LS-DYNA program and the principle of ALE method were introduced, and the target features of the reinforced concrete penetration were analyzed by using the D material model and the ALE method. A numerical simulation ha...LS-DYNA program and the principle of ALE method were introduced, and the target features of the reinforced concrete penetration were analyzed by using the D material model and the ALE method. A numerical simulation has been done to show the penetration visually and veritably. The simulation results are analyzed carefully and explicitly prove their significance to the research of reinforced concrete penetration.展开更多
In order to optimize gob-side entry in fully-mechanized working face in moderate-thick-coal seams, we adopt a new attempt to pack roadside by pumping ordinary concrete, which is very important for the development of g...In order to optimize gob-side entry in fully-mechanized working face in moderate-thick-coal seams, we adopt a new attempt to pack roadside by pumping ordinary concrete, which is very important for the development of gob-side entry technology. The concrete has a long initial setting time and a low initial strength. So it is difficult to control the surrounding rock. In this paper, we analyze the effect of using roadside cable to reinforce supporting in gob-side entry surrounding rock controlling based on elas-tic-plastic and material mechanics knowledge. And then we propose a scheme that cable is used to reinforce roadside supporting and a single hydraulic prop is used as the temporary supporting in gob side. Using the numerical simulation software FLAC2D, we numerically simulated supporting scheme. Results of both the 2D modeling and the industrial test on No.3117 face in Jingang Mine prove that the scheme is feasible. The results show that the technology of protecting the roadway in gob-entry retained efficiently make up the deficiency of roadside packing with ordinary concrete, effectively control the roof strata and acquire a good result of retaining roadway.展开更多
An experimental study and computer simulation on non-equilibriumgrain-boundary segregation kinetics and the critical time for phosphorus in 12CrlMoV steel (which isused in steam pipeline of ships) are put forward in t...An experimental study and computer simulation on non-equilibriumgrain-boundary segregation kinetics and the critical time for phosphorus in 12CrlMoV steel (which isused in steam pipeline of ships) are put forward in this paper. The segregation level ofphosphorus with solution temperature 1 050 ℃ at the isothermal holding temperature of 5401 , havebeen measured at grain-boundaries. A non-equilibrium grain-boundary segregation kinetics curve ofphosphorus is given. The critical time for phosphorus non-equilibrium grain-boundary segregation isabout 500h at 540 ℃ for the experimental steel. When the holding time is longer than 1 500 h ,non-equilibrium segregation disappears and the level of segregation reaches full equilibrium. Thesimulation using the kinetic equations of non-equilibrium grain-boundary segregation is in goodaccordance with the experimental observation for phosphorus in steel 12Crl MoV. The non-equilibriumgrain-boundary segregation kinetic model is therefore proved.展开更多
文摘LS-DYNA program and the principle of ALE method were introduced, and the target features of the reinforced concrete penetration were analyzed by using the D material model and the ALE method. A numerical simulation has been done to show the penetration visually and veritably. The simulation results are analyzed carefully and explicitly prove their significance to the research of reinforced concrete penetration.
基金support from the National Nature Science Foundation of China (No50874124)
文摘In order to optimize gob-side entry in fully-mechanized working face in moderate-thick-coal seams, we adopt a new attempt to pack roadside by pumping ordinary concrete, which is very important for the development of gob-side entry technology. The concrete has a long initial setting time and a low initial strength. So it is difficult to control the surrounding rock. In this paper, we analyze the effect of using roadside cable to reinforce supporting in gob-side entry surrounding rock controlling based on elas-tic-plastic and material mechanics knowledge. And then we propose a scheme that cable is used to reinforce roadside supporting and a single hydraulic prop is used as the temporary supporting in gob side. Using the numerical simulation software FLAC2D, we numerically simulated supporting scheme. Results of both the 2D modeling and the industrial test on No.3117 face in Jingang Mine prove that the scheme is feasible. The results show that the technology of protecting the roadway in gob-entry retained efficiently make up the deficiency of roadside packing with ordinary concrete, effectively control the roof strata and acquire a good result of retaining roadway.
文摘An experimental study and computer simulation on non-equilibriumgrain-boundary segregation kinetics and the critical time for phosphorus in 12CrlMoV steel (which isused in steam pipeline of ships) are put forward in this paper. The segregation level ofphosphorus with solution temperature 1 050 ℃ at the isothermal holding temperature of 5401 , havebeen measured at grain-boundaries. A non-equilibrium grain-boundary segregation kinetics curve ofphosphorus is given. The critical time for phosphorus non-equilibrium grain-boundary segregation isabout 500h at 540 ℃ for the experimental steel. When the holding time is longer than 1 500 h ,non-equilibrium segregation disappears and the level of segregation reaches full equilibrium. Thesimulation using the kinetic equations of non-equilibrium grain-boundary segregation is in goodaccordance with the experimental observation for phosphorus in steel 12Crl MoV. The non-equilibriumgrain-boundary segregation kinetic model is therefore proved.
