• Journal of Advanced Marine Engineering and Technology
• /
• 제37권1호
• /
• pp.59-65
• /
• 2013

본 논문은 헬리컬 풍력터빈을 이용한 풍력터빈 나무의 구조적 안정성을 검토하는데 목적이 있다. 복합재료를 적용하여 헬리컬 로터 블레이드를 설계하였으며, 유한요소 해석을 통하여 안정성을 검토하였다. 또한 4개의 헬리컬 로터를 지지하고 있는 풍력터빈 나무에 대하여 풍압, 로터의 회전 그리고 자중을 고려한 구조해석을 수행하여 설계 타당성을 검토 하였다.

• Journal of Advanced Marine Engineering and Technology
• /
• 제30권5호
• /
• pp.562-571
• /
• 2006

Finite element analysis is performed to evaluate structural reliability of an automotive pedal arm under conditions of the stiffness, the load and the endurance test specifications. Results of the analysis shows that the pedal arm is safe enough under the tests. A topology optimization is numerically implemented, overall shape of the pedal arm being verified to be reasonable, A design concept to insert holes in the arm is established, which may be used to reduce its weight.

• 대한조선학회논문집
• /
• 제43권2호
• /
• pp.246-257
• /
• 2006

In the ship building industry, the generation of a structural analysis model, that is, a finite element model of a hull structure, has been manually performed by a designer and thus has required lots of time as compared with that of a mechanical part, because of many constraints, the complexity, and the huge size of the hull structure. To make this task automatic, a generation method of the structural analysis model is proposed through the reconstruction of the topological information of a hull structural model in this study. The applicability of the proposed method is demonstrated by applying it to the generation of the structural analysis model of a deadweight 300,000ton VLCC(Very Large Crude oil Carrier).

• Journal of Ship and Ocean Technology
• /
• 제10권4호
• /
• pp.24-33
• /
• 2006

So far, the generation of a hull structural analysis model, that is, a finite element model of a hull structure, has been manually performed by a designer using design experience, and thus has required lots of time because of many constraints, the complexity, and the huge size of the hull structure. To make this task automatic, an algorithm for generating the hull structural analysis model is developed using the seam information of the hull structure. A generating system of the hull structural analysis model is implemented based on the developed algorithm. The applicability of the developed algorithm is demonstrated by applying it to the generation of the global and hold structural analysis models of a deadweight 300,000 ton VLCC (Very Large Crude oil Carrier). The results show that the developed algorithm can quickly generate these models at the initial design stage.

• 정보화연구
• /
• 제10권1호
• /
• pp.71-77
• /
• 2013

XML 스키마 매칭은 두 스키마의 엘리먼트들 간의 의미적인 유사성을 찾는 작업이다. XML 스키마 매칭은 스키마 통합, 데이터 통합, 데이터 웨어하우징, 데이터 변환, P2P 데이터 관리, 시멘틱 웹 등과 같은 응용체계에서 중요한 역할을 한다. 본 논문은 룰과 구조적 속성에 기반한 XML 엘리먼트 매칭 알고리즘을 제안한다. 제안한 알고리즘에서는 먼저 XML 문서의 구조적 속성을 이용하여 엘리먼트들이 unique와 non-unique로 분류되며, 이후 룰에 따라 엘리먼트의 매칭여부를 결정한다. 제안 알고리즘의 효과성을 보이기 위해 인터넷에 공개된 XML 스키마를 이용하여 성능을 평가하였다. 또한 제안 알고리즘은 문서의 구조적 속성을 이용함으로써 사용자 주관성을 배제하고 객관성을 보장하며 특정 유형이 아닌 다양한 형태의 XML에 적용이 가능하다.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제10권4호
• /
• pp.439-449
• /
• 2018

In this paper, multi-objective optimization of a multi-bubble pressure cabin in the underwater glider with Blended-Wing-Body (BWB) is carried out using Kriging and the Non-dominated Sorting Genetic Algorithm (NSGA-II). Two objective functions are considered: buoyancy-weight ratio and internal volume. Multi-bubble pressure cabin has a strong compressive capacity, and makes full use of the fuselage space. Parametric modeling of the multi-bubble pressure cabin structure is automatic generated using UG secondary development. Finite Element Analysis (FEA) is employed to study the structural performance using the commercial software ANSYS. The weight of the primary structure is determined from the volume of the Finite Element Structure (FES). The stress limit is taken into account as the constraint condition. Finally, Technique for Ordering Preferences by Similarity to Ideal Solution (TOPSIS) method is used to find some trade-off optimum design points from all non-dominated optimum design points represented by the Pareto fronts. The best solution is compared with the initial design results to prove the efficiency and applicability of this optimization method.

