Long-term responses of floating structures pose a great concern in their design phase. Existing approaches for addressing long-term extreme responses are extremely cumbersome for adoption. This work aims to develop an...Long-term responses of floating structures pose a great concern in their design phase. Existing approaches for addressing long-term extreme responses are extremely cumbersome for adoption. This work aims to develop an approach for the long-term extreme-response analysis of floating structures. A modified gradient-based retrieval algorithm in conjunction with the inverse first-order reliability method(IFORM) is proposed to enable the use of convolution models in long-term extreme analysis of structures with an analytical formula of response amplitude operator(RAO). The proposed algorithm ensures convergence stability and iteration accuracy and exhibits a higher computational efficiency than the traditional backtracking method. However, when the RAO of general offshore structures cannot be analytically expressed, the convolutional integration method fails to function properly. A numerical discretization approach is further proposed for offshore structures in the case when the analytical expression of the RAO is not feasible. Through iterative discretization of environmental contours(ECs) and RAOs, a detailed procedure is proposed to calculate the long-term response extremes of offshore structures. The validity and accuracy of the proposed approach are tested using a floating offshore wind turbine as a numerical example. The long-term extreme heave responses of various return periods are calculated via the IFORM in conjunction with a numerical discretization approach. The environmental data corresponding to N-year structural responses are located inside the ECs, which indicates that the selection of design points directly along the ECs yields conservative design results.展开更多
In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heati...In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heating time,microwave power,microwave heating time on the center temperature,moisture content,the chroma(C*),the total color difference(ΔE*),shape fidelity,hardness,and the total anthocyanin content of 3D printed raspberry preserves were analyzed by response surface method(RSM).The results showed that under combining with the two methods,infrared heating improved the fidelity and quality degradation of printed products,while microwave heating enhanced the efficiency of infrared heating.Infrared-microwave combination cooking could maintain relatively stable color appearance and shape of 3D printed raspberry preserves.The AHP–CRITIC hybrid weighting method combined with the response surface test to determine the comprehensive weights of the evaluation indicators optimized the process parameters,and the optimal process parameters were obtained:infrared heating temperature of 190℃,infrared heating time of 10 min and 30 s,microwave power of 300 W,and microwave heating time of 2 min and 6 s.The 3D printed raspberry cooking methods obtained under the optimal conditions seldom had color variation,porous structure,uniform texture,and high shape fidelity,which retained the characteristics of personalized manufacturing by 3D printing.This study could provide a reference for the postprocessing and quality control of 3D cooking methods.展开更多
Magneto-electro-elastic(MEE)materials are widely utilized across various fields due to their multi-field coupling effects.Consequently,investigating the coupling behavior of MEE composite materials is of significant i...Magneto-electro-elastic(MEE)materials are widely utilized across various fields due to their multi-field coupling effects.Consequently,investigating the coupling behavior of MEE composite materials is of significant importance.The traditional finite element method(FEM)remains one of the primary approaches for addressing such issues.However,the application of FEM typically necessitates the use of a fine finite element mesh to accurately capture the heterogeneous properties of the materials and meet the required computational precision,which inevitably leads to a reduction in computational efficiency.To enhance the computational accuracy and efficiency of the FEM for heterogeneous multi-field coupling problems,this study presents the coupling magneto-electro-elastic multiscale finite element method(CM-MsFEM)for heterogeneous MEE structures.Unlike the conventional multiscale FEM(MsFEM),the proposed algorithm simultaneously constructs displacement,electric,and magnetic potential multiscale basis functions to address the heterogeneity of the corresponding parameters.The macroscale formulation of CM-MsFEM was derived,and the macroscale/microscale responses of the problems were obtained through up/downscaling calculations.Evaluation using numerical examples analyzing the transient behavior of heterogeneous MEE structures demonstrated that the proposed method outperforms traditional FEM in terms of both accuracy and computational efficiency,making it an appropriate choice for numerically modeling the dynamics of heterogeneous MEE structures.展开更多
