• Title/Summary/Keyword: shear ring

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Development of a CAD program for optimal design of a cylinderical die with one stress-ring (단일보강링 원통형 금형의 최적 설계용 CAD 프로그램 개발)

  • 신중호;손주리;류갑상
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10a
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    • pp.556-561
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    • 1988
  • Shrink-rings (Stress-rings) are used in the fabrication of dies for cold forming and powder compaction processes to increase the allowable pressures for a given die material. Optimum procedures are to minimize a die thickness under the conditions that the stress distributions in the die and stress-rings utilize fully the strength available in each of the die elements. This paper proposes a new approach, where the maximum allowable shrinking pressures are calculated on shrinkage plans in the radial direction and the fractional shrinking pressures below the maximum allowable pressures are used as the design values. Two criteria for the optimal die design are used: Maximum shear stress limit for one-piece dies and zero tensile stress limit for combined dies. A computer program, DIECOM, is developed for illustrating the computer-aided design procedures. Finally, examples for each case are presented in this paper.

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Prediction and Evaluation of Rubber Components using Large Deformation Non-linear Finite Element Analysis (비선형 대변형 유한요소해석을 이용한 방진고무부품의 특성예측 및 평가)

  • Woo, Chang-Su;Kim, Wan-Doo;Cho, Seong-Do-Seong
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.286-291
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    • 2000
  • The finite element analyses of mechanical rubber components are executed to predict the behavior of deformation and stress distribution in destgn step. The non-linear properties of rubber which are described as strain energy functions are important parameters to design and evaluate rubber components. These are determined by material tests which are tension, compression and shear test. The behaviors of loads-displacements of rubber components such as a roll tubber spring and resilient ring and additional spring for railway suspension system are evaluated by using commercial FEA code. It is shown that the results by FEA simulations are in close agreement with the test results.

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A study on minimization of fracture surface in fine blanking process using factorial analysis (요인분석법을 이용한 파인 블랭킹 공정의 파단면 최소화에 관한 연구)

  • Lee, Beom-Soon;Kim, Ok-Hwan
    • Design & Manufacturing
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    • v.15 no.1
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    • pp.41-47
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    • 2021
  • The Fine Blanking process is an effective precision shearing process that can obtain a smooth cutting surface and high product precision through a single blanking process. It is widely used in various manufacturing fields. However, shearing through this fine blanking process is only intended to minimize burrs, die rolls and fracture surfaces and does not completely remove them. Therefore, it is necessary to study the minimization of burrs, die rolls and fracture surfaces in the fine blanking process. In this study, a study was conducted on the relationship between the fracture surface and process conditions that occurred during product production using the fine blanking process. For this purpose, the shape of the V-ring indenter, the distance to the punch, and the pressure force, clearance, shear rate, and physical properties of the material were selected as process and design variables, and the relationship with the fracture surface according to each process and design condition was tested. It was analyzed through the Experimental Design Method.

Dynamic response of segment lining due to train-induced vibration (세그먼트 라이닝의 열차 진동하중에 대한 동적 응답특성)

  • Gyeong-Ju Yi;Ki-Il Song
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.25 no.4
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    • pp.305-330
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    • 2023
  • Unlike NATM tunnels, Shield TBM tunnels have split linings. Therefore, the stress distribution of the lining is different even if the lining is under the same load. Representative methods for analyzing the stress generated in lining in Shield TBM tunnels include Non-joint Mode that does not consider connections and a 2-ring beam-spring model that considers ring-to-ring joints and segment connections. This study is an analysis method by Break-joint Mode. However, we do not consider the structural role of segment lining connections. The effectiveness of the modeling is verified by analyzing behavioral characteristics against vibration loads by modeling with segment connection interfaces to which vertical stiffness and shear stiffness, which are friction components, are applied. Unlike the Non-joint mode, where the greatest stress occurs on the crown for static loads such as earth pressure, the stress distribution caused by contact between segment lining and friction stiffness produced the smallest stress in the crown key segment where segment connections were concentrated. The stress distribution was clearly distinguished based on segment connections. The results of static analysis by earth pressure, etc., produced up to seven times the stress generated in Non-joint mode compared to the stress generated by Break-joint Mode. This result is consistent with the stress distribution pattern of the 2-ring beam-spring model. However, as for the stress value for the train vibration load, the stress of Break-joint Mode was greater than that of Non-joint mode. This is a different result from the static mechanics concept that a segment ring consisting of a combination of short members is integrated in the circumferential direction, resulting in a smaller stress than Non-joint mode with a relatively longer member length.

