• Title/Summary/Keyword: Quality Design Simulation

Search Result 873, Processing Time 0.029 seconds

Prediction of Welding Pressure in the Non Steady State Porthole Die Extrusion of Al7003 Tubes

  • Jo, Hyung-Ho;Lee, Jung-Min;Lee, Seon-Bong;Kim, Byung-Min
    • International Journal of Precision Engineering and Manufacturing
    • /
    • v.4 no.3
    • /
    • pp.36-41
    • /
    • 2003
  • This paper describes a numerical analysis of a non-steady state porthole die extrusion, which is useful for manufacturing long tubes with a hollow section. Materials divided through several portholes are gathered within a chamber and are then welded under high pressure. This weldability classifies the quality of tube products and is affected by process variables and die shapes. However, porthole die extrusion has been executed based on the experience of experts, due to the complicated die assembly and the complexity of metal flow. In order to better assist the design of die and to obtain improvement of productivity, non-steady state 3D FE simulation of porthole die extrusion is required. Therefore, the objective of this study is to analyze the behavior of metal flow and to determine the welding pressure of hot extrusion products under various billet temperatures, bearing length, and tube thickness by FE analysis. The results of FE analysis are compared with those of experiments.

Numerical Analysis on the High Speed Precision Press for Ultra-thin Sheet Metal Forming (초박판 성형용 고속 정밀프레스에 대한 해석적 연구)

  • Kang, J.J.;Kim, J.E.;Hong, S.K.;Kim, J.D.;Heo, Y.M.;Cho, C.
    • Transactions of Materials Processing
    • /
    • v.17 no.8
    • /
    • pp.643-648
    • /
    • 2008
  • Ultra-thin sheet metal forming techniques are required in precision forming of miniaturized and integrated products. In order to manufacture a good quality and low cost ultra-thin sheet metal products, a highly precise high-speed press is needed. The precision of a press is related with its vibration characteristics during pressing operation. This study evaluated the vibration characteristics of a proposed press design using computer simulation. The analysis compares the static deformation characteristics of the slide and the slide motion for the metal forming of an ultra-thin sheet of thickness less than 0.1mm. Further, in order to minimize the vibrations during high speed pressing operation, revolution balances of the eccentric shaft and the balance weight device is also considered. Finally, modal analysis is used to characterize the natural frequency of vibration of the press.

THE INTEGRATION OF CAD/CAM/CAE BASED ON MULTI MODEL TECHNOLOGY IN THE DEVELOPMENT OF CYLINDER HEAD

  • Xu, Xiangyang;Weiss, Ulrich;Gao, Guoan
    • International Journal of Automotive Technology
    • /
    • v.3 no.2
    • /
    • pp.47-52
    • /
    • 2002
  • The integration of CAD/CAM/CAE in product development is the key to realize concurrent engineering. Generally, different systems are employed in product development departments. These different systems create a lot of trout)toes such as difficulty in communication, misunderstanding and so on. A new approach to integrate CAD/CAM/CAE in one system based on CATIA thor the end-to-end process in cylinder head development is presented. Hulti Model Technology (MMT) is used to create consistent and associated CAD models for the end-to-end process in cylinder head development. The concept and method to create and organize multi models are discussed. A typical four-layer structure of HHT for mechanical products is defined. The multi level structure of the cylinder head models based on MMT is provided. The CAD models of cylinder head created based on MMT can be used as the consistent model. All models in the downstream of cylinder head development such as structure analysis, CFD, sand core design , casting simulation and so oil are associated with the CAD models. Practice shows the approach in this paper enables the development process to be carried concurrently and can obviously shorten time to the market, reduce product cost and improve product quality.

