To further enhance the recovery rate of low-temperature waste heat,the low-temperature flue gas in the sinter annular cooler was chosen as the heat source of an organic Rankine cycle(ORC)system,and the comprehensive e...To further enhance the recovery rate of low-temperature waste heat,the low-temperature flue gas in the sinter annular cooler was chosen as the heat source of an organic Rankine cycle(ORC)system,and the comprehensive evaluation of energy,exergy and economic performance of the ORC system was conducted deeply.The energy,exergy and economic performance models of the ORC system were established,and proper candidate organic working fluids(OWFs)were selected based on the thermo-physical properties of OWF and operating characteristics of ORC system.Then,the effects of ORC crucial parameters on the system energy,exergy and economic performances were evaluated in detail.Finally,the bi-objective optimization based on the genetic algorithm was conducted to analyze the optimal performance of the ORC system under the designed ORC crucial parameters,and the exergy efficiency and electricity production cost were set as the evaluation indexes of parametric optimization.The results indicate that the ORC system with the higher evaporation temperature and lower condensation temperature can obtain the larger system exergy efficiency and smaller electricity production cost.The smaller the superheat degree of OWF and pinch-point temperature difference in the evaporator are,the better the energy and exergy performances of the ORC system are.Under the optimization results,R245fa has the best comprehensive performance with the exergy efficiency of 46.34%and electricity production cost of 0.12123$/kWh among the selected candidate OWFs,which should be preferentially chosen as the OWF of the ORC system.展开更多
Taking the ratio of heat transfer area to net power and heat recovery efficiency into account, a multi-objective mathematical model was developed for organic Rankine cycle （ORC）. Working fluids considered were R123,...Taking the ratio of heat transfer area to net power and heat recovery efficiency into account, a multi-objective mathematical model was developed for organic Rankine cycle （ORC）. Working fluids considered were R123, R134a, R141b, R227ea and R245fa. Under the given conditions, the parameters including evaporating and condensing pressures, working fluid and cooling water velocities were optimized by simulated annealing algorithm. The results show that the optimal evaporating pressure increases with the heat source temperature increasing. Compared with other working fluids, R123 is the best choice for the temperature range of 100--180℃ and R141 b shows better performance when the temperature is higher than 180 ℃. Economic characteristic of system decreases rapidly with the decrease of heat source temperature. ORC system is uneconomical for the heat source temperature lower than 100℃.展开更多
with the merits of the easy manufacture and the long service life and the processing the inside or outside form surface, round body form tool is extensive use in large scales production. Its main demerit is the big hy...with the merits of the easy manufacture and the long service life and the processing the inside or outside form surface, round body form tool is extensive use in large scales production. Its main demerit is the big hyperbolic error which is caused in the process of processing cone, but about the discussion of hyperbolic error, there are two drawbacks in the current books and documents: (1) The error measuring plane is established on the rake face of tool, which doesn’t coincide with the actual measuring plane (axial plane) of work piece; (2) When the influential elements of error are analyzed, single parameter is only discussed. In order to overcome these demerits, the mathematical model of hyperbolic error on the axial plane of work piece is built in this paper when round body form tool processes cone. The fundamental reason which causes hyperbolic error when round body form tool processes cone is that the line profile replaces the curve profile of theory in the radial cut plane of tool in the design and manufacture of tool. In order to evaluate the mathematical formula of its error, firstly, the equation of cone of work piece must be established, secondly, the equation of cutting lip in the rake face is established, then, the profile equation of the radial plane of tool is evaluated on the condition that coordinate is changed, at last, the hyperbolic error is derived according to the equation and the substitutional line equation, and the error is converted to the axial plane of work piece which is coincided with the measuring plane. The actual calculation and the theory analysis indicated that if the cone length and the coning of the cone of work piece are fixed, the main elements which affect the hyperbolic error in the axial plane of work piece are the outside diameter R of round body form tool, the rake angle and the rear angle in "base point". If these three parameters are combined rationally, the hyperbolic error is minimum when round body form tool process cone, and the machining precision of work piece can be improved, on the condition that neither the work capacity of the tool design nor the manufacture cost of tool increases.展开更多
In aerospace engineering,design and optimization of mechanical structures are usually performed with respect to elastic limit.Besides causing insufcient use of the material,such design concept fails to meet the ever g...In aerospace engineering,design and optimization of mechanical structures are usually performed with respect to elastic limit.Besides causing insufcient use of the material,such design concept fails to meet the ever growing needs of the light weight design.To remedy this problem,in the present study,a shakedown theory based numerical approach for performing parametric optimization is presented.Within this approach,strength of the structure is measured by its shakedown limit calculated from the direct method.The numerical method developed for the structural optimization consists of nested loops:the inner loop adopts the interior point method to solve shakedown problems pertained to fxed design parameters,while the outer loop employs the genetic algorithm to fnd optimal design parameters leading to the greatest shakedown limit.The method established is frst verifed by the classic plate-with-a-circular-hole example,and after that it is applied to an airtight module for determining few key design parameters.By carefully analyzing results generated during the optimization process,it is convinced that the approach can become a viable means for designing similar aerospace structures.展开更多
