Freight quantity is usually less than the half of vehicle capacity,and the effectiveness of transportation utilizing a single vehicle is not satisfactory enough. In this paper,a sequential heuristic algorithm is prese...Freight quantity is usually less than the half of vehicle capacity,and the effectiveness of transportation utilizing a single vehicle is not satisfactory enough. In this paper,a sequential heuristic algorithm is presented, whichconsists of clustering and chaining. Lastly, the method is applied to a casestudy.展开更多
The paper presents a method of calculating the full load engine characteristics based on the Leiderman–Khlystov relation. Because the values of the coefficients of the discussed function available in literature were ...The paper presents a method of calculating the full load engine characteristics based on the Leiderman–Khlystov relation. Because the values of the coefficients of the discussed function available in literature were determined for obsolete engine designs, an attempt was made to update them. To this end, a chassis dynamometer was used where a database of results had been built for a variety of vehicles. Following the data collection, the coefficients for variety of fueling system(six groups: fuel injected gasoline and turbocharged gasoline, spark ignition LPG Ⅰ–Ⅱ and Ⅳ generation, naturally aspirated diesel and turbocharged diesel) were determined. The identification of the coefficients was carried out in Matlab-Simulink indicating the applicability of the said function for most of the engines, yet the recent popularity of turbocharged gasoline engines requires an additional analysis of the possibility of use of a different functional description. The full load engine characteristics is a basis for the vehicle performance characteristics and, further, for modeling of traffic in a variety of aspects of the vehicle operation.展开更多
In order to obtain a deeper understanding of the behavior of the structure under high wind load,this paper conducted an experimental study on a full-scale L-shaped single story light frame wood house under the uniform...In order to obtain a deeper understanding of the behavior of the structure under high wind load,this paper conducted an experimental study on a full-scale L-shaped single story light frame wood house under the uniform lateral load simulated using a gasbag.The investigation involved the performance of light frame wood structure after it experienced the repeated cyclic lateral wind load as well as the performance of the structure under the ultimate lateral load.Then,the study verified that light frame wood structure can resist repeated cyclic wind loads without observable degradation in stiffness during the anticipated serve life,and recommended shear wall percent drift restriction for lateral wind load design of wood structure in serviceability limit states is 1/400 drift,and in ultimate limit states is 1/80 drift.The conclusions of this paper can be benefit for the engineering practice of the light frame wood structures in high wind load regions.展开更多
Several questions have emerged in relation to deep cover bleeder entry performance and support loading:how well do current modeling procedures calculate the rear abutment extent and loading? Does an improved understan...Several questions have emerged in relation to deep cover bleeder entry performance and support loading:how well do current modeling procedures calculate the rear abutment extent and loading? Does an improved understanding of the rear abutment extent warrant a change in standing support in bleeder entries? To help answer these questions and to determine the current utilization of standing support in bleeder entries, four bleeder entries at varying distances from the startup room were instrumented,observed, and numerically modeled.This paper details observations made by NIOSH researchers in the bleeder entries of a deep cover longwall panel—specifically data collected from instrumented pumpable cribs, observations of the conditions of the entries, and numerical modeling of the bleeder entries during longwall extraction.The primary focus was on the extent and magnitude of the abutment loading experienced by the standing support.As expected, the instrumentation of the standing supports showed very little loading relative to the capacity of the standing supports—less than 23 Mg load and 2.54 cm convergence.The Flac3D program was used to evaluate these four bleeder entries using previously defined modeling and input parameter estimation procedures.The results indicated only a minor increase in load during the extraction of the longwall panel.The model showed a much greater increase in stress due to the development of the gateroad and bleeder entries, with about 80% of the increase associated with development and 20% with longwall extraction.The Flac3D model showed very good correlation between expected gateroad loading during panel extraction and that expected based on previous studies.The results of this study showed that the rear abutment stress experienced by this bleeder entry design was minimal.The farther away from the startup room, the lower the applied load and smaller the convergence in the entry if all else is held constant.Finally, the numerical modeling method used in this study was capable of replicating the expected and measured results near seam.展开更多
