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October 2012 www.sname.org/sname/mt ( abstracts )SNAME Paper Abstracts A Comparison of Methods for Computing the Added Resistance BY S. A. JONCQUEZ, P. ANDERSEN, AND H.B. BINGHAM PUBLISHED IN THE JUNE JOURNAL OF SHIP RESEARCHSecond-order forces and moments are derived for the pressure integration and the momentum conservation methods. ey are implemented in the time-domain boundary element code AEGIR. Both Neumann-Kelvin and double-body ow linearization are used. Good agreement is found between AEGIRs results and experimental data for three kinds of hull. Fatigue Life Assessment and Life- time Management of Aluminum Ships Using Life-Cycle Optimization BY KIHYON KWON AND DAN M. FRANGOPOL PUBLISHED IN THE JUNE JOURNAL OF SHIP RESEARCHe development of aluminum ship struc- tures has been promoted in the context of the rapid evolution of high-speed and light- weight vessels. Under the repeated and/or fluctuating application of stresses during voyages, fatigue damage of structural ship members is accumulated. For this reason, fatigue reliability analysis has to be conducted for assessing and predicting lifetime perfor- mance of aluminum ships. is assessment oers the opportunity to optimally perform the lifetime ship structural management plan- ning. To allocate limited nancial resources required to balance the lifetime reliability of ship structural details and the life-cycle cost, single- or multi-objective optimization can be used. e multi-objective optimization prob- lem has several competing objectives such as: (a) minimizing the lifecycle maintenance cost, (b) maximizing the fatigue reliability of details with welded attachments, and (c) min- imizing the fatigue damage. e S-N (stress vs. number of cycles) approach and available sea loading information are used to evalu- ate the time-dependent fatigue reliability. In this paper, the estimated fatigue reliability is incorporated into a lifecycle cost optimization problem to nd the optimal inspection and repair interventions. e proposed approach is illustrated on an aluminum ship detail. Ship Springing Response in Finite Water Depth BY JELENA VIDIC-PERUNOVIC PUBLISHED IN THE JUNE JOURNAL OF SHIP RESEARCHThe influence of water depth on the verti- cal wave induced bending moment acting on a hull has been studied. e deep-water second-order nonlinear hydroelastic strip theory, which is based on the relative motion concept, has been generalized to account for a nite water depth. Results for an analyti- cal beam and for a tanker ship are presented and discussed. Short-term load predictions that account for a range of dierent sea states are given for a tanker ship. As seen from the present study, the eect of intermediate water depth may be a signicant factor in calcula- tions of ship springing response. Welding Distortion Analysis of Hull Blocks using Equivalent Load Method Based on Inherent Strain BY YONG TAI KIM, TAE JUN KIM, TAE YOON PARK, AND CHANG DOO JANG PUBLISHED IN THE JUNE JOURNAL OF SHIP RESEARCHWelding deformation reduces the dimen- sional accuracy of ship hull blocks and decreases productivity due to the correction work. Prediction and minimizing of weld- ing distortion at the design stage will lead to higher quality as well as higher productivity. Therefore, the development of an effec- tive method to predict accurately the weld distortion of hull blocks considering the fab- rication sequences is required. In the case of hull block welding work in shipyards, the welding process of curved stiffened plates has large amounts of workload. is paper suggests an ecient method for predicting the welding deformation of stiened curved plates based on the inherent strain theory combined with the nite element method. e equivalent load was determined by inte- grating inherent strain components which are calculated in the vicinity of heat aected zone using the highest temperature and the degree of restraint. e welding distortion of curved stiened panels under equivalent load is calculated by elastic analysis and compared with that by intensive elasto-plastic nite ele- ment analysis. It is veried that the proposed method has high eciency and accuracy. The Impact of Contracts on Ship Design Preparation BY KENNETH W. FISHER PUBLISHED IN THE MAY JOURNAL OF SHIP PRODUCTION AND DESIGN The implementation of vessel designs is usually achieved through contracts for ship construction or conversion. Accordingly, the design process and the design organi- zations product have to anticipate and take into account the constraints and require- ments of the contracts that control the use of the design, as well as the contract that initiates the design process. This paper addresses the most common contractual factors that have to be considered during preparation of ship designs. A Numerical Study of a Two-Di- mensional Stepped Planing Surface BY WILLIAM R. GARLAND AND KEVIN J. MAKI PUBLISHED IN THE MAY JOURNAL OF SHIP PRODUCTION AND DESIGN In this paper, the performance of a stepped planing hull is analyzed through numerical simulation of the fully nonlinear ow under a two-dimensional body. The height and location of the step are systematically var- ied to investigate the resulting free-surface elevation, pressure prole on the body, and Editors note: The following are abstracts of papers recently presented at SNAME events and/or published in SNAME publications. The paper s can be found at www.sname.org/ sname/mt/featuredabstracts View current and previous issues of Journal of Ship Production and Design and Journal of Ship Research at http://www.sname.org/SNAME/Pubs/Journals1/