Development of Wide Connection Method for Vertical Joints of Precast Concrete Walls (프리캐스트 콘크리트 벽체 수직접합부의 광폭형 연결방식 개발)

  • Choi, Eun-Gyu;Shin, Yeong-Soo
    • Journal of the Korea Concrete Institute
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    • v.21 no.5
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    • pp.549-556
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    • 2009
  • This research analyzed the structural efficiency and application by improving the 100 mm width vertical joint to 150 mm and developing three connection methods to reduce the difficulty in assembling and handling PC walls. Moreover, nonlinear finite analysis was used for analyzing. From the analysis results, when double width connection was applied, the PC wall showed larger load capacity and ductility due to the steel bar sharing loads efficiently. Moreover, as the dimension of loops and the number of bars increased, the maximum load capacity increased as well. Also, among the double width connections, the largest capacity showed in the order of welding, ring and C type loop. However, in case of welding type loop connection, the ring type loop is more stable due to changes in different site conditions. Therefore, thorough quality control of welding is necessary.

Study on Friction Characteristic of Sintered Friction Component for Synchronizer-Ring of Diesel Vehicle (디젤차량 싱크로나이저링을 위한 소결마찰재 개발 및 접합특성 평가)

  • Song, Joon Hyuk;Kim, Eun Sung;Kim, Kyung-Jae;Oh, Je-Ha;Yang, Sung Mo;Kang, Shin Jae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.3
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    • pp.373-378
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    • 2013
  • The speed change performance of transmissions has become a serious issue because of the increase in the inertia moment that has accompanied increases in engine output and transmission size. Therefore, it is necessary to develop better wear resistant friction materials. In this study, an appropriate sintered friction component for the synchronizer ring of a diesel manual transmission was developed, and its bonding characteristics were analyzed. That is, a process for bonding an Fe-based base material and Cu-based sintered friction material was developed. BSE and EDX analyses of this bonding layer were conducted, along with a shear strength test, to determine the bonding characteristics.

Numerical Study of Flow Pattern and Drug Deposition in Drug-Eluting Stent (약물분출 스텐트 주위 유동형태와 약물침전에 대한 수치해석)

  • Seo, Tae-Won
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.10
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    • pp.1053-1060
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    • 2011
  • This study is performed to determine the drug concentration profiles of drug-eluting stents (DES) for an ideal circular ring stent and intertwined stent models for various Reynolds numbers (Re = 200, 400, and 800). The Navier.Stokes equations coupled with the advection-diffusion equation are solved numerically in order to determine how the flow patterns and drug deposition are affected in the in-stent and post-stent regions where flow separation and recirculation occur. The presence of DES within the arterial segment affects the local drug distribution in the flow field. As a result, the drug concentration for the intertwined stent is higher over the in-stent region in comparison with the ideal stents. For a given stent geometry, the local drug concentration in the in-stent region decreases with Reynolds number, while for a given Reynolds number, the local drug concentration is relatively insensitive to the stent geometry. The results show that drug concentration along the arterial wall is significantly higher within the in-stent and post-stent regions for the intertwined stent geometry than for the ideal stent geometries.