Steep bedding slopes are widely distributed in Southwestern China’s mountainous regions and have complex seismic responses and instability risks,causing casualties and property losses.Considering the high-seismic-int...Steep bedding slopes are widely distributed in Southwestern China’s mountainous regions and have complex seismic responses and instability risks,causing casualties and property losses.Considering the high-seismic-intensity environment,the dynamic failure evolution and instability mechanism of high-steep bedding slopes are simulated via the discrete element method and shaking table test.The dynamic response characteristics and cumulative failure effects of slopes subjected to continuous ground motion are investigated.The results show that the dynamic response characteristics of slopes under continuous earthquakes are influenced by geological and topographic conditions.Elevation has a distinct impact on both the slope interior and surface,with amplification effects more pronounced on the surface.The weak interlayers have different influences on the dynamic amplification effect of slopes.Weak interlayers have dynamic magnification effects on the slope surface at relative elevations of 0-0.33 and 0.82-1.0 but have weakening effects between 0.33 and 0.82.Moreover,the weak interlayers also have controlling effects on the dynamic instability mode of slopes.The characteristics of intergranular contact failure,fracture propagation,and displacement distribution are analyzed to reveal the dynamic failure evolution and instability mechanism through the discrete-element model.The dynamic instability process of slopes includes three stages:fracture initiation(0-0.2g),fracture expansion(0.2g-0.3g),and sliding instability(0.3g-0.6g).This work can provide a valuable reference for the seismic stability and reinforcement of complex slopes.展开更多
This study proposes a method for calculating the probability distribution of structural responses at different intensities using the endurance time(ET)method.The results can be used to calculate the fragility curve of...This study proposes a method for calculating the probability distribution of structural responses at different intensities using the endurance time(ET)method.The results can be used to calculate the fragility curve of structural collapse.The ET method involves dynamic analysis of a structure under an intensifying record over time.While conventional ET methods can determine the median of the structural response,they lack the ability to calculate its dispersion.To address this limitation,the present study utilizes ET analysis and single-degree-of-freedom(SDOF)systems to develop a method that considers the record-to-record variability for calculating the probability distribution of structural response.The accuracy of this method is evaluated by comparing it with the incremental dynamic analysis(IDA)method using special moment frames.The results demonstrate that the proposed method achieves a reasonably accurate estimation of dispersion while significantly reducing the computational burden(by approximately 95%)compared to the IDA method.展开更多
This paper aims to evaluate the stochastic response of steel columns subjected to blast loads using the modified single degree of freedom(MSDOF)method,which assessed towards the conventional single degree of freedom(S...This paper aims to evaluate the stochastic response of steel columns subjected to blast loads using the modified single degree of freedom(MSDOF)method,which assessed towards the conventional single degree of freedom(SDOF)and the experimentally validated Finite Element(FE)methods(LSDYNA).For this purpose,special atten-tion is given to calculating the response of H-shaped steel columns under blast.The damage amount is determined based on the support rotation criterion,which is expressed as a function of their maximum lateral mid-span dis-placement.To account for uncertainties in input parameters and obtain the failure probability,the Monte Carlo simulation(MCS)method is employed,complemented by the Latin Hypercube Sampling(LHS)method to reduce the number of simulations.A parametric analysis is hence performed to examine the effect of several input pa-rameters(including both deterministic and probabilistic parameters)on the probability of column damage as a function of support rotation.First,the MSDOF method confirms its higher accuracy in estimating the probability of column damage due to blast,compared to the conventional SDOF.The collected results also show that un-certainties of several input parameters have significant effects on the column behavior.In particular,geometric parameters(including cross-sectional characteristics,boundary conditions and column length)have major effect on the corresponding column response,in the same way of input blast load parameters and material properties.展开更多