Inflatable deployable structures inspired by origami have significant applications in space missions such as solar arrays and antennas.In this paper,a generalized Miura-ori tubular cell(GMTC)is presented as the basic ...Inflatable deployable structures inspired by origami have significant applications in space missions such as solar arrays and antennas.In this paper,a generalized Miura-ori tubular cell(GMTC)is presented as the basic cell to design a family of inflatable origami tubular structures with the targeted configuration.First,the classification of rigid foldable degree-4 vertices is studied thoroughly.Since the proposed GMTC is comprised of forming units(FU)and linking units(LU),types of FUs and LUs are investigated based on the classification of degree-4 vertices,respectively.The rigid foldability of the GMTC is presented by studying the kinematics of the FUs and LUs.Volume of the GMTC is analyzed to investigate multistable configurations of the basic cell.The variations in volume of the GMTC offer great potential for developing the inflatable tubular structure.Design method and parametric optimization of the tubular structure with targeted configuration are proposed.The feasibility of the approach is validated by the approximation of four different cases,namely parabolic,semicircular,trapezoidal,and straight-arc hybrid tubular structures.展开更多
This paper mainly investigates the semicontinuity of solution mappings for set optimization problems under a partial order set relation instead of upper and lower set less order relations. To this end, we propose two ...This paper mainly investigates the semicontinuity of solution mappings for set optimization problems under a partial order set relation instead of upper and lower set less order relations. To this end, we propose two types of monotonicity definition for the set-valued mapping introduced by two nonlinear scalarization functions which are presented by these partial order relations. Then, we give some sufficient conditions for the semicontinuity and closedness of solution mappings for parametric set optimization problems. The results presented in this paper are new and extend the main results given by some authors in the literature.展开更多
A metamaterial plate is designed by embedding a periodic array of local nonlinear resonators for its supersonic flutter control.Based on the von Karman large deformation theory and supersonic piston aerodynamic theory...A metamaterial plate is designed by embedding a periodic array of local nonlinear resonators for its supersonic flutter control.Based on the von Karman large deformation theory and supersonic piston aerodynamic theory,the nonlinear aeroelastic equations of the metamaterial plate are obtained by using the Hamilton principle.The comparisons for aeroelastic behaviors of the metamaterial plate and pure plate show that the proposed metamaterial plate can lead to an enlarged flutter boundary and lower vibration amplitude.Furthermore,a parametric optimization strategy for local nonlinear resonators is proposed to improve the nonlinear flutter behaviors of the metamaterial plate,and a significant enhancement of passive control performance can be achieved through optimization design.The present study demonstrates that the design of the metamaterial plate can provide an effective approach and potential application for nonlinear flutter suppression of supersonic plate.展开更多
To realize the stabilization and the tracking of flight control for an air-breathing hypersonic cruise vehicle, the linearization of the longitudinal model under trimmed cruise condition is processed firstly. Furtherm...To realize the stabilization and the tracking of flight control for an air-breathing hypersonic cruise vehicle, the linearization of the longitudinal model under trimmed cruise condition is processed firstly. Furthermore, the flight control problem is formulated as a robust model tracking control problem. And then, based on the robust parametric approach, eigenstructure assignment and reference model tracking theory, a parametric optimization method for robust controller design is presented. The simulation results show the effectiveness of the proposed approach.展开更多
High volumetric power density （VPD） is the basis for the commercial success of micro-tubular solid oxide fuel cells （mtSOFCs）. To find maximal VPD （MVPD） for anode-supported mtSOFC （as-mtSOFC）, the effects of ...High volumetric power density （VPD） is the basis for the commercial success of micro-tubular solid oxide fuel cells （mtSOFCs）. To find maximal VPD （MVPD） for anode-supported mtSOFC （as-mtSOFC）, the effects of geometric parameters on VPD are analyzed and the anode thickness, tan, and the cathode length, lea, are identified as the key design parameters. Thermo-fluid electrochemical models were built to examine the dependence of the electrical output on the cell parameters. The multiphysics model is validated by reproducing the experimental I-V curves with no adjustable parameters. The optimal lea and the corresponding MVPDs are then determined by the multiphysics model for 20 combinations of rin, the inner tube radius, and tan. And all these optimization are made at 1073.15 K. The results show that： （i） significant performance improvement may be achieved by geometry optimization, （ii） the seemingly high MVPD of 11 and 14 W/cm^3 can be easily realized for as-mtSOFC with single- and double-terminal anode current collection, respectively. Moreover, the variation of the area specific power density with/cac（2 mm, 40 mm） is determined for three representative （tin, tan） combinations. Besides, it is demonstrated that the current output of mtSOFC with proper geometric parameters is comparable to that of planar SOFC.展开更多
In the present work,the conventional natural gas dehydration method(CDM)and stripping gas method(SGM)are technically and economically analyzed,utilizing Aspen HYSYS and Aspen Process Economic Analyzer(APEA),respective...In the present work,the conventional natural gas dehydration method(CDM)and stripping gas method(SGM)are technically and economically analyzed,utilizing Aspen HYSYS and Aspen Process Economic Analyzer(APEA),respectively.To optimize the CDM and SGM,the sensitivities of the water content of dry gas,reboiler duty and raw material loss are analyzed against solvent rate and stripping gas rate.The optimized processes are set to achieve a targeted value of water content in dry gas and analyzed at optimized point.The analysis shows that SGM gives 46%lower TEG feed rate,42%lower reboiler duty and 99.97%pure regenerated TEG.Moreover,economic analysis reveals that SGM has 38%lower annual operating cost compared to CDM.According to results,from both technical and economic point of view,SGM is more feasible for natural gas dehydration compared to CDM.展开更多
