A data-driven model ofmultiple variable cutting(M-VCUT)level set-based substructure is proposed for the topology optimization of lattice structures.TheM-VCUTlevel setmethod is used to represent substructures,enriching...A data-driven model ofmultiple variable cutting(M-VCUT)level set-based substructure is proposed for the topology optimization of lattice structures.TheM-VCUTlevel setmethod is used to represent substructures,enriching their diversity of configuration while ensuring connectivity.To construct the data-driven model of substructure,a database is prepared by sampling the space of substructures spanned by several substructure prototypes.Then,for each substructure in this database,the stiffness matrix is condensed so that its degrees of freedomare reduced.Thereafter,the data-drivenmodel of substructures is constructed through interpolationwith compactly supported radial basis function(CS-RBF).The inputs of the data-driven model are the design variables of topology optimization,and the outputs are the condensed stiffness matrix and volume of substructures.During the optimization,this data-driven model is used,thus avoiding repeated static condensation that would requiremuch computation time.Several numerical examples are provided to verify the proposed method.展开更多
In the present study,a single parameter governing the substructure and the strengthening for martensitic transformation was tentatively explored by detailing the microstructure and the strengthening of a Fe15 wt.%Cr b...In the present study,a single parameter governing the substructure and the strengthening for martensitic transformation was tentatively explored by detailing the microstructure and the strengthening of a Fe15 wt.%Cr binary alloy subjected to thermal cycle under high pressure(cooled at 10℃ s^(-1) from 1050℃ under hydrostatic pressure of 1.0-4.0 GPa).Experimental results show that high pressure makes martensitic transformation occur in a Fe-15Cr alloy that traditionally has no high-temperature austenite under atmospheric pressure.The phase transformation begins with the pairing of twinned variants,and the strengthening is solely dependent upon the density of dislocations and variants.The austenite strength at the transformation temperature governs the substructure and the induced strengthening by influencing:(1)The critical size below which twinned variants are solely allowed;(2)the orientation spreading of the pioneer twinned variants toward Bain pairs;(3)the variant thickness and in turn the strengthening extent.The present study sheds light on tuning the substructure and hardening during martensitic transformation via the austenite strength,showing potential scientific and technological importance.展开更多
The spray-deposition was used to produce billets of Mg-4Al-1.5Zn-3Ca-1Nd(A alloy)and Mg-13Al-3Zn-3Ca-1Nd(B alloy),and evolution of deformation substructure and Mg_(x)Zn_(y)Ca_(z)metastable phase in fine-grained(3μm)M...The spray-deposition was used to produce billets of Mg-4Al-1.5Zn-3Ca-1Nd(A alloy)and Mg-13Al-3Zn-3Ca-1Nd(B alloy),and evolution of deformation substructure and Mg_(x)Zn_(y)Ca_(z)metastable phase in fine-grained(3μm)Mg alloys was investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and electron backscattered diffraction(EBSD).It was found that different dislocation configurations were formed in A and B alloys.Redundant free dislocations(RFDs)and dislocation tangles were the ways to form deformation substructure in A alloy,no RFDs except dislocation tangles were found in B alloy.The interaction between nano-scale second phase particles(nano-scale C15 andβ-Mg_(17)(Al,Zn)_(12)phase)and different dislocation configurations had a significant effect on the deformation substructures formation.The mass transfer of Mg_(x)Zn_(y)Ca_(z)metastable phases and the stacking order of stacking faults were conducive to the Mg-Nd-Zn typed long period stacking ordered(LPSO)phases formation.Nano-scale C15 phases,Mg-Nd-Zn typed LPSO phases,c/a ratio,β-Mg_(17)(Al,Zn)_(12)phases were the key factors influencing the formation of textures.Different textures and grain boundary features(GB features)had a significant effect on k-value.The non-basal textures were the main factor affecting k-value in A alloy,while the high-angle grain boundary(HAGB)was the main factor affecting k-value in B alloy.展开更多
In order to decrease model complexity of rice panicle for its complicated morphological structure,an interactive L-system based on substructure algorithm was proposed to model rice panicle in this study.Through the an...In order to decrease model complexity of rice panicle for its complicated morphological structure,an interactive L-system based on substructure algorithm was proposed to model rice panicle in this study.Through the analysis of panicle morphology,the geometrical structure models of panicle spikelet,axis and branch were constructed firstly.Based on that,an interactive panicle L-system model was developed by using substructure algorithm to optimize panicle geometrical models with the similar structure.Simulation results showed that the interactive L-system panicle model based on substructure algorithm could fast construct panicle morphological structure in reality.In addition,this method had the well reference value for other plants model research.展开更多
