We present the High-Throughput Computing and Statistical Analysis(HCSA)scheme,which efficiently and accurately predicts the stacking fault energies(SFEs)of multi-principal element alloys(MPEAs).Our approach estimates ...We present the High-Throughput Computing and Statistical Analysis(HCSA)scheme,which efficiently and accurately predicts the stacking fault energies(SFEs)of multi-principal element alloys(MPEAs).Our approach estimates the SFE of a single complex supercell by averaging numerous SFEs from small supercells,resulting in superior accuracy compared to traditional density functional theory(DFT)calculations.To validate our scheme,we applied it to NiFe and Ni_(10)Co_(60)Cr_(25)W_(5)alloys,achieving an SFE error of only 11%,in contrast to the 45%error obtained from traditional DFT calculations for NiFe.We observed a strong correlation between the average SFEs of samples with the same valence electron concentration as that of the experimental data.Our scheme provides an efficient and reliable tool for predicting SFEs in MPEAs and holds the potential to significantly accelerate materials design and discovery processes.展开更多
The first-principles method based on the projector augmented wave method within the generalized gradient approximation was employed to calculate the superlattice intrinsic stacking fault（SISF） and complex stacking f...The first-principles method based on the projector augmented wave method within the generalized gradient approximation was employed to calculate the superlattice intrinsic stacking fault（SISF） and complex stacking fault（CSF） energies of the binary Ni3Al alloys with different Al contents and the ternary Ni3Al intermetallic alloys with addition of alloying elements,such as Pd,Pt,Ti,Mo,Ta,W and Re.The results show that the energies of SISF and CSF increase significantly with increase of Al contents in Ni3Al.Addition of Pd and Pt occupying the Ni sublattices does not change the SISF and CSF energies of Ni3Al markedly in comparison with the Ni-23.75Al alloy.While addition of alloying elements,such as Ti,Mo,Ta,W and Re,occupying the Al sublattices dramatically increases the SISF and CSF energies of Ni3Al.The results suggest that the energies of SISF and CSF are dependent both on the Al contents and on the site occupancy of the ternary alloying element in Ni3Al intermetallic alloys.展开更多
The influence of temperature on the hydrogen diffusion behavior in X80 pipeline steel during stacking for slow cooling was studied using electrochemical penetration method, the temperature field and the hydrogen diffu...The influence of temperature on the hydrogen diffusion behavior in X80 pipeline steel during stacking for slow cooling was studied using electrochemical penetration method, the temperature field and the hydrogen diffusion in this pipeline steel during stacking for slow cooling were simulated by ABAQUS finite element method （FEM） software. The results show that in this process there is a reciprocal relationship between the natural logarithm of hydrogen diffusion coefficient and temperature. The cooling rate decreases gradually with the increase of steel plate thickness. The hydrogen content is higher at high temperature （500-400 ℃） than that in low temperature region （300-100 ℃）. The FEM simulation results are consistent with the experimental ones, and the model can be used to predict the hydrogen diffusion behavior in industrial production of X80 pipeline steel.展开更多
