An S-lay crane barge,named CNOOC 201,has been built for pipe laying in deepwater oil/gas fields in the South China Sea.It is due to be commissioned by the end of the year 2010.A special lifting system is developed to ...An S-lay crane barge,named CNOOC 201,has been built for pipe laying in deepwater oil/gas fields in the South China Sea.It is due to be commissioned by the end of the year 2010.A special lifting system is developed to meet the challenge that installing deepwater risers from an S-lay barge is difficult and has not been achieved.The purpose of this paper was to investigate the model test on such an innovative system,which has to be done before field application.By applying the similarity theory,the movement of the S-lay barge is simulated through a six degrees-of-freedom motion platform,and a truncated model riser is utilized for the model testing.The displacement and force boundary conditions at the truncated position of the riser are obtained from the catenary governing equation and become realized by a slideway cart and a loading system designed to control the configuration of the model riser,which presents a similar configuration to a real riser in deepwater.The test results are in very good agreement with theoretical calculations,showing that the active truncated test is applicable for controlling the configuration of the deepwater riser in model testing investigation.展开更多
In lifting sub-system of deep-sea mining system, spherical joint is used to connect lifting pipes to replace fixed joint. Based on Dynamics of Flexible Multi-body systems, the mechanics model of articulated lifting sy...In lifting sub-system of deep-sea mining system, spherical joint is used to connect lifting pipes to replace fixed joint. Based on Dynamics of Flexible Multi-body systems, the mechanics model of articulated lifting system is established. Under the four-grade and six-grade oceanic condition, dynamic responses of lifting system are simulated and experiment verified. The simulation results are consistent with experimental ones. The maximum moment of flexion is 322 kN-m on the first pipe under six-grade sea condition. It is seen that the articulated connection can reduce the moment of flexion. The bending deformation of pipe center is researched, and the maximum is 0. 000479 m on the first pipe. Deformation has a little effect on the motion of system. It is feasible to analyze articulated lifting system by applying the theory of flexible multi-body dynamics. The articulated lifting system is obviously better than the fixed one.展开更多
With the arrival of the big data era, the modern higher education model has undergone radical changes, and higher requirements have been put forward for the data literacy of college teachers. The paper first analyzes ...With the arrival of the big data era, the modern higher education model has undergone radical changes, and higher requirements have been put forward for the data literacy of college teachers. The paper first analyzes the connotation of teacher data literacy, and then combs through the status quo and dilemmas of teachers’ data literacy ability in applied universities. The paper proposes to enhance the data literacy ability of teachers from the perspective of organizational learning. Through building a digital culture, building a data-driven teaching environment, and constructing an interdisciplinary learning community to further promote the application of the theory and practice of datafication inside and outside the organization, and ultimately improve the quality of teaching.展开更多
The experiment system of 1000 m deep sea mining system is built up with the similarity theory. Sine mechanism is used to simulate mining ship to generate lateral shock excitation by ocean wave. Simulation and experime...The experiment system of 1000 m deep sea mining system is built up with the similarity theory. Sine mechanism is used to simulate mining ship to generate lateral shock excitation by ocean wave. Simulation and experiment of spherical joint connecting deep sea mining system has been done in band six marine conditions. The results indicate that the moment of spherical joint connecting deep sea mining is smaller than that of the thread connected ones, the lifting pipe of sphelical joint is "flexible pipe". The flexural torque of the articulated lifting pipe system in pump and buffer is generally periodic variation with some irregularity, the value is stable on 60 N·S, and it is obviously smaller than that of the fixed lifting pipe system; The total displacement exhibits cyclic variation pattern, and the periodicity of them is longer than that of sea current. The results of experiment and simulation are basically consistent. And the analysis in the paper offers theoretical foundation of 1000 m deep sea mining system in China.展开更多
The dynamics of the gravitational lifting system of the deep sea mining industry is demonstrated in this article.A simplified dynamic model is obtained when gravity,buoyancy and drag force are the major concerns.By qu...The dynamics of the gravitational lifting system of the deep sea mining industry is demonstrated in this article.A simplified dynamic model is obtained when gravity,buoyancy and drag force are the major concerns.By quantitative analysis,different variables like bucket size,distribution distance,and filling rate are considered to measure their influence on lifting speed and production rate,which ends up with that the most influential factor is the bucket size,and it has a positive correlation with both the two targets:lifting speed and production rate.Due to the breaking strength of the cable wire rope,a feasible design of such a lifting system should take the tension force into consideration.Hence,the feasibility is also examined and a conclusion is summarized that a combination of the bucket size and the distribution distance should be optimized according to the concrete working conditions.展开更多
