• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 춘계학술대회 논문집
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• pp.81-84
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• 2001

Some trials to simulate the spinning process by which V-belt pulley is usually being manufactured are done in this study. 2D finite element analysis (FEA) for the whole process to produce a mono-typed pulley including preforming, 1st spinning, axial compression and 2nd spinning processes is carried out using the commercial code $DEFORM2D^{TM}$. The sectional shape after each process is compared with that of real product. The deformed shape obtained from the FEA, on the whole, coincides with the experimental result well, but the thickness around the bottom of the V-groove is somewhat different each other.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.142-147
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• 2004

The aluminum tube hydroforming is a manufacturing process which can provide lightweight components as automotive parts. In this paper, the hydroformability of aluminium tube in different condition of bending process is presented. An investigation has been conducted on how to control the deformed shape and its effect on thinning distribution after hydroforming by using finite element simulation. Finite element simulation of tube hydroforming for automotive trailing arm is carried out to explore the effect of 2-dimensional and 3-dimensional bending.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.243-246
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• 2005

A tube hydroformability testing system was designed and manufactured to observe the forming steps and to provide arbitrary combination of internal pressure and axial feed. The forming limit diagram of an aluminum tube was obtained from the free bulge test and the T-shape forming test using this system, giving the criteria for predicting failure in the hydroforming process. The hydroformability of aluminum tube according to different conditions of a prebending process was discussed, based on the finite element analysis and the forming limit test. The effects of 2D and 3D prebending on the tube hydroforming process of an automotive failing arm were evaluated and compared with each other.

• Coupled systems mechanics
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• 제8권1호
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• pp.71-93
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• 2019

Finite element simulations of solid mechanics problems often involve the use of Non-Confirming Meshes (NCM) to increase accuracy in capturing nonlinear behavior, including damage and plasticity, in part of a solid domain without an undue increase in computational costs. In the presence of material nonlinearity and plasticity, higher-order variables are often needed to capture nonlinear behavior and material history on non-conforming interfaces. The most popular formulations for coupling non-conforming meshes are dual methods that involve the interpolation of a traction field on the interface. These methods are subject to the Ladyzhenskaya-Babuska-Brezzi (LBB) stability condition, and are therefore limited in their implementation with the higher-order elements needed to capture nonlinear material behavior. Alternatively, the enriched discontinuous Galerkin approach (EDGA) (Haikal and Hjelmstad 2010) is a primal method that provides higher order kinematic fields on the interface, and in which interface tractions are computed from local finite element estimates, therefore facilitating its implementation with nonlinear material models. The inclusion of higher-order interface variables, however, presents the issue of preserving material history at integration points when a increase in integration order is needed. In this study, the enriched discontinuous Galerkin approach (EDGA) is extended to the case of small-deformation plasticity. An interface-driven Gauss-Kronrod integration rule is proposed to enable adaptive enrichment on the interface while preserving history-dependent material data at existing integration points. The method is implemented using classical J2 plasticity theory as well as the pressure-dependent Drucker-Prager material model. We show that an efficient treatment of interface variables can improve algorithmic performance and provide a consistent approach for coupling non-conforming meshes in inelasticity.

• 소성∙가공
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• 제25권2호
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• pp.141-146
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• 2016

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.394-397
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• 2008

In this research, the fine-structure TiO2+Ti bulks have been fabricated by the combined application of magnetic pulsed compaction (MPC) and subsequent sintering, and their densification behavior was investigated. The obtained density of $TiO_2$+Ti bulk prepared by the combined processes was increased with increasing MPC pressure from 0.7 to 1.7 GPa. Relatively higher density (88%) in the MPCed specimen at 0.7Gpa was attributed to the decreasing of the inter-particle distance of pre-compacted component. High pressure and rapid compaction by Magnetic Pulsed Compaction could reduce shrinkage rate (about 10%) of the sintered bulks compared to that of general processing (about 20%). Mixing conditions of PVA, water, Ti and $TiO_2$ nano powder for compaction of $TiO_2$ nano powder did not affect on density and shrinkage of the sintered bulks due to high pressure of MPC.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 추계학술대회 논문집
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• pp.66-70
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• 2001

The purpose of this paper is to investigate the characteristics of springback for the U-bending of steel sheets for automotive body panels. This study presents the experimental and analytical approach for the two kind of steel sheets, namely SCP1 and TRIP(Transformation-induced plasticity), the newly developed high strength steel. The adopted thicknesses are 0.8, 1.2 and 1.6 mm for SCP1, and 1.0 mm for TRIP. The punch profile radii are designed in 3, 6, 9, 12, and 15 mm. As results, the springgo aspect could be observed experimently in the small punch profile radius. The degree of springback for TRIP sheets was more than the SCP1 sheets.

• 소성∙가공
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• 제26권3호
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• pp.144-149
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• 2017

In order to characterize the macroscopic mechanical response of ultra-thin (0.1 mm thick) ferritic stainless steel sheet at various loading paths, a crystal plasticity finite element method (CP-FEM) was introduced. The accuracy of the prediction results was validated by comparing with the experimental data. Based on the results, the forming limit diagram (FLD) was predicted using a modified Marchinicak-Kuczinski model coupled to a non-quadratic anisotropic yield function, namely, Yld2000-2d. The predicted FLD was found to be in good agreement with the experimental data.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.40-43
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• 2009

This study is for investigating the effect of induction heating with various alloy elements to manufacture the pre-heat treated steels of 100kgf/$mm^2$ for cold heading. For four kinds of steels, the condition of induction heating (especially, induction tempering) were observed, and their microstructure and tensile and compressive properties were investigated. The middle carbon steel and the low carbon Cr-Mo steel are needed the higher Grange-Baughman tempering parameter than that of the low carbon Cr steel to obtain 100kgf/$mm^2$ tensile strength. For accomplishing the pre-heat treated steel of 100kgf/$mm^2$ tensile strength having advanced cold heading. It is needed that the pre-heat treated steel is manufactured by induction quenching and tempering with the low carbon alloy steel to have the high ratio of ferrite and the fine globular cementite simultaneously.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 추계학술대회 논문집
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• pp.174-177
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• 2001

The automated computer-aided drafting technique is attempted for drawing process pictures of axisymmetric solid forgings which are mainly used in automobile industry. For this study basic concepts to draw the shape of an element are described and applied to the 2-dimensional and 3-dimensional modeling of forged parts. 2-dimensional display of process pictures is developed by using AutoLISP language in AutoCAD software of a drafting technique and 3-dimensional view of process pictures is based on the UG/open API and UG/open GRIP languages of Unigraphics software. Testing the developed program to forging of bolts and ballstuds, it was shown to give good results to be applicable in forging industry.