Numerical simulation of concrete-faced rockfill dams(CFRDs)considering the spatial variability of rockfill has become a popular research topic in recent years.In order to determine uncertain rockfill properties effici...Numerical simulation of concrete-faced rockfill dams(CFRDs)considering the spatial variability of rockfill has become a popular research topic in recent years.In order to determine uncertain rockfill properties efficiently and reliably,this study developed an uncertainty inversion analysis method for rockfill material parameters using the stacking ensemble strategy and Jaya optimizer.The comprehensive implementation process of the proposed model was described with an illustrative CFRD example.First,the surrogate model method using the stacking ensemble algorithm was used to conduct the Monte Carlo stochastic finite element calculations with reduced computational cost and improved accuracy.Afterwards,the Jaya algorithm was used to inversely calculate the combination of the coefficient of variation of rockfill material parameters.This optimizer obtained higher accuracy and more significant uncertainty reduction than traditional optimizers.Overall,the developed model effectively identified the random parameters of rockfill materials.This study provided scientific references for uncertainty analysis of CFRDs.In addition,the proposed method can be applied to other similar engineering structures.展开更多
为解决利用离散元法对艾草机械化收割、脱叶和切碎等关键作业环节进行仿真分析时缺乏准确模型的问题,采用物理试验与仿真试验相结合的方法,以成熟期新鲜艾草茎秆为研究对象,基于EDEM仿真软件中的Hertz-Mindlin(no slip)模型和Hertz-Mind...为解决利用离散元法对艾草机械化收割、脱叶和切碎等关键作业环节进行仿真分析时缺乏准确模型的问题,采用物理试验与仿真试验相结合的方法,以成熟期新鲜艾草茎秆为研究对象,基于EDEM仿真软件中的Hertz-Mindlin(no slip)模型和Hertz-Mindlin with bonding模型对茎秆物理参数和黏结参数进行标定。通过Plackett-Burman试验、最陡爬坡试验和Central-Composite试验确定艾草茎秆接触参数和黏结参数,并利用艾草茎秆堆积角台架试验和剪切物理试验验证参数值的准确性。结果表明:艾草茎秆间的碰撞恢复系数、静摩擦因数和动摩擦因数分别为0.13、1.09和0.026;艾草茎秆与作业装备间的碰撞恢复系数、静摩擦因数和动摩擦因数分别为0.43、0.73和0.0156;艾草茎秆法向接触刚度、切向接触刚度、临界法向应力和临界切向应力分别为3.91×10^(9)N/m、2.43×10^(9)N/m、4.35×10^(6)Pa和6.14×10^(6)Pa;堆积角台架试验和剪切物理试验验证出的相对误差分别为0.96%、2.89%,误差较小。艾草茎秆离散元模型及标定的仿真参数准确可靠,能够真实反映其物理和力学特性,为艾草茎秆离散元仿真研究提供参考。展开更多
目的颗粒的堆积高度反映了包装袋的填充密度,堆积高度越大,则填充密度越小;反之,填充密度越大。探究不同振动参数(振动时间、振动频率、振动幅度和振动方向)对颗粒堆积高度的影响规律,以提高包装袋的填充密度。方法基于DEM(Discrete Ele...目的颗粒的堆积高度反映了包装袋的填充密度,堆积高度越大,则填充密度越小;反之,填充密度越大。探究不同振动参数(振动时间、振动频率、振动幅度和振动方向)对颗粒堆积高度的影响规律,以提高包装袋的填充密度。方法基于DEM(Discrete Element Method),利用EDEM数值模拟软件建立PET颗粒堆积模型,并通过Matlab图像处理技术与实验相结合验证模型的准确性;在此模型基础上,仿真模拟颗粒在静止和振动状态下的堆积行为。结论竖直方向的振动更能降低颗粒的堆积高度,增大填充密度;随着振动时间的延长,颗粒的堆积高度逐渐降低,随后趋于平稳,最大可降低约17.70%;随着振动频率的增加,颗粒的堆积高度显著降低,最大可降低约16.67%;随着振动幅度的减小,颗粒的堆积高度逐渐降低,最大可降低约18.59%。结果通过改变振动皮带机的振动参数,可以有效提升包装袋的颗粒填充密度。展开更多
This study tried to explore the ground movement induced by triple stacked tunneling(TST) with different construction sequences. A case study in Tianjin, China was used to investigate the ground movement during the TST...This study tried to explore the ground movement induced by triple stacked tunneling(TST) with different construction sequences. A case study in Tianjin, China was used to investigate the ground movement during the TST(upper tunneling(UT)). For this, a modified Peck formula was proposed to predict the surface settlement induced by TST. Next, three sets of finite element analyses(FEA) were used to compare the effects of construction sequences(i.e. UT, middle tunneling(MT), and lower tunneling(LT)) on vertical and lateral ground displacements. The results of Tianjin case and UT reveal that compared to a Gaussian distribution for a single tunnel, the surface settlement curve of triple stacked tunnels is a bimodal distribution. It seems that the proposed modified Peck formula can effectively predict the surface settlement induced by TST. The results of the three sets of FEA demonstrate that the construction sequence has a significant influence on the ground movement. Among the three construction sequences, the largest lateral displacement is observed in the MT and the smallest one in UT.The existing tunnel has an inhibitory effect on the vertical displacement. The maximum value of the lateral displacement occurs at the depth of the new tunnel in each construction sequence.展开更多
