The novelty of this research lies in the successful fabrication of a 3D-printed honeycomb structure filled with nanofillers for acoustic properties,utilizing an impedance tube setup in accordance with ASTM standard E ...The novelty of this research lies in the successful fabrication of a 3D-printed honeycomb structure filled with nanofillers for acoustic properties,utilizing an impedance tube setup in accordance with ASTM standard E 1050-12.The Creality Ender-3,a 3D printer,was used for printing the honeycomb structures,and polylactic acid(PLA)material was employed for their construction.The organic,inorganic,and polymeric compounds within the composites were identified using fourier transformation infrared(FTIR)spectroscopy.The structure and homogeneity of the samples were examined using a field emission scanning electron microscope(FESEM).To determine the sound absorption coefficient of the 3D printed honeycomb structure,numerous samples were systematically developed using central composite design(CCD)and analysed using response surface methodology(RSM).The RSM mathematical model was established to predict the optimum values of each factor and noise reduction coefficient(NRC).The optimum values for an NRC of 0.377 were found to be 1.116 wt% carbon black,1.025 wt% aluminium powder,and 3.151 mm distance between parallel edges.Overall,the results demonstrate that a 3Dprinted honeycomb structure filled with nanofillers is an excellent material that can be utilized in various fields,including defence and aviation,where lightweight and acoustic properties are of great importance.展开更多
A new horn failure mechanism was constructed for tunnel faces in the soft rock mass by means of the logarithmic spiral curve. The seismic action was incorporated into the horn failure mechanism using the pseudo-static...A new horn failure mechanism was constructed for tunnel faces in the soft rock mass by means of the logarithmic spiral curve. The seismic action was incorporated into the horn failure mechanism using the pseudo-static method. Considering the randomness of rock mass parameters and loads, a three-dimensional (3D) stochastic collapse model was established. Reliability analysis of seismic stability of tunnel faces was presented via the kinematical approach and the response surface method. The results show that, the reliability of tunnel faces is significantly affected by the supporting pressure, geological strength index, uniaxial compressive strength, rock bulk density and seismic forces. It is worth noting that, if the effect of seismic force was not considered, the stability of tunnel faces would be obviously overestimated. However, the correlation between horizontal and vertical seismic forces can be ignored under the condition of low calculation accuracy.展开更多
The product of high complex profile,high strength,high productivity and excellent material properties with infinite length can be produced by Continuous Extrusion(CE)process.The numerical simulation of Aluminum(AA 110...The product of high complex profile,high strength,high productivity and excellent material properties with infinite length can be produced by Continuous Extrusion(CE)process.The numerical simulation of Aluminum(AA 1100)feedstock material at different wheel velocities,product diameter,feedstock temperature,die temperature and friction condition has been carried out using 3D simulation tool Design Environment for Forming(DEFORM-3D)in this paper.The development of mathematical model is carried out to investigate the influence of wheel velocity,extrusion ratio,feedstock temperature,die temperature and friction conditions on total load required for the deformation and extrusion of feedstock material through Response Surface Methodology(RSM).The statistical significance of mathematical model is verified through analysis of variance(ANOVA).The most optimum value of extrusion load has been found to be 136.4 kN through iterative process of Genetic Algorithm(GA)using Artificial Neural Network(ANN).The optimized value of input process variables for minimum value of extrusion load obtained has been found to be 13 Revolutions per Minute(RPM)as wheel velocity,5 mm as product diameter,0.95 as friction condition,650◦C as feedstock temperature and 550◦C as die temperature.This paper with proposed methodology will be helpful for industries working in the area of CE in terms of minimizing energy consumption during production process of bus bars,tubes,wires,cables,sheets,plates,strips,etc.展开更多
