International Journal of Maritime Technology最新文献_第2页

Dynamic Analyses of Jacket Type Offshore Platforms against Progressive Collapse Considering Pile-Soil-Structure Interaction 考虑桩土结构相互作用的导管架式海洋平台抗渐进倒塌动力分析

International Journal of Maritime Technology Pub Date : 2019-07-01 DOI: 10.29252/ijmt.12.31

Hossein Gholami, B. Asgarian, F. H. Rezvani

{"title":"Dynamic Analyses of Jacket Type Offshore Platforms against Progressive Collapse Considering Pile-Soil-Structure Interaction","authors":"Hossein Gholami, B. Asgarian, F. H. Rezvani","doi":"10.29252/ijmt.12.31","DOIUrl":"https://doi.org/10.29252/ijmt.12.31","url":null,"abstract":"Article History: Received: 19 Jun. 2019 Accepted: 17 Sep. 2019 This research aims to present a practical framework to study the structural response of a jacket type offshore platforms subjected to a sudden member removal considering the pile-soil-structure interaction. To this end, a series of nonlinear dynamic analyses are performed, and the progressive collapse resistance of the generic structure is determined. Consequently, the members prone to failure are detected. As a case study, the application of the proposed framework to control the capability of these type of structures for the prevention of progressive collapse occurrence are investigated. In the model structure, some legs and vertical braces in different locations are eliminated, and the effect of each damage case on the performance of the structure is investigated while the environmental wind and wave loads are imposed to the platform. The simulation results demonstrated that although the jacket structure can sustain the loss of primary members safely, it is susceptible to failure progression while a leg and the connected brace are eliminated simultaneously. The safety margin, in this case, is about 20% only. In addition, it was revealed that in the case in which a leg and the connected brace are eliminated, progressive collapse resistance is about a third in comparison with the case of a leg damaged only.","PeriodicalId":34429,"journal":{"name":"International Journal of Maritime Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47467858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Assessment of Offshore Pipeline Reliability against Lateral Buckling 海上管道抗侧向屈曲可靠性评估

International Journal of Maritime Technology Pub Date : 2019-07-01 DOI: 10.29252/ijmt.12.41

Mohammad Hossein Sharifi, A. Taheri, Mohammad Bagher Faraji Pool

{"title":"Assessment of Offshore Pipeline Reliability against Lateral Buckling","authors":"Mohammad Hossein Sharifi, A. Taheri, Mohammad Bagher Faraji Pool","doi":"10.29252/ijmt.12.41","DOIUrl":"https://doi.org/10.29252/ijmt.12.41","url":null,"abstract":"Subsea pipelines are used to transport gas and oil around the world. Oil is transported through subsea pipelines at high pressure and high temperature to smooth the way for its flow and to prevent its solidification. The present paper assesses a pipeline located in South Pars Gas Field against lateral buckling. As more and more pipelines operate at higher temperatures (over 100°C), the likelihood of lateral buckling becomes more relevant. The uncertainty in the lateral buckling parameters of the pipeline is a source of error in determining effective axial compressive force. Uncontrolled lateral buckling can cause excessive plastic deformation of the pipeline, which can lead to localized buckling collapse or cyclic fatigue failure during operation due to multiple heat-up and cool-down cycles, if it is not properly managed. This research reports the results of a reliability analysis to study and quantify the variations of the reliability index (β) with the main parameters involved during the lateral buckling of the subsea pipelines. Uncertainty is considered in the geometric parameters of the pipeline. The probability of failure (P f ) and the reliability index (β) can be determined by the reliability methods. The First-Order Reliability Method (FORM), the Second-Order Reliability Method (SORM) and the sampling method are the three main methods used here to determine P f and β. The results show that the pipelines, in the case of lateral buckling and corrosion, will be in safe condition for up to 30 years after construction.","PeriodicalId":34429,"journal":{"name":"International Journal of Maritime Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43749006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Seismic Analysis of an Offshore Structure in Persian Gulf Utilizing a Physical Model 利用物理模型对波斯湾近海结构进行地震分析

