Steel fenders are increasingly used for ship-impact resistance structures in the design of navigable bridges. As an important approach to investigating this anti-impact structure effectiveness to reduce influences of ...Steel fenders are increasingly used for ship-impact resistance structures in the design of navigable bridges. As an important approach to investigating this anti-impact structure effectiveness to reduce influences of vessel impact, simulation analyses are still not perfect yet. So this paper is intended to discuss several issues related to ship collision simulations, including steel constitutive relationship, connections between steel box and pile cap, contacts definition and friction consideration, and the determination of impact waterlines and angles. Consequently based on two examples of ship-steel fender-bridge structure systems, some conclusions about effectiveness and design of fenders to reduce ship impact are drawn.展开更多
In this paper,the multi-body coupled dynamic characteristics of a semisubmersible platform and an HYSY 229 barge were investigated.First,coupled hydrodynamic analysis of the HYSY 229 barge and the semisubmersible plat...In this paper,the multi-body coupled dynamic characteristics of a semisubmersible platform and an HYSY 229 barge were investigated.First,coupled hydrodynamic analysis of the HYSY 229 barge and the semisubmersible platform was performed.Relevant hydrodynamic parameters were obtained using the retardation function method of three-dimensional frequency-domain potential flow theory.The results of the hydrodynamic analysis were highly consistent with the test findings,verifying the accuracy of the multifloating hydrodynamic coupling analysis,and key hydrodynamic parameters were solved for different water depths and the coupling effect.According to the obtained results,the hydrodynamic influence was the largest in shallow waters when the coupling effect was considered.Furthermore,the coupled motion equation combined with viscous damping,fender system,and mooring system was established,and the hydrodynamics,floating body motion,and dynamic response of the fender system were analyzed.Motion analysis revealed good agreement among the surge,sway,and yaw motions of the two floating bodies.However,when the wave period reached 10 s,the motion of the two floating bodies showed severe shock,and a relative motion was also observed.Therefore,excessive constraints should be added between the two floating bodies during construction to ensure construction safety.The numerical analysis and model test results of the semisubmersible platform and HYSY 229 barge at a water depth of 42 m and sea conditions of 0°,45°,and 90° were in good agreement,and the error was less than 5%.The maximum movement of the HYSY 229 barge reached 2.61 m in the sway direction,whereas that of the semisubmersible platform was 2.11 m.During construction,excessive constraints should be added between the two floating bodies to limit their relative movement and ensure construction safety.展开更多
In this paper,a numerical investigation of a float-over installation for an offshore platform is presented to verify the feasibility of the actual installation.The hydrodynamic performance of a T-barge is investigated...In this paper,a numerical investigation of a float-over installation for an offshore platform is presented to verify the feasibility of the actual installation.The hydrodynamic performance of a T-barge is investigated in the frequency domain,and the coupled motions are analyzed in the time domain.We then compare with those of the model test and determine that the response amplitude operator and the time series agree quite well.The barge exhibits favorable hydrodynamic behavior in the considered sea state,and the equipment loads are allowable.Themooring systemand sway fender forces are within the permissible range.Based on these results,we can verify that the actual installation of the offshore platform is feasible.We accurately simulated many important factors and effectively reduced the risk associated with the offshore installation,which is of great importance.As such,we demonstrate that the numerical simulation of the float-over installation for offshore platforms has practical engineering significance.展开更多
Automotive lightweight and safety performance come into play as key technologies to promote competiveness, and average applied amount of automotive plastics has become a significant sign for automotive industrial deve...Automotive lightweight and safety performance come into play as key technologies to promote competiveness, and average applied amount of automotive plastics has become a significant sign for automotive industrial development level of a country.Various performances of a vehicle with plastic automotive fenders are analyzed in the paper.The research is emphasized on sinking-resistance and pedestrian protection performance of the plastic fenders by studying plastics characteristics and simulation analysis.It offers references for engineering design in which both automotive lightweight and safety performance are achieved and well balanced.展开更多
Textiles are among the most fragile artefacts in the world. They are difficult to preserve even in the best circumstances. Herein, we studied an artefacts fabric of a special nature in terms of usage. Despite the mult...Textiles are among the most fragile artefacts in the world. They are difficult to preserve even in the best circumstances. Herein, we studied an artefacts fabric of a special nature in terms of usage. Despite the multiple applications of textiles, the piece understudy is one of the unique pieces that the ancient Egyptian used as fenders for King Khufu’s first solar boat, the second-largest discovery in Egypt history. The boat was discovered inside a limestone pit. It was disassembled and arranged in several layers. Four pillows of wrapped fabric were found in the first layer, which w<span style="font-family:Verdana;">as</span><span style="font-family:Verdana;"> used as boat fenders. This use is a great discovery of the role of textiles in the manufacture of ancient boats. Thus, we conducted tests and analytical studies of those fenders using scanning electron microscopy (SEM) and an optical microscope to identify the type and nature of fibers, spinning method, and aspects of damage. Both energy-dispersive X-ray (EDX) analysis and infrared analysis (FT-IR) were employed to explore the sample’s elemental content and study the functional groups of the fabric. These analytical processes were useful in carrying out the restoration and preservation work necessary for the artefact under study.</span>展开更多
Eric Johnson不仅是位出众的吉他手,他还是一名很有品位的艺术鉴赏家,从他指间滑出的音符充满了甜蜜的爱意与美丽的畅想!
