On the basis of the two dimensional finite element analysis model, the pile foundations' mechanical effect of the rigid pile composite foundation under the dynamic load was researched. Through the research, the de...On the basis of the two dimensional finite element analysis model, the pile foundations' mechanical effect of the rigid pile composite foundation under the dynamic load was researched. Through the research, the development law and deformation property of axial force of pile body, shaft resistance of pile, and cumulative settlement of pile head under vertical cyclic dynamic loads were concluded. Through the comparison and analysis of the test results of dynamic models, the test results of Poulos(1989) and cumulative settlement model of the single pile under cyclic loads were confirmed. Based on the above research, Fortran language was adopted to introduce the soil attenuation factor, the secondary development of relevant modules of ABAQUS was carried out, and the effect of soil attenuation factor on dynamic property of pile-soil was discussed further.展开更多
The pile-soil system interaction computational model in liquefaction-induced lateral spreading ground was established by the finite difference numerical method.Considering an elastic-plastic subgrade reaction method,n...The pile-soil system interaction computational model in liquefaction-induced lateral spreading ground was established by the finite difference numerical method.Considering an elastic-plastic subgrade reaction method,numerical methods involving finite difference approach of pile in liquefaction-induced lateral spreading ground were derived and implemented into a finite difference program.Based on the monotonic loading tests on saturated sand after liquefaction,the liquefaction lateral deformation of the site where group piles are located was predicted.The effects of lateral ground deformation after liquefaction on a group of pile foundations were studied using the fmite difference program mentioned above,and the failure mechanism of group piles in liquefaction-induced lateral spreading ground was obtained.The applicability of the program was preliminarily verified.The results show that the bending moments at the interfaces between liquefied and non-liquefied soil layers are larger than those at the pile＇s top when the pile＇s top is embedded.The value of the additional static bending moment is larger than the peak dynamic bending moment during the earthquake,so in the pile foundation design,more than the superstructure＇s dynamics should be considered and the effect of lateral ground deformation on pile foundations cannot be neglected.展开更多
This paper proposes a longitudinal vulnerability-based analysis method to evaluate the impact of foundation pit excavation on shield tunnels,accounting for geological uncertainties.First,the shield tunnel is modeled a...This paper proposes a longitudinal vulnerability-based analysis method to evaluate the impact of foundation pit excavation on shield tunnels,accounting for geological uncertainties.First,the shield tunnel is modeled as an Euler Bernoulli beam resting on the Pasternak foundation incorporating variability in subgrade parameters along the tunnel’s length.A random analysis method using random field theory is introduced to evaluate the tunnel’s longitudinal responses to excavation.Next,a risk assessment index system is established.The normalized relative depth between the excavation and the shield tunnel is used as a risk index,while the maximum longitudinal deformation,the maximum circumferential opening,and the maximum longitudinal bending moment serve as performance indicators.Based on these,a method for analyzing the longitudinal fragility of shield tunnels under excavation-induced disturbances is proposed.Finally,the technique is applied to a case study involving a foundation pit excavation above a shield tunnel,which is the primary application scenario of this method.Vulnerability curves for different performance indicators are derived,and the effects of tunnel stiffness and subgrade stiffness on the tunnel vulnerability are explored.The results reveal significant differences in vulnerability curves depending on the performance index used.Compared to the maximum circumferential opening and the maximum longitudinal bending moment,selecting the maximum longitudinal deformation as the control index better ensures the tunnel’s usability and safety under excavation disturbances.The longitudinal vulnerability of the shield tunnel nonlinearly decreases with the increase of the tunnel stiffness and subgrade stiffness,and the subgrade stiffness has a more pronounced effect.Parametric analyses suggest that actively reinforcing the substratum is more effective on reducing the risk of tunnel failure due to adjacent excavations than passive reinforcement of the tunnel structure.展开更多
