• Transactions of Materials Processing
• /
• v.7 no.5
• /
• pp.439-444
• /
• 1998

Recently many automotive parts have been made with stainless steels by deep drawing processes, But there are various problems occurred in deep drawing works of stainless steels compared with low carbon steels. For the severe deep drawing of complex cylindrical housing optimum process planning is required to eliminate intermediate annealing improve shape accuracy and maintain surface integrity without drawing defects such as tears wrinkles and scratches or galling. Therefore in this study a sample process planning of the severe of the severe deep drawing process is applied to a complex cylindrical housing needed for a 6 multi-stepped deep drawing of type STS 305 . A series of experiments are performed to investigate optimum process variables such as drawing rate radius and clearance. Through experiments the variations of the thickness strain distribution and hardness distribution in each drawing step are observed. Also the effects of other factors on formability such as drawing oil, blank holding force and die geometry are examined and discussed.

• Structural Engineering and Mechanics
• /
• v.13 no.1
• /
• pp.1-16
• /
• 2002

This paper presents the findings of an investigation carried out to determine the most appropriate connections, in terms of rotational stiffness, to use for the optimum design of cold-formed Zed section sleeve joint purlin system. Experiments and parametric studies were conducted to investigate the effects of geometric variables on the behavior of the sleeve-purlin and cleat-purlin connections of the sleeve joint purlin system. The variables considered were purlin size and thickness, sleeve size, thickness, length and bolt position. The test results were used to verify the empirical expressions, developed herein, employed to determine the rotational stiffness of connections. With the predicted connection stiffness, the most suitable sleeve-purlin and cleat-purlin connections can be selected so as to produce an optimum condition for the sleeve joint purlin system.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.31A no.12
• /
• pp.100-105
• /
• 1994

Analytical expressions for the breakdown voltage and the optimum drift region length (L$_{dr}$) of SOI (Silicon-On-Insulator) pn diodes are derived in terms of the doping concentration and the thickness of the n- drift region and the buried oxide thickness. The optimum L$_{dr}$ is obtained from the condition that the breakdown voltage of the vertical electric field of n+n- junction equals to the of the lateral electric field of n+n-p+ junction. Analytical results agree reasonably with the numerical simulations using PISCESII.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1997.04a
• /
• pp.95-101
• /
• 1997

A general method is presented for the analysis of the damping effectiveness of viscoelastic layer applied to elastic beam. The damping is attributed to the shear deformations of the treatment. Specific results are then given for sandwich beams with dissipative cores. The calculated results by this method are validated by comparison with the experimental results. Optimum design of a viscoelastic damping layer which is constrainedly cohered on a steel beam is discussed from the viewpoint of the modal loss factor. An object function is a loss factor of 3-layered beam and design variable is the thickness of constraining layer and viscoelastic layer. Optimum thickness can be obtained when 3-layered beam has a maximum loss factor.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.16 no.6
• /
• pp.81-87
• /
• 2008

A geometrically asymmetric trapezoidal fin with variable fin base thickness and height is optimized based on the fixed fin base height using a one-dimensional analytic method. The temperature profile along the normalized X position in the fin is presented. For the fixed fin base height, the optimum heat loss, fin length and efficiency as a function of inside fluid convection characteristic number, fin base thickness and height, fin shape factor, convection characteristic numbers ratio and ambient convection characteristic number are represented. One of the results shows that the effect of fin base height and ambient convection characteristic number on the optimum values is remarkable.

• Journal of information and communication convergence engineering
• /
• v.8 no.4
• /
• pp.449-452
• /
• 2010

We have analyzed channel doping and dimensions(channel length, width and thickness) for the optimum subthreshold characteristics of DG(Double Gate) MOSFET based on the model of MicroTec 4.0. Since the DGMOSFET is the candidate device to shrink short channel effects, the determination of design rule for DGMOSFET is very important to develop sub-100nm devices for high speed and low power consumption. As device size scaled down, the controllability of dimensions and oxide thickness is very low. We have analyzed the short channel effects for the variation of channel dimensions, and found the design conditions of DGMOSFET having the optimum subthreshold characteristics for digital applications.

• Proceedings of the KSME Conference
• /
• 2001.06d
• /
• pp.311-318
• /
• 2001

A three-dimensional numerical analysis of the flow and heat transfer characteristic of wood-flour-filled polypropylene melt in an extrusion die was carried out Used for this analysis were Finite Concept Method based on FVM, unstructured grid and non-Newtonian fluid viscosity model. Temperature and flow fields are closely coupled through temperature dependent viscosity and viscous dissipation. With large Peclet, Nahme, Brinkman numbers, viscous heating caused high temperature belt near die housing, Changing taper plate thickness and examining some predefined parameters at die exit investigated the effect of taper plate on velocity and temperature uniformities. In the presence of taper plate, uniformity at die exit could be improved and there existed an optimum thickness to maximize it.

• International Journal of Fluid Machinery and Systems
• /
• v.2 no.1
• /
• pp.1-12
• /
• 2009

Surrogate modeling is applied to a compressor blade shape optimization to modify its stacking line and thickness to enhance adiabatic efficiency and total pressure ratio. Six design variables are defined by parametric curves and three objectives; efficiency, total pressure and a combined objective of efficiency and total pressure are considered to enhance the performance of compressor blade. Latin hypercube sampling of design of experiments is used to generate 55 designs within design space constituted by the lower and upper limits of variables. Optimum designs are found by formulating a PRESS (predicted error sum of squares) based averaging (PBA) surrogate model with the help of a gradient based optimization algorithm. The optimum designs using the current variables show that, to optimize the performance of turbomachinery blade, the adiabatic efficiency objective is improved substantially while total pressure ratio objective is increased a very small amount. The multi-objective optimization shows that the efficiency can be increased with the less compensation of total pressure reduction or both objectives can be increased simultaneously.

• Journal of the Korean Society for Advanced Composite Structures
• /
• v.7 no.1
• /
• pp.39-44
• /
• 2016

This study analyzes gestation stall structures with high strength concrete. The ANSYS program described in this paper is effective not only because it shows good accuracy but also it shows the goodness of parameter studies by using APDL(ANSYS Parametric Design Language). We have performed the various parameter studies by thickness change. The results is presented by using contours and tables. The analysis results showed that it was effective to increase the height thickness(tz) rather than longitudinal thickness(tx).

• Journal of Industrial Technology
• /
• v.28 no.B
• /
• pp.3-7
• /
• 2008

A cylindrical pin fin with variable fin base thickness is optimized based on fixed outer radius by using the one dimensional analytic method. Heat loss from the pin fin with fixed outer radius is presented as a function of the fin length. The ratio of in length for optimum heat loss to that for the maximum heat loss is listed. The maximum heat loss and effectiveness and the fin length for the optimum heat loss are presented as a function of fin base thickness and outer radius. One of the results presents the maximum effectiveness decreases rapidly first and then decreases slowly as the fin outer radius increases.