• 소성∙가공
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• 제32권6호
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• pp.321-328
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• 2023

To ensure driver safety, high-strength steel pipes are utilized in the chassis and internal structures design of automobiles. ERW(electric resistance welding) pipes, fabricated through welding at joints using electrical resistance, form a Heat-Affected Zone (HAZ) during the welding process. Due to characteristics such as increased hardness and reduced ductility compared to the base material, HAZ poses challenges in finite element analysis (FEA) for pipe shapes. In this study, for FEA considering HAZ properties, mechanical properties were measured through uniaxial tensile testing and digital image correlation (DIC) techniques after specimen fabrication. These measurements were validated using reverse engineering methods. Furthermore, hardness measurements and gaussian functions were employed to ascertain the hardness distribution within the HAZ, serving as a basis for subdividing the HAZ and modeling the pipe shape. To validate the effectiveness of the HAZ modeling approach, models were interpreted incorporating only base material properties and models incorporating average-calculated HAZ properties. Comparative analysis was performed, revealing that the model subdividing the HAZ based on hardness measurements closely approximated experimental values. This validation offered a methodology for HAZ modeling in FEA.

• Tribology and Lubricants
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• 제26권4호
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• pp.219-223
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• 2010

Despite the increasing need of nanometer-scale accuracy in abrasive machining using ultrasmall particles such as abrasive jet and chemical mechanical polishing(CMP), the process mechanism is still unknown. Based on the background, research on the effects of various process parameters on the machined surface at abrasive machining was motivated and performed by using finite element analysis where the effect of slurry fluid flow involved. The effect of particle shape on the machined surface during particle-surface collision was discussed in this paper. The results from FEA simulation revealed that any damage or defect generation on machined surface by the impact may occur only if the particle has enough impact energy. Therefore, it could be concluded that generation of the defects and damage on the wafer surface after CMP process was mainly due to direct contact of the 3 bodies, i.e., pad-particle-wafer.

• 상하수도학회지
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• 제28권4호
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• pp.491-500
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• 2014

Due to rapid urbanization and industrialization, water supply and sewer line systems are also developed relevantly. Manhole is an essential component structure of the pipeline system. Manhole is a structure constructed to accommodate the direction, dimension, differences in level, and easy of maintenance in the pipeline system. In this paper we present the result of investigations pertaining to the structural behavior of PVC sewer manhole buried underground. In the paper mechanical properties of PVC material are reported. In addition, by the finite element analysis (FEA), we confirmed that a PVC double-wall corrugated pipe manhole, when it is buried underground, is safe for the stress as well as buckling strength if the manhole is constructed within the suggested limit of buried depth.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 추계학술발표논문집 2부
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• pp.634-637
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• 2010

본 논문은 미세구조의 마이크로 액추에이터의 구동해석을 위한 결과로써 3차원 유한요소해석(Finite Element Analysis, FEA)을 이용하여 수행하였다. 마이크로머신과 같은 미소구조물을 해석하는 경우, 컴퓨터의 메인 프로세스에 비해 프리프로세서(pre-processor)의 비중이 높아지고 있어 그 효율화가 가장 중요하다. 수작업에 의존해야 했던 지난날의 요소분할법 기술은 최근에 들어 여러 연구자들에 의해 개발되고 있다. 특히, 복합현상을 다루는 정전 액추에이터에 직접적인 적용에 다소 어려움이 있는데 3차원적인 수치 및 실험평가는 실용적인 문제에서 비추어 볼 때 매우 중요하다. 따라서 본 논문에서는 센서로서의 역할을 하는 마이크로 정전 액추에이터의 기본설계를 위한 토대를 구축하고자 3차원적인 FEA 시뮬레이션을 수행하여 미세 회전운동을 분석하였다. 그 결과 설계된 모델에서 먼저 자중해석과 Mode 해석에서 기준치를 모두 만족하였다. 또한 설계된 액추에이터의 형상에 따른 회전자의 변형해석을 수행하여 시작토오크와 탄성한계까지의 위치제어에 필요한 회전각을 구하였으며, 정전장 해석을 통하여 시작토오크는 전압 $V^2$에 비례함을 알 수 있었다.