Natural fiber composites have been proved to have the ability to replace the synthetic fiber composites in many structural applications. Unprecedented growth in the field of computational techniques has opened the doo...Natural fiber composites have been proved to have the ability to replace the synthetic fiber composites in many structural applications. Unprecedented growth in the field of computational techniques has opened the doors of analysis and simulation of composite materials under various environment.Modelling and simulation using various available softwares saves a lot of time and resources. In the present work, an attempt has been made to analyze the tensile behavior of jute fiber reinforced epoxy based polymer composite materials using the student version of commercially available finite element code Siemens PLM NX 10.0. In most of the structural applications, materials are required to have enough stiffness to resist the shape deformation under normal loading conditions. Therefore, emphasis is given to the load-deformation behavior of the developed composites. A 3-dimensional model of the test specimen was developed using ply-stacking method and the strain-stress values were verified by the available literature. The model showed a good agreement between the experimental and software results. Effect of ply angle, fiber percentage, fiber type, number of layers and weft fiber angle on the stiffness of laminate have been studied.展开更多
In order to improve the performance of whole-spacecraft vibration isolation systems,choosing piezoelectric stacks and viscoelastic material as the active and passive vibration isolation components,an innovative whole-...In order to improve the performance of whole-spacecraft vibration isolation systems,choosing piezoelectric stacks and viscoelastic material as the active and passive vibration isolation components,an innovative whole-spacecraft hybrid vibration isolation system (WSHVIS) is designed and studied.The finite element method is used to establish the dynamic model of WSHVIS and analyze its frequency response characteristic.According to the analysis results,eigensystem realization algorithm is applied to obtain the minimum-order state-space model of WSHVIS,which is used to design controller.On this basis,off-line simulation and on-line realization for the WSHVIS is performed.The simulation and experimental results showed that WSHVIS can effectively reduce the vibration loads transmitted from launch vehicle to spacecraft.Compared with passive vibration isolation system,the hybrid vibration isolation system has a significant inhibitory effect on the low-frequency vibration components,and can greatly increase the safety and reliability of spacecraft.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.22173047 and 51931003)the Natural Science Foundation of Jiangsu Province(No.BK20211198)+1 种基金the Sino-German Mobility Program of the Sino-German Center for Research Promotion(Grant M-0147)the Fundamental Research Funds for the Central Universities(Nos.30920041116,30919011254,and 30919011405).
文摘We present the High-Throughput Computing and Statistical Analysis(HCSA)scheme,which efficiently and accurately predicts the stacking fault energies(SFEs)of multi-principal element alloys(MPEAs).Our approach estimates the SFE of a single complex supercell by averaging numerous SFEs from small supercells,resulting in superior accuracy compared to traditional density functional theory(DFT)calculations.To validate our scheme,we applied it to NiFe and Ni_(10)Co_(60)Cr_(25)W_(5)alloys,achieving an SFE error of only 11%,in contrast to the 45%error obtained from traditional DFT calculations for NiFe.We observed a strong correlation between the average SFEs of samples with the same valence electron concentration as that of the experimental data.Our scheme provides an efficient and reliable tool for predicting SFEs in MPEAs and holds the potential to significantly accelerate materials design and discovery processes.