The initial motivation of the lifting technique is to solve the H∞control problems. However, the conventional weighted H∞design does not meet the conditions required by lifting, so the result often leads to a misjud...The initial motivation of the lifting technique is to solve the H∞control problems. However, the conventional weighted H∞design does not meet the conditions required by lifting, so the result often leads to a misjudgement of the design. Two conditions required by using the lifting technique are presented based on the basic formulae of the lifting. It is pointed out that only the H∞disturbance attenuation problem with no weighting functions can meet these conditions, hence, the application of the lifting technique is quite limited.展开更多
A flexible connector of lifting pipes in a deep sea mining system is designed. The buttress thread ( based on API standard) is used and foreign experience in connector design is referred to. With this kind of connec...A flexible connector of lifting pipes in a deep sea mining system is designed. The buttress thread ( based on API standard) is used and foreign experience in connector design is referred to. With this kind of connector, the lifting pipe wiU only bear the axial force, free of moment. The strength of the connector is analyzed in detail, including the connecting strength of the buttress thread, the dynamic load of the pipe system, pressures inside and outside of the pipe, the lateral stress of the pipe wall and so on. Especially, a geometric model is built for 3-D contact stress analysis. The distribution graph of contact stress is presented. It is indicated that the strength of the spherical connector meets the demand.展开更多
With the increase of bridge reconstruction schemes, synchronous lifting of a bridge is more and more widely used. In order to solve the problems associated with the synchronoas lifting of a bridge, a multi-cylinder sy...With the increase of bridge reconstruction schemes, synchronous lifting of a bridge is more and more widely used. In order to solve the problems associated with the synchronoas lifting of a bridge, a multi-cylinder synchronous lifting power and monitoring system has been developed. This is a distributed control system, which is com- posed of an industrial computer workstation, a programmable logical controller and a hydraulic control system. The system can achieve distributed control and centralized operation of actuators, and centralized management of infor- mation. It not only can implement multi-cylinder synchronous lifting with an unbalanced load, but also can moni- tor the pressure, displacement and stress at each lifting point. The performance of the multi-cylinder synchronous system is verified through its application to several bridge lifting engineering projects. The details of such a project are given.展开更多
In order to achieve a wheelchair lift function, this paper designs a tri-scissors mechanism. Through the so-called H-type transmission and L-type swing rod, the three scissors mechanisms lift in the same rate with onl...In order to achieve a wheelchair lift function, this paper designs a tri-scissors mechanism. Through the so-called H-type transmission and L-type swing rod, the three scissors mechanisms lift in the same rate with only one liner motor while ensuring the stability of the lift. Finite element analysis in ANSYS is performed to verify the material strength. The control system with Sunplus SCM achieves the voice control of wheelchair walking and lifting.展开更多
Pipelines are widely used for transporting oil resources in the context of offshore oil exploitation.The pipeline stress-strength analysis is an important stage in related design and ensuing construction techniques.In...Pipelines are widely used for transporting oil resources in the context of offshore oil exploitation.The pipeline stress-strength analysis is an important stage in related design and ensuing construction techniques.In this study,assuming representative work environment parameters,pipeline lifting operations are investigated numerically.More specifically,a time-domain coupled dynamic analysis method is used to conduct a hydrodynamic analysis under different current velocities and wave heights.The results show that proper operation requires the lifting points are reasonably set in combination with the length of the pipeline and the position of the lifting device on the construction ship.The impact of waves on the pipeline is limited,however lifting operations under strong wind and waves should be avoided as far as possible.展开更多
This paper uses the commutant lifting theorem for representations of the nest algebra to deal with the optimal control of infinite dimensional linear time- varying systems. We solve the model matching problem and a ce...This paper uses the commutant lifting theorem for representations of the nest algebra to deal with the optimal control of infinite dimensional linear time- varying systems. We solve the model matching problem and a certain optimal feedback control problem, each of which corresponds with one type of four-block problem. We also obtain a new formula for the optimal performance and prove the existence of an optimal controller.展开更多
The kinetic model of the four-post-frame lifting mechanical system was established. The stiffness and damping matrices of differential equations of motion were obtained by using Lagrange’s equations. And the dynamic ...The kinetic model of the four-post-frame lifting mechanical system was established. The stiffness and damping matrices of differential equations of motion were obtained by using Lagrange’s equations. And the dynamic characteristics of system were analyzed by modal analysis method. Based upon this, the modifications of structural parameters which can improve dynamic performance were discussed. The low-level high-speed palletizer MDJ1200L was taken as a real case in the paper.展开更多
Deficiencies of the performance-based iterative learning control (ILC) for the non-regular systems are investigated in detail, then a faster control input updating and lifting technique is introduced in the design o...Deficiencies of the performance-based iterative learning control (ILC) for the non-regular systems are investigated in detail, then a faster control input updating and lifting technique is introduced in the design of performance index based ILCs for the partial non-regular systems. Two ldnds of optimal ILCs based on different performance indices are considered. Finally, simulation examples are given to illustrate the feasibility of the proposed learning controls.展开更多
