• Journal of the Korean Institute of Gas
• /
• v.10 no.2 s.31
• /
• pp.40-46
• /
• 2006

In this paper, the optimized design of a rectangular O-ring groove has been analyzed for a maximum Cauchy stress and maximum strain using the Taguchi method. This method may efficiently optimize the design parameters for an O-ring groove of a LPG filling unit. The computed FEM results indicate that the optimized design parameters can only be drawn by nine experimental numbers of iterations when the Taguchi design technique has been employed with a finite element method. This means that the Taguchi design method is very useful for the optimization design of O-ring rectangular groove geometry. Based on the computed FEM results by the Taguchi design technique, the dimensions of a groove geometry are given as h=2.5 mm, d=2.74 mm, c=0.15 mm, and w=3.0 mm. In this study, the initial compression ratio of O-rings is recommended as 8.7% for a gas supply pressure of 18 $kg/cm^2$.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.38 no.6
• /
• pp.48-55
• /
• 2001

This paper presents a 1.8 GHz CMOS frequency synthesizer with high-speed on-chip pseudo 2-stage ring VCO. We introduce and analysis the conditions in which the ring VCO can oscillate. For high speed operation, we propose the pseudo 2-stage ring VCO that eliminates dummy loads. It can operate up to 1.87 GHz with 0.6 m CMOS process, which shows 21.3% improvement aginst the conventional 4-stage ring VCO in the aspect of the speed. When the frequency synthsizer with the psedo 2-stage ring VCO is locked at 1.85GHz, the jitter measured to 24 psec. The proposed VCO and the frequency synthesizer are directly applicable to high speed clocky synhtesizers.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.10a
• /
• pp.72-75
• /
• 2009

Design and Manufacturing processes of Ti-6Al-4V profiled ring-products were investigated with three-dimensional FEM simulation and experimental analyses. FEM simulation for the ring-rolling process was used to calculate the state variables such as strain, strain rate and temperature. In the simulation results of strain and temperature distributions for a plane ring rolling process, the strain level at the surface area is higher than that at the mid-plane, but the temperature level at the surface area is lower than that at mid-plane due to heat transfer between the workpiece and the work roll. These distributions showed a great influence on the evolution of microstructure in different positions. In order to induce the uniform deformation of the profile ring and reduce the applied load, the final blank was prepared by two-step processes. The mechanical properties of Ti-6Al-4V alloy ring products made in this work were investigated with tensile and impact tests and analyzed with the evolution of microstructures during the ring rolling process.

• Journal of the Korea Concrete Institute
• /
• v.22 no.6
• /
• pp.817-824
• /
• 2010

The concrete containment structures have been widely used in nuclear power plants, LNG storage tanks, etc., due to their high safety and economic efficiency. The containment structure consists of a bottom slab, wall, ring beam and dome. The shape of the roof dome has a very significant effect on structural safety, the quantity of materials, and constructability; the thickness and curvature of the dome should therefore be determined to give the optimum design. The ring beam plays the role as supports for the dome, resulting in a minimized deformation of the wall. The main issues in designing the ring beam are the correct dimensions of the section and the prestress level. In this study, an efficient design procedure is proposed that can be used to determine an optimal shape and prestress level of the dome and ring beam. In the preliminary design stage of the procedure, the membrane theory of shells of revolution is adopted to determine several plausible alternatives which can be obtained even by hand calculation. Based on the proposed procedures, domes and ring beams of the existing domestic containment structures are analyzed and some improvements are discussed.

• Structural Engineering and Mechanics
• /
• v.66 no.6
• /
• pp.713-727
• /
• 2018

Thin-walled mental tubes under lateral crushing are desirable and reliable energy absorbers against impact or blast loads. However, the early formations of plastic hinges in the thin cylindrical wall limit the energy absorption performance. This study investigates the energy absorption performance of a simple, light and efficient energy absorber called the ring stiffened tube. Due to the increase of section modulus of tube wall and the restraining effect of the T-stiffener flange, key energy absorption parameters (peak crushing force, energy absorption and specific energy absorption) have been significantly improved against the empty tube. Its potential application in the offshore blast wall design has also been investigated. It is proposed to replace the blast wall endplates at the supports with the energy absorption devices that are made up of the ring stiffened tubes and springs. An analytical model based on beam vibration theory and virtual work theory, in which the boundary conditions at each support are simplified as a translational spring and a rotational spring, has been developed to evaluate the blast mitigation effect of the proposed design scheme. Finite element method has been applied to validate the analytical model. Comparisons of key design criterions such as panel deflection and energy absorption against the traditional design demonstrate the effectiveness of the proposed design in blast alleviation.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.24 no.3
• /
• pp.233-238
• /
• 2014