Following recent insights on structure-cell-function interactions and the critical role of the extracellular matrix(ECM),the latest biofabrication approaches have increasingly focused on designing materials with biomi...Following recent insights on structure-cell-function interactions and the critical role of the extracellular matrix(ECM),the latest biofabrication approaches have increasingly focused on designing materials with biomimetic microarchitecture.Divergence electrospinning is a novel fabrication method for three-dimensional(3D)nanofiber scaffolds.It is introduced to produce 3D nanofiber mats that have numerous applications in regenerative medicine and tissue engineering.One of the most important characteristics of 3D nanofiber mats is the density gradient.This study provides a statistical analysis and response surface modeling framework based on experimental data to evaluate the manner by which the geometric designs of double-bevel collectors influence the fiber density gradient.Specifically,variance of analysis and sensitivity analysis were performed to identify parameters that had significant effects,and a response surface model embedded with seven location indicators was developed to predict the spatial distribution of fiber density for different collector designs.It was concluded that the collector height,bevel angle,and their interactions were significant factors influencing the density gradient.This study revealed the sensitivity of system configuration and provided an optimization tool for process controllability of microstructure gradients.展开更多
无轭分块电枢轴向磁场永磁电机(Yokeless and Segmented Armature Machine,YASA)是一种高功率密度、高效率的电机,适于电牵引驱动特别是电动车的轮毂和轮边直驱。本文针对基于软磁复合材料(SMC)的YASA电机的齿槽转矩进行研究。首先比较...无轭分块电枢轴向磁场永磁电机(Yokeless and Segmented Armature Machine,YASA)是一种高功率密度、高效率的电机,适于电牵引驱动特别是电动车的轮毂和轮边直驱。本文针对基于软磁复合材料(SMC)的YASA电机的齿槽转矩进行研究。首先比较了基于SMC和叠压硅钢材料的YASA电机齿槽转矩波形,然后分析了永磁体极弧系数、永磁体斜极、定子齿靴宽度系数以及定子齿靴偏移对基于SMC的YASA电机齿槽转矩的影响,在此基础上建立响应面模型并利用遗传算法对齿槽转矩进行优化,最后,通过3-D FEM验证了优化结果的准确性。结果表明,在选取一定极弧系数的前提下,存在最优的永磁体斜极角度、定子齿靴宽度系数和定子齿靴偏移角度组合能够使电机的齿槽转矩降为最小,且优化前后电机的其他性能基本保持不变。展开更多
This paper describes the study on aerodynamics design optimization of turbomachinery blading developed by the authors at the Institute of Engineering Thermophysics, Chinese Academy of Sciences, during the recent few y...This paper describes the study on aerodynamics design optimization of turbomachinery blading developed by the authors at the Institute of Engineering Thermophysics, Chinese Academy of Sciences, during the recent few years. The present paper describes the aspects mainly on how to use a rapid approach of profiling a 3D blading and of grid generation for computation, a fast and accurate viscous computation method and an appropriate optimization methodology_ including a blade parameterization algorithm to optimize tm-bomachinery blading aerodynamically. Any blade configuration can be expressed by three curves, they are the camber lines, the thickness distributions and the radial stacking line, and then the blade geometry can be easily parameterized by a number of parameters with three polynomials. A gradient-based parameterization analytical method and a response surface method were applied herein for blade optimization. It was found that the optimization process provides reliable design for turbomachinery with reasonable computing time.展开更多
文摘The novelty of this research lies in the successful fabrication of a 3D-printed honeycomb structure filled with nanofillers for acoustic properties,utilizing an impedance tube setup in accordance with ASTM standard E 1050-12.The Creality Ender-3,a 3D printer,was used for printing the honeycomb structures,and polylactic acid(PLA)material was employed for their construction.The organic,inorganic,and polymeric compounds within the composites were identified using fourier transformation infrared(FTIR)spectroscopy.The structure and homogeneity of the samples were examined using a field emission scanning electron microscope(FESEM).To determine the sound absorption coefficient of the 3D printed honeycomb structure,numerous samples were systematically developed using central composite design(CCD)and analysed using response surface methodology(RSM).The RSM mathematical model was established to predict the optimum values of each factor and noise reduction coefficient(NRC).The optimum values for an NRC of 0.377 were found to be 1.116 wt% carbon black,1.025 wt% aluminium powder,and 3.151 mm distance between parallel edges.Overall,the results demonstrate that a 3Dprinted honeycomb structure filled with nanofillers is an excellent material that can be utilized in various fields,including defence and aviation,where lightweight and acoustic properties are of great importance.
