• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.1
• /
• pp.50-55
• /
• 2011

In this study, simultaneous aero-structural design was performed for HALE aircraft wing. The span and the shape of main spar were considered as design variables. To maximize aerodynamic performance and to minimize weight, multi-objective optimization was used. Nonlinear static aeroelastic analysis was performed to compute large deflection of wing. Design of experiment and response surface method were used to reduce computation cost in the design process. Also, aerodynamic performances of deformed wing and rigid wing were compared.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.18 no.12
• /
• pp.59-66
• /
• 2019

In this study, we developed a novel laser sintering deposition system (LSDS) based on solid free-form fabrication (SFF) technology as it has the potential to fabricate complex geometries with controllable architecture for bone tissue engineering applications. The 3D biphasic calcium phosphate (BCP) scaffolds were fabricated with a pore size of 800㎛, a line width and height of 1000㎛, and an overall size of 8.2×8.2×8.0 mm3 according to the design of experiment (DOE) results. Additionally, an optimized manufacturing process using response surface analysis was established to fabricate 3D BCP scaffolds. The fabricated 3D BCP scaffolds were sintered at 950℃, 1050℃, 1150℃, and 1250℃ according to sintering processes with a furnace. As the sintering temperature increased, the porosity increased. Through the compressive strength test, the 3D BCP scaffolds sintered at 1050℃ presented good results of about 0.76 MPa. These results suggest that fabrication methods for 3D bioceramic scaffolds using LSDS may meet the basic requirements for bone tissue engineering.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.4
• /
• pp.1879-1884
• /
• 2014

Recently, the micro bonding technology comes into the spotlight as the miniaturization of the electronic product. The micro bonding technique can classify by way of laser welding and ultrasonic bonding and etc. However, the research on the micro bonding is much lacks. In this paper, carried out the cooling analysis of the 60 [kHz] ultrasonic bonding equipment to know heat effect of the piezoelectric element when the ultrasonic bonding equipment was operated. The ultrasonic horn having the natural frequency with 60 [kHz] for the dissimilar material bonding of the glass and solder tried to be designed. The parameters and response was set through the basic experiment. The dissimilar material bonding strength analysis using the 60 [kHz] ultrasonic bonding equipment was done. We carried out the bonding for improving bonding strength to using the silver paste. air thightness of bonding surface was confirmed by analysis of bonding interfaces.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.7
• /
• pp.716-726
• /
• 2010

In this research, design optimization of an aircraft wing has been performed using the fully automated Multidisciplinary Design Optimization (MDO) framework, which integrates aerodynamic and structural analysis considering nonlinear structural behavior. A computational fluid dynamics (CFD) mesh is generated automatically from parametric modeling using CATIA and Gambit, followed by an automatic flow analysis using FLUENT. A computational structure mechanics (CSM) mesh is generated automatically by the parametric method of the CATIA and visual basic script of NASTRAN-FX. The structure is analyzed by ABAQUS. Interaction between CFD and CSM is performed by a fully automated system. The Response Surface Method (RSM) is applied for optimization, helping to achieve the global optimum. The optimization design result demonstrates successful application of the fully automated MDO framework.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.36 no.3
• /
• pp.229-237
• /
• 2008

In this research, a MDO(multi-disciplinary design optimization) framework, which integrates aerodynamic and structural analysis to design an aircraft wing, is constructed. Whole optimization process is automated by a parametric-modeling approach. A CFD mesh is generated automatically from parametric modeling of CATIA and Gridgen followed by automatic flow analysis using Fluent. Finite element mesh is generated automatically by parametric method of MSC.Patran PCL. Aerodynamic load is transferred to Finite element model by the volume spline method. RSM(Response Surface Method) is applied for optimization, which helps to achieve global optimum. As the design problem to test the current MDO framework, a wing weight minimization with constraints of lift-drag ratio and deflection of the wing is selected. Aspect ratio, taper ratio and sweepback angle are defined as design variables. The optimization result demonstrates the successful construction of the MDO framework.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.4
• /
• pp.72-81
• /
• 2014

In this study, we perform the optimization of trailing arm bush in a vehicle rear suspension to improve the ride and handling performance. A design problem was formulated considering 2 objective functions and 7 constraints related to vehicle ride and handling performance. PIAnO, one of the PIDO (Process Integration and Design Optimization) tool, was used to automate analysis procedures and perform a design optimization. In order to assess relation between performances and design variables, we perform the DOE (Design of Experiments). To find the optimal solution, we used Progressive quadratic response surface method (PQRSM), one of the design optimization techniques equipped in PIAnO. As an optimization result, we got an optimal solution and could improve lateral force steer off-center by 43.0% while decreasing brake compliance at wheel center by 8.1%.