Those various cross-sectional vessels in trees transfer water to as high as 100 meters,but the traditional fabrication methods limit the manufacturing of those vessels,resulting in the non-availability of those bionic...Those various cross-sectional vessels in trees transfer water to as high as 100 meters,but the traditional fabrication methods limit the manufacturing of those vessels,resulting in the non-availability of those bionic microchannels.Herein,we fabricate those bionic microchannels with various cross-sections by employing projection micro-stereolithography(PμSL)based 3D printing technique.The circumradius of bionic microchannels(pentagonal,square,triangle,and five-pointed star)can be as small as 100μm with precisely fabricated sharp corners.What's more,those bionic microchannels demonstrate marvelous microfluidic performance with strong precursor effects enabled by their sharp corners.Most significantly,those special properties of our bionic microchannels enable them outstanding step lifting performance to transport water to tens of millimeters,though the water can only be transported to at most 20 mm for a single bionic microchannel.The mimicked transpiration based on the step lifting of water from bionic microchannels is also achieved.Those precisely fabricated,low-cost,various cross-sectional bionic microchannels promise applications as microfluidic chips,long-distance unpowered water transportation,step lifting,mimicked transpiration,and so on.展开更多
At present,the cranes used at sea have several shortcomings in terms of flexibility,efficiency,and safety.Therefore,a floating multi-robot coordinated lifting system is proposed to fulfill the offshore lifting require...At present,the cranes used at sea have several shortcomings in terms of flexibility,efficiency,and safety.Therefore,a floating multi-robot coordinated lifting system is proposed to fulfill the offshore lifting requirements.First,the structure of the lifting system is established according to the lifting task,the kinematic model of the system is developed by using the D–H coordinate transformation,and the dynamic model is developed based on rigid-body dynamics and hydrodynamics.Then,the static and dynamic workspace of the lifting system are analyzed,and the solving steps of the workspace are given by using the Monte–Carlo method.The effect of the load mass and the maximum allowable tension of the cable on the workspace is examined by simulation.Results show that the lifting system has limited carrying capacity and a data reference for selecting the structural parameters by analyzing the factors affecting the workspace.Findings provide a basis for further research on the optimal design of structural parameters and the determination of safe configurations of the lifting system.展开更多
One of the crucial and challenging issues for researchers is presenting an appropriate approach to evaluate the aerodynamic characteristics of air cushion vehicles(ACVs)in terms of system design parameters.One of thes...One of the crucial and challenging issues for researchers is presenting an appropriate approach to evaluate the aerodynamic characteristics of air cushion vehicles(ACVs)in terms of system design parameters.One of these issues includes introducing a suitable approach to analyze the effect of geometric shapes on the aerodynamic characteristics of ACVs.The main novelty of this paper lies in presenting an innovative method to study the geometric shape effect on air cushion lift force,which has not been investigated thus far.Moreover,this paper introduces a new approximate mathematical formula for calculating the air cushion lift force in terms of parameters,including the air gap,lateral gaps,air inlet velocity,and scaling factor for the first time.Thus,we calculate the aerodynamic lift force applied to nine different shapes of the air cushions used in the ACVs in the present paper through the ANSYS Fluent software.The geometrical shapes studied in this paper are rectangular,square,equilateral triangle,circular,elliptic shapes,and four other combined shapes,including circle-rectangle,circle-square,hexagonal,and fillet square.Results showed that the cushion with a circular pattern produces the highest lift force among other geometric shapes with the same conditions.The increase in the cushion lift force can be attributed to the fillet with a square shape and its increasing radius compared with the square shape.展开更多
基金support from the National Natural Science Foundation of China (granted number 50979113)the National 863 Program of China (granted number 2006AA09A105)
文摘An S-lay crane barge,named CNOOC 201,has been built for pipe laying in deepwater oil/gas fields in the South China Sea.It is due to be commissioned by the end of the year 2010.A special lifting system is developed to meet the challenge that installing deepwater risers from an S-lay barge is difficult and has not been achieved.The purpose of this paper was to investigate the model test on such an innovative system,which has to be done before field application.By applying the similarity theory,the movement of the S-lay barge is simulated through a six degrees-of-freedom motion platform,and a truncated model riser is utilized for the model testing.The displacement and force boundary conditions at the truncated position of the riser are obtained from the catenary governing equation and become realized by a slideway cart and a loading system designed to control the configuration of the model riser,which presents a similar configuration to a real riser in deepwater.The test results are in very good agreement with theoretical calculations,showing that the active truncated test is applicable for controlling the configuration of the deepwater riser in model testing investigation.