We calculate the multicomponent responses of surface-hole transient electromagnetic method. The methods and models are unsuitable as geoelectric models of conductive surrounding rocks because they are based on regular...We calculate the multicomponent responses of surface-hole transient electromagnetic method. The methods and models are unsuitable as geoelectric models of conductive surrounding rocks because they are based on regular local targets. We also propose a calculation and analysis scheme based on numerical simulations of the subsurface transient electromagnetic fields. In the modeling of the electromagnetic fields, the forward modeling simulations are performed by using the finite-difference time-domain method and the discrete image method, which combines the Gaver–Stehfest inverse Laplace transform with the Prony method to solve the initial electromagnetic fields. The precision in the iterative computations is ensured by using the transmission boundary conditions. For the response analysis, we customize geoelectric models consisting of near-borehole targets and conductive wall rocks and implement forward modeling simulations. The observed electric fields are converted into induced electromotive force responses using multicomponent observation devices. By comparing the transient electric fields and multicomponent responses under different conditions, we suggest that the multicomponent-induced electromotive force responses are related to the horizontal and vertical gradient variations of the transient electric field at different times. The characteristics of the response are determined by the varying the subsurface transient electromagnetic fields, i.e., diffusion, attenuation and distortion, under different conditions as well as the electromagnetic fields at the observation positions. The calculation and analysis scheme of the response consider the surrounding rocks and the anomalous field of the local targets. It therefore can account for the geological data better than conventional transient field response analysis of local targets.展开更多
An effective optimization method for the shape/sizing design of composite wing structures is presented with satisfying weight-cutting results. After decoupling, a kind of two-layer cycled optimization strategy suitabl...An effective optimization method for the shape/sizing design of composite wing structures is presented with satisfying weight-cutting results. After decoupling, a kind of two-layer cycled optimization strategy suitable for these integrated shape/sizing optimization is obtained. The uniform design method is used to provide sample points, and approximation models for shape design variables. And the results of sizing optimization are construct- ed with the quadratic response surface method （QRSM）. The complex method based on QRSM is used to opti- mize the shape design variables and the criteria method is adopted to optimize the sizing design variables. Compared with the conventional method, the proposed algorithm is more effective and feasible for solving complex composite optimization problems and has good efficiency in weight cutting.展开更多
The aim of the present study was to optimize the supercritical CO_2 extraction conditions of icariin from Herba Epimedii by response surface method(RSM) and central composite design(CCD).A 3-factor,5-level CCD was use...The aim of the present study was to optimize the supercritical CO_2 extraction conditions of icariin from Herba Epimedii by response surface method(RSM) and central composite design(CCD).A 3-factor,5-level CCD was used for the optimization.Independent variables were extraction temperature,extraction pressure and entrainer flow rate.Dependent variable was yield ratio of icariin from Herba Epimedii.A two-order polynomial equation was fitted to the data.The results showed that the optimum extraction conditions were as follows:extraction temperature 46.5℃,extraction pressure 30.6 MPa,entrainer flow rate 3.3 mL/min.CCD/ RSM is convenient and highly predictive for optimizing the extraction process of icariin from Herba Epimedii.展开更多
A new method for measuring the characteristic of electrostriction by a digital speckle correlation method （DSCM） is presented. The in-plane displacement is obtained by using the DSCM, and the out-plane displacement ...A new method for measuring the characteristic of electrostriction by a digital speckle correlation method （DSCM） is presented. The in-plane displacement is obtained by using the DSCM, and the out-plane displacement is obtained by the geometrical relation of the triangle theory. In this application, high field electrostrictive strains of barium titanate/polyurethane elastomer composite materials are measured. The electrostrictive strain is evaluated when the application of an electric field is repeated, and then the electrostrictive coefficient of the sample is obtained. To improve the measuring accuracy, the bilinear interpolation of gray value is used to obtain the sub-pixel gray value. The results are compared with those obtained from the surface fitting algorithm. The experimental results demonstrate that the electrostrictive response of polyurethane increases with the introduction of barium titanate into polyurethane. And by using the DSCM, the measurement of the characteristic of electrostriction can be done quickly and accurately. The DSCM provides an effective tool for the evaluation of electrostrictive response.展开更多
