보강판의 압축최종강도 설계식에 관한 비교연구

백점기,김도형 釜山大學校生産技術硏究所 1997 生産技術硏究所論文集 Vol.53 No.-

본 연구에서는 1축 압축력을 받는 보강판의 최종강도에 관한 각종 설계식의 계산정도를 비교 조사한다. 이를 위해 보강판의 압축최종강도 추정을 목적으로 널리 사용되고 있는 11개의 간이설계식을 조사하였다. 또한 보강판의 압축최종강도에 관한 각종 실험적 및 수치적 연구결과를 수집하여 이들 결과와 간이설계식에 의한 계산 결과를 비교 검토 하였다. 연구결과 기존의 간이설계식에 의한 최종강도 계산치는 서로 큰 차이를 보여주고 있었으며, 그 주된 이유는 1) 각종 발생가능한 붕괴모드, 2) 판재의 유효폭, 3) 초기결함 및 4) 보강재와 판재간의 회전속도를 엄밀하게 고려하지 않은데서 비롯된 것으로 분석되었다. A benchmark study is carried out on eleven existing formulations available to predict the ultimate strength of longitudinally stiffened panels under uniaxial compression. For this purpose, existing experimental data and numerical results related to the ultimate compressive strength of stiffened panels are first collected. Comparison of these experimental data / numerical results with the simplified solutions by the candidate methods is then performed. The formulations of effective width used to calculate the effective section properties of the stiffened panel within those formulations, after occurrence of buckling of plating between stiffeners, are also compared. Based on the calculated results, it is seen that there can be significant differences between the various estimates for ultimate strength based on the different formulations. Af potential reasons for the differences, the roles of four aspects, namely the collapse mode(s) involved, the effective width of plating, initial imperfections and rotational restraints due to stiffening are studied.

침수시 산적화물선 파형 횡격벽 붕괴강도에 대한 이론적·수치적 연구

백점기,김성근 釜山大學校生産技術硏究所 1998 生産技術硏究所論文集 Vol.54 No.-

본 논문에서는 침수시 산적화물선 파형 횡격벽의 붕괴강도에 미치는 주변구조의 영향에 대해서 조사한다. 저자들은 파형 횡격벽의 붕괴강도를 계산하기 위한 비선형 전용 유한요소 프로그램을 개발하였으며, 간단한 수치입력만으로 파형격벽 유한요소 모델링이 자동적으로 프로그램내에서 수행되고 사용자는 스툴과 Shedder plates, 갑판 및 이중저와 같은 주변구조를 선택적으로 포함시킬 수 있다. 수치해석 예로서는 실제 Capesize급 산적화물선에 적용하여 파형격벽과 주변구조간의 다양한 경계조건하에서 붕괴강도 특성을 분석하였으며, 그 결과를 기준의 간이설계식과 비교·검토하였다. This paper investigates the influence of influence of adjoining structures on the collapse strength of bulk carrier corrugated bulkheads subject to accidental flooding. A special purpose nonlinear finite element program suitable for direct calculations of strength is developed as part of the study. In the program, the adjoining structures such as lower and upper stools, shedder plates, double bottom and deck structures, are included as options in the automated finite element structural modeling of the corrugated bulkhead. To illustrate application, a hypothetical Capesize bulk carrier bulkhead is analyzed in several different ways to investigate the variation in its ultimate strength and stiffness for different end conditions of the bulkhead. A comparison of the finite element based ultimate strength against predictions based on simplified design formulae is also made.