International Journal of Maritime Technology Pub Date : 2019-03-10 DOI: 10.29252/IJMT.11.21

F. Hosseinlou, Hamid Hokmabady, A. Mojtahedi, Samira Mohammadyzadeh

引用次数: 0

Hydrodynamic Characteristics of Inverse T-Type Floating Breakwaters 反t型浮式防波堤水动力特性研究

International Journal of Maritime Technology Pub Date : 2019-03-10 DOI: 10.29252/IJMT.11.13

Esmaeel Masoudi

{"title":"Hydrodynamic Characteristics of Inverse T-Type Floating Breakwaters","authors":"Esmaeel Masoudi","doi":"10.29252/IJMT.11.13","DOIUrl":"https://doi.org/10.29252/IJMT.11.13","url":null,"abstract":"Article History: Received: 6 Feb. 2019 Accepted: 16 Mar. 2019 Various types of floating breakwaters in different configuration and shapes are used to reduce wave height in coastal areas. The most important parameter in designing breakwaters are their shapes which determines hydrodynamic reaction to incident waves. Some cross sections are more effective and more efficient than others. In framework of numerical methods, finite element and boundary element methods are two popular and effective approaches which have been widely applied to floating body problems. In this study by using boundary element method, diffraction problem is solved for a new type of breakwater, which is called inverse T-type floating breakwater. To have a validated results, a rectangular cross section floating breakwater is analyzed and results are compared to previous researches. The final goal of this study is obtaining hydrodynamic characteristics of this new type of breakwater and comparing its response to sinusoidal waves with other conventional floating breakwaters. It is shown that in same weight, this new type of breakwater has better transmission coefficient among other conventional breakwaters and might be used as an efficient alternative.","PeriodicalId":34429,"journal":{"name":"International Journal of Maritime Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47844955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Transient Behavior of Saltwater Wedge and Mixing Zone in Head-Controlled Coastal Aquifer: Experimental Measurements and Numerical Modeling 水头控制的沿海含水层中盐水楔和混合带的瞬态特性:实验测量和数值模拟

International Journal of Maritime Technology Pub Date : 2019-03-10 DOI: 10.29252/IJMT.11.41

Abbasali Rezapour, Fazlolah Saghravani, A. Ahmadyfard, M. Rezapour

{"title":"Transient Behavior of Saltwater Wedge and Mixing Zone in Head-Controlled Coastal Aquifer: Experimental Measurements and Numerical Modeling","authors":"Abbasali Rezapour, Fazlolah Saghravani, A. Ahmadyfard, M. Rezapour","doi":"10.29252/IJMT.11.41","DOIUrl":"https://doi.org/10.29252/IJMT.11.41","url":null,"abstract":"Article History: Received: 6 Dec. 2018 Accepted: 21 Feb. 2019 Saltwater intrusion is a transient process that affects the coastal aquifers quality and hydrodynamics. The transient behavior of the saltwater wedge (SW) and mixing zone (MZ) due to the changes of the inland freshwater head was investigated through experimental and numerical approaches using image processing technique and the numerical code SUTRA. To acquire data in the transient conditions, automated algorithms were designed and employed for both methods. Numerical simulations were extended to a reference problem of field scale for further study of the transient aspect of the saltwater intrusion phenomena. The results demonstrated that the behavior of SW area is significantly similar to the behavior of SW toe length in transient conditions. Also, in the advancing case, the SW height reaches the steady state condition much sooner than the SW toe length and the SW area, while in the receding case, all the three indicators are stabilized almost simultaneously. Furthermore, the results showed that the MZ expanded at early stages of the receding and after a while condensed again gradually until it finally reaches to its original state at the beginning of the advancing case. Although local velocity of brackish water toward sea boundary in the dilute region of the MZ is more than in the dense region, the flushing and mixing process causes to increase the MZ in the receding case. Sensitivity analyzes showed that the speed of SW advancing or receding does not affect the MZ thickness in a steady state condition.","PeriodicalId":34429,"journal":{"name":"International Journal of Maritime Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43074353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Simulation and Evaluation of Network Simplex Algorithm and its Extensions for Vehicle Scheduling Problems in Ports 港口车辆调度问题的网络单纯形算法及其扩展仿真与评价