A Study on the Thermal Load Patterns for a Exterior Wall in a House According to a Variation of Earth Sheltering Thickness (복토 주택의 외벽면 복토 두께 변화에 따른 열부하 패턴에 관한 연구)

  • Lee, Jae-Hyuk;Choi, Won-Ki;Suh, Seung-Jik;Cho, Dong-Woo
    • Proceedings of the SAREK Conference
    • /
    • 2008.06a
    • /
    • pp.807-812
    • /
    • 2008
  • The various attempts is made to solve the energy and environment problems. In addition, people interested in their life quality want the more eco-friendly living space. So we suggested that the earth-sheltered house could be one of the eco-friendly and low energy consuming houses to meet the social interest. And we also made data for design of the earth-sheltered house to be applicable to climate of Korea. In this study, a simulation was performed to estimate a boundary temperature according to earth sheltering thickness at the earth-sheltered part(exterior wall) in the case of earth sheltering on the plane ground not using a sloped site. And we analyzed the reduction of a thermal load by using this boundary temperature. We also compared a case of earth sheltering at the vertical wall with a case of earth sheltering at the roof to know the thermal reduction effect of a case of earth sheltering at the vertical wall.

  • PDF

Fuzzy Rule Optimization Using Genetic Algorithms with Adaptive Probability (적응 확률을 갖는 유전자 알고리즘을 사용한 퍼지규칙의 최적화)

  • 정성훈
    • Journal of the Korean Institute of Intelligent Systems
    • /
    • v.6 no.2
    • /
    • pp.43-51
    • /
    • 1996
  • Fuzzy rules in fuzzy logic control play a major role in deciding the control dynamics of a fuzzy logic controller. Thus, control performance is mainly determined by the quality of fuzzy rules. This paper introduces an optimization method for fuzzy rules using GAS with adaptive probabilies of crossover and mutation. Also we design two fitness measures to satisfy control objectives by partitioning the response of a plant into two parts. An initial population is generated by an automatic fuzzy rule generation method instead of random selection for fast a.pproaching to the final solution. We employed a nonlinear plant to simulate our method. It is shown through simulation that our method is reasonable and can be useful for optimizing fuzzy rules.

  • PDF

Wireless Packet Scheduling Algorithm for OFDMA System Based on Time-Utility and Channel State

  • Ryu, Seung-Wan;Ryu, Byung-Han;Seo, Hyun-Hwa;Shin, Mu-Yong;Park, Sei-Kwon
    • ETRI Journal
    • /
    • v.27 no.6
    • /
    • pp.777-787
    • /
    • 2005
  • In this paper, we propose an urgency- and efficiency-based wireless packet scheduling (UEPS) algorithm that is able to schedule real-time (RT) and non-real-time (NRT) traffics at the same time while supporting multiple users simultaneously at any given scheduling time instant. The UEPS algorithm is designed to support wireless downlink packet scheduling in an orthogonal frequency division multiple access (OFDMA) system, which is a strong candidate as a wireless access method for the next generation of wireless communications. The UEPS algorithm uses the time-utility function as a scheduling urgency factor and the relative status of the current channel to the average channel status as an efficiency indicator of radio resource usage. The design goal of the UEPS algorithm is to maximize throughput of NRT traffics while satisfying quality-of-service (QoS) requirements of RT traffics. The simulation study shows that the UEPS algorithm is able to give better throughput performance than existing wireless packet scheduling algorithms such as proportional fair (PF) and modified-largest weighted delay first (M-LWDF), while satisfying the QoS requirements of RT traffics such as average delay and packet loss rate under various traffic loads.

  • PDF

A Genetic Algorithm for Clustering Nodes in Wireless Ad-hoc Networks (무선 애드 혹 네트워크에서 노드 클러스터링을 위한 유전 알고리즘)

  • Jang, Kil-woong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2017.05a
    • /
    • pp.649-651
    • /
    • 2017
  • A clustering problem is one of the organizational problems to improve the network lifetime and scalability in wireless ad-hoc networks. This problem is a difficult combinatorial optimization problem associated with the design and operation of these networks. In this paper, we propose an efficient clustering algorithm to maximize the network lifetime and consider scalability in wireless ad-hoc networks. The clustering problem is known to be NP-hard. We thus solve the problem by using optimization approaches that are able to efficiently obtain high quality solutions within a reasonable time for a large size network. The proposed algorithm selects clusterheads and configures clusters by considering both nodes' power and the clustering cost. We evaluate this performance through some experiments in terms of nodes' transmission energy. Simulation results indicate that the proposed algorithm performs much better than the existing algorithms.

