the power seat. Further, the results of crash analysis showed that the distorted deformation was so low that it could not bring the danger for passengers. However, the forward displacement of the seat was much more to cause a large deformation of the hook plate, which was dangerous for passengers. Therefore, further modifications of the power seat should be made to ensure better performance, especially to reduce the forward displacement when the crash happens.
Yi Qi Wang,Yu Shi,Foisal Ahmand Mirza,Ali Md. Afsar,Jung Il Song(송정일) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.10
This study investigates the room temperature sliding wear mechanisms of Al₂O₃<SUB>f</SUB> and SiC<SUB>p</SUB> reinforced Al metal matrix composites (MMCs). The effects of fiber orientation and fiber to particle hybrid ratio on the wear behaviors at both the dry and lubricant conditions are discussed in details. The MMC specimens were fabricated by squeeze casting method with different hybrid ratios and fiber orientations. The tests were carried out by a pin-on-disk friction and wear tester at a constant sliding speed of 0.36 ㎧ (570 rpm) against a steel counter disk. The results of dry sliding tests showed that the F20P0 (unhybrid) MMCs with normal (N) orientation of fibers had better wear behaviors than those with planer-random (PR) orientation of fibers. However, for hybrid MMCs, the wear behavior was better for PR-orientation of fibers. On the contrary, the lubricant wear behaviors of F20P0 MMCs with PR-orientation of fibers were superior to those with N-orientation of fibers and the reverse lubricant wear behaviors were observed for hybrid MMCs. Finally, the scanning electron microscope (SEM) images of the wear surface and debris were used for investigating the modes of wear.
Taguchi Method to Optimize Brazing Conditions of a Discharge Tube for Air-Conditioner
Yi Qi Wang,Won Kyung Joo,Yu Shi,Ali Md. Afsar,Jung-Il Song(송정일) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
Brazing process was applied and optimized for joining the two dissimilar materials Oxygen-free high conductivity (OFHC) copper and ASTM A501 low carbon steel for a D-Tube using Ag-based (65%) alloy filler metal. Brazing joint clearance, length, temperature, and time were selected as design variables with the objective of producing the brazed joint having maximum bonding force and corresponding optimum brazing conditions. Taguchi method was used as a statistical design of experiment (DOE) technique for optimizing the brazing conditions in terms of tensile strength. L? (3⁴) orthogonal array design was used for conducting the experiments. The results verified that the brazing conditions developed in this study were the optimum ones for joining the OFHC copper and ASTM A501 low carbon steel.