The existing analytical models for umbrella arch method(UAM)based on elastic foundation beams often overlook the influence of the surrounding soil beyond the beam edges on the shear stresses acting on the beam.Consequ...The existing analytical models for umbrella arch method(UAM)based on elastic foundation beams often overlook the influence of the surrounding soil beyond the beam edges on the shear stresses acting on the beam.Consequently,such models fail to adequately reflect the continuity characteristics of soil deformation.Leveraging the Pasternak foundation-Euler beam model,this study considers the generalized shear force on the beam to account for the influence of soil outside the beam ends on the shear stress.An analytical model for the deformation and internal forces of finite-length beams subjected to arbitrary loads is derived based on the initial parameter method under various conditions.The mechanical model of the elastic foundation beam for advanced umbrella arch under typical tunnel excavation cycles is established,yielding analytical solutions for the longitudinal response of the umbrella arch.The reliability of the analytical model is verified with the existing test data.The improved model addresses anomalies in existing models,such as abnormal upward deformation in the loosened segment and maximum deflection occurring within the soil mass.Additionally,dimensionless characteristic parameters reflecting the relative stiffness between the umbrella arch structure and the foundation soil are proposed.Results indicate that the magnitude of soil characteristic parameters significantly influences the deformation and internal forces of the umbrella arch.Within common ranges of soil values,the maximum deformation and internal forces of the umbrella arch under semi-logarithmic coordinates exhibit nearly linear decay with decreasing soil characteristic parameters.The impact of tunnel excavation height on the stress of unsupported sections of the umbrella arch is minor,but it is more significant for umbrella arch buried within the soil mass.Conversely,the influence of tunnel excavation advance on the umbrella arch is opposite.展开更多
To understand the specific behaviors of coastal coral sand slope foundations,discrete element method(DEM)was employed to examine the effect of breakable particle corners on the performance of coral sand slope foundati...To understand the specific behaviors of coastal coral sand slope foundations,discrete element method(DEM)was employed to examine the effect of breakable particle corners on the performance of coral sand slope foundations under a strip footing,from macro to micro scales.The results demonstrate that the bearing characteristics of coral sand slope foundations can be successfully modeled by utilizing breakable corner particles in simulations.The dual effects of interlocking and breakage of corners well explained the specific shallower load transmission and narrower shear stress zones in breakable corner particle slopes.Additionally,the study revealed the significant influence of breakable corners on soil behaviors on slopes.Furthermore,progressive corner breakage within slip bands was successfully identified as the underling mechanism in determining the unique bearing characteristics and the distinct failure patterns of breakable corner particle slopes.This study provides a new perspective to clarify the behaviors of slope foundations composed of breakable corner particle materials.展开更多
This study presents a significant advancement in the vibration analysis of functionally graded sandwich plates with auxetic cores by introducing a general viscoelastic foundation model that more accurately reflects th...This study presents a significant advancement in the vibration analysis of functionally graded sandwich plates with auxetic cores by introducing a general viscoelastic foundation model that more accurately reflects the complex interactions between the plate and the foundation.The novelty of this study is that the proposed viscoelastic foundation model incorporates elastic and damping effects in both the Winkler and Pasternak layers.To develop the theoretical framework for this analysis,the higher-order shear deformation theory is employed,while Hamilton's principle is used to derive the governing equations of motion.The closed-form solution is used to determine the damped vibration behaviors of the sandwich plates.The precision and robustness of the proposed mathematical model are validated through several comparison studies with existing numerical results.A detailed parametric study is conducted to investigate the influence of various parameters,including the elastic and damping coefficients of the foundation,the material gradation,and the properties of the auxetic core on the vibration behavior of the plates.The numerical results provide new insights into the vibration characteristics of sandwich plates with auxetic cores resting on viscoelastic foundation,highlighting the significant role of the two damping coefficients and auxetic cores in the visco-vibration behavior of the plates.展开更多
Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis r...Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis remain significant challenges.This research aims to develop an effective computational method for analyzing the free vibration of functionally graded(FG)microplates under high temperatures while resting on a Pasternak foundation(PF).This formulation leverages a new thirdorder shear deformation theory(new TSDT)for improved accuracy without requiring shear correction factors.Additionally,the modified couple stress theory(MCST)is incorporated to account for sizedependent effects in microplates.The PF is characterized by two parameters including spring stiffness(k_(w))and shear layer stiffness(k_(s)).To validate the proposed method,the results obtained are compared with those of the existing literature.Furthermore,numerical examples explore the influence of various factors on the high-temperature free vibration of FG microplates.These factors include the length scale parameter(l),geometric dimensions,material properties,and the presence of the elastic foundation.The findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the results of this research will have great potential in military and defense applications such as components of submarines,fighter aircraft,and missiles.展开更多
The main goal of this study is to use higher-order isogeometric analysis(IGA)to study the dynamic response of sandwich shells with an auxetic honeycomb core and two different functionally graded materials(FGM)skin lay...The main goal of this study is to use higher-order isogeometric analysis(IGA)to study the dynamic response of sandwich shells with an auxetic honeycomb core and two different functionally graded materials(FGM)skin layers(namely honeycomb-FGS shells)subjected to dynamic loading.Touratier's non-polynomial higher-order shear deformation theory(HSDT)is used due to its simplicity and performance.The governing equation is derived from Hamilton's principle.After verifying the present approach,the effect of input parameters on the dynamic response of honeycomb-FGS shells is carried out in detail.展开更多
At the first time,the finite element method was used to model and analyze the free vibration and transient response of non-uniform thickness bi-directional functionally graded sandwich porous(BFGSP)skew plates.The who...At the first time,the finite element method was used to model and analyze the free vibration and transient response of non-uniform thickness bi-directional functionally graded sandwich porous(BFGSP)skew plates.The whole BFGSP skew-plates is placed on a variable visco-elastic foundation(VEF)in the hygro-thermal environment and subjected to the blast load.The BFGSP skew-plate thickness is permitted to vary non-linearly over both the length and width of the skew-plate,thereby faithfully representing the real behavior of the structure itself.The analysis is based on a four-node planar quadrilateral element with eight degrees of freedom per node,which is approximated using Lagrange Q_(4)shape function and C^(1)level non-conforming Hermite shape function based on refined higher-order shear deformation plate theory.The forced vibration parameters of the non-uniform thickness BFGSP skew-plate are fully determined using Hamilton's principle and the Newmark-βdirect integration technique.Accuracy of the calculation program is validated by comparing its numerical results with those from reputable sources.Furthermore,a thorough assessment is conducted to determine the impact of various parameters on the free and forced vibration responses of the non-uniform thickness BFGSP skew-plate.The findings of the paper may be used in the development of civil and military structures in situations that are prone to exceptional forces,such as explosions and impacts load.展开更多
为实现电网检修计划管理业务流程的网络化、自动化,利用微软的工作流新技术W indows W orkflowFoundation(WWF),提出了基于MS.NET平台的电网检修计划管理系统解决方案。利用Petri网对一个典型的电网检修计划业务流程建模并分析所建模型...为实现电网检修计划管理业务流程的网络化、自动化,利用微软的工作流新技术W indows W orkflowFoundation(WWF),提出了基于MS.NET平台的电网检修计划管理系统解决方案。利用Petri网对一个典型的电网检修计划业务流程建模并分析所建模型的正确性,给出了基于WWF模型驱动和面向组件实现所建电网检修计划工作流模型的可视化设计方法,能够较好地满足实际应用的需要,具有实现成本低、开发难度小,系统灵活性、可扩展性好等优点。展开更多
