To further reduce the explosive thickness and to improve the bonding quality of titanium/steel composite plates,explosive welding experiments of TA1/Q235 were conducted using a low detonation velocity explosive(53#)un...To further reduce the explosive thickness and to improve the bonding quality of titanium/steel composite plates,explosive welding experiments of TA1/Q235 were conducted using a low detonation velocity explosive(53#)under the guidance of the explosive welding lower limit principle with the flyer plate thicknesses of 1,2,and 4 mm and gaps of 3,6,and 8 mm.The weldability window for titanium/steel explosive welding was calculated,and a quantitative relationship between dynamic and static process parameters was developed.Aβ-V_(p) high-speed inclined collision model was proposed,and two-dimensional numerical simulations for the explosive welding tests were performed using the smoothed particle hydrodynamics(SPH)algorithm,revealing the growth evolution mechanisms of the typical waveform morphology characteristics.Through microstructural characterization techniques,such as optical microscope,scanning electron microscope,energy dispersive spectrometer,and electron backscattered diffractometer,and mechanical property tests in terms of shear strength,bending performance,and impact toughness,the microstructure and mechanical properties of the interfaces of explosively welded TA1/Q235 composite plates were investigated.Results show that the quality of interface bonding is excellent,presenting typical waveform morphology with an average interface shear strength above 330 MPa and an average impact toughness exceeding 81 J.All samples can be bent to 180°without significant delamination or cracking defects.展开更多
In order to examine the process of a rotary engine primary compressor impacted by bird, a finite element model of a bird impacted on plate is developed with the explicit code PAM-CRASH. The smooth particles hydrodynam...In order to examine the process of a rotary engine primary compressor impacted by bird, a finite element model of a bird impacted on plate is developed with the explicit code PAM-CRASH. The smooth particles hydrodynamic （SPH） method is used to simulate the bird because of the SPH method showing no signs of instability and correctly modeling the breaking-up of the bird into particles. Good agreement between the simulation results and experimental results indicates that the numerical method of bird strike used in the present paper is reasonable. Then a rotary engine primary compressor impacted by three different configurations bird named straight-ended cylinder bird, quadrangular bird, hemispherical-ended bird are investigated using the numerical simulation method. It is found that the whole process of bird strike sustained about 3.5 ms and the bird is slashed by blade during the strike. The geometry configuration of bird affected the displacement and von Mises stress of some blades severely, just because the breaking bird＇s mass is affected by the bird＇s configuration. In the event of bird striking on the site of＂up＂some blades may develop plastic deformation and it is very adverse for the safety work of the engine.展开更多
The geometry of a landslide dam plays a critical role in its stability and failure mode,and is influenced by the damming process.However,there is a lack of understanding of the factors that affect the 3D geometry of a...The geometry of a landslide dam plays a critical role in its stability and failure mode,and is influenced by the damming process.However,there is a lack of understanding of the factors that affect the 3D geometry of a landslide dam.To address this gap,we conducted a study using the smoothed particle hydrodynamics numerical method to investigate the evolution of landslide dams.Our study included 17 numerical simulations to examine the effects of several factors on the geometry of landslide dams,including valley inclination,sliding angle,landslide velocity,and landslide mass repose angle.Based on this,three rapid prediction models were established for calculating the maximum height,the minimum height,and the maximum width of a landslide dam.The results show that the downstream width of a landslide dam remarkably increases with the valley inclination.The position of the maximum dam height along the valley direction is independent of external factors and is always located in the middle of the landslide width area.In contrast,that position of the maximum dam height across the valley direction is significantly influenced by the sliding angle and landslide velocity.To validate our models,we applied them to three typical landslide dams and found that the calculated values of the landslide dam geometry were in good agreement with the actual values.The findings of the current study provide a better understanding of the evolution and geometry of landslide dams,giving crucial guidance for the prediction and early warning of landslide dam disasters.展开更多
基金Jiangsu Provincial Natural Science Foundation of China(BK20211232)2023 Major Science and Technology Projects of Nanjing City(202309011)。
文摘To further reduce the explosive thickness and to improve the bonding quality of titanium/steel composite plates,explosive welding experiments of TA1/Q235 were conducted using a low detonation velocity explosive(53#)under the guidance of the explosive welding lower limit principle with the flyer plate thicknesses of 1,2,and 4 mm and gaps of 3,6,and 8 mm.The weldability window for titanium/steel explosive welding was calculated,and a quantitative relationship between dynamic and static process parameters was developed.Aβ-V_(p) high-speed inclined collision model was proposed,and two-dimensional numerical simulations for the explosive welding tests were performed using the smoothed particle hydrodynamics(SPH)algorithm,revealing the growth evolution mechanisms of the typical waveform morphology characteristics.Through microstructural characterization techniques,such as optical microscope,scanning electron microscope,energy dispersive spectrometer,and electron backscattered diffractometer,and mechanical property tests in terms of shear strength,bending performance,and impact toughness,the microstructure and mechanical properties of the interfaces of explosively welded TA1/Q235 composite plates were investigated.Results show that the quality of interface bonding is excellent,presenting typical waveform morphology with an average interface shear strength above 330 MPa and an average impact toughness exceeding 81 J.All samples can be bent to 180°without significant delamination or cracking defects.
基金co-supported by National Natural Science Foundation of China(No.11102167)the Basic Research Foundation of Northwestern Polytechnical University(No.JCY20130102)
文摘In order to examine the process of a rotary engine primary compressor impacted by bird, a finite element model of a bird impacted on plate is developed with the explicit code PAM-CRASH. The smooth particles hydrodynamic （SPH） method is used to simulate the bird because of the SPH method showing no signs of instability and correctly modeling the breaking-up of the bird into particles. Good agreement between the simulation results and experimental results indicates that the numerical method of bird strike used in the present paper is reasonable. Then a rotary engine primary compressor impacted by three different configurations bird named straight-ended cylinder bird, quadrangular bird, hemispherical-ended bird are investigated using the numerical simulation method. It is found that the whole process of bird strike sustained about 3.5 ms and the bird is slashed by blade during the strike. The geometry configuration of bird affected the displacement and von Mises stress of some blades severely, just because the breaking bird＇s mass is affected by the bird＇s configuration. In the event of bird striking on the site of＂up＂some blades may develop plastic deformation and it is very adverse for the safety work of the engine.
基金funding from the National Natural Science Foundation of China(42207228,51879036,51579032)the Liaoning Revitalization Talents Program(XLYC2002036)the Sichuan Science and Technology Program(2022NSFSC1060)。
文摘The geometry of a landslide dam plays a critical role in its stability and failure mode,and is influenced by the damming process.However,there is a lack of understanding of the factors that affect the 3D geometry of a landslide dam.To address this gap,we conducted a study using the smoothed particle hydrodynamics numerical method to investigate the evolution of landslide dams.Our study included 17 numerical simulations to examine the effects of several factors on the geometry of landslide dams,including valley inclination,sliding angle,landslide velocity,and landslide mass repose angle.Based on this,three rapid prediction models were established for calculating the maximum height,the minimum height,and the maximum width of a landslide dam.The results show that the downstream width of a landslide dam remarkably increases with the valley inclination.The position of the maximum dam height along the valley direction is independent of external factors and is always located in the middle of the landslide width area.In contrast,that position of the maximum dam height across the valley direction is significantly influenced by the sliding angle and landslide velocity.To validate our models,we applied them to three typical landslide dams and found that the calculated values of the landslide dam geometry were in good agreement with the actual values.The findings of the current study provide a better understanding of the evolution and geometry of landslide dams,giving crucial guidance for the prediction and early warning of landslide dam disasters.