基金Project(50871065) supported by the National Natural Science Foundation of ChinaProjects(08DJ1400402,09JC1407200,10DZ2290904) supported by the Science and Technology Committee of Shanghai Municipality,China
文摘The first-principles method based on the projector augmented wave method within the generalized gradient approximation was employed to calculate the superlattice intrinsic stacking fault（SISF） and complex stacking fault（CSF） energies of the binary Ni3Al alloys with different Al contents and the ternary Ni3Al intermetallic alloys with addition of alloying elements,such as Pd,Pt,Ti,Mo,Ta,W and Re.The results show that the energies of SISF and CSF increase significantly with increase of Al contents in Ni3Al.Addition of Pd and Pt occupying the Ni sublattices does not change the SISF and CSF energies of Ni3Al markedly in comparison with the Ni-23.75Al alloy.While addition of alloying elements,such as Ti,Mo,Ta,W and Re,occupying the Al sublattices dramatically increases the SISF and CSF energies of Ni3Al.The results suggest that the energies of SISF and CSF are dependent both on the Al contents and on the site occupancy of the ternary alloying element in Ni3Al intermetallic alloys.
文摘The influence of temperature on the hydrogen diffusion behavior in X80 pipeline steel during stacking for slow cooling was studied using electrochemical penetration method, the temperature field and the hydrogen diffusion in this pipeline steel during stacking for slow cooling were simulated by ABAQUS finite element method （FEM） software. The results show that in this process there is a reciprocal relationship between the natural logarithm of hydrogen diffusion coefficient and temperature. The cooling rate decreases gradually with the increase of steel plate thickness. The hydrogen content is higher at high temperature （500-400 ℃） than that in low temperature region （300-100 ℃）. The FEM simulation results are consistent with the experimental ones, and the model can be used to predict the hydrogen diffusion behavior in industrial production of X80 pipeline steel.
基金supported by the National Natural Science Foundation of China(Grants No.51879185 and 52179139)the Open Fund of the Hubei Key Laboratory of Construction and Management in Hydropower Engineering(Grant No.2020KSD06).
文摘Numerical simulation of concrete-faced rockfill dams(CFRDs)considering the spatial variability of rockfill has become a popular research topic in recent years.In order to determine uncertain rockfill properties efficiently and reliably,this study developed an uncertainty inversion analysis method for rockfill material parameters using the stacking ensemble strategy and Jaya optimizer.The comprehensive implementation process of the proposed model was described with an illustrative CFRD example.First,the surrogate model method using the stacking ensemble algorithm was used to conduct the Monte Carlo stochastic finite element calculations with reduced computational cost and improved accuracy.Afterwards,the Jaya algorithm was used to inversely calculate the combination of the coefficient of variation of rockfill material parameters.This optimizer obtained higher accuracy and more significant uncertainty reduction than traditional optimizers.Overall,the developed model effectively identified the random parameters of rockfill materials.This study provided scientific references for uncertainty analysis of CFRDs.In addition,the proposed method can be applied to other similar engineering structures.
文摘为解决利用离散元法对艾草机械化收割、脱叶和切碎等关键作业环节进行仿真分析时缺乏准确模型的问题,采用物理试验与仿真试验相结合的方法,以成熟期新鲜艾草茎秆为研究对象,基于EDEM仿真软件中的Hertz-Mindlin(no slip)模型和Hertz-Mindlin with bonding模型对茎秆物理参数和黏结参数进行标定。通过Plackett-Burman试验、最陡爬坡试验和Central-Composite试验确定艾草茎秆接触参数和黏结参数,并利用艾草茎秆堆积角台架试验和剪切物理试验验证参数值的准确性。结果表明:艾草茎秆间的碰撞恢复系数、静摩擦因数和动摩擦因数分别为0.13、1.09和0.026;艾草茎秆与作业装备间的碰撞恢复系数、静摩擦因数和动摩擦因数分别为0.43、0.73和0.0156;艾草茎秆法向接触刚度、切向接触刚度、临界法向应力和临界切向应力分别为3.91×10^(9)N/m、2.43×10^(9)N/m、4.35×10^(6)Pa和6.14×10^(6)Pa;堆积角台架试验和剪切物理试验验证出的相对误差分别为0.96%、2.89%,误差较小。艾草茎秆离散元模型及标定的仿真参数准确可靠,能够真实反映其物理和力学特性,为艾草茎秆离散元仿真研究提供参考。