The main objective of this study is to investigate the buckling analysis of CCSs reinforced by CNTs subjected to combined loading of hydrostatic pressure and axial compression resting on the twoparameter elastic found...The main objective of this study is to investigate the buckling analysis of CCSs reinforced by CNTs subjected to combined loading of hydrostatic pressure and axial compression resting on the twoparameter elastic foundation(T-P-EF).It is one of the first attempts to derive the governing equations of the CCSs reinforced with CNTs,based on a generalized first-order shear deformation shell theory(FSDST)which includes shell-foundation interaction.By adopting the extended mixing rule,the effective material properties of CCSs reinforced by CNTs with linear distributions are approximated by introducing some efficiency parameters.Three carbon nanotube distribution in the matrix,i.e.uniform distribution(U)and V and X-types linear distribution are taken into account.The stability equations are solved by using the Galerkin procedure to determine the combined buckling loads(CBLs)of the structure selected here.The numerical illustrations cover CBLs characteristics of CCSs reinforced by CNTs in the presence of the T-P-EF.Finally,a parametric study is carried out to study the influences of the foundation parameters,the volume fraction of carbon nanotubes and the types of reinforcement on the CBLs.展开更多
新型城市化建设和管理过程中,借助建筑信息模型(building information modeling,BIM)与地理信息系统(geographic information system,GIS)的数据集成,不但能实现建筑物的精细化表达,而且室外信息得以兼顾,实现空间分析及室内外一体化表...新型城市化建设和管理过程中,借助建筑信息模型(building information modeling,BIM)与地理信息系统(geographic information system,GIS)的数据集成,不但能实现建筑物的精细化表达,而且室外信息得以兼顾,实现空间分析及室内外一体化表达。但BIM与GIS两种不同的数据格式无法直接实现数据的互通。为此,首先分析了模型IFC和CityGML在文档形式等方面的差异,并实现了多个简单建筑物IFC模型到CityGML3.0 LOD2、LOD3的转换。其次,针对上述数据集成实验中语义丢失问题,扩展GIS的CityGML3.0数据格式,提出CityGML B-Con扩展模型,完善IFC到CityGML3.0的一对一映射关系。最后,实现多个不同复杂程度建筑物IFC模型到CityGML B-Con扩展模型的转换。实验结果表明,利用CityGML B-Con模型能实现BIM与GIS的数据集成。宏观层面来说,能够增强转换后建筑物外观的细节程度,微观层面而言,BuildingConstructiveElement和BuildingInstallation的子类得以区分,IfcStair、IfcRamp和IfcBeam等建筑构件都能通过一对一映射的方式转换至CityGML中,克服了CityGML原有标准在建筑物构件表达方面的缺陷,有效减少了BIM源数据语义信息的丢失。展开更多
基金Projects(51478178,51508181) supported by the National Natural Science Foundation of China
文摘On the basis of the two dimensional finite element analysis model, the pile foundations' mechanical effect of the rigid pile composite foundation under the dynamic load was researched. Through the research, the development law and deformation property of axial force of pile body, shaft resistance of pile, and cumulative settlement of pile head under vertical cyclic dynamic loads were concluded. Through the comparison and analysis of the test results of dynamic models, the test results of Poulos(1989) and cumulative settlement model of the single pile under cyclic loads were confirmed. Based on the above research, Fortran language was adopted to introduce the soil attenuation factor, the secondary development of relevant modules of ABAQUS was carried out, and the effect of soil attenuation factor on dynamic property of pile-soil was discussed further.
基金Project(51109208)supported by the National Natural Science Foundation of ChinaProject(2013M531688)supported by the Postdoctoral Science Foundation of China+1 种基金Project(Z012009)supported by the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering(Institute of Rock and Soil Mechanics,Chinese Academy of Sciences)Project(CKSF2012054)supported by the Foundation of Changjiang River Scientific Research Institute,China
文摘The pile-soil system interaction computational model in liquefaction-induced lateral spreading ground was established by the finite difference numerical method.Considering an elastic-plastic subgrade reaction method,numerical methods involving finite difference approach of pile in liquefaction-induced lateral spreading ground were derived and implemented into a finite difference program.Based on the monotonic loading tests on saturated sand after liquefaction,the liquefaction lateral deformation of the site where group piles are located was predicted.The effects of lateral ground deformation after liquefaction on a group of pile foundations were studied using the fmite difference program mentioned above,and the failure mechanism of group piles in liquefaction-induced lateral spreading ground was obtained.The applicability of the program was preliminarily verified.The results show that the bending moments at the interfaces between liquefied and non-liquefied soil layers are larger than those at the pile＇s top when the pile＇s top is embedded.The value of the additional static bending moment is larger than the peak dynamic bending moment during the earthquake,so in the pile foundation design,more than the superstructure＇s dynamics should be considered and the effect of lateral ground deformation on pile foundations cannot be neglected.