基金This research project was financially supported by China Ocean Mineral Resources R&D Association(Grant No.DY105-03-02-17)Ph.D.Programs Foundation of Ministry of Education of China(Grant No.20060008025)
文摘In lifting sub-system of deep-sea mining system, spherical joint is used to connect lifting pipes to replace fixed joint. Based on Dynamics of Flexible Multi-body systems, the mechanics model of articulated lifting system is established. Under the four-grade and six-grade oceanic condition, dynamic responses of lifting system are simulated and experiment verified. The simulation results are consistent with experimental ones. The maximum moment of flexion is 322 kN-m on the first pipe under six-grade sea condition. It is seen that the articulated connection can reduce the moment of flexion. The bending deformation of pipe center is researched, and the maximum is 0. 000479 m on the first pipe. Deformation has a little effect on the motion of system. It is feasible to analyze articulated lifting system by applying the theory of flexible multi-body dynamics. The articulated lifting system is obviously better than the fixed one.
文摘With the arrival of the big data era, the modern higher education model has undergone radical changes, and higher requirements have been put forward for the data literacy of college teachers. The paper first analyzes the connotation of teacher data literacy, and then combs through the status quo and dilemmas of teachers’ data literacy ability in applied universities. The paper proposes to enhance the data literacy ability of teachers from the perspective of organizational learning. Through building a digital culture, building a data-driven teaching environment, and constructing an interdisciplinary learning community to further promote the application of the theory and practice of datafication inside and outside the organization, and ultimately improve the quality of teaching.
基金This research was financially supported by China Ocean Mineral Resources Reasearch and Design Association (GrantNo DY105-03-02-17)Ph.D Programs Foundation of Ministry of Education of China (Grant No20060008025)
文摘The experiment system of 1000 m deep sea mining system is built up with the similarity theory. Sine mechanism is used to simulate mining ship to generate lateral shock excitation by ocean wave. Simulation and experiment of spherical joint connecting deep sea mining system has been done in band six marine conditions. The results indicate that the moment of spherical joint connecting deep sea mining is smaller than that of the thread connected ones, the lifting pipe of sphelical joint is "flexible pipe". The flexural torque of the articulated lifting pipe system in pump and buffer is generally periodic variation with some irregularity, the value is stable on 60 N·S, and it is obviously smaller than that of the fixed lifting pipe system; The total displacement exhibits cyclic variation pattern, and the periodicity of them is longer than that of sea current. The results of experiment and simulation are basically consistent. And the analysis in the paper offers theoretical foundation of 1000 m deep sea mining system in China.
文摘The dynamics of the gravitational lifting system of the deep sea mining industry is demonstrated in this article.A simplified dynamic model is obtained when gravity,buoyancy and drag force are the major concerns.By quantitative analysis,different variables like bucket size,distribution distance,and filling rate are considered to measure their influence on lifting speed and production rate,which ends up with that the most influential factor is the bucket size,and it has a positive correlation with both the two targets:lifting speed and production rate.Due to the breaking strength of the cable wire rope,a feasible design of such a lifting system should take the tension force into consideration.Hence,the feasibility is also examined and a conclusion is summarized that a combination of the bucket size and the distribution distance should be optimized according to the concrete working conditions.
