Cranes used at sea have some shortcomings in terms of flexibility,efficiency,and safety.Therefore,a floating multi-robot coordinated towing system is planned to fulfill the offshore towing requirements.It is difficult...Cranes used at sea have some shortcomings in terms of flexibility,efficiency,and safety.Therefore,a floating multi-robot coordinated towing system is planned to fulfill the offshore towing requirements.It is difficult to study the stability of a floating multi-robot coordinated towing system by ancient strategies.First,the minimum tension of the rope and the minimum singular value of the stiffness matrix were separately used to analyze the load stability.The advantages and disadvantages of the two methods were discussed.Then,the two stability analysis methods were normalized and weighted to obtain the method based on minimum tension and minimum singular to comprehensively analyze the stability of the load.Finally,the effect of different weighting coefficients on the load stability was analyzed,which led to a reasonable weighting coefficient to evaluate the load stability by comparing with a single analysis method.The research results provide a basis for the motion planning and coordinated control of the towing system.展开更多
In this paper, a set of variational formulas of solving nonlinear instability critical loads are established from the viewpoint of variational principle. The paper shows that it is very convenient to solve nonlinear i...In this paper, a set of variational formulas of solving nonlinear instability critical loads are established from the viewpoint of variational principle. The paper shows that it is very convenient to solve nonlinear instability critical load by using the variational formulas suggested in this paper.展开更多
Liapunov's 2nd method is applied to analyse the Stability of a ciamped poleorthotropic round plate acted by a radial axisymmetrical impact load on its periphery. The analysis is carried cut under the assumptions o...Liapunov's 2nd method is applied to analyse the Stability of a ciamped poleorthotropic round plate acted by a radial axisymmetrical impact load on its periphery. The analysis is carried cut under the assumptions of small deflection and elasticity The impact load is supposed to have a step impulsive form. A sufficient stability condition is given.展开更多
Pipelines are the critical link between major offshore oil and gas developments and the mainland. Any inadequate on-bottom stability design could result in disruption and failure, having a devastating impact on the ec...Pipelines are the critical link between major offshore oil and gas developments and the mainland. Any inadequate on-bottom stability design could result in disruption and failure, having a devastating impact on the economy and environment. Predicting the stability behavior of offshore pipelines in hurricanes is therefore vital to the assessment of both new design and existing assets. The Gulf of Mexico has a very dense network of pipeline systems constructed on the seabed. During the last two decades, the Gulf of Mexico has experienced a series of strong hurricanes, which have destroyed, disrupted and destabilized many pipelines. This paper first reviews some of these engineering cases. Following that, three case studies are retrospectively simulated using an in-house developed program. The study utilizes the offshore pipeline and hurricane details to conduct a Dynamic Lateral Stability analysis, with the results providing evidence as to the accuracy of the modeling techniques developed.展开更多
this paper gives the resultant forces and moments strain energy and work of external forces on the basis of the deformation theory of flexible body therefore in aqcfordance with the principle of virtual displacement t...this paper gives the resultant forces and moments strain energy and work of external forces on the basis of the deformation theory of flexible body therefore in aqcfordance with the principle of virtual displacement the energy criterion of critical lad is obtained and the equilibrium equation and boundary conditions of stability problem are derived展开更多
Early adequate fluid loading was the corner stone of hemodynamic optimization for sepsis and septic shock. Meanwhile, recent recommended protocol for fluid resuscitation was increasingly debated on hemodynamic stabili...Early adequate fluid loading was the corner stone of hemodynamic optimization for sepsis and septic shock. Meanwhile, recent recommended protocol for fluid resuscitation was increasingly debated on hemodynamic stability vs risk of overloading. In recent publications, it was found that a priority was often given to hemodynamic stability rather than organ function alternation in the early fluid resusci- tation of sepsis. However, no safety limits were used at all in most of these reports. In this article, the rationality and safety of early aggressive fluid loading for septic patients were discussed. It was concluded that early aggressive fluid loading improved hemodynamics transitorily, but was probably traded off with a follow-up organ function impairment, such as worsening oxygenation by reduction of lung aeration, in a part of septic patients at least. Thus, a safeguard is needed against unnecessary excessive fluids in early aggressive fluid loading for set）tic patients.展开更多
