The Experts below are selected from a list of 72 Experts worldwide ranked by ideXlab platform
Šime Malenica - One of the best experts on this subject based on the ideXlab platform.
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hydroelastic response of 19 000 teu class ultra large container ship with novel mobile deckhouse for maximizing cargo capacity
International Journal of Naval Architecture and Ocean Engineering, 2017Co-Authors: HONG IL IM, Nikola Vladimir, Šime MalenicaAbstract:Abstract This paper is related to structural design evaluation of 19,000 TEU ultra large container ship, dealing with hydroelastic response, i.e. springing and whipping. It illustrates application of direct calculation tools and methodologies to both fatigue and ultimate strength assessment, simultaneously taking into account ship motions and her elastic deformations. Methodology for springing and whipping assessment within so called WhiSp notation is elaborated in details, and in order to evaluate innovative container ship design with increased loading capacity, a series of independent hydroelastic computations for container ship with mobile deckhouse and conventional one are performed with the same calculation setup. Fully coupled 3D FEM – 3D BEM model is applied, while the ultimate bending capacity of hull girder is determined by means of MARS software. Beside comparative analysis of representative quantities for considered ships, relative influence of hydroelasticity on ship response is addressed.
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Hydroelastic response of 19,000 TEU class ultra large container ship with novel mobile deckhouse for maximizing cargo capacity
International Journal of Naval Architecture and Ocean Engineering, 2017Co-Authors: HONG IL IM, Nikola Vladimir, Šime Malenica, Dae-seung ChoAbstract:This paper is related to structural design evaluation of 19,000 TEU ultra large container ship, dealing with hydroelastic response, i.e. springing and whipping. It illustrates application of direct calculation tools and methodologies to both fatigue and ultimate strength assessment, simultaneously taking into account ship motions and her elastic deformations. Methodology for springing and whipping assessment within so called WhiSp notation is elaborated in details, and in order to evaluate innovative container ship design with increased loading capacity, a series of independent hydroelastic computations for container ship with mobile deckhouse and conventional one are performed with the same calculation setup. Fully coupled 3D FEM – 3D BEM model is applied, while the ultimate bending capacity of hull girder is determined by means of MARS software. Beside comparative analysis of representative quantities for considered ships, relative influence of hydroelasticity on ship response is addressed.
HONG IL IM - One of the best experts on this subject based on the ideXlab platform.
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hydroelastic response of 19 000 teu class ultra large container ship with novel mobile deckhouse for maximizing cargo capacity
International Journal of Naval Architecture and Ocean Engineering, 2017Co-Authors: HONG IL IM, Nikola Vladimir, Šime MalenicaAbstract:Abstract This paper is related to structural design evaluation of 19,000 TEU ultra large container ship, dealing with hydroelastic response, i.e. springing and whipping. It illustrates application of direct calculation tools and methodologies to both fatigue and ultimate strength assessment, simultaneously taking into account ship motions and her elastic deformations. Methodology for springing and whipping assessment within so called WhiSp notation is elaborated in details, and in order to evaluate innovative container ship design with increased loading capacity, a series of independent hydroelastic computations for container ship with mobile deckhouse and conventional one are performed with the same calculation setup. Fully coupled 3D FEM – 3D BEM model is applied, while the ultimate bending capacity of hull girder is determined by means of MARS software. Beside comparative analysis of representative quantities for considered ships, relative influence of hydroelasticity on ship response is addressed.
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Hydroelastic response of 19,000 TEU class ultra large container ship with novel mobile deckhouse for maximizing cargo capacity
International Journal of Naval Architecture and Ocean Engineering, 2017Co-Authors: HONG IL IM, Nikola Vladimir, Šime Malenica, Dae-seung ChoAbstract:This paper is related to structural design evaluation of 19,000 TEU ultra large container ship, dealing with hydroelastic response, i.e. springing and whipping. It illustrates application of direct calculation tools and methodologies to both fatigue and ultimate strength assessment, simultaneously taking into account ship motions and her elastic deformations. Methodology for springing and whipping assessment within so called WhiSp notation is elaborated in details, and in order to evaluate innovative container ship design with increased loading capacity, a series of independent hydroelastic computations for container ship with mobile deckhouse and conventional one are performed with the same calculation setup. Fully coupled 3D FEM – 3D BEM model is applied, while the ultimate bending capacity of hull girder is determined by means of MARS software. Beside comparative analysis of representative quantities for considered ships, relative influence of hydroelasticity on ship response is addressed.
Dae-seung Cho - One of the best experts on this subject based on the ideXlab platform.
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Hydroelastic response of 19,000 TEU class ultra large container ship with novel mobile deckhouse for maximizing cargo capacity
International Journal of Naval Architecture and Ocean Engineering, 2017Co-Authors: HONG IL IM, Nikola Vladimir, Šime Malenica, Dae-seung ChoAbstract:This paper is related to structural design evaluation of 19,000 TEU ultra large container ship, dealing with hydroelastic response, i.e. springing and whipping. It illustrates application of direct calculation tools and methodologies to both fatigue and ultimate strength assessment, simultaneously taking into account ship motions and her elastic deformations. Methodology for springing and whipping assessment within so called WhiSp notation is elaborated in details, and in order to evaluate innovative container ship design with increased loading capacity, a series of independent hydroelastic computations for container ship with mobile deckhouse and conventional one are performed with the same calculation setup. Fully coupled 3D FEM – 3D BEM model is applied, while the ultimate bending capacity of hull girder is determined by means of MARS software. Beside comparative analysis of representative quantities for considered ships, relative influence of hydroelasticity on ship response is addressed.