The parametric optimization of the Ne-CuBr UV laser excited by longitudinal pulsed discharge is analysed by using a self-consistent kinetic model. Consistent characteristics of the optimization process are obtained by...The parametric optimization of the Ne-CuBr UV laser excited by longitudinal pulsed discharge is analysed by using a self-consistent kinetic model. Consistent characteristics of the optimization process are obtained by comparing with the experimental results. Simulation results show that neon ions come into being along with considerable depletion of the ground-state copper atoms. And the optimization of the discharge tube diameter is the tradeoff between the specific output photon density and the total active volume. Both the optimal neon gas pressure and the optimal reservoir temperature result from the balance between the neon ion density and the ground-state copper atom density to arrive at a maximum of their product.展开更多
A comparison on subcritical and transcritical organic Rankine cycle（ORC） system with a heat source of 110 ℃ geothermal water was presented. The net power output, thermal and exergy efficiencies and the products of ...A comparison on subcritical and transcritical organic Rankine cycle（ORC） system with a heat source of 110 ℃ geothermal water was presented. The net power output, thermal and exergy efficiencies and the products of the heat transfer coefficient（U） and the total heat exchange area（A）（UA values） were calculated for parametric optimization. Nine candidate working fluids were investigated and compared. Under the given conditions, transcritical systems have higher net power outputs than subcritical ones. The highest net power output of transcritical systems is 18.63 k W obtained by R218, and that of subcritical systems is 13.57 k W obtained by R600 a. Moreover, with the increase of evaporating pressure, the thermal and exergy efficiencies of transcritical systems increase at first and then decrease, but the efficiencies of subcritical ones increase. As a result, the efficiencies of transcritical systems cannot always outperform those of the subcritical ones. However, the subcritical systems have lower minimum UA values and lower expansion ratios than the transcritical ones at the maximum net power output. In addition, the transcritical cycles have higher expansion ratios than the subcritical ones at their maximum net power output.展开更多
The divertor target components for the Chinese fusion engineering test reactor(CFETR)and the future experimental advanced superconducting tokamak(EAST)need to remove a heat flux of up to20 MW m-2.In view of such a hig...The divertor target components for the Chinese fusion engineering test reactor(CFETR)and the future experimental advanced superconducting tokamak(EAST)need to remove a heat flux of up to20 MW m-2.In view of such a high heat flux removal requirement,this study proposes a conceptual design for a flat-tile divertor target based on explosive welding and brazing technology.Rectangular water-cooled channels with a special thermal transfer structure(TTS)are designed in the heat sink to improve the flat-tile divertor target’s heat transfer performance(HTP).The parametric design and optimization methods are applied to study the influence of the TTS variation parameters,including height(H),width(W*),thickness(T),and spacing(L),on the HTP.The research results show that the flat-tile divertor target’s HTP is sensitive to the TTS parameter changes,and the sensitivity is T>L>W*>H.The HTP first increases and then decreases with the increase of T,L,and W*and gradually increases with the increase of H.The optimal design parameters are as follows:H=5.5 mm,W*=25.8 mm,T=2.2 mm,and L=9.7 mm.The HTP of the optimized flat-tile divertor target at different flow speeds and tungsten tile thicknesses is studied using the numerical simulation method.A flat-tile divertor mock-up is developed according to the optimized parameters.In addition,high heat flux(HHF)tests are performed on an electron beam facility to further investigate the mock-up HTP.The numerical simulation calculation results show that the optimized flat-tile divertor target has great potential for handling the steady-state heat load of 20 MW m-2under the tungsten tile thickness<5 mm and the flow speed7 m s^(-1).The heat transfer efficiency of the flat-tile divertor target with rectangular cooling channels improves by13%and30%compared to that of the flat-tile divertor target with circular cooling channels and the ITER-like monoblock,respectively.The HHF tests indicate that the flat-tile divertor mock-up can successfully withstand 1000 cycles of20 MW m-2of heat load without visible deformation,damage,and HTP degradation.The surface temperature of the flat-tile divertor mock-up at the 1000th cycle is only930℃.The flat-tile divertor target’s HTP is greatly improved by the parametric design and optimization method,and is better than the ITER-like monoblock and the flat-tile mock-up for the WEST divertor.This conceptual design is currently being applied to the engineering design of the CFETR and EAST flat-tile divertors.展开更多
In this paper,under some suitable assumptions without any involving information on the solution set,we give some sufficient conditions for the upper semicontinuity,lower semicontinuity,and closedness of the solution s...In this paper,under some suitable assumptions without any involving information on the solution set,we give some sufficient conditions for the upper semicontinuity,lower semicontinuity,and closedness of the solution set mapping to a parametric set optimization problem with possible less order relation.展开更多
