This paper presents a substructure online hybrid test system that is extensible for geographically distributed tests. This system consists of a set of devices conventionally used for cyclic tests to load the tested su...This paper presents a substructure online hybrid test system that is extensible for geographically distributed tests. This system consists of a set of devices conventionally used for cyclic tests to load the tested substructures onto the target displacement or the target force. Due to their robustness and portability, individual sets of conventional loading devices can be transported and reconfigured to realize physical loading in geographically remote laboratories. Another appealing feature is the flexible displacement-force mixed control that is particularly suitable for specimens having large disparities in stiffness during various performance stages. To conduct a substructure online hybrid test, an extensible framework is developed, which is equipped with a generalized interface to encapsulate each substructure. Multiple tested substructures and analyzed substructures using various structural program codes can be accommodated within the single framework, simply interfaced with the boundary displacements and forces. A coordinator program is developed to keep the boundaries among all substructures compatible and equilibrated. An Interuet-based data exchange scheme is also devised to transfer data among computers equipped with different software environments. A series of online hybrid tests are introduced, and the portability, flexibility, and extensibility of the online hybrid test system are demonstrated.展开更多
In this paper, a concept for the joint modeling of the device load and user intention is presented. It consists of two coupled models, a device load model to characterize the power consumption of an electric device of...In this paper, a concept for the joint modeling of the device load and user intention is presented. It consists of two coupled models, a device load model to characterize the power consumption of an electric device of interest, and a user intention model for describing the user intentions which cause the energy consumption. The advantage of this joint model is the ability to predict the device load from the user intention and to reconstruct the user intention from the measured device load. This opens a new way for load monitoring, simulation and prediction from the perspective of users instead of devices.展开更多
A model test system with a dynamic load device for geotechnical engineering in cold regions is presented. This system consists of a model test tank, a refrigeration device and temperature controller, a dynamic load de...A model test system with a dynamic load device for geotechnical engineering in cold regions is presented. This system consists of a model test tank, a refrigeration device and temperature controller, a dynamic load device, together with sensors and data loggers for detecting stress, deformation, and temperature changes. The system can accommodate soil blocks up to 3 m in length, 2.5 m in width, and 1 m in height. The lowest temperature provided by the refrigeration device is -20 ℃. The maximum load provided by the dynamic load device is 100 kN and the vibration fi＇equency of the dynamic load can range from 0.1 to 10 Hz. A number of waveforms, such as sine waves, rectangular waves, triangle waves, and other user-defined waves can be generated by the dynamic load device controller.展开更多
To investigate the structural stress conditions during the excavation and failure stages of subway stations under adjustable water and soil pressures,a 1∶10 scaled model was created based on similarity theory.Conside...To investigate the structural stress conditions during the excavation and failure stages of subway stations under adjustable water and soil pressures,a 1∶10 scaled model was created based on similarity theory.Considering the equivalent soil pressure load,the loading procedures that controlled the excavation and failure of a metro station created via the cover excavation reverse construction method were evaluated.Additionally,an excavation unloading device and an external soil pressure-based graded loading device were developed for a metro station created via the cover excavation reverse construction method.By comparing the experimental results with the finite element simulation results,the axial force variations in the balance props during the excavation process were revealed,and the crack development process of the metro station was summarized.The external soil pressure remained unchanged;furthermore,the increase in the axial force of the balance props was negatively correlated with the distance to the previous balance prop and positively correlated with the axial force of the previous balance prop at the time of unloading.According to the graded soil pressure load and the corresponding crack initiation,development,and structural failure states,the model failure process was divided into four stages:the no-crack stage,initial cracking stage,crack penetration stage,and local damage stage.The first cracks in the station structure appeared at the corners and centers of the excavation openings.The first penetration of transverse cracks appeared in the middle of the basement first-floor wall.The cracks at the excavation opening corners and middle locations developed obliquely,forming an overall horseshoe shape.Localized damage first occurred at the corners where concrete spalled,exposing the reinforcement.展开更多