提起Eric Johnson,我想大家再熟悉不过了,他毕生都在追求完美的吉他旋律与和声,他那带有魔法般的手指落... Eric Johnson不仅是位出众的吉他手,他还是一名很有品位的艺术鉴赏家,从他指间滑出的音符充满了甜蜜的爱意与美丽的畅想!
提起Eric Johnson,我想大家再熟悉不过了,他毕生都在追求完美的吉他旋律与和声,他那带有魔法般的手指落在他的吉他上简直就像行云流水一样,一切那么的自然、和谐.如此这般的吉他大师怎能缺少一把适合自己的"御用吉他"?……展开更多
In the designing of the flexible fender pile, M-method is usually adopted. But M-method is usable only in the case that the value of the force (moment M and shear force Q) exerted on the pile above the soil is known. ...In the designing of the flexible fender pile, M-method is usually adopted. But M-method is usable only in the case that the value of the force (moment M and shear force Q) exerted on the pile above the soil is known. In practical cases, only the percussive energy of the ship can be found, while the exact value of the percussive force cannot be computed directly. In this paper, a method is introduced which can be used to calculate the inner force of flexible fender piles by a computer in these cases. First, according to the known docking dynamic energy of a ship, the absorbed energy can be found from the deformation of the pile and the rubber fender respectively, at the same time the value of the force acting on the fender piles and the reaction of fenders can be calculated. Then the inner force and displacement of the fender piles can also be calculated further by M-method. The whole computing process is realized by a computer program and the results obtained are reasonable. In this paper, the computation, the iteration method and the computer program are all expounded in detail. This method can be applied to the design of fender piles and type selection of rubber fenders in practical projects.展开更多
This paper analyzes fender selection process in berth design and focuses on the case of a rigid berth with rubber cone fenders.Fender types and performance comparison methods are studied along with current numerical m...This paper analyzes fender selection process in berth design and focuses on the case of a rigid berth with rubber cone fenders.Fender types and performance comparison methods are studied along with current numerical models.Berth design methods are analyzed with a focus on berthing energy calculation and fender selection.A new approach to determine the required fender capacity is suggested.A finite elements rubber cone model is tested and used in simulations of angular side berthing.Results show that the energy absorbed by the fender can be much higher than what can be calculated with the current berth design method.A new form for the expression of the energy that must be absorbed by the fender during angular berthing impact is suggested.展开更多
文摘Steel fenders are increasingly used for ship-impact resistance structures in the design of navigable bridges. As an important approach to investigating this anti-impact structure effectiveness to reduce influences of vessel impact, simulation analyses are still not perfect yet. So this paper is intended to discuss several issues related to ship collision simulations, including steel constitutive relationship, connections between steel box and pile cap, contacts definition and friction consideration, and the determination of impact waterlines and angles. Consequently based on two examples of ship-steel fender-bridge structure systems, some conclusions about effectiveness and design of fenders to reduce ship impact are drawn.
基金the National Natural Science Foundation of China(No.U20A20328).
文摘In this paper,the multi-body coupled dynamic characteristics of a semisubmersible platform and an HYSY 229 barge were investigated.First,coupled hydrodynamic analysis of the HYSY 229 barge and the semisubmersible platform was performed.Relevant hydrodynamic parameters were obtained using the retardation function method of three-dimensional frequency-domain potential flow theory.The results of the hydrodynamic analysis were highly consistent with the test findings,verifying the accuracy of the multifloating hydrodynamic coupling analysis,and key hydrodynamic parameters were solved for different water depths and the coupling effect.According to the obtained results,the hydrodynamic influence was the largest in shallow waters when the coupling effect was considered.Furthermore,the coupled motion equation combined with viscous damping,fender system,and mooring system was established,and the hydrodynamics,floating body motion,and dynamic response of the fender system were analyzed.Motion analysis revealed good agreement among the surge,sway,and yaw motions of the two floating bodies.However,when the wave period reached 10 s,the motion of the two floating bodies showed severe shock,and a relative motion was also observed.Therefore,excessive constraints should be added between the two floating bodies during construction to ensure construction safety.The numerical analysis and model test results of the semisubmersible platform and HYSY 229 barge at a water depth of 42 m and sea conditions of 0°,45°,and 90° were in good agreement,and the error was less than 5%.The maximum movement of the HYSY 229 barge reached 2.61 m in the sway direction,whereas that of the semisubmersible platform was 2.11 m.During construction,excessive constraints should be added between the two floating bodies to limit their relative movement and ensure construction safety.