In this study,the structural control strategy utilizing a passive tuned mass damper(TMD)system as a seismic damping device is outlined,highlighting the parametric optimization approach for displacement and acceleratio...In this study,the structural control strategy utilizing a passive tuned mass damper(TMD)system as a seismic damping device is outlined,highlighting the parametric optimization approach for displacement and acceleration control.The theory of stationary random processes and complex frequency response functions are explained and adopted.For the vibration control of an undamped structure,the optimal parameters of a TMD,such as the optimal tuning frequency and optimal damping ratio,to stationary Gaussian white noise acceleration are investigated by using a parametric optimization procedure.For damped structures,a numerical searching technique is used to obtain the optimal parameters of the TMD,and then the explicit formulae for these optimal parameters are derived through a sequence of curve-fitting schemes.Using these specified optimal parameters,several different controlled responses are examined,and then the displacement and acceleration based control effectiveness indices of the TMD are examined from the view point of RMS values.From the viewpoint of the RMS values of displacement and acceleration,the optimal TMDs adopted in this study shows clear performance improvements for the simplified model examined,and this means that the effective optimization of the TMD has a good potential as a customized target response-based structural strategy.展开更多
The global reduction in agricultural labor owing to rural depopulation and an aging workforce necessitates advancements in agricultural automation.This paper presents the design,optimization,and experimental validatio...The global reduction in agricultural labor owing to rural depopulation and an aging workforce necessitates advancements in agricultural automation.This paper presents the design,optimization,and experimental validation of an innovative automatic lettuce-harvesting robot tailored to address the challenges posed by variable lettuce sizes,irregular shapes,and complex harvesting environments.The robot integrates three primary functional modules:root-cutting,leaf-removal,and adaptive transfer mechanisms.Employing a six-bar linkage for leaf removal,the mechanism achieves superior adaptability,durability,and precision while minimizing design complexity.The transfer system,featuring dual-layer toothed belts and self-adjusting spring mechanisms,ensures the stability and efficiency of lettuce of varying sizes.The system’s performance was enhanced through systematic kinematic and dynamic modeling,followed by Monte Carlo-based parametric optimization.Experimental evaluation of the prototype validated the robot’s operational effectiveness,achieving a root-cutting success rate of 98%,a leaf-removal completion rate of over 97%,and the ability to complete the full process of handling 29 lettuces per minute in a laboratory setting.This study advances the field of agricultural robotics by offering scalable solutions for efficient lettuce harvesting and potential adaptation to other crops,laying the foundation for sustainable automation in precision agriculture.展开更多
We propose a broadband fiber optic parametric amplifier（FOPA） based on a near-zero ultra-flat dispersion profile with a single zero-dispersion wavelength（ZDW） by using a selective liquid infiltration technique.The...We propose a broadband fiber optic parametric amplifier（FOPA） based on a near-zero ultra-flat dispersion profile with a single zero-dispersion wavelength（ZDW） by using a selective liquid infiltration technique.The amplifier gain and bandwidth is investigated for a variety of fiber lengths, pump power, and operating wavelengths. It is observed that sufficient peak gains and broader bandwidths can be achieved with a small negative anomalous dispersion（β2≤ 0） and a positive value of the 4th-order dispersion parameter（t β4）around the pump. We can optimize an FOPA with a bandwidth of more than 220 nm around the communications wavelength.展开更多
The seismic performance of“added stories isolation”(ASI)systems are investigated for 12-story moment resisting frames.The newly added and isolated upper stories on the top of the existing structure are rolled to act...The seismic performance of“added stories isolation”(ASI)systems are investigated for 12-story moment resisting frames.The newly added and isolated upper stories on the top of the existing structure are rolled to act as a large tuned mass damper(TMD)to overcome the limitation of the size of tuned mass,resulting to“12+2”and“12+4”stories building configurations.The isolation layer,as a core design strategy,is optimally designed based on optimal TMD design principle,entailing the insertion of passive flexible laminated rubber bearings to segregate two or four upper stories from a conventionally constructed lower superstructure system.Statistical performance metrics are presented for 30 earthquake records from the 3 suites of the SAC project.Time history analyses are used to compute various response performances and reduction factors across a wide range of seismic hazard intensities.Results show that ASI systems can effectively manage seismic response for multi-degree-of freedom(MDOF)systems across a broader range of ground motions without requiring burdensome extra mass.Specific results include the identification of differences in the number of added story by which the suggested isolation systems remove energy.展开更多
Based on the variable heat capacities of the working fluid, the irreversibility coming from the com- pression and expansion processes, and the heat leak losses through the cylinder wall, an irreversible cycle model of...Based on the variable heat capacities of the working fluid, the irreversibility coming from the com- pression and expansion processes, and the heat leak losses through the cylinder wall, an irreversible cycle model of the Miller heat engine was established, from which expressions for the efficiency and work output of the cycle were derived. The performance characteristic curves of the Miller heat engine were generated through numerical calculation, from which the optimal regions of some main parameters such as the work output, efficiency and pressure ratio were determined. Moreover, the influence of the compression and expansion efficiencies, the variable heat capacities and the heat leak losses on the performance of the cycle was discussed in detail, and consequently, some significant results were obtained.展开更多
基金the financial support for this work provided by the National Natural Science Foundation of China(51974087)Anhui Provincial Natural Science Foundation(1908085QE203)+1 种基金University Natural Science Research Foundation of Anhui Province(2022AH050262)Science Research Foundation of Anhui Jianzhu University(2020QDZ02).