Nikola Vladimir - One of the best experts on this subject based on the ideXlab platform.
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hydroelastic response of 19 000 teu class ultra large container ship with novel mobile deckhouse for maximizing cargo capacity
International Journal of Naval Architecture and Ocean Engineering, 2017Co-Authors: HONG IL IM, Nikola Vladimir, Šime MalenicaAbstract:Abstract This paper is related to structural design evaluation of 19,000 TEU ultra large container ship, dealing with hydroelastic response, i.e. springing and whipping. It illustrates application of direct calculation tools and methodologies to both fatigue and ultimate strength assessment, simultaneously taking into account ship motions and her elastic deformations. Methodology for springing and whipping assessment within so called WhiSp notation is elaborated in details, and in order to evaluate innovative container ship design with increased loading capacity, a series of independent hydroelastic computations for container ship with mobile deckhouse and conventional one are performed with the same calculation setup. Fully coupled 3D FEM – 3D BEM model is applied, while the ultimate bending capacity of hull girder is determined by means of MARS software. Beside comparative analysis of representative quantities for considered ships, relative influence of hydroelasticity on ship response is addressed.
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Hydroelastic response of 19,000 TEU class ultra large container ship with novel mobile deckhouse for maximizing cargo capacity
International Journal of Naval Architecture and Ocean Engineering, 2017Co-Authors: HONG IL IM, Nikola Vladimir, Šime Malenica, Dae-seung ChoAbstract:This paper is related to structural design evaluation of 19,000 TEU ultra large container ship, dealing with hydroelastic response, i.e. springing and whipping. It illustrates application of direct calculation tools and methodologies to both fatigue and ultimate strength assessment, simultaneously taking into account ship motions and her elastic deformations. Methodology for springing and whipping assessment within so called WhiSp notation is elaborated in details, and in order to evaluate innovative container ship design with increased loading capacity, a series of independent hydroelastic computations for container ship with mobile deckhouse and conventional one are performed with the same calculation setup. Fully coupled 3D FEM – 3D BEM model is applied, while the ultimate bending capacity of hull girder is determined by means of MARS software. Beside comparative analysis of representative quantities for considered ships, relative influence of hydroelasticity on ship response is addressed.
Alaeddin Arpaci - One of the best experts on this subject based on the ideXlab platform.
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Free and forced vibration analyses of ship structures using the finite element method
Journal of Marine Science and Technology, 2013Co-Authors: Adil Yucel, Alaeddin ArpaciAbstract:With increases in ship size and speed, shipboard vibration becomes a significant concern in the design and construction of vessels. Excessive ship vibration is to be avoided for passenger comfort and crew habitability. In addition to the undesired effects on humans, excessive ship vibration may result in the fatigue failure of local structural members or malfunctioning of machinery and equipment. The propeller induces fluctuating pressure on the surface of the hull, which induces vibration in the hull structure. These pressure pulses acting on the ship hull surface above the propeller are the predominant factor for vibrations of ship structures are taken as excitation forces for forced vibration analysis. Ship structures are complex and may be analyzed after idealization of the structure. Several simplifying assumptions are made in the finite element idealization of the hull structure. In this study, a three-dimensional finite element model representing the entire ship hull, including the deckhouse and machinery propulsion system, has been developed using solid modeling software for local and global vibration analyses. Vibration analyses have been conducted under two conditions: free–free (dry) and in-water (wet). The wet analysis has been implemented using acoustic elements. The total damping associated with overall ship hull structure vibration has been considered as a combination of the several damping components. As a result of the global ship free vibration analysis, global natural frequencies and mode shapes have been determined. Moreover, the responses of local ship structures have been determined as a result of the propeller-induced forced vibration analysis.