To develop herbicides with a novel mechanism of action,a series of 1,3,4-oxadiazolpyridine derivatives were designed and synthesized based on active substructure splicing and structure optimization.These derivatives(5...To develop herbicides with a novel mechanism of action,a series of 1,3,4-oxadiazolpyridine derivatives were designed and synthesized based on active substructure splicing and structure optimization.These derivatives(5aa-5bd)were characterized by their melting points,^(1)H and^(13)C nuclear magnetic resonance spectroscopy,and high-resolution mass spectrometry.The configuration of 5 al was determined using single-crystal X-ray diffraction.Additionally,5 al exhibited excellent herbicidal activity at a dosage of 75 g/hm^(2),showing an EC 50 of 4.03 g/hm^(2)against both E.crus-galli and quinclorac-resistant E.crus-galli.At a dosage of 375 g/hm 2,5 al was safe for application on rice and sorghum and showed low toxicity(>200μg/g)towards Apis mellifera.After treatment with 5 al,the lamellae of the chloroplast grana of barnyard grass leaves were stacked disorderly and arranged loosely,and some thylakoids were broken,as observed by transmission electron microscopy.Transcriptomics analysis of E.crus-galli revealed that 5 al affects the defense response,membranes,plasma membranes,and chloroplasts of differentially expressed genes,which alter membrane permeability and energy metabolism,potentially leading to plant death.Thus,we successfully developed a novel molecular scaffold with a new mechanism of action that exhibits herbicidal activity against resistant E.crus-galli.Therefore,further development of lead herbicides based on this scaffold is required.展开更多
The wave-shaped space truss is used as the roof of the natatorium in Tianjin University,which ingeniously displays the function of the building.In this paper,the wave-shaped space truss is analyzed and designed,consid...The wave-shaped space truss is used as the roof of the natatorium in Tianjin University,which ingeniously displays the function of the building.In this paper,the wave-shaped space truss is analyzed and designed,considering the substructure made of reinforced concrete rigid frame and the space truss working together.Also,the anti-seismic characteristic of the wave-shaped space truss is studied based on the integral model.展开更多
The method of inputting the seismic wave determines the accuracy of the simulation of soil-structure dynamic interaction. The wave method is a commonly used approach for seismic wave input, which converts the incident...The method of inputting the seismic wave determines the accuracy of the simulation of soil-structure dynamic interaction. The wave method is a commonly used approach for seismic wave input, which converts the incident wave into equivalent loads on the cutoff boundaries. The wave method has high precision, but the implementation is complicated, especially for three-dimensional models. By deducing another form of equivalent input seismic loads in the fi nite element model, a new seismic wave input method is proposed. In the new method, by imposing the displacements of the free wave fi eld on the nodes of the substructure composed of elements that contain artifi cial boundaries, the equivalent input seismic loads are obtained through dynamic analysis of the substructure. Subsequently, the equivalent input seismic loads are imposed on the artifi cial boundary nodes to complete the seismic wave input and perform seismic analysis of the soil-structure dynamic interaction model. Compared with the wave method, the new method is simplifi ed by avoiding the complex processes of calculating the equivalent input seismic loads. The validity of the new method is verifi ed by the dynamic analysis numerical examples of the homogeneous and layered half space under vertical and oblique incident seismic waves.展开更多
A solution scheme is proposed in this paper for an existing RTDHT system to simulate large-scale finite element （FE） numerical substructures. The analysis of the FE numerical substructure is split into response anal...A solution scheme is proposed in this paper for an existing RTDHT system to simulate large-scale finite element （FE） numerical substructures. The analysis of the FE numerical substructure is split into response analysis and signal generation tasks, and executed in two different target computers in real-time. One target computer implements the response analysis task, wherein a large time-step is used to solve the FE substructure, and another target computer implements the signal generation task, wherein an interpolation program is used to generate control signals in a small time-step to meet the input demand of the controller. By using this strategy, the scale of the FE numerical substructure simulation may be increased significantly. The proposed scheme is initially verified by two FE numerical substructure models with 98 and 1240 degrees of freedom （DOFs）. Thereafter, RTDHTs of a single frame-foundation structure are implemented where the foundation, considered as the numerical substructure, is simulated by the FE model with 1240 DOFs. Good agreements between the results of the RTDHT and those from the FE analysis in ABAQUS are obtained.展开更多