文摘To further enhance the recovery rate of low-temperature waste heat,the low-temperature flue gas in the sinter annular cooler was chosen as the heat source of an organic Rankine cycle(ORC)system,and the comprehensive evaluation of energy,exergy and economic performance of the ORC system was conducted deeply.The energy,exergy and economic performance models of the ORC system were established,and proper candidate organic working fluids(OWFs)were selected based on the thermo-physical properties of OWF and operating characteristics of ORC system.Then,the effects of ORC crucial parameters on the system energy,exergy and economic performances were evaluated in detail.Finally,the bi-objective optimization based on the genetic algorithm was conducted to analyze the optimal performance of the ORC system under the designed ORC crucial parameters,and the exergy efficiency and electricity production cost were set as the evaluation indexes of parametric optimization.The results indicate that the ORC system with the higher evaporation temperature and lower condensation temperature can obtain the larger system exergy efficiency and smaller electricity production cost.The smaller the superheat degree of OWF and pinch-point temperature difference in the evaporator are,the better the energy and exergy performances of the ORC system are.Under the optimization results,R245fa has the best comprehensive performance with the exergy efficiency of 46.34%and electricity production cost of 0.12123$/kWh among the selected candidate OWFs,which should be preferentially chosen as the OWF of the ORC system.
基金Project(2009GK2009) supported by Science and Technology Department Funds of Hunan Province,ChinaProject(08C26224302178) supported by Innovation Fund for Technology Based Firms of China
文摘Taking the ratio of heat transfer area to net power and heat recovery efficiency into account, a multi-objective mathematical model was developed for organic Rankine cycle （ORC）. Working fluids considered were R123, R134a, R141b, R227ea and R245fa. Under the given conditions, the parameters including evaporating and condensing pressures, working fluid and cooling water velocities were optimized by simulated annealing algorithm. The results show that the optimal evaporating pressure increases with the heat source temperature increasing. Compared with other working fluids, R123 is the best choice for the temperature range of 100--180℃ and R141 b shows better performance when the temperature is higher than 180 ℃. Economic characteristic of system decreases rapidly with the decrease of heat source temperature. ORC system is uneconomical for the heat source temperature lower than 100℃.
文摘with the merits of the easy manufacture and the long service life and the processing the inside or outside form surface, round body form tool is extensive use in large scales production. Its main demerit is the big hyperbolic error which is caused in the process of processing cone, but about the discussion of hyperbolic error, there are two drawbacks in the current books and documents: (1) The error measuring plane is established on the rake face of tool, which doesn’t coincide with the actual measuring plane (axial plane) of work piece; (2) When the influential elements of error are analyzed, single parameter is only discussed. In order to overcome these demerits, the mathematical model of hyperbolic error on the axial plane of work piece is built in this paper when round body form tool processes cone. The fundamental reason which causes hyperbolic error when round body form tool processes cone is that the line profile replaces the curve profile of theory in the radial cut plane of tool in the design and manufacture of tool. In order to evaluate the mathematical formula of its error, firstly, the equation of cone of work piece must be established, secondly, the equation of cutting lip in the rake face is established, then, the profile equation of the radial plane of tool is evaluated on the condition that coordinate is changed, at last, the hyperbolic error is derived according to the equation and the substitutional line equation, and the error is converted to the axial plane of work piece which is coincided with the measuring plane. The actual calculation and the theory analysis indicated that if the cone length and the coning of the cone of work piece are fixed, the main elements which affect the hyperbolic error in the axial plane of work piece are the outside diameter R of round body form tool, the rake angle and the rear angle in "base point". If these three parameters are combined rationally, the hyperbolic error is minimum when round body form tool process cone, and the machining precision of work piece can be improved, on the condition that neither the work capacity of the tool design nor the manufacture cost of tool increases.
基金Supported by National Natural Science Foundation of China(Grant No.52075033)Fundamental Research Funds for the Central Universities of China(Grant No.2020RC202).