Full face rock tunnel boring machine（TBM） has been widely used in hard rock tunnels, however, there are few published theory about cutter-head design, and the design criteria of cutter-head under complex geological ...Full face rock tunnel boring machine（TBM） has been widely used in hard rock tunnels, however, there are few published theory about cutter-head design, and the design criteria of cutter-head under complex geological is not clear yet. To deal with the complex relationship among geological parameters, cutter parameters, and operating parameters during tunneling processes, a cutter-head load model is established by using CSM（Colorado school of mines） prediction model. Force distribution on cutter-head under a certain geology is calculated with the new established load model, and result shows that inner cutters bear more force than outer cutters, combining with disc cutters abrasion; a general principle of disc cutters＇ layout design is proposed. Within the model, the relationship among rock uniaxial compressive strength（UCS）, penetration and thrust on cutter-head are analyzed, and the results shows that with increasing penetration, cutter thrust increases, but the growth rate slows and higher penetration makes lower special energy（SE）. Finally, a fitting mathematical model of ZT（ratio of cutter-head torque and thrust） and penetration is established, and verified by TB880 E, which can be used to direct how to set thrust and torque on cutter-head. When penetration is small, the cutter-head thrust is the main limiting factor in tunneling; when the penetration is large, cutter-head torque is the major limiting factor in tunneling. Based on the new cutter-head load model, thrust and torque characteristics of TBM further are researched and a new way for cutter-head layout design and TBM tunneling operations is proposed.展开更多
This paper presents an integrated simulation model for full digital controlled PMIG/MAG welding system with Matlab/Simulink, and it consists of power inverter, digital control system and dynamic arc-load model. An int...This paper presents an integrated simulation model for full digital controlled PMIG/MAG welding system with Matlab/Simulink, and it consists of power inverter, digital control system and dynamic arc-load model. An integrated simulation study was done for full digital PMIG/MAG welding, and a method of connecting dynamic arc-load model to the system with controlled current source was presented, in addition, the simulation results were utilized to study the issues of digital control PMIG/MAG welding in this paper. The experimental results validated the developed simulation model, and this simulation study can be applied in implementation of the full digital PMIG/MAG welding and analysis of system dynamic process.展开更多
文摘Freight quantity is usually less than the half of vehicle capacity,and the effectiveness of transportation utilizing a single vehicle is not satisfactory enough. In this paper,a sequential heuristic algorithm is presented, whichconsists of clustering and chaining. Lastly, the method is applied to a casestudy.
基金carried out within work no.S/WM/1/2018 realized at Bialystok University of Technologyfinanced from the funding allocated fo science by the Ministry of Science and Higher Education—Poland
文摘The paper presents a method of calculating the full load engine characteristics based on the Leiderman–Khlystov relation. Because the values of the coefficients of the discussed function available in literature were determined for obsolete engine designs, an attempt was made to update them. To this end, a chassis dynamometer was used where a database of results had been built for a variety of vehicles. Following the data collection, the coefficients for variety of fueling system(six groups: fuel injected gasoline and turbocharged gasoline, spark ignition LPG Ⅰ–Ⅱ and Ⅳ generation, naturally aspirated diesel and turbocharged diesel) were determined. The identification of the coefficients was carried out in Matlab-Simulink indicating the applicability of the said function for most of the engines, yet the recent popularity of turbocharged gasoline engines requires an additional analysis of the possibility of use of a different functional description. The full load engine characteristics is a basis for the vehicle performance characteristics and, further, for modeling of traffic in a variety of aspects of the vehicle operation.