International Journal of Maritime Technology Pub Date : 2019-03-01 DOI: 10.29252/IJMT.11.1

H. Rashidi

引用次数: 4

Design of Dynamic Positioning Control System for an ROV with Unknown Dynamics Using Modified Time Delay Estimation 基于改进时延估计的未知动力学ROV动态定位控制系统设计

International Journal of Maritime Technology Pub Date : 2019-03-01 DOI: 10.29252/IJMT.11.53

Alireza Hosseinnajad, M. Loueipour

{"title":"Design of Dynamic Positioning Control System for an ROV with Unknown Dynamics Using Modified Time Delay Estimation","authors":"Alireza Hosseinnajad, M. Loueipour","doi":"10.29252/IJMT.11.53","DOIUrl":"https://doi.org/10.29252/IJMT.11.53","url":null,"abstract":"Article History: Received: 31 Oct. 2018 Accepted: 27 Feb. 2019 In this paper, a control system is designed for dynamic positioning of an ROV with unknown dynamics, subject to external disturbances using passive arm measurements. To estimate uncertain dynamics and external disturbances, a new method based on time delay estimation (TDE) is proposed. The proposed TDE, not only maintains the advantages of conventional TDE, but also eliminates its sensitivity to sensor noise and fast-varying external disturbances which in turn, results in smooth control signal. The proposed control system is considered as a nonlinear PD-type controller together with feedforward of estimated dynamics and disturbances. This structure presents good performance against uncertainties and external disturbances which is guaranteed via stability analysis presented. To evaluate the performance of proposed TDE, simulations are conducted and comparison are made with conventional TDE. Besides, the performance of the proposed control system is compared with conventional time delay controller (TDC) and PID controller to verify its performance. Simulations show high accuracy and superior performance of the proposed control system.","PeriodicalId":34429,"journal":{"name":"International Journal of Maritime Technology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42789433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Sensitivity Analysis of Pile Supported Wharves against Directional Uncertainty of Earthquakes Using Fragility Curves 基于易损性曲线的桩基码头对地震方向不确定性的敏感性分析

International Journal of Maritime Technology Pub Date : 2019-03-01 DOI: 10.29252/IJMT.11.33

M. Soltani, R. Amirabadi

{"title":"Sensitivity Analysis of Pile Supported Wharves against Directional Uncertainty of Earthquakes Using Fragility Curves","authors":"M. Soltani, R. Amirabadi","doi":"10.29252/IJMT.11.33","DOIUrl":"https://doi.org/10.29252/IJMT.11.33","url":null,"abstract":"Article History: Received: 18 Feb. 2018 Accepted: 13 Mar. 2018 This paper aims to tackle an important uncertainty which extremely affects seismic performance of wharf structures in earthquake events. According to previous studies performed for structures on land, it is shown that structures on land are highly susceptible to unknown orientation of earthquakes called as the directional uncertainty. However, for marine structures, especially pile supported wharves, research efforts are rare to assess the effect of directional uncertainty of earthquakes on structural responses. Therefore, to show this effect on seismic performance of pile supported wharves, fragility analysis is performed based on methodology suggested by Pacific Earthquake Engineering Research Center (PEER) for the modeled pile supported wharf located in Maah-shahr port as a case study. As the first phase of this methodology, nonlinear static pushover analyses are performed for randomly chosen incident angles in order to quantitatively measure damage states suggested by marine design code. After damage states are obtained, IDA analyses are conducted in the selected incident angles to obtain nonlinear structural responses which are supposed to be used for fragility analysis as inputs. Finally, once fragility curves have been developed according to the last phase of PEER methodology, the more vulnerable direction(s) of wharf from those incident angles is represented.","PeriodicalId":34429,"journal":{"name":"International Journal of Maritime Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48358782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Hydrodynamic Simulation of Oil Blowout and Response Action to Evaluate Environmental Consequences on Prawns 石油井喷对对虾环境影响的水动力学模拟及响应行为