Semi-analytical Annular Mindlin Plate Element for Out-of-plane Vibration Analysis of Thick Disks (두꺼운 디스크의 면외 진동 해석을 위한 준-해석적 환상 민드린 평판 요소)

  • Kim, Chang-Boo;Cho, Hyeon Seok;Beom, Hyeon Gyu
    • Journal of the Korean Society for Railway
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    • v.15 no.6
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    • pp.588-596
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    • 2012
  • This paper presents a new semi-analytical annular Mindlin plate element with which out-of-plane natural vibration of thick disks can be analyzed simply, efficiently, and accurately through FEM by including effects of rotary inertia and transverse shear deformation. Using static deformation modes which are exact solutions of equilibrium equations of annular Mindlin plate, the element interpolation functions, stiffness and mass matrices corresponding to each number of nodal diameters are derived. The element is capable of representing out-of-plane rigid-body motions exactly and free from shear locking. Natural frequencies of uniform and multi-step disks with or without concentric ring support are analyzed by applying the presented element. Such results are compared with theoretical predictions of previous works or FEA results obtained by using two-dimensional shell element to investigate the convergence and accuracy of the presented element.

Flexural Design and Experiments on Reinforced Concrete Filled PHC Pile (철근 콘크리트 충전 PHC말뚝의 휨 설계 및 성능 평가)

  • Kim, Jeong-Hoi;Jung, Hae-Kwang;Park, Young-Shik;Min, Chang-Shik
    • Journal of the Korea Concrete Institute
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    • v.29 no.4
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    • pp.353-360
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    • 2017
  • The objective of this study is theoretical and empirical evaluation of the flexural performance of concrete filled pretensioned spun high strength concrete pile with ring type composite shear connectors (CFP pile). The specimens are comprised of standard CFP pile, PHC pile+composite shear connector+filed concrete (CFP-N-N), standard CFP pile with $1^{st}$ reinforcements (H13-8ea), and standard CFP pile with $1^{st}$ and $2^{nd}$ reinforcements(H19-8ea). Flexural performance evaluation results showed that the ductility is improved with increased steel ratio, which leads to the increased maximum load by 46.4% (with $1^{st}$ reinforcement) and 103.9% (with $1^{st}$ and $2^{nd}$ reinforcements) compared to standard CFP ( CFP-N-N). Comparing with the predicted ultimate limit state values of the CFP pile design method and the experimental results, the design method presented in this study is reasonable since safety factor of 1.23 and 1.40 times for each reinforcement step are secured.

Bonding Properties of 14K White-Red Gold Alloy by Diffusion Bonding Process (14K 화이트-레드골드의 확산접합 공정에 따른 접합 물성 연구)

  • Song, Jeongho;Song, Ohsung
    • Korean Journal of Materials Research
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    • v.27 no.7
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    • pp.386-391
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    • 2017
  • Using a customized diffusion bonder, we executed diffusion bonding for ring shaped white gold and red gold samples (inner, outer diameter, and thickness were 15.7, 18.7, and 3.0 mm, respectively) at a temperature of $780^{\circ}C$ and applied pressure of 2300 N in a vacuum of $5{\times}10^{-2}$ torr for 180 seconds. Optical microscopy, field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS) were used to investigate the microstructure and compositional changes. The mechanical properties were confirmed by Vickers hardness and shear strength tests. Optical microscopy and FE-SEM confirmed the uniform bonding interface, which was without defects such as micro pores. EDS mapping analysis confirmed that each gold alloy was 14K with the intended composition; Ni and Cu was included as coloring metals in the white and red gold alloys, respectively. The effective diffusion coefficient was estimated based on EDS line scanning. Individual values of Ni and Cu were $5.0{\times}10^{-8}cm^2/s$ and $8.9{\times}10^{-8}cm^2/s$, respectively. These values were as large as those of the melting points due to the accelerated diffusion in this customized diffusion bonder. Vickers hardness results showed that the hardness values of white gold and red gold were 127.83 and 103.04, respectively, due to solid solution strengthening. In addition, the value at the interface indicated no formation of intermetallic compound around the bonding interface. From the shear strength test, the sample was found not to be destroyed at up to 100,000 gf due to the high bonding strength. Therefore, these results confirm the successful diffusion bonding of 14K white-red golds with a diffusion bonder at a low temperature of $780^{\circ}C$ and a short processing time of 180 seconds.