基金Projects(51804113,51434006,51874130)supported by the National Natural Science Foundation of ChinaProject(E51768)supported by the Doctoral Initiation Foundation of Hunan University of Science and Technology,China+1 种基金Project(E61610)supported by the Postdoctoral Research Foundation of Hunan University of Science and Technology,ChinaProject(E21734)supported by the Open Foundation of Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Coal Mines,China
文摘A new horn failure mechanism was constructed for tunnel faces in the soft rock mass by means of the logarithmic spiral curve. The seismic action was incorporated into the horn failure mechanism using the pseudo-static method. Considering the randomness of rock mass parameters and loads, a three-dimensional (3D) stochastic collapse model was established. Reliability analysis of seismic stability of tunnel faces was presented via the kinematical approach and the response surface method. The results show that, the reliability of tunnel faces is significantly affected by the supporting pressure, geological strength index, uniaxial compressive strength, rock bulk density and seismic forces. It is worth noting that, if the effect of seismic force was not considered, the stability of tunnel faces would be obviously overestimated. However, the correlation between horizontal and vertical seismic forces can be ignored under the condition of low calculation accuracy.
文摘The product of high complex profile,high strength,high productivity and excellent material properties with infinite length can be produced by Continuous Extrusion(CE)process.The numerical simulation of Aluminum(AA 1100)feedstock material at different wheel velocities,product diameter,feedstock temperature,die temperature and friction condition has been carried out using 3D simulation tool Design Environment for Forming(DEFORM-3D)in this paper.The development of mathematical model is carried out to investigate the influence of wheel velocity,extrusion ratio,feedstock temperature,die temperature and friction conditions on total load required for the deformation and extrusion of feedstock material through Response Surface Methodology(RSM).The statistical significance of mathematical model is verified through analysis of variance(ANOVA).The most optimum value of extrusion load has been found to be 136.4 kN through iterative process of Genetic Algorithm(GA)using Artificial Neural Network(ANN).The optimized value of input process variables for minimum value of extrusion load obtained has been found to be 13 Revolutions per Minute(RPM)as wheel velocity,5 mm as product diameter,0.95 as friction condition,650◦C as feedstock temperature and 550◦C as die temperature.This paper with proposed methodology will be helpful for industries working in the area of CE in terms of minimizing energy consumption during production process of bus bars,tubes,wires,cables,sheets,plates,strips,etc.
文摘Following recent insights on structure-cell-function interactions and the critical role of the extracellular matrix(ECM),the latest biofabrication approaches have increasingly focused on designing materials with biomimetic microarchitecture.Divergence electrospinning is a novel fabrication method for three-dimensional(3D)nanofiber scaffolds.It is introduced to produce 3D nanofiber mats that have numerous applications in regenerative medicine and tissue engineering.One of the most important characteristics of 3D nanofiber mats is the density gradient.This study provides a statistical analysis and response surface modeling framework based on experimental data to evaluate the manner by which the geometric designs of double-bevel collectors influence the fiber density gradient.Specifically,variance of analysis and sensitivity analysis were performed to identify parameters that had significant effects,and a response surface model embedded with seven location indicators was developed to predict the spatial distribution of fiber density for different collector designs.It was concluded that the collector height,bevel angle,and their interactions were significant factors influencing the density gradient.This study revealed the sensitivity of system configuration and provided an optimization tool for process controllability of microstructure gradients.
文摘This paper describes the study on aerodynamics design optimization of turbomachinery blading developed by the authors at the Institute of Engineering Thermophysics, Chinese Academy of Sciences, during the recent few years. The present paper describes the aspects mainly on how to use a rapid approach of profiling a 3D blading and of grid generation for computation, a fast and accurate viscous computation method and an appropriate optimization methodology_ including a blade parameterization algorithm to optimize tm-bomachinery blading aerodynamically. Any blade configuration can be expressed by three curves, they are the camber lines, the thickness distributions and the radial stacking line, and then the blade geometry can be easily parameterized by a number of parameters with three polynomials. A gradient-based parameterization analytical method and a response surface method were applied herein for blade optimization. It was found that the optimization process provides reliable design for turbomachinery with reasonable computing time.