International Journal of Maritime Technology Pub Date : 2018-07-01 DOI: 10.29252/IJMT.10.15

M. Shafieefar, Pooya Rangbar

{"title":"Hydrodynamic Simulation of Oil Blowout and Response Action to Evaluate Environmental Consequences on Prawns","authors":"M. Shafieefar, Pooya Rangbar","doi":"10.29252/IJMT.10.15","DOIUrl":"https://doi.org/10.29252/IJMT.10.15","url":null,"abstract":"Article History: Received: 23 Oct. 2017 Accepted: 12 Jul. 2018 A scenario-specific modeling of oil blowout from the Khark island pipelines in the Persian Gulf has been carried out to evaluate the environmental impact of oil spill on the local coast, seabed and prawns. Also, various scenarios for response actions have been considered. The analyses have been performed by SINTEF Oil Spill Contingency and Response (OSCAR), a 3-dimensional model system. At the first step, OSCAR as the oil spill analysis model was successfully verified in the Persian Gulf using Mina Al-Ahmadi oil spill field observed data. The oil path and predicted time resulted from the OSCAR model were in a very good agreement with the field observed data. Results related to the scenarios of oil blowout from the Khark Island pipelines indicate that the wind is the key factor for advection and spreading of oil in the area. Due to wind conditions in Khark area, the Khark South-East coast has the maximum oil contamination potential. The results show the spilled oil may extremely threat the Khark area environment and especially the local prawns due to the high concentration of hydrocarbons in the water column. The reason for high level of entrainment and dispersion of oil in the water column is the possibility of high-speed blowout from the pipeline in form of a jet. Results indicates that the response action not only may have a low efficiency to reduce the potential environmental damages on the coast, but also may increase the potential environmental hazards on the local prawns due to the utilization of chemical dispersants.","PeriodicalId":34429,"journal":{"name":"International Journal of Maritime Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44935310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A boundary element study for evaluation of the effects of the rigid baffles on liquid sloshing in rigid containers 用于评估刚性折流板对刚性容器中液体晃动影响的边界元研究

International Journal of Maritime Technology Pub Date : 2018-07-01 DOI: 10.29252/IJMT.10.45

A. Behshad, M. Shekari

{"title":"A boundary element study for evaluation of the effects of the rigid baffles on liquid sloshing in rigid containers","authors":"A. Behshad, M. Shekari","doi":"10.29252/IJMT.10.45","DOIUrl":"https://doi.org/10.29252/IJMT.10.45","url":null,"abstract":"Article History: Received: 5 Oct. 2017 Accepted: 10 Sep. 2018 In this paper, the sloshing response of liquid in a two dimensional rigid rectangular tank with rigid baffles is investigated using boundary element technique. A baffle is a supplementary structural element which supplies a kind of passive control on the effects of ground shaking. The complicated liquid domain is divided into two simple sub-domains so that the liquid velocity potential in each liquid sub-domain is specified employing Green’s theorem, and the walls and free surface boundary conditions are applied. The liquid region is modeled by internal quadrilateral boundary elements, which reduce the three-dimensional fluid problem into a two-dimensional-surface one. The validity of the present algorithm is assessed through the comparison with the accessible results for the rectangular tank without baffle and then developed to the solution of tanks with rigid baffles. Several parametric studies are performed to show the liquid sloshing effects in terms of the slosh frequencies and free surface displacement by consideration of the effects of baffle parameters such as position and dimension. From these analyses, it may be concluded that in the special case of long-period ground earthquake, the baffle device amplifies the dynamic responses of liquid tank which may be interpreted by the fact that the predominant period of the ground shaking is set at the fundamental natural sloshing periods.","PeriodicalId":34429,"journal":{"name":"International Journal of Maritime Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43675536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4