• 대한기계학회논문집A
• /
• 제30권4호
• /
• pp.379-386
• /
• 2006

The hyper-elastic material has been used gradually and its range was extended all over the industry. The performance prediction of hyper-elastic material was required not only experimental methods but also numerical methods. In this study, we presented the process how to use numerical method for hyper-elastic material and applied it to seat-ring of butterfly valve. The finite element analysis was executed to evaluate the mechanical characteristics of hyper-elastic material. And the optimum model considered conditions and features. According to that model, the load conditions were obtained by using CFD analysis.

• Steel and Composite Structures
• /
• 제20권6호
• /
• pp.1173-1182
• /
• 2016

The objective of this work was to evaluate the ductile cracked structures with bonded composite patch used in probabilistic elastic plastic fracture mechanics subjected to tensile load. The finite element method is used to analyze the stress intensity factors for elastic case, the effect of cracks and the thickness of the patch ($e_r$) are presented for calculating the stress intensity factors. For elastic-plastic the Monte Carlo method is used to predict the distribution function of the mechanical response. According to the obtained results, we note that the stress variations are important factors influencing on the distribution function of (J/Je).

• 대한기계학회논문집
• /
• 제14권5호
• /
• pp.1129-1137
• /
• 1990

본 연구에서 사용된 유한요소 방정식은 국부 질점좌표계(natural convected coordinate system)를 이용하여 변형을 묘사하는 대변형을 고려한 탄소성 증분 수식을 사용하였고, 국부 질점 좌표계를 사용함으로써 변형도 성분이나 구성 방정식의 성분들 에 대한 좌표 변환 과정을 생략할 수 있다. 재료는 수직 이방성으로 가정하였다.

• 전산구조공학
• /
• 제6권2호
• /
• pp.103-114
• /
• 1993

유전적분형 물성방정식에 근거한 선형 점탄성문제의 효율적인 수치해석을 위해서 새로운 유한요소해법을 공식화하였다. 각 시간구간에서 변수변화를 선형적으로 가정하고 유전적분의 계산을 매우 효율적으로 처리하였다. 그 결과 과거의 해석법에 비하여 수치정확도 및 경제성에서 큰 향상을 얻었다.

• 한국정밀공학회지
• /
• 제14권2호
• /
• pp.145-151
• /
• 1997

In this paper, we discuss the cathode ray tube(CRT) glass bulb stress and sagging recovery by the contact band pressure using finite element method. We analyzed the band pressure and stress using contact element method between band and bulb before and after banding process which was conducted to decrease the stress concentration using finite element method, and calculated sagging recovery. The analysis results were confirmed by experiments using strain gauge and sagging recovery test apparatus.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 1999년도 제29회 춘계학술대회
• /
• pp.297-302
• /
• 1999

Finite element analysis is peformed about the crack propagation in half-space due to sliding contact. The analysis is based on linear elastic fracture mechanics and stress intensity factor concept. The crack location is fixed and the friction coefficient between asperity and half-space is varied to analyze the effect of surface friction on stress Intensity factor for horizontal crack. The crack propagation direction is predicted based on the maximum range of shear and tensile stress intensity factor.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1994년도 박판성형기술의 진보
• /
• pp.191-198
• /
• 1994

A practical example of the axisymmetric deep drawing process is simulated by the elastic-plastic finite element analysis using updated Lagrangian approach considering the large deformation. An approach is suggested to solve the problem of the ductile fracture that may encounter during the deep drawing process. The result can be applied to the design of the die for the axisymmetric deep drawing.

• Structural Engineering and Mechanics
• /
• 제15권5호
• /
• pp.579-608
• /
• 2003

This paper deals with adaptive finite element analysis of linearly elastic structures using different error estimators based on flux projection (or best guess stress values) and residual methods. Presentations are given on a typical h-type adaptive analysis, a mesh refinement scheme and the coupling of adaptive finite element analysis with automatic mesh generation. Details about different error estimators are provided and their performance, reliability and convergence are studied using six node quadratic triangular elements. Several examples are presented to demonstrate the reliability of different error estimators.

• Nuclear Engineering and Technology
• /
• 제42권6호
• /
• pp.680-689
• /
• 2010

The crack-tip stress fields and fracture mechanics assessment parameters for a surface crack, such as the elastic stress intensity factor or the elastic-plastic J-integral, can be affected significantly by the adjacent cracks. Such a crack interaction effect due to multiple cracks can alter the fracture mechanics assessment parameters significantly. There are many factors to be considered, for instance the relative distance between adjacent cracks, the crack shape, and the loading condition, to quantify the crack interaction effect on the fracture mechanics assessment parameters. Thus, the current assessment codes on crack interaction effects (crack combination rules), including ASME Sec. XI, BS7910, British Energy R6 and API 579-1/ASME FFS-1, provide different rules for combining multiple surface cracks into a single surface crack. The present paper investigates crack interaction effects by evaluating the elastic stress intensity factor and the elastic-plastic J-integral of adjacent in-plane surface cracks in a plate through detailed 3-dimensional elastic and elastic-plastic finite element analyses. The effects on the fracture mechanics assessment parameters of the geometric parameters, the relative distance between two cracks, and the crack shape are investigated systematically. As for the loading condition, an axial tension is considered. Based on the finite element results, the acceptability of the crack combination rules provided in the existing guidance was investigated, and the relevant recommendations on a crack interaction for in-plane surface cracks are discussed. The present results can be used to develop more concrete guidance on crack interaction effects for crack shape characterization to evaluate the integrity of defective components.

• Structural Engineering and Mechanics
• /
• 제62권5호
• /
• pp.519-535
• /
• 2017

In this article, static analysis of a magneto-electro-elastic (MEE) beam subjected to various thermal loading and boundary conditions has been investigated. Influence of pyroeffects (pyroelectric and pyromagnetic) on the direct quantities (displacements and the potentials) of the MEE beam under different boundary conditions is studied. The finite element (FE) formulation of the MEE beam is developed using the total potential energy principle and the constitutive equations of the MEE material taking into account the coupling between elastic, electric, magnetic and thermal properties. Using the Maxwell electrostatic and electromagnetic relations, variation of stresses, displacements, electric and magnetic potentials along the length of the MEE beam are investigated. Effect of volume fractions, aspect ratio and boundary conditions on the direct quantities in thermal environment has been determined. The present investigation may be useful in design and analysis of magnetoelectroelastic smart structures and sensor applications.