Both sea battles and testing of ship in underwater explosions reveal unacceptably poor anti-shock performance of important shipboard equipment. Anti-shock performance of shipboard equipment is a significant factor det...Both sea battles and testing of ship in underwater explosions reveal unacceptably poor anti-shock performance of important shipboard equipment. Anti-shock performance of shipboard equipment is a significant factor determining fighting strength and survivability. The anti-shock performance of a shipboard gear case based on BV043/85 was investigated using numerical simulation. A geometric model of the gear case was built using MDT software and meshed in HyperMesh software, and then the finite element model of the gear case was formed. Using ABAQUS software, the anti-shock performance of the gear case was simulated. First, shock response of typical regions of gear case was determined. Next, some generalizations were made about the anti-shock performance of the gear case by analyzing the Mises stress of typical regions varied with shock inputs. Third, weak regions were determined from simulation results. The threshold values of shock resistance of the gear case at different impulse widths were obtained through interpolating the numerical simulation results selected from the most dangerous spot. This research provides a basis for further optimization of the design of gear cases.展开更多
The method of utilizing rain water has been well developed in foreign countries to realize the sustainable development of water recourse while the method is still at the initial level in China. When considering the in...The method of utilizing rain water has been well developed in foreign countries to realize the sustainable development of water recourse while the method is still at the initial level in China. When considering the increasing of water shortage and urban flood, the awareness of utilizing rain water, as an inevitable trend, has been applied to various engineering technologies. This article has analyzed the principle of conventional road drainage system and the application of artificial wetland technology, also proposed to combine the road drainage system and artificial wetland, as a complex drainage system, to utilize the urban rain water, decrease urban flood pressure, and improve urban micro environment. The calculation principle and method for the complex drainage system are included as well.展开更多
Due to special topographical, geological and meteorological conditions, debris flows occur frequently and result in heavy losses of lives and properties in mountainous areas, which become a great threaten to the susta...Due to special topographical, geological and meteorological conditions, debris flows occur frequently and result in heavy losses of lives and properties in mountainous areas, which become a great threaten to the sustainable development of regional economy and society in western China. At present, debris-flow prevention has performed well in many mountainous countries and has made headway in early warning, disaster mitigation by structural engineering methods, and risk analysis and management. In this paper, debris-flow prevention techniques have been introduced from the aspects of botanical methods, geotechnical engineering methods, and synthetic prevention system based on the above two methods. In addition, the treatment system of multilevel runoff and unconsolidated soil in the catchment with a chain of ＂slope-gully-valley＂ is set up in consideration of sediment load of main rivers, incorporation of slope improvement and gully retention, as well as micro-site factors for matching species with the site. Furthermore, attentions should be paid to the mechanism and technical details of vegetation measures for debris-flow prevention, as well as effective incorporation between botanical method and geotechnical method.展开更多
文摘Both sea battles and testing of ship in underwater explosions reveal unacceptably poor anti-shock performance of important shipboard equipment. Anti-shock performance of shipboard equipment is a significant factor determining fighting strength and survivability. The anti-shock performance of a shipboard gear case based on BV043/85 was investigated using numerical simulation. A geometric model of the gear case was built using MDT software and meshed in HyperMesh software, and then the finite element model of the gear case was formed. Using ABAQUS software, the anti-shock performance of the gear case was simulated. First, shock response of typical regions of gear case was determined. Next, some generalizations were made about the anti-shock performance of the gear case by analyzing the Mises stress of typical regions varied with shock inputs. Third, weak regions were determined from simulation results. The threshold values of shock resistance of the gear case at different impulse widths were obtained through interpolating the numerical simulation results selected from the most dangerous spot. This research provides a basis for further optimization of the design of gear cases.
文摘The method of utilizing rain water has been well developed in foreign countries to realize the sustainable development of water recourse while the method is still at the initial level in China. When considering the increasing of water shortage and urban flood, the awareness of utilizing rain water, as an inevitable trend, has been applied to various engineering technologies. This article has analyzed the principle of conventional road drainage system and the application of artificial wetland technology, also proposed to combine the road drainage system and artificial wetland, as a complex drainage system, to utilize the urban rain water, decrease urban flood pressure, and improve urban micro environment. The calculation principle and method for the complex drainage system are included as well.
基金supported by the National Key Fundamental Research (973) Project (2011CB409902)the NSFC project (41030742),the NSFC project (41201564)
文摘Due to special topographical, geological and meteorological conditions, debris flows occur frequently and result in heavy losses of lives and properties in mountainous areas, which become a great threaten to the sustainable development of regional economy and society in western China. At present, debris-flow prevention has performed well in many mountainous countries and has made headway in early warning, disaster mitigation by structural engineering methods, and risk analysis and management. In this paper, debris-flow prevention techniques have been introduced from the aspects of botanical methods, geotechnical engineering methods, and synthetic prevention system based on the above two methods. In addition, the treatment system of multilevel runoff and unconsolidated soil in the catchment with a chain of ＂slope-gully-valley＂ is set up in consideration of sediment load of main rivers, incorporation of slope improvement and gully retention, as well as micro-site factors for matching species with the site. Furthermore, attentions should be paid to the mechanism and technical details of vegetation measures for debris-flow prevention, as well as effective incorporation between botanical method and geotechnical method.