• Transactions of Materials Processing
• /
• v.23 no.8
• /
• pp.501-506
• /
• 2014

Progressive shearing with blanking dies is commonly employed to produce large quantities of tiny sheet metal electronic parts. Sheet metal pins, which are narrow and long, that are sheared with a progressive die set are often twisted. The twist in the sheet metal pins, which usually occurs in the final shearing operation, generally decreases with increasing blank holding force. The blank holding forces in all shearing operations are not the same because of different shearing positions and areas. In the current study, the optimal layout of the springs in a progressive die set to minimize the twist of the sheet metal pin is proposed. In order to find the holding force acting on the tiny narrow blanks produced with the proposed springs during the shearing process, the equivalent area method is used in the structural analysis. The shearing of the sheet-metal pin was simulated to compute the twist angle associated with the blank holding force. The constraint condition satisfying the pre-set blank holding force from the previous shearing operations was imposed. A design of experiments (DOE) was numerically implemented by analyzing the progressive die structure and by simulating the shearing process. From the meta-model created from the experimental results and by using a quadratic response surface method (PQRSM), the optimal layout of the springs was determined. The twist of sheet metal pin associated with the optimal layout of the springs found in the current study was compared with that of an existing progressive die to obtain a minimal amount of twist.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.11
• /
• pp.1397-1405
• /
• 2013

The optimal rib pattern design of B-pillar trim considering occupant head protection can be determined by two methods. One is the conventional approximate optimization method that uses the statistical design of experiments (DOE) and response surface method (RSM). Generally, approximated optimum results are obtained through the iterative process by trial-and-error. The quality of results strongly depends on the factors and levels assigned by a designer. The other is a methodology derived from previous work by the authors, called the sequential design of experiments (SDOE), to reduce the trial-and-error procedure and to find an appropriate condition for using artificial neural network (ANN) systematically. An appropriate condition is determined from the iterative process based on the analysis of means. With this new technique and ANN, it is possible to find an optimum design accurately and efficiently.

• Journal of Adhesion and Interface
• /
• v.9 no.1
• /
• pp.22-27
• /
• 2008

The effect of functional monomers on the acrylic pressure sensitive adhesive (PSA) property was measured. Design of experiments in order to optimal peel adhesion was applied and commercial program (MINITAB) was used. Analysis was used to mixture design (special cubic model) in response surface methodology. Optimal monomer compositions was construed by 2-EHA (0.8861), EA (0.0639), MAA (0.03) and AAm (0.02). The estimated regression equation was as follows : $$y=54.8816x_1+80.7067x_2-44.4700x_3-99.0288x_1x_2+60.7706x_1x_3-441.030x_2x_3+974.341x_1x_2x_3$$.

• Design & Manufacturing
• /
• v.11 no.2
• /
• pp.1-8
• /
• 2017

In this study, we applied microcellular foaming injection molding process to improve the performance of system air-conditioner drain fan which had been produced by injection molding process and studied the optimization of process conditions through 6-sigma process and response surface method (RSM) to reduce weight and deformation of products. Additive type, melt temperature, mold temperature, and injection screw shape were selected as the factor affecting the weight and deformation of the products by carrying out analysis of trivial many through ANOVA and design of experiment (DOE) method. Among the effect factor, we set the addictive type to Long G/F and screw shape to foaming screw which had the highest level of weight reduction and deformation reduction. The amount of foaming agent gas was set at 60 ml, which was the limit beyond which the weight of product did not decrease any more. For melt temperature and mold temperature, we studied the conditions where both weight and deformation were minimized using the RSM. As a result, we set the melt temperature to $250^{\circ}C$, fixed mold temperature to $20^{\circ}C$, and moving mold temperature to $40^{\circ}C$. The improvement effect was analyzed by appling the selected optimal conditions to the production process using the microcellular foaming injection molding. The results showed that the mean weight of product was measured to be 1,420g which was 19% lower than that measured in the current process. The standard deviations of the weights were found to be similar to those in the current process and it showed a low dispersion. The mean deformation was measured to be 0.9237mm, which represented a 57% reduction compared to the mean deformation in the current process, and the standard deviation decreased from 0.3298mm to 0.1398mm. Moreover, we analyzed the process capability for deformation, and the results showed that the short-term process capability increased from 2.73 to 6.60 which was even higher than targeted level of 6.0.