基金Supported by the Harbin Engineering University Fund for Basic Projects (heuft06041)
文摘The initial motivation of the lifting technique is to solve the H∞control problems. However, the conventional weighted H∞design does not meet the conditions required by lifting, so the result often leads to a misjudgement of the design. Two conditions required by using the lifting technique are presented based on the basic formulae of the lifting. It is pointed out that only the H∞disturbance attenuation problem with no weighting functions can meet these conditions, hence, the application of the lifting technique is quite limited.
基金This research was financially supported by China Ocean Mineral Resources R &D Association (Grant No. DY105-03-02-17) .
文摘A flexible connector of lifting pipes in a deep sea mining system is designed. The buttress thread ( based on API standard) is used and foreign experience in connector design is referred to. With this kind of connector, the lifting pipe wiU only bear the axial force, free of moment. The strength of the connector is analyzed in detail, including the connecting strength of the buttress thread, the dynamic load of the pipe system, pressures inside and outside of the pipe, the lateral stress of the pipe wall and so on. Especially, a geometric model is built for 3-D contact stress analysis. The distribution graph of contact stress is presented. It is indicated that the strength of the spherical connector meets the demand.
基金supported by the Ph.D. Programs Foundation of Ministry of Education of China under Grant No. 20070056010Tianjin Municipal Natural Science Foundation under Grant No.07JCZBJC09900Tianjin key technology research for majorproject under Contract No.05ZHGCGX00500
文摘With the increase of bridge reconstruction schemes, synchronous lifting of a bridge is more and more widely used. In order to solve the problems associated with the synchronoas lifting of a bridge, a multi-cylinder synchronous lifting power and monitoring system has been developed. This is a distributed control system, which is com- posed of an industrial computer workstation, a programmable logical controller and a hydraulic control system. The system can achieve distributed control and centralized operation of actuators, and centralized management of infor- mation. It not only can implement multi-cylinder synchronous lifting with an unbalanced load, but also can moni- tor the pressure, displacement and stress at each lifting point. The performance of the multi-cylinder synchronous system is verified through its application to several bridge lifting engineering projects. The details of such a project are given.
基金Supported by Special Topic of the Ministry of Education about Humanities and Social Sciences(12JDGC007)ZheJiang Henglin Chair Industry Co.,Ltd.-Hefei University of Technology Green Seat and Intelligent House Innovate Team
文摘In order to achieve a wheelchair lift function, this paper designs a tri-scissors mechanism. Through the so-called H-type transmission and L-type swing rod, the three scissors mechanisms lift in the same rate with only one liner motor while ensuring the stability of the lift. Finite element analysis in ANSYS is performed to verify the material strength. The control system with Sunplus SCM achieves the voice control of wheelchair walking and lifting.
基金This study was financially supported by the Program for Scientific Research Start-Up Funds of Guangdong Ocean University(060302072101)Comparative Study,and Optimization of Horizontal Lifting of Subsea Pipeline(2021E05011).
文摘Pipelines are widely used for transporting oil resources in the context of offshore oil exploitation.The pipeline stress-strength analysis is an important stage in related design and ensuing construction techniques.In this study,assuming representative work environment parameters,pipeline lifting operations are investigated numerically.More specifically,a time-domain coupled dynamic analysis method is used to conduct a hydrodynamic analysis under different current velocities and wave heights.The results show that proper operation requires the lifting points are reasonably set in combination with the length of the pipeline and the position of the lifting device on the construction ship.The impact of waves on the pipeline is limited,however lifting operations under strong wind and waves should be avoided as far as possible.
文摘This paper uses the commutant lifting theorem for representations of the nest algebra to deal with the optimal control of infinite dimensional linear time- varying systems. We solve the model matching problem and a certain optimal feedback control problem, each of which corresponds with one type of four-block problem. We also obtain a new formula for the optimal performance and prove the existence of an optimal controller.
文摘The kinetic model of the four-post-frame lifting mechanical system was established. The stiffness and damping matrices of differential equations of motion were obtained by using Lagrange’s equations. And the dynamic characteristics of system were analyzed by modal analysis method. Based upon this, the modifications of structural parameters which can improve dynamic performance were discussed. The low-level high-speed palletizer MDJ1200L was taken as a real case in the paper.