基金Public Benefit Research Foundation under Grant No.201108006Natural Science Foundation under Grant No.51161120360+2 种基金Heilongjiang Overseas Funding under Grant No.LC201002 of ChinaGrant-in-Aid for Scientific Research(Basic Research Category A,19206060)Japan Society for the Promotion of Science
文摘This paper presents a substructure online hybrid test system that is extensible for geographically distributed tests. This system consists of a set of devices conventionally used for cyclic tests to load the tested substructures onto the target displacement or the target force. Due to their robustness and portability, individual sets of conventional loading devices can be transported and reconfigured to realize physical loading in geographically remote laboratories. Another appealing feature is the flexible displacement-force mixed control that is particularly suitable for specimens having large disparities in stiffness during various performance stages. To conduct a substructure online hybrid test, an extensible framework is developed, which is equipped with a generalized interface to encapsulate each substructure. Multiple tested substructures and analyzed substructures using various structural program codes can be accommodated within the single framework, simply interfaced with the boundary displacements and forces. A coordinator program is developed to keep the boundaries among all substructures compatible and equilibrated. An Interuet-based data exchange scheme is also devised to transfer data among computers equipped with different software environments. A series of online hybrid tests are introduced, and the portability, flexibility, and extensibility of the online hybrid test system are demonstrated.
文摘In this paper, a concept for the joint modeling of the device load and user intention is presented. It consists of two coupled models, a device load model to characterize the power consumption of an electric device of interest, and a user intention model for describing the user intentions which cause the energy consumption. The advantage of this joint model is the ability to predict the device load from the user intention and to reconstruct the user intention from the measured device load. This opens a new way for load monitoring, simulation and prediction from the perspective of users instead of devices.
基金supported by the National Natural Science Foundation of China (No. 40971046,41023003,40901039)the Project from the State Key Laboratory of Frozen Soil Engineering of China (No. 09SF102003)
文摘A model test system with a dynamic load device for geotechnical engineering in cold regions is presented. This system consists of a model test tank, a refrigeration device and temperature controller, a dynamic load device, together with sensors and data loggers for detecting stress, deformation, and temperature changes. The system can accommodate soil blocks up to 3 m in length, 2.5 m in width, and 1 m in height. The lowest temperature provided by the refrigeration device is -20 ℃. The maximum load provided by the dynamic load device is 100 kN and the vibration fi＇equency of the dynamic load can range from 0.1 to 10 Hz. A number of waveforms, such as sine waves, rectangular waves, triangle waves, and other user-defined waves can be generated by the dynamic load device controller.
基金supported by the National Natural Science Foundation of China(Grant No.52178302)the Key R&D Projects in Shaanxi Province(No.2020SF-373).
文摘To investigate the structural stress conditions during the excavation and failure stages of subway stations under adjustable water and soil pressures,a 1∶10 scaled model was created based on similarity theory.Considering the equivalent soil pressure load,the loading procedures that controlled the excavation and failure of a metro station created via the cover excavation reverse construction method were evaluated.Additionally,an excavation unloading device and an external soil pressure-based graded loading device were developed for a metro station created via the cover excavation reverse construction method.By comparing the experimental results with the finite element simulation results,the axial force variations in the balance props during the excavation process were revealed,and the crack development process of the metro station was summarized.The external soil pressure remained unchanged;furthermore,the increase in the axial force of the balance props was negatively correlated with the distance to the previous balance prop and positively correlated with the axial force of the previous balance prop at the time of unloading.According to the graded soil pressure load and the corresponding crack initiation,development,and structural failure states,the model failure process was divided into four stages:the no-crack stage,initial cracking stage,crack penetration stage,and local damage stage.The first cracks in the station structure appeared at the corners and centers of the excavation openings.The first penetration of transverse cracks appeared in the middle of the basement first-floor wall.The cracks at the excavation opening corners and middle locations developed obliquely,forming an overall horseshoe shape.Localized damage first occurred at the corners where concrete spalled,exposing the reinforcement.