Due to the size effects of rockfill materials, the settlement difference between numerical simulation and in situ monitoring of rockfill dams is a topic of general concern.The constitutive model parameters obtained fr...Due to the size effects of rockfill materials, the settlement difference between numerical simulation and in situ monitoring of rockfill dams is a topic of general concern.The constitutive model parameters obtained from laboratory triaxial tests often underestimate the deformation of high rockfill dams.Therefore, constitutive model parameters obtained by back analysis were used to calculate and predict the long-term deformation of rockfill dams.Instead of using artificial neural networks (ANNs), the response surface method (RSM) was employed to replace the finite element simulation used in the optimization iteration.Only 27 training samples were required for RSM, improving computational efficiency compared with ANN, which required 300 training samples.RSM can be used to describe the relationship between the constitutive model parameters and dam settlements.The inversion results of the Shuibuya concrete face rockfill dam (CFRD) show that the calculated settlements agree with the measured data, indicating the accuracy and efficiency of RSM.展开更多
Tooth modification technique is widely used in gear industry to improve the meshing performance of gearings. However, few of the present studies on tooth modification considers the influence of inevitable random error...Tooth modification technique is widely used in gear industry to improve the meshing performance of gearings. However, few of the present studies on tooth modification considers the influence of inevitable random errors on gear modification effects. In order to investigate the uncertainties of tooth modification amount variations on system＇s dynamic behaviors of a helical planetary gears, an analytical dynamic model including tooth modification parameters is proposed to carry out a deterministic analysis on the dynamics of a helical planetary gear. The dynamic meshing forces as well as the dynamic transmission errors of the sun-planet 1 gear pair with and without tooth modifications are computed and compared to show the effectiveness of tooth modifications on gear dynamics enhancement. By using response surface method, a fitted regression model for the dynamic transmission error（DTE） fluctuations is established to quantify the relationship between modification amounts and DTE fluctuations. By shifting the inevitable random errors arousing from manufacturing and installing process to tooth modification amount variations, a statistical tooth modification model is developed and a methodology combining Monte Carlo simulation and response surface method is presented for uncertainty analysis of tooth modifications. The uncertainly analysis reveals that the system＇s dynamic behaviors do not obey the normal distribution rule even though the design variables are normally distributed. In addition, a deterministic modification amount will not definitely achieve an optimal result for both static and dynamic transmission error fluctuation reduction simultaneously.展开更多
Because of the randomness of many impact factors influencing the dynamic assembly relationship of complex machinery, the reliability analysis of dynamic assembly relationship needs to be accomplished considering the r...Because of the randomness of many impact factors influencing the dynamic assembly relationship of complex machinery, the reliability analysis of dynamic assembly relationship needs to be accomplished considering the randomness from a probabilistic perspective. To improve the accuracy and efficiency of dynamic assembly relationship reliability analysis, the mechanical dynamic assembly reliability（MDAR） theory and a distributed collaborative response surface method（DCRSM） are proposed. The mathematic model of DCRSM is established based on the quadratic response surface function, and verified by the assembly relationship reliability analysis of aeroengine high pressure turbine（HPT） blade-tip radial running clearance（BTRRC）. Through the comparison of the DCRSM, traditional response surface method（RSM） and Monte Carlo Method（MCM）, the results show that the DCRSM is not able to accomplish the computational task which is impossible for the other methods when the number of simulation is more than 100 000 times, but also the computational precision for the DCRSM is basically consistent with the MCM and improved by 0.40-4.63% to the RSM, furthermore, the computational efficiency of DCRSM is up to about 188 times of the MCM and 55 times of the RSM under 10000 times simulations. The DCRSM is demonstrated to be a feasible and effective approach for markedly improving the computational efficiency and accuracy of MDAR analysis. Thus, the proposed research provides the promising theory and method for the MDAR design and optimization, and opens a novel research direction of probabilistic analysis for developing the high-performance and high-reliability of aeroengine.展开更多
A modified cellular automata （CA） model of dynamic recrystallization （DRX） and a flow stress-based nucleation parameter identification method have been developed. In the method, the modified CA model, which takes ...A modified cellular automata （CA） model of dynamic recrystallization （DRX） and a flow stress-based nucleation parameter identification method have been developed. In the method, the modified CA model, which takes the role of deformation degree on nucleation behavior into consideration, is coupled with an adaptive response surface model （ARSM） to search for the optimum nucleation parameter. The DRX behavior of an oxygen free high conductivity （OFHC） copper with different initial grain sizes has been taken as an example to validate the model. Good agreement is found between the simulated and the experimental results, which demonstrates that the new method can effectively improve the simulation accuracy.展开更多