基金supported by the National Natural Science Foundation of China (No.60774023)Hunan Provincial Natural Science Foundation (No.06JJ50141)
文摘Deficiencies of the performance-based iterative learning control (ILC) for the non-regular systems are investigated in detail, then a faster control input updating and lifting technique is introduced in the design of performance index based ILCs for the partial non-regular systems. Two ldnds of optimal ILCs based on different performance indices are considered. Finally, simulation examples are given to illustrate the feasibility of the proposed learning controls.
基金supported by the National Natural Science Foundation of China(52006056)the Experiments for Space Exploration Program and the Qian Xuesen Laboratory,China Academy of Space Technology(TKTSPY-2020-01-04)+2 种基金the Key-Area Research and Development Program of Guangdong Province(2020B090923003)partly supported by Natural Science Foundation of Hunan through Grant No.2020JJ3012Natural Research Institute for Family Planning。
文摘Those various cross-sectional vessels in trees transfer water to as high as 100 meters,but the traditional fabrication methods limit the manufacturing of those vessels,resulting in the non-availability of those bionic microchannels.Herein,we fabricate those bionic microchannels with various cross-sections by employing projection micro-stereolithography(PμSL)based 3D printing technique.The circumradius of bionic microchannels(pentagonal,square,triangle,and five-pointed star)can be as small as 100μm with precisely fabricated sharp corners.What's more,those bionic microchannels demonstrate marvelous microfluidic performance with strong precursor effects enabled by their sharp corners.Most significantly,those special properties of our bionic microchannels enable them outstanding step lifting performance to transport water to tens of millimeters,though the water can only be transported to at most 20 mm for a single bionic microchannel.The mimicked transpiration based on the step lifting of water from bionic microchannels is also achieved.Those precisely fabricated,low-cost,various cross-sectional bionic microchannels promise applications as microfluidic chips,long-distance unpowered water transportation,step lifting,mimicked transpiration,and so on.
基金Supported by the National Natural Science Foundation of China under Grant No.51965032the National Natural Science Foundation of Gansu Province of China under Grant No.22JR5RA319+1 种基金the Science and Technology Foundation of Gansu Province of China under Grant No.21YF5WA060the Excellent Doctoral Student Foundation of Gansu Province of China under Grant No.23JRRA842。
文摘At present,the cranes used at sea have several shortcomings in terms of flexibility,efficiency,and safety.Therefore,a floating multi-robot coordinated lifting system is proposed to fulfill the offshore lifting requirements.First,the structure of the lifting system is established according to the lifting task,the kinematic model of the system is developed by using the D–H coordinate transformation,and the dynamic model is developed based on rigid-body dynamics and hydrodynamics.Then,the static and dynamic workspace of the lifting system are analyzed,and the solving steps of the workspace are given by using the Monte–Carlo method.The effect of the load mass and the maximum allowable tension of the cable on the workspace is examined by simulation.Results show that the lifting system has limited carrying capacity and a data reference for selecting the structural parameters by analyzing the factors affecting the workspace.Findings provide a basis for further research on the optimal design of structural parameters and the determination of safe configurations of the lifting system.
文摘One of the crucial and challenging issues for researchers is presenting an appropriate approach to evaluate the aerodynamic characteristics of air cushion vehicles(ACVs)in terms of system design parameters.One of these issues includes introducing a suitable approach to analyze the effect of geometric shapes on the aerodynamic characteristics of ACVs.The main novelty of this paper lies in presenting an innovative method to study the geometric shape effect on air cushion lift force,which has not been investigated thus far.Moreover,this paper introduces a new approximate mathematical formula for calculating the air cushion lift force in terms of parameters,including the air gap,lateral gaps,air inlet velocity,and scaling factor for the first time.Thus,we calculate the aerodynamic lift force applied to nine different shapes of the air cushions used in the ACVs in the present paper through the ANSYS Fluent software.The geometrical shapes studied in this paper are rectangular,square,equilateral triangle,circular,elliptic shapes,and four other combined shapes,including circle-rectangle,circle-square,hexagonal,and fillet square.Results showed that the cushion with a circular pattern produces the highest lift force among other geometric shapes with the same conditions.The increase in the cushion lift force can be attributed to the fillet with a square shape and its increasing radius compared with the square shape.