基金Project(52178402) supported by the National Natural Science Foundation of China。
文摘This paper proposes a longitudinal vulnerability-based analysis method to evaluate the impact of foundation pit excavation on shield tunnels,accounting for geological uncertainties.First,the shield tunnel is modeled as an Euler Bernoulli beam resting on the Pasternak foundation incorporating variability in subgrade parameters along the tunnel’s length.A random analysis method using random field theory is introduced to evaluate the tunnel’s longitudinal responses to excavation.Next,a risk assessment index system is established.The normalized relative depth between the excavation and the shield tunnel is used as a risk index,while the maximum longitudinal deformation,the maximum circumferential opening,and the maximum longitudinal bending moment serve as performance indicators.Based on these,a method for analyzing the longitudinal fragility of shield tunnels under excavation-induced disturbances is proposed.Finally,the technique is applied to a case study involving a foundation pit excavation above a shield tunnel,which is the primary application scenario of this method.Vulnerability curves for different performance indicators are derived,and the effects of tunnel stiffness and subgrade stiffness on the tunnel vulnerability are explored.The results reveal significant differences in vulnerability curves depending on the performance index used.Compared to the maximum circumferential opening and the maximum longitudinal bending moment,selecting the maximum longitudinal deformation as the control index better ensures the tunnel’s usability and safety under excavation disturbances.The longitudinal vulnerability of the shield tunnel nonlinearly decreases with the increase of the tunnel stiffness and subgrade stiffness,and the subgrade stiffness has a more pronounced effect.Parametric analyses suggest that actively reinforcing the substratum is more effective on reducing the risk of tunnel failure due to adjacent excavations than passive reinforcement of the tunnel structure.
基金Projects(52008403,52378421)supported by the National Natural Science Foundation of ChinaProject(2022-Key-10)supported by the Science and Technology Research and Development Program Project of China Railway Group LimitedProject(202207)supported by the Hunan Provincial Transportation Science and Technology,China。
文摘The existing analytical models for umbrella arch method(UAM)based on elastic foundation beams often overlook the influence of the surrounding soil beyond the beam edges on the shear stresses acting on the beam.Consequently,such models fail to adequately reflect the continuity characteristics of soil deformation.Leveraging the Pasternak foundation-Euler beam model,this study considers the generalized shear force on the beam to account for the influence of soil outside the beam ends on the shear stress.An analytical model for the deformation and internal forces of finite-length beams subjected to arbitrary loads is derived based on the initial parameter method under various conditions.The mechanical model of the elastic foundation beam for advanced umbrella arch under typical tunnel excavation cycles is established,yielding analytical solutions for the longitudinal response of the umbrella arch.The reliability of the analytical model is verified with the existing test data.The improved model addresses anomalies in existing models,such as abnormal upward deformation in the loosened segment and maximum deflection occurring within the soil mass.Additionally,dimensionless characteristic parameters reflecting the relative stiffness between the umbrella arch structure and the foundation soil are proposed.Results indicate that the magnitude of soil characteristic parameters significantly influences the deformation and internal forces of the umbrella arch.Within common ranges of soil values,the maximum deformation and internal forces of the umbrella arch under semi-logarithmic coordinates exhibit nearly linear decay with decreasing soil characteristic parameters.The impact of tunnel excavation height on the stress of unsupported sections of the umbrella arch is minor,but it is more significant for umbrella arch buried within the soil mass.Conversely,the influence of tunnel excavation advance on the umbrella arch is opposite.
