In this study,we propose a method for estimating the amount of expansion that occurs in subsea pipelines,which could be applied in the design of robust structures that transport oil and gas from offshore wells.We begi...In this study,we propose a method for estimating the amount of expansion that occurs in subsea pipelines,which could be applied in the design of robust structures that transport oil and gas from offshore wells.We begin with a literature review and general discussion of existing estimation methods and terminologies with respect to subsea pipelines.Due to the effects of high pressure and high temperature,the production of fluid from offshore wells is typically caused by physical deformation of subsea structures,e.g.,expansion and contraction during the transportation process.In severe cases,vertical and lateral buckling occurs,which causes a significant negative impact on structural safety,and which is related to on-bottom stability,free-span,structural collapse,and many other factors.In addition,these factors may affect the production rate with respect to flow assurance,wax,and hydration,to name a few.In this study,we developed a simple and efficient method for generating a reliable pipe expansion design in the early stage,which can lead to savings in both cost and computation time.As such,in this paper,we propose an applicable diagram,which we call the standard dimensionless ratio(SDR)versus virtual anchor length(LA)diagram,that utilizes an efficient procedure for estimating subsea pipeline expansion based on applied reliable scenarios.With this user guideline,offshore pipeline structural designers can reliably determine the amount of subsea pipeline expansion and the obtained results will also be useful for the installation,design,and maintenance of the subsea pipeline.展开更多
A mechanical metamaterial that has a tailorable coefficient of thermal expansion(CTE)is promising for guaranteeing the reliability of electrical and optical instruments under thermal fluctuations.Despite growing resea...A mechanical metamaterial that has a tailorable coefficient of thermal expansion(CTE)is promising for guaranteeing the reliability of electrical and optical instruments under thermal fluctuations.Despite growing research on the design and manufacturing of metamaterials with extraordinary CTEs,it remains challenging to achieve a nearly isotropic tailorable CTE while ensuring a sufficient load bearing capacity for applications,such as mechanical supporting frames.In this research,we propose a type of bi-metallic lattice whose CTE is artificially programmed from positive(75 ppm/K)to negative(−45 ppm/K),and whose equivalent modulus can be as high as 80 MPa.The bi-metallic lattice with a tailorable CTE in two orthogonal directions can be readily assembled without special modifications to construct large-scale planar structures with desired isotropic CTEs.A theoretical model that considers the actual configuration of the bi-metallic joint is developed;the model precisely captures the thermal deformations of lattice structures with varied geometries and material compositions.Guided by our theoretical design method,planar metallic structures that were manufactured using Al,Ti,and Invar alloy were experimentally characterized;the structures exhibited outstanding performance when compared with typical engineering materials.展开更多
低温共烧陶瓷(Low Temperature Co-fired Ceramic,简称LTCC)技术是实现电子设备小型化、集成化的主流技术。在LTCC封装时,由于封装金属与LTCC的热膨胀系数很难匹配,导致组件在焊接以及交变温度载荷下产生位移,进而产生热应力,严重时甚...低温共烧陶瓷(Low Temperature Co-fired Ceramic,简称LTCC)技术是实现电子设备小型化、集成化的主流技术。在LTCC封装时,由于封装金属与LTCC的热膨胀系数很难匹配,导致组件在焊接以及交变温度载荷下产生位移,进而产生热应力,严重时甚至导致LTCC基板产生裂纹,丧失其工作性能。在高、低温环境下,通过对LTCC基板焊接组件表面位移进行试验测量与软件仿真,并将二者进行对比,验证了仿真结果的合理性与准确性。本文工作为今后提升LTCC基板焊接组件的力学性能提供了一种便捷、经济、可靠的有限元软件仿真分析技术手段。展开更多
基金Supported by the Technology Innovation Program(Grant No.:10053121 and 10051279) funded by the Ministry of Trade,Industry&Energy(MI,Korea)
文摘In this study,we propose a method for estimating the amount of expansion that occurs in subsea pipelines,which could be applied in the design of robust structures that transport oil and gas from offshore wells.We begin with a literature review and general discussion of existing estimation methods and terminologies with respect to subsea pipelines.Due to the effects of high pressure and high temperature,the production of fluid from offshore wells is typically caused by physical deformation of subsea structures,e.g.,expansion and contraction during the transportation process.In severe cases,vertical and lateral buckling occurs,which causes a significant negative impact on structural safety,and which is related to on-bottom stability,free-span,structural collapse,and many other factors.In addition,these factors may affect the production rate with respect to flow assurance,wax,and hydration,to name a few.In this study,we developed a simple and efficient method for generating a reliable pipe expansion design in the early stage,which can lead to savings in both cost and computation time.As such,in this paper,we propose an applicable diagram,which we call the standard dimensionless ratio(SDR)versus virtual anchor length(LA)diagram,that utilizes an efficient procedure for estimating subsea pipeline expansion based on applied reliable scenarios.With this user guideline,offshore pipeline structural designers can reliably determine the amount of subsea pipeline expansion and the obtained results will also be useful for the installation,design,and maintenance of the subsea pipeline.
基金supported by the National Natural Science Foundation of China(Grant Nos.12122202,12002032,and 12002031).
文摘A mechanical metamaterial that has a tailorable coefficient of thermal expansion(CTE)is promising for guaranteeing the reliability of electrical and optical instruments under thermal fluctuations.Despite growing research on the design and manufacturing of metamaterials with extraordinary CTEs,it remains challenging to achieve a nearly isotropic tailorable CTE while ensuring a sufficient load bearing capacity for applications,such as mechanical supporting frames.In this research,we propose a type of bi-metallic lattice whose CTE is artificially programmed from positive(75 ppm/K)to negative(−45 ppm/K),and whose equivalent modulus can be as high as 80 MPa.The bi-metallic lattice with a tailorable CTE in two orthogonal directions can be readily assembled without special modifications to construct large-scale planar structures with desired isotropic CTEs.A theoretical model that considers the actual configuration of the bi-metallic joint is developed;the model precisely captures the thermal deformations of lattice structures with varied geometries and material compositions.Guided by our theoretical design method,planar metallic structures that were manufactured using Al,Ti,and Invar alloy were experimentally characterized;the structures exhibited outstanding performance when compared with typical engineering materials.
文摘低温共烧陶瓷(Low Temperature Co-fired Ceramic,简称LTCC)技术是实现电子设备小型化、集成化的主流技术。在LTCC封装时,由于封装金属与LTCC的热膨胀系数很难匹配,导致组件在焊接以及交变温度载荷下产生位移,进而产生热应力,严重时甚至导致LTCC基板产生裂纹,丧失其工作性能。在高、低温环境下,通过对LTCC基板焊接组件表面位移进行试验测量与软件仿真,并将二者进行对比,验证了仿真结果的合理性与准确性。本文工作为今后提升LTCC基板焊接组件的力学性能提供了一种便捷、经济、可靠的有限元软件仿真分析技术手段。