보강판의 트리핑에 관한 연구

백점기,이원호 釜山大學校生産技術硏究所 1997 生産技術硏究所論文集 Vol.52 No.-

본 연구의 목적은 보강재의 트리핑의 특성을 수치적으로 조사하고 보강재웨브의 국부좌굴강도를 예측하기 위한 설계식의 정도를 검증하는데 있다. 또한 비선형 유한요소법을 이용하여 보강재의 트리핑과 보강재간 패널의 국부좌굴의 상관효과 및 판과 보강재의 접합선에서 탄소성 회전구속의 영향등을 조사하는 것이다. 기존의 유한요소법은 구조물의 비선형해석을 수행함에 있어서 상당한 컴퓨터계산을 요하지만, 본 연구에서는 보강판의 비선형거동을 보다 효율적으로 계산하기 위하여 간이화된 비선형유한요소법을 적용하였다. 압축력을 받는 flat-bar형 보강재가 붙은 보강판에 대하여 탄소성대변형 유한요소해석을 판과 보강재웨브의 치수를 변화시켜 가면서 시리즈해석을 수행하여, 그 결과를 바탕으로 flat-bar형 보강재의 트리핑에 대한 기본적인 조사를 수행하였다. 또한, 본 연구에서는 보강재웨브의 임계 좌굴강도를 예측하기 위한 2개의 설계식 즉, IACS설계식과 Paik등이 개발한 간이식을 이용한 이론해와 유한요소해석 결과를 비교함으로써 그 정도를 검증하였다. The twin aims of the present study are to numerically investigate the characteristics of tripping failure of flat-bar stiffened panels subject to uniaxial compressive loads and also to study the accuracy of two available design formulations. A special purpose nonlinear finite element method capable of efficiently analyzing the elasto-plastic large deformation behavior of stiffened panels is developed and used in the study. A benefit of the application of the nonlinear finite element method is that it makes possible a rigorous accounting of the interacting effects of stiffener tripping and plating collapse and also the inclusion of the influence of elasto-plastic rotational restraints at the plate-stiffener intersection prior to and during failure. A parametric series of elasto-plastic large deformation analyses for stiffened panels with flat-bar type of stiffeners under uniaxial compressive loads are carried out varying member proportions and structural parameters. Based on the computed results, a basic investigation of tripping behavior of flat-bars is made, and the accuracy of design formulations is studied.

[논문]Ship Collisions and Grounding: A State-of-The-Art Review

Jeom Kee PaiK 釜山大學校生産技術硏究所 2004 生産技術硏究所論文集 Vol.63 No.-

This article presents the state-of-the-art review results on ship collisions and grounding which are based on the activities of the 2003 ISSC (International Ship and Offshore Structures Congress) Cornmittee V.3 chaired by the first author. It is concemed with structural arrangements on ships and floating structures with regard to their integrity and adequacy in the events of collisions and grounding, taking into account the probabilistic and physical nature of such accidents. Consideration is also given to the effectiveness of structural arrangements for reducing or avoiding pollution due to leakage, and to residual strength of damaged structures.

Advanced method for the development of an empirical model to predict time-dependent corrosion wastage

Paik, Jeom Kee,Kim, Do Kyun Elsevier 2012 Corrosion science Vol.63 No.-

Test database of the mechanical properties of mild, high-tensile and stainless steel and aluminium alloy associated with cold temperatures and strain rates

Paik, Jeom Kee,Kim, Ki Jong,Lee, Jong Hwan,Jung, Bo Gyeong,Kim, Sang Jin Informa UK (Taylor Francis) 2017 SHIPS AND OFFSHORE STRUCTURES Vol.12 No.suppl1

<P>In structural analysis and design, it is essential to define the material properties associated with the targeted structural systems. When harsh environmental or operational conditions are of primary concern, the mechanical properties of materials must be quantified by considering the effects of the conditions. The aim of this study is to develop a new test database on the mechanical properties of materials for marine applications, such as mild steel, high-tensile steel, aluminium alloy 5083-O and stainless steel 304L, focusing on the effects of cold temperatures and strain rates. Discussion of the new test database refers to extant test databases where available. Moreover, test coefficients that may be useful in the existing constitutive equations for the materials are suggested and the details of the test database are documented.</P>

Analysis of the Elastic Large Deflection Behavior for Metal Plates under Nonuniformly Distributed Lateral Pressure with In-Plane Loads

