• 대한기계학회논문집A
• /
• 제33권4호
• /
• pp.396-400
• /
• 2009

The demand of JIB crane to handle a container or a bulk in a vessel is increasingly because of the growth of the scale of trade through the sea. This deck crane such as JIB crane is required the weight reduction design because it is installed in the deck of a vessel due to the environment regulation. In this study first we carry out the structural analysis of JIB with respect to the luffing angle of it to calculate the maximum equivalent stress of JIB, and next the optimum design for the weight reduction design of JIB. The thickness in a cross section of JIB is adopted as the design variable, the weight of JIB as the objective function, and the von mises stress as the constraint condition for the optimum design of JIB using the ANSYS 10.0.

• 대한기계학회논문집A
• /
• 제23권11호
• /
• pp.2096-2101
• /
• 1999

This paper presents the effect of shape of external corrosion in pipeline on failure prediction by using numerical simulation. The numerical study for the pipeline failure analysis is based on the FEM(Finite Element Method) with an elastic-plastic and large-deformation analysis. The predicted failure stress assessed for the simulated corrosion defects having different corroded shapes along the pipeline axis are compared with those by methods specified in ANSl/ASME B31G code and a modified B31G code.

• 한국안전학회지
• /
• 제26권2호
• /
• pp.1-5
• /
• 2011

In order to evaluate fatigue endurance for an ultra-light weight inline skate frame, FEM analysis was performed. Tensile properties and a S-N curve were determined through tensile and fatigue tests on a modified Al-7075+$S_c$ alloy. The yield and ultimate tensile strengths were 553.3 MPa and 705.5 MPa, respectively. The fatigue endurance limit of this alloy was 201.2 MPa. For evaluating the fatigue endurance of the inline skate frame, the S-N data were compared with the stress analysis results through FEM analysis of the frame. The maximum Von-Mises stress of the frame was determined 106 MPa through FEM analysis of the frame, assuming that the rider weight is 75 Kg. Conclusively, on the basis of fatigue limit, the inline skate frame has a safety factor of approximately 2.0.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 2001년도 제34회 추계학술대회 개최
• /
• pp.331-340
• /
• 2001

Elastic-Plasitc Finite element analysis is peformed about the TiN coated medium. The normal contact is simulated by a rigid asperity pressing the surface of an elastic-plastic half-surface. The case of a surface film stiffer than the substrate is considered, and general solutions for the subsurface stress and deformation fields are presented for several coating thickness. Additionally, the critical normal loads for deformation in the substrate and coating fracture are calculated when the yield of TiN film follows the Maximum Principal Stress Theory and Von Mises Theory. The results can be subsumed in failure maps for TiN thin film on steel.

• 한국자동차공학회논문집
• /
• 제23권2호
• /
• pp.208-213
• /
• 2015

In this study, two models due to the configuration of caliper cylinder among the parts of automotive brake system are studied by structural and fatigue analysis. As the maximum equivalent stress at model 2 becomes 1.5 times lower than model 1, model 2 can endure load higher than model 1. In case of fatigue damage analysis on model 1 and 2, model 1 has the damage area more than model 2. Fatigue damage at model 1 happen more than model 2. These study results can be effectively utilized with the design on caliper cylinder by anticipating prevention against its damage and investigating durability.

• 한국전산구조공학회논문집
• /
• 제12권4호
• /
• pp.681-690
• /
• 1999

본 논문에서는 요소를 사용하지 않은 수치해석기법인 무요소법 중에서 다중해상도(multi-resolution)특성이 내재되어 있는 Reproducing Kernel Particle Method (RKPM)의 이중스케일 분해기법을 사용하여 RKPM의 형상함수를 상단성분과 하단성분으로 분리하고 이를 3차원 선형탄성해석과정에 적용하여 von Mises 응력장의 상·하단성분을 유도하였다. 유도된 응력장의 상단성분을 이용하여 후처리과정을 거치지 않고도 응력의 고변화도 부위를 손쉽게 파악할 수 있는 기법을 개발하였으며 이를 이용한 효율적인 적응적 세분화기법의 적용가능성을 연구하였다. 대표적인 2차원 및 3차원 응력집중 문제에 적용하여 응력집중부위를 파악하고 간단한 적응적 세분화과정에 따른 절점추가를 통하여 해의 정도 향상을 파악해 본 결과, 본 연구에서 개발된 기법이 응력집중부위를 정확히 판정할 수 있었으며 효율적인 적응적 세분화기법의 유용한 도구로서 활용될 수 있음을 검증하였다.