文摘In aerospace engineering,design and optimization of mechanical structures are usually performed with respect to elastic limit.Besides causing insufcient use of the material,such design concept fails to meet the ever growing needs of the light weight design.To remedy this problem,in the present study,a shakedown theory based numerical approach for performing parametric optimization is presented.Within this approach,strength of the structure is measured by its shakedown limit calculated from the direct method.The numerical method developed for the structural optimization consists of nested loops:the inner loop adopts the interior point method to solve shakedown problems pertained to fxed design parameters,while the outer loop employs the genetic algorithm to fnd optimal design parameters leading to the greatest shakedown limit.The method established is frst verifed by the classic plate-with-a-circular-hole example,and after that it is applied to an airtight module for determining few key design parameters.By carefully analyzing results generated during the optimization process,it is convinced that the approach can become a viable means for designing similar aerospace structures.
基金supported by the National Natural Science Foundation of China(No.52222501,52075016,52192632)the Fundamental Research Funds for the Central Universities(Grant No.YWF-23-L-904).
文摘Inflatable deployable structures inspired by origami have significant applications in space missions such as solar arrays and antennas.In this paper,a generalized Miura-ori tubular cell(GMTC)is presented as the basic cell to design a family of inflatable origami tubular structures with the targeted configuration.First,the classification of rigid foldable degree-4 vertices is studied thoroughly.Since the proposed GMTC is comprised of forming units(FU)and linking units(LU),types of FUs and LUs are investigated based on the classification of degree-4 vertices,respectively.The rigid foldability of the GMTC is presented by studying the kinematics of the FUs and LUs.Volume of the GMTC is analyzed to investigate multistable configurations of the basic cell.The variations in volume of the GMTC offer great potential for developing the inflatable tubular structure.Design method and parametric optimization of the tubular structure with targeted configuration are proposed.The feasibility of the approach is validated by the approximation of four different cases,namely parabolic,semicircular,trapezoidal,and straight-arc hybrid tubular structures.
文摘This paper mainly investigates the semicontinuity of solution mappings for set optimization problems under a partial order set relation instead of upper and lower set less order relations. To this end, we propose two types of monotonicity definition for the set-valued mapping introduced by two nonlinear scalarization functions which are presented by these partial order relations. Then, we give some sufficient conditions for the semicontinuity and closedness of solution mappings for parametric set optimization problems. The results presented in this paper are new and extend the main results given by some authors in the literature.
基金supported by the National Natural Science Foundation of China(No.11972296)the Overseas Expertise Introduction Project for Discipline Innovation,China(111 Project,No.BP0719007)。
文摘A metamaterial plate is designed by embedding a periodic array of local nonlinear resonators for its supersonic flutter control.Based on the von Karman large deformation theory and supersonic piston aerodynamic theory,the nonlinear aeroelastic equations of the metamaterial plate are obtained by using the Hamilton principle.The comparisons for aeroelastic behaviors of the metamaterial plate and pure plate show that the proposed metamaterial plate can lead to an enlarged flutter boundary and lower vibration amplitude.Furthermore,a parametric optimization strategy for local nonlinear resonators is proposed to improve the nonlinear flutter behaviors of the metamaterial plate,and a significant enhancement of passive control performance can be achieved through optimization design.The present study demonstrates that the design of the metamaterial plate can provide an effective approach and potential application for nonlinear flutter suppression of supersonic plate.
基金Sponsored by the Major Program of National Natural Science Foundation of China (Grant No.60710002)the Program for Changjiang Scholars and Innovative Research Team in University
文摘To realize the stabilization and the tracking of flight control for an air-breathing hypersonic cruise vehicle, the linearization of the longitudinal model under trimmed cruise condition is processed firstly. Furthermore, the flight control problem is formulated as a robust model tracking control problem. And then, based on the robust parametric approach, eigenstructure assignment and reference model tracking theory, a parametric optimization method for robust controller design is presented. The simulation results show the effectiveness of the proposed approach.
基金This work was supported by the National Natural Science Foundation of China （No.11374272 and No.11574284） and the Collaborative Innovation Center of Suzhou Nano Science and Technology.
文摘High volumetric power density （VPD） is the basis for the commercial success of micro-tubular solid oxide fuel cells （mtSOFCs）. To find maximal VPD （MVPD） for anode-supported mtSOFC （as-mtSOFC）, the effects of geometric parameters on VPD are analyzed and the anode thickness, tan, and the cathode length, lea, are identified as the key design parameters. Thermo-fluid electrochemical models were built to examine the dependence of the electrical output on the cell parameters. The multiphysics model is validated by reproducing the experimental I-V curves with no adjustable parameters. The optimal lea and the corresponding MVPDs are then determined by the multiphysics model for 20 combinations of rin, the inner tube radius, and tan. And all these optimization are made at 1073.15 K. The results show that： （i） significant performance improvement may be achieved by geometry optimization, （ii） the seemingly high MVPD of 11 and 14 W/cm^3 can be easily realized for as-mtSOFC with single- and double-terminal anode current collection, respectively. Moreover, the variation of the area specific power density with/cac（2 mm, 40 mm） is determined for three representative （tin, tan） combinations. Besides, it is demonstrated that the current output of mtSOFC with proper geometric parameters is comparable to that of planar SOFC.