A response surface method was employed to study the effect of α-amylase concentration, hydrolysis temperature and time on the production of high protein glutinous rice flour(HPGRF). The suspension of glutinous rice f...A response surface method was employed to study the effect of α-amylase concentration, hydrolysis temperature and time on the production of high protein glutinous rice flour(HPGRF). The suspension of glutinous rice flour(15%) that contained 6.52% protein was gelatinized and subsequently hydrolyzed by thermostable α-amylase. The hydrolysis yielded 0.144–0.222 g/g HPGRF with 29.4%–45.4% protein content. Hydrolysis time exerted a significant effect, while enzyme concentration and hydrolysis temperature showed insignificant effect on the protein content and production yield of HPGRF. The result of response surface method showed that the optimum condition for the production of HPGRF that contained at least 36% protein was treating gelatinized 15% glutinous rice flour suspension with 0.90 Kilo Novo α-amylase Unit(KNU)/g α-amylase at 80 oC for 99 min. By carrying out the predicted hydrolysis condition, HPGRF with 35.9% protein and 61.8% carbohydrates was resulted. The process yielded 0.172 g/g HPGRF. HPGRF contained higher amount of essential amino acids compared to glutinous rice flour. HPGRF had higher solubility and lower swelling power, and also showed no pasting peak compared with glutinous rice flour.展开更多
Two non-probabilistic, set-theoretical methods for determining the maximum and minimum impulsive responses of structures to uncertain-but-bounded impulses are presented. They are, respectively, based on the theories o...Two non-probabilistic, set-theoretical methods for determining the maximum and minimum impulsive responses of structures to uncertain-but-bounded impulses are presented. They are, respectively, based on the theories of interval mathematics and convex models. The uncertain-but-bounded impulses are assumed to be a convex set, hyper-rectangle or ellipsoid. For the two non-probabilistic methods, less prior information is required about the uncertain nature of impulses than the probabilistic model. Comparisons between the interval analysis method and the convex model, which are developed as an anti-optimization problem of finding the least favorable impulsive response and the most favorable impulsive response, are made through mathematical analyses and numerical calculations. The results of this study indicate that under the condition of the interval vector being determined from an ellipsoid containing the uncertain impulses, the width of the impulsive responses predicted by the interval analysis method is larger than that by the convex model; under the condition of the ellipsoid being determined from an interval vector containing the uncertain impulses, the width of the interval impulsive responses obtained by the interval analysis method is smaller than that by the convex model.展开更多
Many variables affect the sealing performance, and their distribution characteristics are difficult to obtain with probabilistic methods owing to the high cost involved. Numerous problems in engineering are similar du...Many variables affect the sealing performance, and their distribution characteristics are difficult to obtain with probabilistic methods owing to the high cost involved. Numerous problems in engineering are similar due to the appearance of small-sample parameters. In this study, the sealing reliability of an aviation seal was defined as the research object, and an interval uncertainty method and multidimensional response surface were proposed to calculate the sealing reliability.Based on this, we first analyzed the failure mechanism of the aviation seal and established a leakage rate model. Then, based on the non-probabilistic interval model, an interval uncertainty method was proposed to construct the analytical model. With reference to the limit state equation from the structural reliability theory, the multidimensional response surface was used for fast calculation.Then, we chose the single-cylinder gas steering gear used in aircraft as the case study, its sealing reliability in working and non-working statuses were calculated, and the results were verified with the actual maintenance records. By analyzing the sensitivity of some variables, we can improve the sealing reliability of the aviation seal by improving the surface roughness only if the cost allows.Finally, we consider that the method proposed in this study realizes the application of smallsample uncertainty analysis in reliability analysis, and could provide a feasible way to solve the similar problems in engineering with multidimensional and small-sample parameters.展开更多