The objective of the investigation is to evaluate the influence of the Zener-Hollomon parameter on substructure and texture evolution in iron-containing wrought aluminium alloys (type AA8011). Methods applied are X-ra...The objective of the investigation is to evaluate the influence of the Zener-Hollomon parameter on substructure and texture evolution in iron-containing wrought aluminium alloys (type AA8011). Methods applied are X-ray texture analysis, electron backscatter diffraction (EBSD) and optical microscopy. The results show a serious impact of the Zener-Hollomon parameter on cube texture evolution during the thermomechanical treatment in iron-containing aluminium alloys. An increase in the Zener-Hollomon parameter reduces the survivability of cube texture during hot deformation and reinforces particle-stimulated nucleation (PSN) during the annealing process. However, thermomechanical treatment at low temperatures leads to active precipitation and as a result fine-dispersed participles tend to block all nuclei except for those producing large cube-oriented grains. It is concluded that in iron-containing wrought aluminium alloys, the general correlation between the Zener-Hollomon parameter and subgrain size is similar to that observed in 3xxx series alloys and can be described by the specific set of equations derived.展开更多
This paper presents an overview on the wide-ranging track structure studies at the Tampere University of Technology(TUT),Finland dealing with the key aspects of track geotechnics related to high-speed passenger traffi...This paper presents an overview on the wide-ranging track structure studies at the Tampere University of Technology(TUT),Finland dealing with the key aspects of track geotechnics related to high-speed passenger traffic on ballasted tracks.Special attention is paid to ballast and sub-ballast,while also considering frost action,embankment stability,track stiffness,track geometry and transition zones.As a result,this paper states that understanding the ballast degradation mechanism and its consequences and assessment of its condition occupy an important role in the construction and maintenance of a smooth high-speed rail line.The choices related to building the sub-ballast also have a dramatic impact on later track deformations and maintenance needs.In cold climate,especially where seasonal frost occurs,understanding and taking into account the frost action mechanism is crucial.Especially in the maintenance and rehabilitation planning of existing tracks,high-class analyses of ground penetrating radar data and its integrated analysis with other data can yield considerable benefits.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12272144).
文摘A data-driven model ofmultiple variable cutting(M-VCUT)level set-based substructure is proposed for the topology optimization of lattice structures.TheM-VCUTlevel setmethod is used to represent substructures,enriching their diversity of configuration while ensuring connectivity.To construct the data-driven model of substructure,a database is prepared by sampling the space of substructures spanned by several substructure prototypes.Then,for each substructure in this database,the stiffness matrix is condensed so that its degrees of freedomare reduced.Thereafter,the data-drivenmodel of substructures is constructed through interpolationwith compactly supported radial basis function(CS-RBF).The inputs of the data-driven model are the design variables of topology optimization,and the outputs are the condensed stiffness matrix and volume of substructures.During the optimization,this data-driven model is used,thus avoiding repeated static condensation that would requiremuch computation time.Several numerical examples are provided to verify the proposed method.
基金supported by the Hundred Outstanding Creative Talents Projects at Hebei University,ChinaThe Natural Science Foundation-Steel and Iron Foundation of Hebei Province(No.E2021203051).
文摘In the present study,a single parameter governing the substructure and the strengthening for martensitic transformation was tentatively explored by detailing the microstructure and the strengthening of a Fe15 wt.%Cr binary alloy subjected to thermal cycle under high pressure(cooled at 10℃ s^(-1) from 1050℃ under hydrostatic pressure of 1.0-4.0 GPa).Experimental results show that high pressure makes martensitic transformation occur in a Fe-15Cr alloy that traditionally has no high-temperature austenite under atmospheric pressure.The phase transformation begins with the pairing of twinned variants,and the strengthening is solely dependent upon the density of dislocations and variants.The austenite strength at the transformation temperature governs the substructure and the induced strengthening by influencing:(1)The critical size below which twinned variants are solely allowed;(2)the orientation spreading of the pioneer twinned variants toward Bain pairs;(3)the variant thickness and in turn the strengthening extent.The present study sheds light on tuning the substructure and hardening during martensitic transformation via the austenite strength,showing potential scientific and technological importance.