基金financially supported by the National Research and Development Program of China(2017YFC0210900)the National Natural Science Foundation of China(21978011)。
文摘In the present work,the conventional natural gas dehydration method(CDM)and stripping gas method(SGM)are technically and economically analyzed,utilizing Aspen HYSYS and Aspen Process Economic Analyzer(APEA),respectively.To optimize the CDM and SGM,the sensitivities of the water content of dry gas,reboiler duty and raw material loss are analyzed against solvent rate and stripping gas rate.The optimized processes are set to achieve a targeted value of water content in dry gas and analyzed at optimized point.The analysis shows that SGM gives 46%lower TEG feed rate,42%lower reboiler duty and 99.97%pure regenerated TEG.Moreover,economic analysis reveals that SGM has 38%lower annual operating cost compared to CDM.According to results,from both technical and economic point of view,SGM is more feasible for natural gas dehydration compared to CDM.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10574111 and 10374081)
文摘The parametric optimization of the Ne-CuBr UV laser excited by longitudinal pulsed discharge is analysed by using a self-consistent kinetic model. Consistent characteristics of the optimization process are obtained by comparing with the experimental results. Simulation results show that neon ions come into being along with considerable depletion of the ground-state copper atoms. And the optimization of the discharge tube diameter is the tradeoff between the specific output photon density and the total active volume. Both the optimal neon gas pressure and the optimal reservoir temperature result from the balance between the neon ion density and the ground-state copper atom density to arrive at a maximum of their product.
基金Project(2012AA053001) supported by the National High Technology Research and Development Program of China
文摘A comparison on subcritical and transcritical organic Rankine cycle（ORC） system with a heat source of 110 ℃ geothermal water was presented. The net power output, thermal and exergy efficiencies and the products of the heat transfer coefficient（U） and the total heat exchange area（A）（UA values） were calculated for parametric optimization. Nine candidate working fluids were investigated and compared. Under the given conditions, transcritical systems have higher net power outputs than subcritical ones. The highest net power output of transcritical systems is 18.63 k W obtained by R218, and that of subcritical systems is 13.57 k W obtained by R600 a. Moreover, with the increase of evaporating pressure, the thermal and exergy efficiencies of transcritical systems increase at first and then decrease, but the efficiencies of subcritical ones increase. As a result, the efficiencies of transcritical systems cannot always outperform those of the subcritical ones. However, the subcritical systems have lower minimum UA values and lower expansion ratios than the transcritical ones at the maximum net power output. In addition, the transcritical cycles have higher expansion ratios than the subcritical ones at their maximum net power output.
基金supported by the National MCF Energy R&D Program(No.2018YFE0312300)the National Key Research and Development Program of China(No.2017YFA0402500)the Science Foundation of the Institute of Plasma Physics,Chinese Academy of Sciences(No.Y45ETY2302)。
文摘The divertor target components for the Chinese fusion engineering test reactor(CFETR)and the future experimental advanced superconducting tokamak(EAST)need to remove a heat flux of up to20 MW m-2.In view of such a high heat flux removal requirement,this study proposes a conceptual design for a flat-tile divertor target based on explosive welding and brazing technology.Rectangular water-cooled channels with a special thermal transfer structure(TTS)are designed in the heat sink to improve the flat-tile divertor target’s heat transfer performance(HTP).The parametric design and optimization methods are applied to study the influence of the TTS variation parameters,including height(H),width(W*),thickness(T),and spacing(L),on the HTP.The research results show that the flat-tile divertor target’s HTP is sensitive to the TTS parameter changes,and the sensitivity is T>L>W*>H.The HTP first increases and then decreases with the increase of T,L,and W*and gradually increases with the increase of H.The optimal design parameters are as follows:H=5.5 mm,W*=25.8 mm,T=2.2 mm,and L=9.7 mm.The HTP of the optimized flat-tile divertor target at different flow speeds and tungsten tile thicknesses is studied using the numerical simulation method.A flat-tile divertor mock-up is developed according to the optimized parameters.In addition,high heat flux(HHF)tests are performed on an electron beam facility to further investigate the mock-up HTP.The numerical simulation calculation results show that the optimized flat-tile divertor target has great potential for handling the steady-state heat load of 20 MW m-2under the tungsten tile thickness<5 mm and the flow speed7 m s^(-1).The heat transfer efficiency of the flat-tile divertor target with rectangular cooling channels improves by13%and30%compared to that of the flat-tile divertor target with circular cooling channels and the ITER-like monoblock,respectively.The HHF tests indicate that the flat-tile divertor mock-up can successfully withstand 1000 cycles of20 MW m-2of heat load without visible deformation,damage,and HTP degradation.The surface temperature of the flat-tile divertor mock-up at the 1000th cycle is only930℃.The flat-tile divertor target’s HTP is greatly improved by the parametric design and optimization method,and is better than the ITER-like monoblock and the flat-tile mock-up for the WEST divertor.This conceptual design is currently being applied to the engineering design of the CFETR and EAST flat-tile divertors.
基金the National Natural Science Foundation of China(No.11426055)the Science and Technology Research Project of Chongqing Municipal Education Commission(No.KJ1500419)+1 种基金the Basic and Advanced Research Project of Chongqing Science and Technology Commission(No.cstc2014jcyjA00044)the Doctor Start-up Foundation of Chongqing University of Posts and Telecommunications(No.A2014-15).