Wind loading is one of the most important loads for controlling the design of large-span roof structures. Equivalent static wind loads, which can generally aim at determining a specific response, are widely used by st...Wind loading is one of the most important loads for controlling the design of large-span roof structures. Equivalent static wind loads, which can generally aim at determining a specific response, are widely used by structural designers. A method for equivalent static wind loads applicable to multi-responses is proposed in this paper. A modified load- response-correlation （LRC） method corresponding to a particular peak response is presented, and the similarity algorithm implemented for the group response is described. The main idea of the algorithm is that two responses can be put into one group if the value of one response is close to that of the other response, when the structure is subjected to equivalent static wind loads aiming at the other response. Based on the modified LRC, the grouping response method is put forward to construct equivalent static wind loading. This technique can simultaneously reproduce peak responses for some grouped responses. To verify its computational accuracy, the method is applied to an actual large-span roof structure. Calculation results show that when the similarity of responses in the same group is high, equivalent static wind loads with high accuracy and reasonable magnitude of equivalent static wind distribution can be achieved.展开更多
The effect of hot stamping parameters on the mechanical properties of 22MnB5 steel sheet with thickness of 1.1 mm is studied. The considered parameters are austenization temperature （800- 1 000 ℃ ）, austenitizing s...The effect of hot stamping parameters on the mechanical properties of 22MnB5 steel sheet with thickness of 1.1 mm is studied. The considered parameters are austenization temperature （800- 1 000 ℃ ）, austenitizing soa king time （60-540 s）, initial deformation temperature （560-800 C） and tool temperature （20-220 ℃）. In order to obtain hot stamped parts with optimal mechanical properties, response surface methodology based on the central composite design has been employed to design the experiment matrix. Tensile strength of hot stamped parts is deter- mined as the relation in the mathematical model. The optimal condition and objective effects of parameters are deter mined via this relation. The statistical analysis showed that all four factors significantly affect the tensile strength of the hot stamped parts. The optimum austenization temperature is found to be 918.89 ℃ with the austenitizing soa- king time, initial deformation temperature and tool temperature of 279.45 s, 684.69 C and 21.85 ℃, respectively. These optimal hot stamping parameters prove to have high tensile strength （1 631.84 MPa） where deviation between predicted and actual response falls within 2 %.展开更多
The aim of this study was to design and construct an improved response surface method(RSM) based on weighted regression for the anti-slide reliability analysis of concrete gravity dam.The limitation and lacuna of the ...The aim of this study was to design and construct an improved response surface method(RSM) based on weighted regression for the anti-slide reliability analysis of concrete gravity dam.The limitation and lacuna of the traditional RSM were briefly analyzed.Firstly,based on small experimental points,research was devoted to an improved RSM with singular value decomposition techniques.Then,the method was used on the basis of weighted regression and deviation coefficient correction to reduce iteration times and experimental points and improve the calculation method of checking point.Finally,a test example was given to verify this method.Compared with other conventional algorithms,this method has some strong advantages:this algorithm not only saves the arithmetic operations but also greatly enhances the calculation efficiency and the storage efficiency.展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos.52088102 and 51879287)National Key Research and Development Program of China (Grant No.2022YFB2602301)。
文摘Long-term responses of floating structures pose a great concern in their design phase. Existing approaches for addressing long-term extreme responses are extremely cumbersome for adoption. This work aims to develop an approach for the long-term extreme-response analysis of floating structures. A modified gradient-based retrieval algorithm in conjunction with the inverse first-order reliability method(IFORM) is proposed to enable the use of convolution models in long-term extreme analysis of structures with an analytical formula of response amplitude operator(RAO). The proposed algorithm ensures convergence stability and iteration accuracy and exhibits a higher computational efficiency than the traditional backtracking method. However, when the RAO of general offshore structures cannot be analytically expressed, the convolutional integration method fails to function properly. A numerical discretization approach is further proposed for offshore structures in the case when the analytical expression of the RAO is not feasible. Through iterative discretization of environmental contours(ECs) and RAOs, a detailed procedure is proposed to calculate the long-term response extremes of offshore structures. The validity and accuracy of the proposed approach are tested using a floating offshore wind turbine as a numerical example. The long-term extreme heave responses of various return periods are calculated via the IFORM in conjunction with a numerical discretization approach. The environmental data corresponding to N-year structural responses are located inside the ECs, which indicates that the selection of design points directly along the ECs yields conservative design results.