  • PDF

A Design of Differential Voltage Clamped VCO for Improved Characteristics of Operating Frequency (개선된 동작 주파수 특성을 갖는 차동 전압 클램프 VCO 설계)

  • Kim, D.G.;Oh, R.;Woo, Y.S.;Sung, Man-Y.
    • Proceedings of the KIEE Conference
    • /
    • 2000.07d
    • /
    • pp.3181-3183
    • /
    • 2000
  • As the fact that the simple data of text and sound in early year have been changed to be high quality images and sounds. PLL(Phase-Locked Loop) system plays an important role in communication system. VCO(Voltage Controlled Oscillator) is the most important part in PLL system because it can have critical effects on operation of PLL. Recently, it has been raised the necessity of high speed and high accuracy circuit application. In this paper, a new differential voltage clamped VCO using negative-skewed path is suggested. Using a dual-delay scheme to implement the VCO, higher operation frequency and wider tuning are achieved simultaneously. The dual-delay scheme means that both the negative skewed delay paths and the normal delay paths exist in the same ring oscillator. The negative skewed delay paths decrease the unit delay time of the ring oscillator below the single inverter delay time. As a result, higher operation frequency can be obtained. The whole characteristics of VCO are simulated by using HSPICE. Simulation results show that the resulting operating frequencies are 50% higher than those obtainable from the conventional approaches.

  • PDF

Study on Thermal Analysis for Heating System of Mobile Smart Device Cover Glass Molding Machine (Mobile Smart Device Cover Glass 성형기기의 가열시스템 열해석에 관한 연구)

  • Shin, Hwan June;Lee, Jun Kyoung
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.13 no.4
    • /
    • pp.50-55
    • /
    • 2014
  • Currently, flat cover glasses are widely applied to mobile devices. However, for a good design and for convenience of use, curved cover glasses are in demand. Thus, many companies are attempting to produce curved cover glasses using a shaving technique, but the production efficiency is very low. Therefore, a molding technique has been adopted to increase the efficiency of curved glass production systems. For a glass molding system, a uniform temperature distribution of the mold is crucial to produce high-quality curved cover glasses. Before setting the heating conditions of the molding system for a uniform temperature distribution by a thermal analysis, verification is required. Therefore, in this study, temperature measurements were conducted for a prototype molding system and the experimental results were compared with simulation computations. The temperatures of the heating block surface were in good agreement with the computational results for transient and steady conditions.

Numerical Study of Secondary Coating Die Geometry Effects on High Speed Optical Glass Fiber Coating Process (광섬유 2차 코팅다이 형상 변화에 따른 유리섬유 고속 코팅공정 영향성 해석연구)

  • Kim, Kyoungjin;Park, Joong-Youn
    • Journal of the Semiconductor & Display Technology
    • /
    • v.18 no.3
    • /
    • pp.12-18
    • /
    • 2019
  • The protective double layer polymer coatings on silica optical fibers are realized by wet-on-wet liquid coating process and they play an important role in final quality of mass produced optical fibers. This numerical study aims to analyze the effects of secondary coating die design parameters by employing two dimensional axisymmetric model of coating cup and coating die geometry and computational fluid dynamics simulations which include temperature dependent viscosity of polymer coating liquids and viscous dissipation heating. Under high speed fiber drawing conditions and pressurized coating liquid supply, the effects of converging die angle are investigated in order to appreciate the change of coating liquid flow patterns such as flow recirculation zone near coating die as well as primary and secondary coating layer thicknesses. The auxiliary coating die to converging coating die is also tested and the results find that this concept is advantageous in achieving stable double layer coatings on silica glass fiber.