文摘目的颗粒的堆积高度反映了包装袋的填充密度,堆积高度越大,则填充密度越小;反之,填充密度越大。探究不同振动参数(振动时间、振动频率、振动幅度和振动方向)对颗粒堆积高度的影响规律,以提高包装袋的填充密度。方法基于DEM(Discrete Element Method),利用EDEM数值模拟软件建立PET颗粒堆积模型,并通过Matlab图像处理技术与实验相结合验证模型的准确性;在此模型基础上,仿真模拟颗粒在静止和振动状态下的堆积行为。结论竖直方向的振动更能降低颗粒的堆积高度,增大填充密度;随着振动时间的延长,颗粒的堆积高度逐渐降低,随后趋于平稳,最大可降低约17.70%;随着振动频率的增加,颗粒的堆积高度显著降低,最大可降低约16.67%;随着振动幅度的减小,颗粒的堆积高度逐渐降低,最大可降低约18.59%。结果通过改变振动皮带机的振动参数,可以有效提升包装袋的颗粒填充密度。
基金financially supported by the Open Project of the State Key Laboratory of Disaster Reduction in Civil Engineering (Grant No. SLDRCE17-01)the National Key Research and Development Program of China (Grant No.2017YFC0805402)the National Natural Science Foundation of China (Grant No. 51808387)。
文摘This study tried to explore the ground movement induced by triple stacked tunneling(TST) with different construction sequences. A case study in Tianjin, China was used to investigate the ground movement during the TST(upper tunneling(UT)). For this, a modified Peck formula was proposed to predict the surface settlement induced by TST. Next, three sets of finite element analyses(FEA) were used to compare the effects of construction sequences(i.e. UT, middle tunneling(MT), and lower tunneling(LT)) on vertical and lateral ground displacements. The results of Tianjin case and UT reveal that compared to a Gaussian distribution for a single tunnel, the surface settlement curve of triple stacked tunnels is a bimodal distribution. It seems that the proposed modified Peck formula can effectively predict the surface settlement induced by TST. The results of the three sets of FEA demonstrate that the construction sequence has a significant influence on the ground movement. Among the three construction sequences, the largest lateral displacement is observed in the MT and the smallest one in UT.The existing tunnel has an inhibitory effect on the vertical displacement. The maximum value of the lateral displacement occurs at the depth of the new tunnel in each construction sequence.
文摘Natural fiber composites have been proved to have the ability to replace the synthetic fiber composites in many structural applications. Unprecedented growth in the field of computational techniques has opened the doors of analysis and simulation of composite materials under various environment.Modelling and simulation using various available softwares saves a lot of time and resources. In the present work, an attempt has been made to analyze the tensile behavior of jute fiber reinforced epoxy based polymer composite materials using the student version of commercially available finite element code Siemens PLM NX 10.0. In most of the structural applications, materials are required to have enough stiffness to resist the shape deformation under normal loading conditions. Therefore, emphasis is given to the load-deformation behavior of the developed composites. A 3-dimensional model of the test specimen was developed using ply-stacking method and the strain-stress values were verified by the available literature. The model showed a good agreement between the experimental and software results. Effect of ply angle, fiber percentage, fiber type, number of layers and weft fiber angle on the stiffness of laminate have been studied.
基金Sponsored by the Commission of Science Technology and Industry for National Defense (Grant No.C4120062301)
文摘In order to improve the performance of whole-spacecraft vibration isolation systems,choosing piezoelectric stacks and viscoelastic material as the active and passive vibration isolation components,an innovative whole-spacecraft hybrid vibration isolation system (WSHVIS) is designed and studied.The finite element method is used to establish the dynamic model of WSHVIS and analyze its frequency response characteristic.According to the analysis results,eigensystem realization algorithm is applied to obtain the minimum-order state-space model of WSHVIS,which is used to design controller.On this basis,off-line simulation and on-line realization for the WSHVIS is performed.The simulation and experimental results showed that WSHVIS can effectively reduce the vibration loads transmitted from launch vehicle to spacecraft.Compared with passive vibration isolation system,the hybrid vibration isolation system has a significant inhibitory effect on the low-frequency vibration components,and can greatly increase the safety and reliability of spacecraft.
