• Journal of Welding and Joining
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• 제35권1호
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• pp.49-54
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• 2017

In this study, the volumetric heat source in electron beam welding (EBW) is modeled through finite element method taking advantage of ABAQUS software package. Since this welding method is being applied in plates with different thicknesses and also considering that residual stresses reduce the strength of these weldments, the effect of thickness in the distribution and magnitude of residual stresses after welding is studied. Regarding the vast application of Inconel 706 super-alloy in aerospace industries, this material was selected in the current research. In order to validate the finite element model, the obtained results were compared to those of other researchers in this area, and good agreement was observed. The simulation results revealed that increase in the plate thickness leads to increase in the residual stresses. In addition heat treatment in the base metal (before welding) increases the residual stresses significantly.

• Journal of the Korea Convergence Society
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• 제7권4호
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• pp.181-190
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• 2016

The objective of this study is to find the effective stiffness and compressive strengths of a unit-cell pinwheel truss and double pinwheel truss model designed following a double helical geometry similar to that of the DNA (deoxyribonucleic acid) structure in biology. The ideal solution for their derived relative density is correlated with a ratio of the truss thickness and length. To validate the relative stiffness or relative strength, ABAQUS software is used for the computational model analysis on five models having a different size of truss diameter from 1mm to 5mm. Applied material properties are stainless steel type 304. The boundary conditions applied were fixed bottom and 5 mm downward displacement. It was assumed that the width, length, and height are all equal. Consequently, it is found that the truss model has a lower effective stiffness and a lower effective yielding strength.

• Journal of Aerospace System Engineering
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• 제4권2호
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• pp.1-9
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• 2010

An airless tire has advantages over the conventional pneumatic tire in terms of flat proof and maintenance free. According to the recently disclosed inventions on the airless tire, non-pneumatic tire (NPT) consists of the flexible polygon spokes. Considering the NPT structure, the spokes undergo the tension-compression cyclic loading while the tire rolls. Therefore the spokes of NPT are required to have both stiffness and resilience under the cyclic tensile-compressible loading. In general, if a material has a high stiffness, it shows a low elastic strain limit. In this paper, using the auxetic honeycomb structure with negative poissons's ratio, the spokes of NPT tire are designed to have both stiffness and resilience. Finite element based numerical simulation of the contact pressure of a NPT is carried out with ABAQUS.

• Transactions of Materials Processing
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• 제4권1호
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• pp.48-58
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• 1995

In this study, a contact algorithm for the finite element analysis of free surface contact problem in materials forming is presented. The proposed contact algorithm consists of two parts. The first is the contact searching part, and the second, the constraint part. The contact searching algorithm does not require any a priori knowledge of the pairs of contact nodes or segments and the impenetrability constraint is satisfied using the penalty function scheme. void colsure in open-die forging was simulated to verify the accuracy and capability of the currently developed contact algorithm. The simulation results, obtained from ABAQUS simulation, were compared well to the experimental data available in the literature.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.113-116
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• 2003

Hem quality can be determined mainly by turn-down and roll-in. Turn-down, that is created by the elastic recovery, can't be easily detected and measured since it is usually as small as 0.03 m. This study is focused on the precise evaluation of the hemming defects through analytical and experimetal approaches, and on the investigation of the influence of process parameters on the final hem quality. Implicit finite element analysis of plane-strain hemming process is performed by using a commercial code ABAQUS/Standard. Experiment and measurement is also carried out for steel and aluminium sheet metals, and the results are compared with those of analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제30권11호
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• pp.1376-1383
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• 2006

Densification behavior of various metal and ceramic powders was investigated under cold compaction. The Cap model was proposed by using the parameters involved in the yield function for sintered metal powder and volumetric strain evolution under cold isostatic pressing. The parameters for ceramic powder can also be obtained from experimental data under triaxial compression. The Cap model was implemented into a finite element program (ABAQUS) to compare with experimental data for densification behavior of various metal and ceramic powders under cold compaction. The agreement between finite element calculations from the Cap model and experimental data is very good for metal and ceramic powder under cold compaction.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제28권6호
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• pp.838-847
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• 2004

The effect of a metal mold on densification behavior of stainless steel 316L powder was investigated under warm isostatic pressing with a metal mold. We use lead as a metal mold and obtain experimental data of metal mold properties. To simulate densification behavior of metal powder, elastoplastic constitutive equation proposed by Shima and Oyane was implemented into a finite element program (ABAQUS) under warm die pressing and warm isostatic pressing with a metal mold. Finite element results were compared with experimental data for densification and deformation of metal powder under warm isostatic pressing and warm die pressing.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제28권6호
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• pp.677-684
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• 2004

Plastic and creep deformations of solder joints during thermal cycling are the main factors of misalignments and power losses in optical telecommunication components. Furthermore, the increased mismatch between solder Joint-bonded areas may cause severe failure in the components. Darveaux's creep model was implemented into a finite element program (ABAQUS) to simulate creep response of solder. Based on the finite element results, thermal fatigue reliability was predicted by using various fatigue life prediction models. Also, the effects of ramp conditions, dwelling time, and solder joint-embedding materials on the reliability were investigated under the thermal cycling conditions of the Telcordia schedule (-40∼75$^{\circ}C$).

• Journal of Power System Engineering
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• 제13권6호
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• pp.35-42
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• 2009

The piping systems in the steam-driven power engines lie under the cyclic condition of thermal expansion and contraction by superheated steam. These phenomena might cause some severe damages on the pipes and the accessory devices. To avoid these damages, the calculation of the proper strength and the consideration of the reduced resultant forces on the materials are needed. In the present study, numerical investigations on the effects of the thermal deformation of the industrial piping system were performed with comparison of the design data. Commercial software, ABAQUS with the thermal-fluidic loadings based on the design conditions was used for the thermal stress analysis of the piping system. From the analysis of the initially-designed pipe supporters, the rearrangement was suggested to improve the piping design.

• Transactions of Materials Processing
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• 제17권7호
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• pp.496-500
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• 2008

Plastics is commonly used in consumer electronics because of it is high strength per unit mass and good productivity. But plastic parts are usually distorted after injection molding due to the residual stress after filling, packing, cooling process, and etc. And plastic material is to be deteriorated according to various temperature conditions and operating time, which can be characterized by stress relaxation and creep. The viscoelastic behavior of plastic materials in time domain can be expressed by the Prony series of the commercial code, ABAQUS. In the paper, the process to predict the post deformation under cyclic thermal loadings was suggested. The process was applied to the real panel, and the deformation predicted by the analysis was compared with that of real test, which showed the possibility of applying the suggested process to predict the post deformation of plastic product under thermal loadings.