• Journal of Welding and Joining
• /
• 제25권4호
• /
• pp.72-78
• /
• 2007

Aluminized steel sheet is a material with excellent heat resistance, thermal reflection and corrosion resistance. It has wide applications, owing to its low cost and excellent performance, in the petrochemical industry, electric power and other energy conversion systems, etc and has attracted the attention of many investigators. But the welding of aluminized steel sheet has a problem of decreasing tensile-shear strength, caused by mixed Al in the weld. This study investigated behavior of Al and its structural properties to resolve this problem. Several analysis equipment(SEM, EDX, EPMA) were used to investigate Al element in the weld. Also microhardness tester and TEM equipment were used to find the intermetallic compound. As a result of this study, Al-rich zones existed in the weld and Fe-Al intermetallic compounds were found in these zones. At the same time, the weldability of aluminized stainless steel sheet was investigated and compared with that of aluminized steel sheet. Although there is a difference between the base metal of the low carbon steel and stainless steel, it is interpreted that a behavior of Al element in the weld is similar.

• Structural Engineering and Mechanics
• /
• 제81권6호
• /
• pp.781-790
• /
• 2022

The present paper describes a general procedure of the structural safety assessment for the independent type C tank of LNG bunkering ship. This strength assessment procedure consists of two main scheme, global Finite Element Analysis (FEA) model primarily for hull structure assessment and detailed LNG Tank structures FEA model including the cylindrical tank itself and saddle-support structures. Two kinds of mechanism are used, fixed and slides constraints in fore and rear of the saddle-support structures that result in a variation of the reaction forces. Finite Element (FE) analyses have been performed and verified by the strength acceptance criteria to evaluate the safety adequacy of yielding and buckling of the hull and supporting structures. The detail of FE model for an LNG type C tank and its saddle supports was made, which includes the structural members such as cylindrical tank shell, ring stiffeners, swash bulkhead, and saddle supports. Subsequently, the FE buckling analysis of the Type C tank has been performed under external pressure following International Gas Containment (IGC) code requirements. Meanwhile, the assessment is also performed for yielding and buckling strength evaluation of the cylindrical LNG tank according to the PD 5500 unfired fusion welded pressure vessels code. Finally, a complete procedure for assessing the structural strength of 500 CBM LNG cargo tank, saddle support and hull structures have been provided.

• Advances in aircraft and spacecraft science
• /
• 제4권3호
• /
• pp.219-235
• /
• 2017

The large container ships and fast patrol boats are complex marine structures. Therefore, their global mechanical behaviour has long been modeled mostly by refined beam theories. Important issues of cross section warping and bending-torsion coupling have been addressed by introducing special functions in these theories with inherent assumptions and thus compromising their robustness. The 3D solid Finite Element (FE) models, on the other hand, are accurate enough but pose high computational cost. In this work, different marine vessel structures have been analysed using the well-known Carrera Unified Formulation (CUF). According to CUF, the governing equations (and consequently the finite element arrays) are written in terms of fundamental nuclei that do not depend on the problem characteristics and the approximation order. Thus, refined models can be developed in an automatic manner. In the present work, a particular class of 1D CUF models that was initially devised for the analysis of aircraft structures has been employed for the analysis of marine structures. This class, which was called Component-Wise (CW), allows one to model complex 3D features, such as inclined hull walls, floors and girders in the form of components. Realistic ship geometries were used to demonstrate the efficacy of the CUF approach. With the same level of accuracy achieved, 1D CUF beam elements require far less number of Degrees of Freedom (DoFs) compared to a 3D solid FE solution.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제5권3호
• /
• pp.431-453
• /
• 2013

The principal purpose of this paper is to present a novel two phases rational scenario applied in constructing an offshore monopod platform; in which the two phases are the all-ground horizontal construction phase and the post-construction phase. Concerning the all-ground construction phase, a brief investigation of its different stages, i.e., pre-fabrication, fabrication, pre-assembling, positioning, assembling, and surface finishing is introduced. The important practical aspects of such construction phase are investigated without going into the nitty-gritty of the details involved therein. Concerning the post-construction phase, a clear investigation of its sequential stages, i.e., lifting, moving and up-righting is introduced. A finite element model (FEM) of the monopod platform is created to perform the structural analysis necessary to decide the suspension points/devices and the handling scenario during the various stages of the post-construction phase on a rational wise. Such structural analysis is performed within the framework of the three dimensional quasi-static modeling and analysis aiming at simulating the realistic handling condition, and hence introducing a reliable physical interpretation of the numerical results. For the whole effort to be demonstrated efficiently, the results obtained are analyzed, the conclusions are presented, and few related recommendations are suggested.