Paik, Jeom Kee,Park, Ju Hye,Kim, Bong Ju Hindawi Limited 2012 Journal of applied mathematics (JAM) Vol.2012 No.-

<P>The Galerkin method is applied to analyze the elastic large deflection behavior of metal plates subject to a combination of in-plane loads such as biaxial loads, edge shear and biaxial inplane bending moments, and uniformly or nonuniformly distributed lateral pressure loads. The motive of the present study was initiated by the fact that metal plates of ships and ship-shaped offshore structures at sea are often subjected to non-uniformly distributed lateral pressure loads arising from cargo or water pressure, together with inplane axial loads or inplane bending moments, but the current practice of the maritime industry usually applies some simplified design methods assuming that the non-uniform pressure distribution in the plates can be replaced by an equivalence of uniform pressure distribution. Applied examples are presented, demonstrating that the current plate design methods of the maritime industry may be inappropriate when the non-uniformity of lateral pressure loads becomes more significant.</P>

A Probabilistic Corrosion Rate Estimation Model for Longitudinal Strength Members of Bulk Carriers

Paik, Jeom-Kee,Kim, Sung-Kyu,Lee, Sang-Kon,Park, Young-Eel The Society of Naval Architects of Korea 1998 Journal of ship and ocean technology Vol.2 No.1

Many bulk carrier losses have been reported of late, and one of the possible causes of such casualties is thought to be the structural failure of aging hulls in rough weather. Clearly, in such cases, vessels that start out belong adequate somehow become marginal later in life. Fatigue and corrosion related potential problems may be the most important factors affecting such age related vessel damage. With respect to fatigue, extensive studies have been done worldwide both experimentally and theoretically, and the results have been applied to some extent. However, in the case of corrosion effects, additional research is still needed to better understand, clarify and address the various strength uncertainties and their effects on structural behavior. This paper develops a probabilistic corrosion rate estimation model for the longitudinal strength members of bulk carriers. The model is based on available statistical data for corrosion of existing bulk carriers. The corrosion data collected are documented for future use.

Advanced Idealized Structural Units Considering Excessive Tension-Deformation Effects

Paik, Jeom-Kee The Society of Naval Architects of Korea 1995 Journal of hydrospace technology Vol.1 No.1

In this paper, three kinds of the existing idealized structural units, namely the idealized beam-column units the idealized unstiffened plate unit and the idealized stiffened plate unit are expanded to deal with the excessive tension-deformation effects. A simplified mechanical model far the stress-strain relationship of steel members under tensile load is suggested. The 1/3-scale hull model for a leander class frigate under sagging moment tested by Dow is analyzed, and it is shown that the excessive tension-deformation is a significant factor affecting the progressive collapse behavior, particularly in the post-collapse range.

Mechanical properties of friction stir welded aluminum alloys 5083 and 5383

Paik, Jeom-Kee The Society of Naval Architects of Korea 2009 International Journal of Naval Architecture and Oc Vol.1 No.1

The use of high-strength aluminum alloys is increasing in shipbuilding industry, particularly for the design and construction of war ships, littoral surface craft and combat ships, and fast passenger ships. While various welding methods are used today to fabricate aluminum ship structures, namely gas metallic arc welding (GMAW), laser welding and friction stir welding (FSW), FSW technology has been recognized to have many advantages for the construction of aluminum structures, as it is a low-cost welding process. In the present study, mechanical properties of friction stir welded aluminum alloys are examined experimentally. Tensile testing is undertaken on dog-bone type test specimen for aluminum alloys 5083 and 5383. The test specimen includes friction stir welded material between identical alloys and also dissimilar alloys, as well as unwelded (base) alloys. Mechanical properties of fusion welded aluminum alloys are also tested and compared with those of friction stir welded alloys. The insights developed from the present study are documented together with details of the test database. Part of the present study was obtained from the Ship Structure Committee project SR-1454 (Paik, 2009), jointly funded by its member agencies.