基金Projects(51878103,52208370)supported by the National Natural Science Foundation of ChinaProject(cstc2020jcyjcxtt X0003)supported by the Innovation Group Science Foundation of the Natural Science Foundation of Chongqing,ChinaProject(2022CDJQY-012)supported by the Fundamental Research Funds for the Central Universities,China。
文摘To understand the specific behaviors of coastal coral sand slope foundations,discrete element method(DEM)was employed to examine the effect of breakable particle corners on the performance of coral sand slope foundations under a strip footing,from macro to micro scales.The results demonstrate that the bearing characteristics of coral sand slope foundations can be successfully modeled by utilizing breakable corner particles in simulations.The dual effects of interlocking and breakage of corners well explained the specific shallower load transmission and narrower shear stress zones in breakable corner particle slopes.Additionally,the study revealed the significant influence of breakable corners on soil behaviors on slopes.Furthermore,progressive corner breakage within slip bands was successfully identified as the underling mechanism in determining the unique bearing characteristics and the distinct failure patterns of breakable corner particle slopes.This study provides a new perspective to clarify the behaviors of slope foundations composed of breakable corner particle materials.
基金the funding of the Deanship of Graduate Studies and Scientific Research,Jazan University,Saudi Arabia,through project number:RG24-M027.
文摘This study presents a significant advancement in the vibration analysis of functionally graded sandwich plates with auxetic cores by introducing a general viscoelastic foundation model that more accurately reflects the complex interactions between the plate and the foundation.The novelty of this study is that the proposed viscoelastic foundation model incorporates elastic and damping effects in both the Winkler and Pasternak layers.To develop the theoretical framework for this analysis,the higher-order shear deformation theory is employed,while Hamilton's principle is used to derive the governing equations of motion.The closed-form solution is used to determine the damped vibration behaviors of the sandwich plates.The precision and robustness of the proposed mathematical model are validated through several comparison studies with existing numerical results.A detailed parametric study is conducted to investigate the influence of various parameters,including the elastic and damping coefficients of the foundation,the material gradation,and the properties of the auxetic core on the vibration behavior of the plates.The numerical results provide new insights into the vibration characteristics of sandwich plates with auxetic cores resting on viscoelastic foundation,highlighting the significant role of the two damping coefficients and auxetic cores in the visco-vibration behavior of the plates.
文摘Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis remain significant challenges.This research aims to develop an effective computational method for analyzing the free vibration of functionally graded(FG)microplates under high temperatures while resting on a Pasternak foundation(PF).This formulation leverages a new thirdorder shear deformation theory(new TSDT)for improved accuracy without requiring shear correction factors.Additionally,the modified couple stress theory(MCST)is incorporated to account for sizedependent effects in microplates.The PF is characterized by two parameters including spring stiffness(k_(w))and shear layer stiffness(k_(s)).To validate the proposed method,the results obtained are compared with those of the existing literature.Furthermore,numerical examples explore the influence of various factors on the high-temperature free vibration of FG microplates.These factors include the length scale parameter(l),geometric dimensions,material properties,and the presence of the elastic foundation.The findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the results of this research will have great potential in military and defense applications such as components of submarines,fighter aircraft,and missiles.
基金funded by Le Quy Don Technical University Research Found (Grant No.2023QHT.03)。
文摘The main goal of this study is to use higher-order isogeometric analysis(IGA)to study the dynamic response of sandwich shells with an auxetic honeycomb core and two different functionally graded materials(FGM)skin layers(namely honeycomb-FGS shells)subjected to dynamic loading.Touratier's non-polynomial higher-order shear deformation theory(HSDT)is used due to its simplicity and performance.The governing equation is derived from Hamilton's principle.After verifying the present approach,the effect of input parameters on the dynamic response of honeycomb-FGS shells is carried out in detail.