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Finite element analysis of global ship vibrations
İTÜDERGİSİ d, 2011Co-Authors: Adil Yucel, Alaeddin ArpaciAbstract:Gemi boyut ve hızlarındaki büyük artış nedeniyle gemi titreşimleri, gemi tasarımı ve yapımında büyük önem taşır hale gelmiştir. Gemi tasarımındaki son gelişmeler, daha büyük stroklu ve daha güçlü dizel motorların kullanıldığı, daha büyük boyutlarda, daha hafif, daha esnek teknelerin yapılmasına yol açmıştır. Deniz taşımacılığında artan talebi karşılamak için ihtiyaç duyulan bu yapıların daha esnek olması titreşim problemlerini de beraberinde getirmektedir. Aşırı gemi titreşimleri, yolcu konforunu ve mürettebat yaşamını önemli ölçüde etkilemektedir. İnsan üzerindeki istenmeyen etkilerinin yanında, aşırı gemi titreşimleri, makina ve cihazlarda bozulmalara neden olmakla birlikte yapısal elemanlarda da yorulma hasarına neden olmaktadır. Gemilerde titreşim problemlerinin çözüm kaynağının erken safhadaki tasarım aşamasında belirlenmesinin önemi ve sonradan yapılacak olan düzeltmelerin çok ağır maliyetler gerektirdiği bilinmektedir. Tasarım aşamasında yapılacak olan bir takım basit çalışmalarla ileride ortaya çıkacak büyük titreşim problemlerinin önlenmesi sağlanabilmektedir. Gemi titreşimleri bakımından, yerel titreşim problemlerinin yanı sıra geminin bütününde ortaya çıkan global titreşimler de gemi emniyeti açısından büyük önem taşımaktadır. Bu çalışma kapsamında tüm gemi, sonlu eleman analizi yöntemiyle global olarak serbest – serbest (susuz) ve su içinde olmak üzere serbest titreşim açısından incelenerek, tüm geminin doğal frekanslarının ve mod şekillerinin belirlenmesine çalışılmıştır. Bu şekilde geminin hangi frekanslarda rezonansa gireceği ve nasıl davranışlar sergileyeceği belirlenmiştir. Ayrıca sonlu eleman yöntemiyle hesaplanan doğal frekans değerleri, klas kuruluşları tarafından kullanılan ampirik formüllerle hesaplanan doğal frekans değerleri ile karşılaştırılarak, sonlu eleman analizinin gerekliliği üzerinde durulmuştur. Anahtar Kelimeler: Gemi titreşimi, sonlu eleman analizi, modal analiz.With the increase of ship size and speed, shipboard vibration becomes a great concern in the design and construction of the vessels. The flexibility of vessels which are needed to meet the demand in sea transportation, causes ship vibrations. In addition to undesired effects on passenger comfort and crew habitability, excessive ship vibration may result in the fatigue failure of local structural members or malfunction of machinery and equipment. The importance of the solutions of vibration problems which are addressed at the earliest design stage and the great cost in later correction efforts are clear. It is possible to avoid great vibration problems by means of simple studies in the early design stage. Besides local vibrations, global vibrations are of great importance to ship safety. In this study, global ship hull free vibration problems are studied under two conditions which are free - free (dry) and in water (wet) using finite element analysis. Excessive ship vibration is of great importance to the performance of precious navigation equipments and usually cause them to malfunction. In the condition of resonance which the propulsion frequency collides with the global natural frequency of the ship and during manoeuvres, the amplitude of oscillations on local structures exceeds certain limits. Concept design is where the vibration avoidance process must begin. It is clear that if the vibration problems, repeatedly identified by experience as the most important, are addressed at the earliest design stage, ultimately serious problems, involving great cost in correction efforts, may be avoided. The focus is on planning for vibration early at the concept design stage, where there has been no development of details. If as much as possible can be done in concept design with the simple tools and rules of thumb available at that level, it will help to avoid major vibration problems. The major potential problems may often be present in the crude concept design definition. Just identifying and addressing those potential problems in terms of the minimal technology available at the concept design stage is considered very important to the success of ship design. The design and construction of a ship free of excessive vibration continues to be a major concern and, as such, it is prudent to investigate, through analysis, the likelihood of vibration problems early in the design stage. Vibration analysis is aimed at the confirmation of the many design considerations associated with stern configuration, main propulsion machinery, propeller/shafting system and location and configuration of major structural assemblies. The ship hull structure includes the outer shell plating and all internal members, which collectively provide the necessary strength to satisfactorily perform the design functions in the expected sea environment. The hull structure responds as a free - free beam (both ends free) when subjected to dynamic loads. The vibration induced by the propulsion system is a common source of ship vibration. The vibration from this source manifests itself in several ways. Dynamic forces from the shafting system are transmitted to the hull through shaft bearings. The propeller induces fluctuating pressures on the surface of the hull, which induces vibration in the hull structure. The main and auxiliary engines can directly cause vibrations through dynamic forces transmitted through their supports and foundations. The response to this forcing can cause the vibration of the hull girder, deckhouse, deck and other structures, local structures and equipment. When attempting to determine the source of vibration, it is necessary to establish the frequency of excitation and to relate the frequency of excitation to the shaft rotational frequency by determining the number of oscillations per shaft revolution. Ship structures are complex and may be analyzed after idealization of the structure. Several simplifying assumptions are made in the finite element idealization of the hull structure. The modeling requirements are that all significant structural sections are to be captured and deflection/ velocity/acceleration are to be sufficiently predicted. A three-dimensional finite element model representing the entire ship hull, including the deckhouse and machinery propulsion system, needs to be developed for vibration analysis. If a global model exists from any previous tasks such as stress analysis, it needs to be conditioned for vibration analysis. In the section which the global vibrations are studied, a three dimensional ship model is prepared using a solid modelling software and the natural frequencies and mode shapes are determined using finite element analysis. In this way, the resonance frequencies and behaviour of the ship are determined. Keywords: Ship vibration, finite element analysis, modal analysis