• Communications for Statistical Applications and Methods
• /
• 제30권2호
• /
• pp.191-213
• /
• 2023

Unit distributions are frequently used in probability theory and statistics to depict meaningful variables having values between zero and one. Using convenient transformation, the unit inverse exponentiated weibull (UIEW) distribution, which is equally useful for modelling data on the unit interval, is proposed in this study. Quantile function, moments, incomplete moments, uncertainty measures, stochastic ordering, and stress-strength reliability are among the statistical properties provided for this distribution. To estimate the parameters associated to the recommended distribution, well-known estimation techniques including maximum likelihood, maximum product of spacings, least squares, weighted least squares, Cramer von Mises, Anderson-Darling, and Bayesian are utilised. Using simulated data, we compare how well the various estimators perform. According to the simulated outputs, the maximum product of spacing estimates has lower values of accuracy measures than alternative estimates in majority of situations. For two real datasets, the proposed model outperforms the beta, Kumaraswamy, unit Gompartz, unit Lomax and complementary unit weibull distributions based on various comparative indicators.

• Structural Engineering and Mechanics
• /
• 제88권3호
• /
• pp.201-208
• /
• 2023

In this work, the effect of the correction fibers direction on the efficiency of repairing damaged composite plates was highlighted. The composite plates studied in this work consist of eight layers of graphite/epoxy, while the patch used in this repair consists of four layers of the same type. The results obtained in this work, whether with regard to the experimental or analytical side, showed that the fibers orientation affects the repair efficiency, so the closer the angle of fibers inclination is to the tensile strength direction, the performance of the composite material is ideal. Hence, we conclude that the composite materials with longitudinal fibers (Parallel to tensile strength) is the most powerful and efficient material in performance.

• Coupled systems mechanics
• /
• 제8권3호
• /
• pp.273-287
• /
• 2019

Elastoplastic analysis of an annular disc, being fully constrained on its outer rim and interacting with a purely elastic inclusion perfectly bonded with its inner rim, is conducted to study its plastic deformation and residual stress under thermal cycles. The system is termed the composite disc. Quasi-static plane-strain deformation is assumed, and the von Mises yield criterion with or without the Ludwik hardening rule is adopted in our finite element calculations. Effects of multiple material properties simultaneously being temperature dependent on the plastic behavior of the composite disc are considered. Residual stress is analyzed from a complete loading and unloading cycle. Results are discussed for various inclusion radii. It is found that when temperature dependent material properties are considered, the maximum residual stress may be greater than the maximum stress inside the disc at the temperature-loaded state due to lower temperature having larger yield stress. Temperature independent material properties overestimate stresses inside materials, as well as the elastic irreversible temperature and plastic collapse temperature.

• 대한치과보철학회지
• /
• 제46권4호
• /
• pp.325-334
• /
• 2008

연구목적: 본 연구의 목적은 하악골 충격 시 구강보호장치의 재료적 성질에 따른 악골과 두부에 미치는 영향을 조사하는 것이다. 연구재료 및 방법: 경질과 연질의 서로 다른 성질을 가지는 구강보호장치를 두부외상이나 뇌질환 병력이 없고 정상교합과 자연치열을 가진 한국 성인 여성에게 제작하고, CT를 이용하여 악골과 두부의 3차원 유한요소모델을 제작하였다. 이 유한요소모델은 두개골, 뇌, 상악골, 하악골, 관절원판, 치아와 구강보호장치를 포함하며 407,825개의 elements와 82,138개의 node로 구성되어 있다. 0.1초동안 하악골 3부위에서 800 N으로 사선 방향의 힘을 가하였을 때 두 가지 재료에 따른 상악 치아, 상악골 및 두개골의 응력분포를 평가하였고 동일한 조건하에서 두 재료에 따른 뇌의 변위량을 비교하였다. 결과: 이 연구를 통해 다음과 같은 결과를 얻었다. 1. 상악치아에서 유효응력 값을 비교하였을 때 연질의 구강보호장치가 경질의 구강보호 장치보다 응력값이 유의차 있게 작게 나타났다 (P < .05). 2. 상악골과 두개골에서 응력값을 비교하였을 때 연질의 구강보호장치가 경질의 구강보호장치보다 응력값이 유의차 있게 작게 나타났다 (P < .05). 3. 경질의 구강보호장치에서 연질의 구강보호장치보다 상악치아 및 상악골과 두개골에 더 많은 응력집중부위를 보였다. 4. 경질의 구강보호장치와 연질의 구강보호장치 간에 하악 충격 시 뇌의 변위량은 연질의 구강보호장치 쪽이 크게 나타났으나 유의차는 없었다. 본 연구를 통하여 악골 충격 시에 경질 및 연질 구강보호장치가 상악골과 두개골에서의 응력분포에 미치는 양상을 알 수 있었지만, 아직도 이의 상관관계를 모두 파악하기에는 불충분한 점이 많으리라 생각되며, 스포츠 외상에 따른 구강보호장치의 재료에 따른 상관관계에 대하여 보다 더 많은 연구가 필요할 것으로 사료된다.