文摘At the first time,the finite element method was used to model and analyze the free vibration and transient response of non-uniform thickness bi-directional functionally graded sandwich porous(BFGSP)skew plates.The whole BFGSP skew-plates is placed on a variable visco-elastic foundation(VEF)in the hygro-thermal environment and subjected to the blast load.The BFGSP skew-plate thickness is permitted to vary non-linearly over both the length and width of the skew-plate,thereby faithfully representing the real behavior of the structure itself.The analysis is based on a four-node planar quadrilateral element with eight degrees of freedom per node,which is approximated using Lagrange Q_(4)shape function and C^(1)level non-conforming Hermite shape function based on refined higher-order shear deformation plate theory.The forced vibration parameters of the non-uniform thickness BFGSP skew-plate are fully determined using Hamilton's principle and the Newmark-βdirect integration technique.Accuracy of the calculation program is validated by comparing its numerical results with those from reputable sources.Furthermore,a thorough assessment is conducted to determine the impact of various parameters on the free and forced vibration responses of the non-uniform thickness BFGSP skew-plate.The findings of the paper may be used in the development of civil and military structures in situations that are prone to exceptional forces,such as explosions and impacts load.
文摘为实现电网检修计划管理业务流程的网络化、自动化,利用微软的工作流新技术W indows W orkflowFoundation(WWF),提出了基于MS.NET平台的电网检修计划管理系统解决方案。利用Petri网对一个典型的电网检修计划业务流程建模并分析所建模型的正确性,给出了基于WWF模型驱动和面向组件实现所建电网检修计划工作流模型的可视化设计方法,能够较好地满足实际应用的需要,具有实现成本低、开发难度小,系统灵活性、可扩展性好等优点。
文摘The main objective of this study is to investigate the buckling analysis of CCSs reinforced by CNTs subjected to combined loading of hydrostatic pressure and axial compression resting on the twoparameter elastic foundation(T-P-EF).It is one of the first attempts to derive the governing equations of the CCSs reinforced with CNTs,based on a generalized first-order shear deformation shell theory(FSDST)which includes shell-foundation interaction.By adopting the extended mixing rule,the effective material properties of CCSs reinforced by CNTs with linear distributions are approximated by introducing some efficiency parameters.Three carbon nanotube distribution in the matrix,i.e.uniform distribution(U)and V and X-types linear distribution are taken into account.The stability equations are solved by using the Galerkin procedure to determine the combined buckling loads(CBLs)of the structure selected here.The numerical illustrations cover CBLs characteristics of CCSs reinforced by CNTs in the presence of the T-P-EF.Finally,a parametric study is carried out to study the influences of the foundation parameters,the volume fraction of carbon nanotubes and the types of reinforcement on the CBLs.
文摘新型城市化建设和管理过程中,借助建筑信息模型(building information modeling,BIM)与地理信息系统(geographic information system,GIS)的数据集成,不但能实现建筑物的精细化表达,而且室外信息得以兼顾,实现空间分析及室内外一体化表达。但BIM与GIS两种不同的数据格式无法直接实现数据的互通。为此,首先分析了模型IFC和CityGML在文档形式等方面的差异,并实现了多个简单建筑物IFC模型到CityGML3.0 LOD2、LOD3的转换。其次,针对上述数据集成实验中语义丢失问题,扩展GIS的CityGML3.0数据格式,提出CityGML B-Con扩展模型,完善IFC到CityGML3.0的一对一映射关系。最后,实现多个不同复杂程度建筑物IFC模型到CityGML B-Con扩展模型的转换。实验结果表明,利用CityGML B-Con模型能实现BIM与GIS的数据集成。宏观层面来说,能够增强转换后建筑物外观的细节程度,微观层面而言,BuildingConstructiveElement和BuildingInstallation的子类得以区分,IfcStair、IfcRamp和IfcBeam等建筑构件都能通过一对一映射的方式转换至CityGML中,克服了CityGML原有标准在建筑物构件表达方面的缺陷,有效减少了BIM源数据语义信息的丢失。