基金the National Natural Science Foundation of China(No.51965032)the Natural Science Foundation of Gansu Province(No.22JR5RA319)+1 种基金the Science and Technology Foundation of Gansu Province(No.21YF5WA060)the Excellent Doctoral Student Foundation of Gansu Province(No.23JRRA842)。
文摘Cranes used at sea have some shortcomings in terms of flexibility,efficiency,and safety.Therefore,a floating multi-robot coordinated towing system is planned to fulfill the offshore towing requirements.It is difficult to study the stability of a floating multi-robot coordinated towing system by ancient strategies.First,the minimum tension of the rope and the minimum singular value of the stiffness matrix were separately used to analyze the load stability.The advantages and disadvantages of the two methods were discussed.Then,the two stability analysis methods were normalized and weighted to obtain the method based on minimum tension and minimum singular to comprehensively analyze the stability of the load.Finally,the effect of different weighting coefficients on the load stability was analyzed,which led to a reasonable weighting coefficient to evaluate the load stability by comparing with a single analysis method.The research results provide a basis for the motion planning and coordinated control of the towing system.
文摘In this paper, a set of variational formulas of solving nonlinear instability critical loads are established from the viewpoint of variational principle. The paper shows that it is very convenient to solve nonlinear instability critical load by using the variational formulas suggested in this paper.
文摘Liapunov's 2nd method is applied to analyse the Stability of a ciamped poleorthotropic round plate acted by a radial axisymmetrical impact load on its periphery. The analysis is carried cut under the assumptions of small deflection and elasticity The impact load is supposed to have a step impulsive form. A sufficient stability condition is given.
基金supported by the Research Development Awards of University of Western Australia,Australia-China Natural Gas Technology Partnership Fund and Lloyd's Register Foundationsupports the advancement of engineering-related education and funds research and development that enhance the safety of life at sea,on land,and in the airforms part of the activities of the Centre for Offshore Foundation Systems(COFS) above,currently supported as a primary node of the Australian Research Council Centre of Excellence for Geotechnical Science and Engineering
文摘Pipelines are the critical link between major offshore oil and gas developments and the mainland. Any inadequate on-bottom stability design could result in disruption and failure, having a devastating impact on the economy and environment. Predicting the stability behavior of offshore pipelines in hurricanes is therefore vital to the assessment of both new design and existing assets. The Gulf of Mexico has a very dense network of pipeline systems constructed on the seabed. During the last two decades, the Gulf of Mexico has experienced a series of strong hurricanes, which have destroyed, disrupted and destabilized many pipelines. This paper first reviews some of these engineering cases. Following that, three case studies are retrospectively simulated using an in-house developed program. The study utilizes the offshore pipeline and hurricane details to conduct a Dynamic Lateral Stability analysis, with the results providing evidence as to the accuracy of the modeling techniques developed.
文摘this paper gives the resultant forces and moments strain energy and work of external forces on the basis of the deformation theory of flexible body therefore in aqcfordance with the principle of virtual displacement the energy criterion of critical lad is obtained and the equilibrium equation and boundary conditions of stability problem are derived
文摘Early adequate fluid loading was the corner stone of hemodynamic optimization for sepsis and septic shock. Meanwhile, recent recommended protocol for fluid resuscitation was increasingly debated on hemodynamic stability vs risk of overloading. In recent publications, it was found that a priority was often given to hemodynamic stability rather than organ function alternation in the early fluid resusci- tation of sepsis. However, no safety limits were used at all in most of these reports. In this article, the rationality and safety of early aggressive fluid loading for septic patients were discussed. It was concluded that early aggressive fluid loading improved hemodynamics transitorily, but was probably traded off with a follow-up organ function impairment, such as worsening oxygenation by reduction of lung aeration, in a part of septic patients at least. Thus, a safeguard is needed against unnecessary excessive fluids in early aggressive fluid loading for set）tic patients.