Creativity is crucial in designing and producing attractive accessaries and daily supplies as well as art works. Generative design can be a paradigm to be used to obtain novel ideas or motifs for creative design works. This paper introduces a generative design method which comes up with unique ring models using genetic algorithm. It presents how the genetic algorithm works in terms of candidate solution coding, operators, and fitness evaluation function. The proposed method allows the customers to express their personal preference and later the preference to be reflected in fitness evaluation. In the final stage of the proposed method, several ring models are suggested for customers to choose on their own. The chosen ring models can be put into physical rings with the help of a 3D printer because the models are expressed in 3D geometric structures.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2010.05a
• /
• pp.139-140
• /
• 2010

Combined analysis is required for the concrete dome and ring beam of containment structure due to the interaction in section forces. In this study, an efficient design procedure is proposed that can be used to determine the preliminary sections of the dome and ring beam as well as a proper level of prestress in the ring beam, prior to a detailed design. The procedure applies the membrane theory of the shell of revolution.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.24 no.6
• /
• pp.1040-1048
• /
• 1987

We propose a hardware architecture called Multiring which is applicable for various geometrical operations on rectilinear objects such as design rule checking in VLSI layout and many image processing operations including noise suppression and coutour extraction. It has both a fast execution speed and extremely high flexibility. The whole architecture is mainly divided into four parts` I/O between host and Multiring, ring memory, linear processor array and instruction decoder. Data transmission between host and Multiring is bit serial thereby reducing the bandwidth requirement for teh channel and the number of external pins, while each row data in the bit map stored in ring memory is processed in the corresponding processor in full parallelism. Each processor is simultaneously configured by the instruction decoder/controller to perform one of the 16 basic instructions such as Boolean (AND, OR, NOT, and Copy), geometrical(Expand and Shrink), and I/O operations each ring cycle, which gives Multiring maximal flexibility in terms of design rule change or the instruction set enhancement. Correct functional behavior of Multiring was confirmed by successfully running a software simulator having one-to-one structural correspondence to the Multiring hardware.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.12
• /
• pp.145-151
• /
• 2001

The dimensional accuracy of the cold forged part is depended on the elastic characteristics of the die. To increase the stiffness of the prestressed die, the first stress ring of the tungsten carbide alloy (WC) is considered. For the design, Lame's equation is used. Diameter ratios and interferences have been determinated by maximum inner pressure without yielding of materials. The design of the prestressed die has been compared with the conventional one. For the comparison, the FE-analysis using ANSYS has been performed. The results indicate that the prestressed die with the high stiffness can be obtained by the using the high stiffness material as the first stress ring.

• Journal of the Institute of Convergence Signal Processing
• /
• v.11 no.1
• /
• pp.63-73
• /
• 2010

This paper presents the optimal design method of an overlapped ultrasonic sensor ring for reduced positional uncertainty, and its application to the obstacle detection with improved resolution. Basically, it is assumed that a set of ultrasonic sensors are installed to form a circle at regular intervals with their beams overlapped. First, exploiting the overlapped beam pattern, the positional uncertainty inherent to an ultrasonic sensor is shown to be significantly reduced. Second, for an ideal ultrasonic sensor ring of zero radius, the effective beam width is defined to represent the positional uncertainty, and the optimal number of ultrasonic sensors required for minimal effective beam width is obtained. Third, for an actual ultrasonic sensor ring of nonzero radius, the design index is defined to represent the degree of positional uncertainty, and an optimal design of an overlapped ultrasonic sensor ring consisting of commercial ultrasonic sensors with low directivity is given. Fourth, given measured distances from ultrasonic sensors, the geometric method is described to compute the obstacle position with reference to the center of a mobile robot. Finally, through experiments using our overlapped ultrasonic sensor ring prototype, the validity and performance of the proposed method is demonstrated.