基金supported by Marine Engineering Equipment Scientific Research Project of Ministry of Industry and Information Technology of PRC and the Application of float-over installation simulation in Wangchang Project of CNOOC Technology ProjectThe Fundamental Research Funds for the Central Universities(HEUCF170102)
文摘In this paper,a numerical investigation of a float-over installation for an offshore platform is presented to verify the feasibility of the actual installation.The hydrodynamic performance of a T-barge is investigated in the frequency domain,and the coupled motions are analyzed in the time domain.We then compare with those of the model test and determine that the response amplitude operator and the time series agree quite well.The barge exhibits favorable hydrodynamic behavior in the considered sea state,and the equipment loads are allowable.Themooring systemand sway fender forces are within the permissible range.Based on these results,we can verify that the actual installation of the offshore platform is feasible.We accurately simulated many important factors and effectively reduced the risk associated with the offshore installation,which is of great importance.As such,we demonstrate that the numerical simulation of the float-over installation for offshore platforms has practical engineering significance.
基金Supporting Program of the"Twelfth Five-year Plan"for Sci & Tech Research of China(No. 2011BAG03B02No.2011BAG03B06)
文摘Automotive lightweight and safety performance come into play as key technologies to promote competiveness, and average applied amount of automotive plastics has become a significant sign for automotive industrial development level of a country.Various performances of a vehicle with plastic automotive fenders are analyzed in the paper.The research is emphasized on sinking-resistance and pedestrian protection performance of the plastic fenders by studying plastics characteristics and simulation analysis.It offers references for engineering design in which both automotive lightweight and safety performance are achieved and well balanced.
文摘Textiles are among the most fragile artefacts in the world. They are difficult to preserve even in the best circumstances. Herein, we studied an artefacts fabric of a special nature in terms of usage. Despite the multiple applications of textiles, the piece understudy is one of the unique pieces that the ancient Egyptian used as fenders for King Khufu’s first solar boat, the second-largest discovery in Egypt history. The boat was discovered inside a limestone pit. It was disassembled and arranged in several layers. Four pillows of wrapped fabric were found in the first layer, which w<span style="font-family:Verdana;">as</span><span style="font-family:Verdana;"> used as boat fenders. This use is a great discovery of the role of textiles in the manufacture of ancient boats. Thus, we conducted tests and analytical studies of those fenders using scanning electron microscopy (SEM) and an optical microscope to identify the type and nature of fibers, spinning method, and aspects of damage. Both energy-dispersive X-ray (EDX) analysis and infrared analysis (FT-IR) were employed to explore the sample’s elemental content and study the functional groups of the fabric. These analytical processes were useful in carrying out the restoration and preservation work necessary for the artefact under study.</span>
文摘 Eric Johnson不仅是位出众的吉他手,他还是一名很有品位的艺术鉴赏家,从他指间滑出的音符充满了甜蜜的爱意与美丽的畅想!
提起Eric Johnson,我想大家再熟悉不过了,他毕生都在追求完美的吉他旋律与和声,他那带有魔法般的手指落在他的吉他上简直就像行云流水一样,一切那么的自然、和谐.如此这般的吉他大师怎能缺少一把适合自己的"御用吉他"?……
文摘In the designing of the flexible fender pile, M-method is usually adopted. But M-method is usable only in the case that the value of the force (moment M and shear force Q) exerted on the pile above the soil is known. In practical cases, only the percussive energy of the ship can be found, while the exact value of the percussive force cannot be computed directly. In this paper, a method is introduced which can be used to calculate the inner force of flexible fender piles by a computer in these cases. First, according to the known docking dynamic energy of a ship, the absorbed energy can be found from the deformation of the pile and the rubber fender respectively, at the same time the value of the force acting on the fender piles and the reaction of fenders can be calculated. Then the inner force and displacement of the fender piles can also be calculated further by M-method. The whole computing process is realized by a computer program and the results obtained are reasonable. In this paper, the computation, the iteration method and the computer program are all expounded in detail. This method can be applied to the design of fender piles and type selection of rubber fenders in practical projects.
基金the National Natural Science Foundation of China(Nos.41172251 and 41330633)
文摘This paper analyzes fender selection process in berth design and focuses on the case of a rigid berth with rubber cone fenders.Fender types and performance comparison methods are studied along with current numerical models.Berth design methods are analyzed with a focus on berthing energy calculation and fender selection.A new approach to determine the required fender capacity is suggested.A finite elements rubber cone model is tested and used in simulations of angular side berthing.Results show that the energy absorbed by the fender can be much higher than what can be calculated with the current berth design method.A new form for the expression of the energy that must be absorbed by the fender during angular berthing impact is suggested.
