• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2014.11a
• /
• pp.306-307
• /
• 2014

진공용 장비의 sealing 방법으로 Cu gasket을 이용한 CF type과 O-ring을 이용한 NW type이 있다. 이중 O-ring을 이용한 sealing 방법에는 clamp를 사용하게 되는데 Al 합금으로 제작된 clamp에 bellows의 수축 시 받는 전단응력과 전단응력한계 이상의 힘을 받았을 때의 clamp 파손에 따른 역압에 의한 TMP 손상 분석.

• Composites Research
• /
• v.25 no.1
• /
• pp.14-18
• /
• 2012

The structural adhesives have the advantage of improving automobile performances and are being applied to joining light weight materials like aluminium and composite. In order to characterize the impact behavior of structural adhesive, instrumented impact tests were performed with respect to pin-ring adhesively bonded joint specimens. Also dynamic FE analysis was carried out using LS-DYNA to compare the results with experiments.

• Journal of the Korean Wood Science and Technology
• /
• v.44 no.1
• /
• pp.67-74
• /
• 2016

The yield shear strength of bolt connection in glass fiber reinforced glulam was predicted using a design-based equation, and was compared to the empirical yield shear strength. For the predicted equation, the mechanical properties of member (the elastic modulus, Poisson's ratio, shear modulus) was tested. The fracture toughness factor ($K_{ft}$) of glass fiber reinforced glulam was reflected to the revision of the design equation of bolted connection. The compressive strength properties to grain direction was influenced by annual ring angle and width of lamina. Compared with the revised yield shear strength of reinforced glulam, it was tended to be similar to the empirical yield shear strength on the diameter of bolt and the reinforcements. The revised yield shear strength from proposed formula of KBC was most appropriately matched in the bolt connection of the glass fiber reinforced glulam.

• Journal of Welding and Joining
• /
• v.18 no.1
• /
• pp.70-76
• /
• 2000

A rolled steel for structural parts and lead bronze alloy were bonded each other by a new semi-solid diffusion bonding process to investigate the effect of the process parameters, for example bonding temperature and bonding time, on the interface characteristics, and bonding behavior. It can be possible that manufacture of the bonded steel/lead bronze which has a cylindrical shape with inserted the lead bronze alloy into the steel ring by the diffusion bonding process under the semi-solid condition of the lead bronze alloy without any pressure and flux. It has been know that the control of the amount of the liquid phase in semi-solid lead bronze alloy was very important to obtain soundness interface, since the shear strength of the bonded steel/lead bronze at 850℃ for 60 minutes under the condition of about 40% of the liquid phase in the lead bronze alloy shows maximum value, 210 MPa. The shear strength increases with an increase in bonding time and show maximum value, and then decreases.

• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.2
• /
• pp.102-109
• /
• 1996

Effects of frictional laws on finite element solutions in metal forming were investigated in this paper. A rigid-viscoplastic finite element formulation was given with emphasis on the frictional laws. The Coulomb friction and the constant shear friction laws were compared through finite element analyses of compression of rings and cylinders with different aspect ratios, ring-gear forging, multi-stage cold extrusion and hot strip rolling under the isothermal condition. It has been shown that two laws may yield quite different results when the aspect ratio of a process and the fractional contact region are large.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.798-803
• /
• 2003

The objective of the present study is to investigate the changes in the acoustic source characteristics and far-field noise propagation in an incompressible round jet at Re=10000 for single-frequency excitations using large eddy simulation and Lighthill acoustic analogy. We apply excitations at a frequency corresponding to the jet-column mode ($St_{D}=0.85$) or maximum growth rate in the shear layer ( $St_{\theta}=0.017$ ). The acoustic source derived from the Lighthill acoustic analogy is the second spatial derivative of the Reynolds stresses. In the case of $St_{D}=0.85$, vortex ring and large scale structures are dominant sources, whereas in the case of $St_{\theta}=0.017$, the main sources are located at an upstream position along the shear layer than in the uncontrolled case. Also, the far-field noise propagates along the axial direction due to excitation.

• Proceedings of the KACD Conference
• /
• 2003.11a
• /
• pp.569-569
• /
• 2003

I. Objectives The purpose of this study was to evaluate the effort of a modified luting procedure called "dual bonding technique" by compare micro-shear bond strength to different luting procedures of ceramics to dentin. II. Materials and Methods Eighty-four freshly extracted caries-and restoration-free human third molar were embedded in epoxy resin using acrylic ring. Flat superficial occlusal dentin surfaces were obtained, initially using a Low speed diamond saw and exposed detin surface was group with ＃600-grit SiC paper.(omitted)

• 한국기계연구소 소보
• /
• s.17
• /
• pp.75-82
• /
• 1987

Shrink-rings (Stress-rings) are used in the fabrication of powder compaction dies to increase the allowable compaction pressures for a given die material. Optimum Procedures are used to insure that the stress distributions in the die and stress-rings ultilize fully the strength available in each of the die elements. Two criteria for the optimum die design are used: Maximum shear stress limit for one-piece dies and zero tensile stress limit for combined dies. Examples for each case are presented in this paper.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.1262-1267
• /
• 2003

TF magnet structures are the main structural components in the KSTAR magnet systems to protect the superconducting coils from mechanical, electrical, and thermal loads. TF coil structure supports CS and PF coil system. The inter-coil structure contains adjustable shear keys and conical bolts to provide pre-loading in toroidal direction and to resist against in-plane and out-of-plane forces that are the most critical loads on the TF magnet system. The conical bolts and shear keys are specially designed to assemble easily and to provide a convenient accommodation for a good alignment. The connection plate that is one of the prototype fabrications had been manufactured to study adjustability of conical bolts and shear keys for assembly of TF coil structure. We could measure the misalignments at the keyways and conical holes with the misalignment measuring instrument.

• Korea-Australia Rheology Journal
• /
• v.21 no.3
• /
• pp.193-200
• /
• 2009

We present a direct simulation technique for two-dimensional mold-filling simulations of fluids filled with a large number of circular disk-like rigid particles. It is a direct simulation in that the hydrodynamic interaction between particles and fluid is fully considered. We employ a pseudo-concentration method for the evolution of the flow front and the DLM (distributed Lagrangian multipliers)-like fictitious domain method for the implicit treatment of the hydrodynamic interaction. Both methods allow the use of a fixed regular discretization during the entire computation. The discontinuous Galerkin method has been used to solve the concentration evolution equation and the rigid-ring description has been introduced for freely suspended particles. A buffer zone, the gate region of a finite area subject to the uniform velocity profile, has been introduced to put discrete particles into the computational domain avoiding any artificial discontinuity. From example problems of 450 particles, we investigated the particle motion and effects of particles on the flow for both Newtonian and shear-thinning fluid media. We report the prolonged particle movement toward the wall in case of a shear-thinning fluid, which has been interpreted with the shear rate distribution.