• 제어로봇시스템학회논문지
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• 제10권11호
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• pp.1012-1016
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• 2004

In the present paper, equivalent beam and equivalent bimorph beam models for IPMC(ionic Polymer-Metal Composite) actuators are described. Physical properties of an IPMC, such as Young's modulus and electro-mechanical coupling coefficient. are determined from the rule of mixture, bimorph beam equations, and measured force-displacement data of a cantilevered IPMC actuator. By using a beam equation with estimated physical properties, actuation displacements of a cantilevered IPMC actuator was calculated and a good agreement between the computed tip displacements and the measured data was observed. Finite element analysis(FEA) combined with the estimated physical properties was used to reproduce the force-displacement relationship of an IPMC actuator. Results from the FEA agreed well with the measure data. The proposed models might be used for modeling of IPMC actuators with complicated shapes and boundary conditions.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.3-8
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• 2001

This study is an investigation for the ADS optimum design by using FEA. We write out program which express ADS perfectly and reduce the required time for correcting of model to the minimum in solution and manufacture result. We complete algorithm which can plan optimum forming of model by feedback error information in CAE. Then we correct model by feedback date obtaining in solution process, repeat course following stress solution again and do modeling rachet wheel for optimum forming. That is our aim. In rachet wheel, greatest equivalence stress originates in key groove corner and KS standard is proved the design for security.

• Structural Engineering and Mechanics
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• 제52권4호
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• pp.815-827
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• 2014

Buckling optimization of laminated composite plates is significant as they fail because of buckling under in-plane compressive loading. The plate is usually modeled without cutout so that the buckling strength is found analytically using classical laminate plate theory (CLPT). However in real world applications, the composite plates are modeled with cutouts for getting them assembled and to offer the provisions like windows, doors and control system. Finite element analysis (FEA) is used to analyze the buckling strength of the plate with cutouts and it leads to high computational cost when the plate is optimized. In this article, a genetic algorithm based optimization technique is used to optimize the composite plate with cutout. The computational time is highly reduced by replacing FEA with artificial neural network (ANN). The effectiveness of the proposed method is explored with two numerical examples.

• 소성∙가공
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• 제10권2호
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• pp.91-100
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• 2001

A sectional FEA program is developed lot analyzing forming processes of sandwich sheets, which are intensively used recently as a lightweight material of an automobile body. The aluminum sandwich sheet consists of two aluminum skins and a polyprophylen core in between. The aluminum sandwich sheet is dominantly effected by the bending effects in small radius of curvature, so that an appropriate description of bending effects is required to analyze the forming processes. For the evaluation of bending effects, the bending equivalent forces are calculated from the bending moment computed using the curvature of the tool and are added to the membrane stretch forces. To verify the validity of the developed program the sectional FEA results in stretch/draw forming Processes of a square cup and draw forming Processes of an outer hood panel were compared with the measurements.

• Structural Engineering and Mechanics
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• 제60권5호
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• pp.851-873
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• 2016

Helidecks are vital structures that act as a last exit in an emergency. They transport people and goods to and from ships and offshore plants. When designing the structure of a helideck, it is necessary to comply with loading conditions and design parameters specified in existing professional design standards and regulations. In the present study, finite element analysis (FEA) was conducted with regard to a steel helideck mounted on the upper deck of a ship considering the emergency landing of the helicopter. The superstructure and substructure were designed, and the influence of various design parameters was analyzed on the basis of the FEA results.

• 한국공작기계학회논문집
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• 제11권3호
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• pp.45-50
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• 2002

This study is an investigation far the Am optimum design using FEA. We write out program which express ADS perfectly and reduce the required time far correcting of model to the minion in solution md manufacture result. We complete algorithm which can plan optimum forming of model by feedback error information in CAE. Then we contract model by feedbback date obtaining in solution process, repeat course following stress solution again iud do modeling rachet wheel for optimum forming. That is our aim. In cachet wheel, greatest equivalence strss originates in key groove comer and KS standard is proved the design far security.