基金financial support by the National Natural Science Foundation of China(No.51364032)the Inner Mongolia Natural Science Foundation(No.2022MS05028)。
文摘The spray-deposition was used to produce billets of Mg-4Al-1.5Zn-3Ca-1Nd(A alloy)and Mg-13Al-3Zn-3Ca-1Nd(B alloy),and evolution of deformation substructure and Mg_(x)Zn_(y)Ca_(z)metastable phase in fine-grained(3μm)Mg alloys was investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and electron backscattered diffraction(EBSD).It was found that different dislocation configurations were formed in A and B alloys.Redundant free dislocations(RFDs)and dislocation tangles were the ways to form deformation substructure in A alloy,no RFDs except dislocation tangles were found in B alloy.The interaction between nano-scale second phase particles(nano-scale C15 andβ-Mg_(17)(Al,Zn)_(12)phase)and different dislocation configurations had a significant effect on the deformation substructures formation.The mass transfer of Mg_(x)Zn_(y)Ca_(z)metastable phases and the stacking order of stacking faults were conducive to the Mg-Nd-Zn typed long period stacking ordered(LPSO)phases formation.Nano-scale C15 phases,Mg-Nd-Zn typed LPSO phases,c/a ratio,β-Mg_(17)(Al,Zn)_(12)phases were the key factors influencing the formation of textures.Different textures and grain boundary features(GB features)had a significant effect on k-value.The non-basal textures were the main factor affecting k-value in A alloy,while the high-angle grain boundary(HAGB)was the main factor affecting k-value in B alloy.
基金Supported by National Natural Science Foundation of China(60802040)Youth Fund in Southwest University of Science and Technology(10zx3106)~~
文摘In order to decrease model complexity of rice panicle for its complicated morphological structure,an interactive L-system based on substructure algorithm was proposed to model rice panicle in this study.Through the analysis of panicle morphology,the geometrical structure models of panicle spikelet,axis and branch were constructed firstly.Based on that,an interactive panicle L-system model was developed by using substructure algorithm to optimize panicle geometrical models with the similar structure.Simulation results showed that the interactive L-system panicle model based on substructure algorithm could fast construct panicle morphological structure in reality.In addition,this method had the well reference value for other plants model research.
基金supported by the National Key Research and Development Program of China(2023YFD1400504)Natural Science Foundation of Hunan Province(2024JJ2036)+3 种基金Natural Science Foundation of China(32172433)Foundation for Tobacco Science of China National Tobacco Corporation(110202401015,(LS-05))Scientific-Innovative of Hunan Agricultural Sciences and Technology(2024CX69)China Agriculture Research System of MOF and MARA(CARS-16-E19)。
文摘To develop herbicides with a novel mechanism of action,a series of 1,3,4-oxadiazolpyridine derivatives were designed and synthesized based on active substructure splicing and structure optimization.These derivatives(5aa-5bd)were characterized by their melting points,^(1)H and^(13)C nuclear magnetic resonance spectroscopy,and high-resolution mass spectrometry.The configuration of 5 al was determined using single-crystal X-ray diffraction.Additionally,5 al exhibited excellent herbicidal activity at a dosage of 75 g/hm^(2),showing an EC 50 of 4.03 g/hm^(2)against both E.crus-galli and quinclorac-resistant E.crus-galli.At a dosage of 375 g/hm 2,5 al was safe for application on rice and sorghum and showed low toxicity(>200μg/g)towards Apis mellifera.After treatment with 5 al,the lamellae of the chloroplast grana of barnyard grass leaves were stacked disorderly and arranged loosely,and some thylakoids were broken,as observed by transmission electron microscopy.Transcriptomics analysis of E.crus-galli revealed that 5 al affects the defense response,membranes,plasma membranes,and chloroplasts of differentially expressed genes,which alter membrane permeability and energy metabolism,potentially leading to plant death.Thus,we successfully developed a novel molecular scaffold with a new mechanism of action that exhibits herbicidal activity against resistant E.crus-galli.Therefore,further development of lead herbicides based on this scaffold is required.