基金Sponsored by the National Natural Science Foundation of China(Grant No. 50508012)
文摘In order to obtain a deeper understanding of the behavior of the structure under high wind load,this paper conducted an experimental study on a full-scale L-shaped single story light frame wood house under the uniform lateral load simulated using a gasbag.The investigation involved the performance of light frame wood structure after it experienced the repeated cyclic lateral wind load as well as the performance of the structure under the ultimate lateral load.Then,the study verified that light frame wood structure can resist repeated cyclic wind loads without observable degradation in stiffness during the anticipated serve life,and recommended shear wall percent drift restriction for lateral wind load design of wood structure in serviceability limit states is 1/400 drift,and in ultimate limit states is 1/80 drift.The conclusions of this paper can be benefit for the engineering practice of the light frame wood structures in high wind load regions.
文摘Several questions have emerged in relation to deep cover bleeder entry performance and support loading:how well do current modeling procedures calculate the rear abutment extent and loading? Does an improved understanding of the rear abutment extent warrant a change in standing support in bleeder entries? To help answer these questions and to determine the current utilization of standing support in bleeder entries, four bleeder entries at varying distances from the startup room were instrumented,observed, and numerically modeled.This paper details observations made by NIOSH researchers in the bleeder entries of a deep cover longwall panel—specifically data collected from instrumented pumpable cribs, observations of the conditions of the entries, and numerical modeling of the bleeder entries during longwall extraction.The primary focus was on the extent and magnitude of the abutment loading experienced by the standing support.As expected, the instrumentation of the standing supports showed very little loading relative to the capacity of the standing supports—less than 23 Mg load and 2.54 cm convergence.The Flac3D program was used to evaluate these four bleeder entries using previously defined modeling and input parameter estimation procedures.The results indicated only a minor increase in load during the extraction of the longwall panel.The model showed a much greater increase in stress due to the development of the gateroad and bleeder entries, with about 80% of the increase associated with development and 20% with longwall extraction.The Flac3D model showed very good correlation between expected gateroad loading during panel extraction and that expected based on previous studies.The results of this study showed that the rear abutment stress experienced by this bleeder entry design was minimal.The farther away from the startup room, the lower the applied load and smaller the convergence in the entry if all else is held constant.Finally, the numerical modeling method used in this study was capable of replicating the expected and measured results near seam.
基金Supported by National Natural Science Foundation of China(Grant No.51275339)National Basic Research Program of China(973 Program,Grant No.2013CB035402)
文摘Full face rock tunnel boring machine（TBM） has been widely used in hard rock tunnels, however, there are few published theory about cutter-head design, and the design criteria of cutter-head under complex geological is not clear yet. To deal with the complex relationship among geological parameters, cutter parameters, and operating parameters during tunneling processes, a cutter-head load model is established by using CSM（Colorado school of mines） prediction model. Force distribution on cutter-head under a certain geology is calculated with the new established load model, and result shows that inner cutters bear more force than outer cutters, combining with disc cutters abrasion; a general principle of disc cutters＇ layout design is proposed. Within the model, the relationship among rock uniaxial compressive strength（UCS）, penetration and thrust on cutter-head are analyzed, and the results shows that with increasing penetration, cutter thrust increases, but the growth rate slows and higher penetration makes lower special energy（SE）. Finally, a fitting mathematical model of ZT（ratio of cutter-head torque and thrust） and penetration is established, and verified by TB880 E, which can be used to direct how to set thrust and torque on cutter-head. When penetration is small, the cutter-head thrust is the main limiting factor in tunneling; when the penetration is large, cutter-head torque is the major limiting factor in tunneling. Based on the new cutter-head load model, thrust and torque characteristics of TBM further are researched and a new way for cutter-head layout design and TBM tunneling operations is proposed.
文摘This paper presents an integrated simulation model for full digital controlled PMIG/MAG welding system with Matlab/Simulink, and it consists of power inverter, digital control system and dynamic arc-load model. An integrated simulation study was done for full digital PMIG/MAG welding, and a method of connecting dynamic arc-load model to the system with controlled current source was presented, in addition, the simulation results were utilized to study the issues of digital control PMIG/MAG welding in this paper. The experimental results validated the developed simulation model, and this simulation study can be applied in implementation of the full digital PMIG/MAG welding and analysis of system dynamic process.