文摘In this paper,under some suitable assumptions without any involving information on the solution set,we give some sufficient conditions for the upper semicontinuity,lower semicontinuity,and closedness of the solution set mapping to a parametric set optimization problem with possible less order relation.
文摘In this study,the structural control strategy utilizing a passive tuned mass damper(TMD)system as a seismic damping device is outlined,highlighting the parametric optimization approach for displacement and acceleration control.The theory of stationary random processes and complex frequency response functions are explained and adopted.For the vibration control of an undamped structure,the optimal parameters of a TMD,such as the optimal tuning frequency and optimal damping ratio,to stationary Gaussian white noise acceleration are investigated by using a parametric optimization procedure.For damped structures,a numerical searching technique is used to obtain the optimal parameters of the TMD,and then the explicit formulae for these optimal parameters are derived through a sequence of curve-fitting schemes.Using these specified optimal parameters,several different controlled responses are examined,and then the displacement and acceleration based control effectiveness indices of the TMD are examined from the view point of RMS values.From the viewpoint of the RMS values of displacement and acceleration,the optimal TMDs adopted in this study shows clear performance improvements for the simplified model examined,and this means that the effective optimization of the TMD has a good potential as a customized target response-based structural strategy.
基金Supported by Beijing Natural Science Foundation(Grant No.QY24093).
文摘The global reduction in agricultural labor owing to rural depopulation and an aging workforce necessitates advancements in agricultural automation.This paper presents the design,optimization,and experimental validation of an innovative automatic lettuce-harvesting robot tailored to address the challenges posed by variable lettuce sizes,irregular shapes,and complex harvesting environments.The robot integrates three primary functional modules:root-cutting,leaf-removal,and adaptive transfer mechanisms.Employing a six-bar linkage for leaf removal,the mechanism achieves superior adaptability,durability,and precision while minimizing design complexity.The transfer system,featuring dual-layer toothed belts and self-adjusting spring mechanisms,ensures the stability and efficiency of lettuce of varying sizes.The system’s performance was enhanced through systematic kinematic and dynamic modeling,followed by Monte Carlo-based parametric optimization.Experimental evaluation of the prototype validated the robot’s operational effectiveness,achieving a root-cutting success rate of 98%,a leaf-removal completion rate of over 97%,and the ability to complete the full process of handling 29 lettuces per minute in a laboratory setting.This study advances the field of agricultural robotics by offering scalable solutions for efficient lettuce harvesting and potential adaptation to other crops,laying the foundation for sustainable automation in precision agriculture.
基金the Science&Engineering ResearchBoard(SERB),New Delhi,India,for the NPDF fellowship(File No.PDF/2016/001827)support received from NationalInstitute of Science Education and Research(NISER),Department of Atomic Energy(DAE),Government of India
文摘We propose a broadband fiber optic parametric amplifier（FOPA） based on a near-zero ultra-flat dispersion profile with a single zero-dispersion wavelength（ZDW） by using a selective liquid infiltration technique.The amplifier gain and bandwidth is investigated for a variety of fiber lengths, pump power, and operating wavelengths. It is observed that sufficient peak gains and broader bandwidths can be achieved with a small negative anomalous dispersion（β2≤ 0） and a positive value of the 4th-order dispersion parameter（t β4）around the pump. We can optimize an FOPA with a bandwidth of more than 220 nm around the communications wavelength.
文摘The seismic performance of“added stories isolation”(ASI)systems are investigated for 12-story moment resisting frames.The newly added and isolated upper stories on the top of the existing structure are rolled to act as a large tuned mass damper(TMD)to overcome the limitation of the size of tuned mass,resulting to“12+2”and“12+4”stories building configurations.The isolation layer,as a core design strategy,is optimally designed based on optimal TMD design principle,entailing the insertion of passive flexible laminated rubber bearings to segregate two or four upper stories from a conventionally constructed lower superstructure system.Statistical performance metrics are presented for 30 earthquake records from the 3 suites of the SAC project.Time history analyses are used to compute various response performances and reduction factors across a wide range of seismic hazard intensities.Results show that ASI systems can effectively manage seismic response for multi-degree-of freedom(MDOF)systems across a broader range of ground motions without requiring burdensome extra mass.Specific results include the identification of differences in the number of added story by which the suggested isolation systems remove energy.
文摘Based on the variable heat capacities of the working fluid, the irreversibility coming from the com- pression and expansion processes, and the heat leak losses through the cylinder wall, an irreversible cycle model of the Miller heat engine was established, from which expressions for the efficiency and work output of the cycle were derived. The performance characteristic curves of the Miller heat engine were generated through numerical calculation, from which the optimal regions of some main parameters such as the work output, efficiency and pressure ratio were determined. Moreover, the influence of the compression and expansion efficiencies, the variable heat capacities and the heat leak losses on the performance of the cycle was discussed in detail, and consequently, some significant results were obtained.