文摘The wave-shaped space truss is used as the roof of the natatorium in Tianjin University,which ingeniously displays the function of the building.In this paper,the wave-shaped space truss is analyzed and designed,considering the substructure made of reinforced concrete rigid frame and the space truss working together.Also,the anti-seismic characteristic of the wave-shaped space truss is studied based on the integral model.
基金National Natural Science Foundation of China under Grant No.51478247National Key Research and Development Program of China under Grant No.2016YFC1402800
文摘The method of inputting the seismic wave determines the accuracy of the simulation of soil-structure dynamic interaction. The wave method is a commonly used approach for seismic wave input, which converts the incident wave into equivalent loads on the cutoff boundaries. The wave method has high precision, but the implementation is complicated, especially for three-dimensional models. By deducing another form of equivalent input seismic loads in the fi nite element model, a new seismic wave input method is proposed. In the new method, by imposing the displacements of the free wave fi eld on the nodes of the substructure composed of elements that contain artifi cial boundaries, the equivalent input seismic loads are obtained through dynamic analysis of the substructure. Subsequently, the equivalent input seismic loads are imposed on the artifi cial boundary nodes to complete the seismic wave input and perform seismic analysis of the soil-structure dynamic interaction model. Compared with the wave method, the new method is simplifi ed by avoiding the complex processes of calculating the equivalent input seismic loads. The validity of the new method is verifi ed by the dynamic analysis numerical examples of the homogeneous and layered half space under vertical and oblique incident seismic waves.
基金National Natural Science Foundation under Grant Nos.51179093,91215301 and 41274106the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No.20130002110032Tsinghua University Initiative Scientific Research Program under Grant No.20131089285
文摘A solution scheme is proposed in this paper for an existing RTDHT system to simulate large-scale finite element （FE） numerical substructures. The analysis of the FE numerical substructure is split into response analysis and signal generation tasks, and executed in two different target computers in real-time. One target computer implements the response analysis task, wherein a large time-step is used to solve the FE substructure, and another target computer implements the signal generation task, wherein an interpolation program is used to generate control signals in a small time-step to meet the input demand of the controller. By using this strategy, the scale of the FE numerical substructure simulation may be increased significantly. The proposed scheme is initially verified by two FE numerical substructure models with 98 and 1240 degrees of freedom （DOFs）. Thereafter, RTDHTs of a single frame-foundation structure are implemented where the foundation, considered as the numerical substructure, is simulated by the FE model with 1240 DOFs. Good agreements between the results of the RTDHT and those from the FE analysis in ABAQUS are obtained.
基金funded by a grant of the Russian Science Foundation (Project 18-79-10099)
文摘The objective of the investigation is to evaluate the influence of the Zener-Hollomon parameter on substructure and texture evolution in iron-containing wrought aluminium alloys (type AA8011). Methods applied are X-ray texture analysis, electron backscatter diffraction (EBSD) and optical microscopy. The results show a serious impact of the Zener-Hollomon parameter on cube texture evolution during the thermomechanical treatment in iron-containing aluminium alloys. An increase in the Zener-Hollomon parameter reduces the survivability of cube texture during hot deformation and reinforces particle-stimulated nucleation (PSN) during the annealing process. However, thermomechanical treatment at low temperatures leads to active precipitation and as a result fine-dispersed participles tend to block all nuclei except for those producing large cube-oriented grains. It is concluded that in iron-containing wrought aluminium alloys, the general correlation between the Zener-Hollomon parameter and subgrain size is similar to that observed in 3xxx series alloys and can be described by the specific set of equations derived.
基金Project supported by the Finnish Transport Agency
文摘This paper presents an overview on the wide-ranging track structure studies at the Tampere University of Technology(TUT),Finland dealing with the key aspects of track geotechnics related to high-speed passenger traffic on ballasted tracks.Special attention is paid to ballast and sub-ballast,while also considering frost action,embankment stability,track stiffness,track geometry and transition zones.As a result,this paper states that understanding the ballast degradation mechanism and its consequences and assessment of its condition occupy an important role in the construction and maintenance of a smooth high-speed rail line.The choices related to building the sub-ballast also have a dramatic impact on later track deformations and maintenance needs.In cold climate,especially where seasonal frost occurs,understanding and taking into account the frost action mechanism is crucial.Especially in the maintenance and rehabilitation planning of existing tracks,high-class analyses of ground penetrating radar data and its integrated analysis with other data can yield considerable benefits.