基金Supported by the National Natural Science Foundation of China(32072352)。
文摘In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heating time,microwave power,microwave heating time on the center temperature,moisture content,the chroma(C*),the total color difference(ΔE*),shape fidelity,hardness,and the total anthocyanin content of 3D printed raspberry preserves were analyzed by response surface method(RSM).The results showed that under combining with the two methods,infrared heating improved the fidelity and quality degradation of printed products,while microwave heating enhanced the efficiency of infrared heating.Infrared-microwave combination cooking could maintain relatively stable color appearance and shape of 3D printed raspberry preserves.The AHP–CRITIC hybrid weighting method combined with the response surface test to determine the comprehensive weights of the evaluation indicators optimized the process parameters,and the optimal process parameters were obtained:infrared heating temperature of 190℃,infrared heating time of 10 min and 30 s,microwave power of 300 W,and microwave heating time of 2 min and 6 s.The 3D printed raspberry cooking methods obtained under the optimal conditions seldom had color variation,porous structure,uniform texture,and high shape fidelity,which retained the characteristics of personalized manufacturing by 3D printing.This study could provide a reference for the postprocessing and quality control of 3D cooking methods.
基金supported by the National Natural Science Foundation of China(Grant Nos.42102346,42172301).
文摘Magneto-electro-elastic(MEE)materials are widely utilized across various fields due to their multi-field coupling effects.Consequently,investigating the coupling behavior of MEE composite materials is of significant importance.The traditional finite element method(FEM)remains one of the primary approaches for addressing such issues.However,the application of FEM typically necessitates the use of a fine finite element mesh to accurately capture the heterogeneous properties of the materials and meet the required computational precision,which inevitably leads to a reduction in computational efficiency.To enhance the computational accuracy and efficiency of the FEM for heterogeneous multi-field coupling problems,this study presents the coupling magneto-electro-elastic multiscale finite element method(CM-MsFEM)for heterogeneous MEE structures.Unlike the conventional multiscale FEM(MsFEM),the proposed algorithm simultaneously constructs displacement,electric,and magnetic potential multiscale basis functions to address the heterogeneity of the corresponding parameters.The macroscale formulation of CM-MsFEM was derived,and the macroscale/microscale responses of the problems were obtained through up/downscaling calculations.Evaluation using numerical examples analyzing the transient behavior of heterogeneous MEE structures demonstrated that the proposed method outperforms traditional FEM in terms of both accuracy and computational efficiency,making it an appropriate choice for numerically modeling the dynamics of heterogeneous MEE structures.
基金Project(52108361)supported by the National Natural Science Foundation of ChinaProjects(BK20231217,BK20220265)supported by the Basic Research Program of Jiangsu Province,China+5 种基金Project(sklhse-KF-2025-D-02)supported by the Open Research Fund Program of the State Key Laboratory of Hydroscience and Engineering,ChinaProject(2023ZB15)supported by the Independent Research Project of the State Key Laboratory of Subtropical Building and Urban Science,ChinaProject(SKLGME023001)supported by the Key Laboratory of Geomechanics and Geotechnical Engineering Safety,the Chinese Academy of SciencesProject(2025A04J3992)supported by the Basic and Applied Basic Research Project of the Guangzhou Science and Technology Bureau,ChinaProject(SKLGP2022Z015)supported by the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project,ChinaProjects(2023YFS0436,2024NSFSC1715)supported by the Science and Technology Department of Sichuan Province,China。
文摘Steep bedding slopes are widely distributed in Southwestern China’s mountainous regions and have complex seismic responses and instability risks,causing casualties and property losses.Considering the high-seismic-intensity environment,the dynamic failure evolution and instability mechanism of high-steep bedding slopes are simulated via the discrete element method and shaking table test.The dynamic response characteristics and cumulative failure effects of slopes subjected to continuous ground motion are investigated.The results show that the dynamic response characteristics of slopes under continuous earthquakes are influenced by geological and topographic conditions.Elevation has a distinct impact on both the slope interior and surface,with amplification effects more pronounced on the surface.The weak interlayers have different influences on the dynamic amplification effect of slopes.Weak interlayers have dynamic magnification effects on the slope surface at relative elevations of 0-0.33 and 0.82-1.0 but have weakening effects between 0.33 and 0.82.Moreover,the weak interlayers also have controlling effects on the dynamic instability mode of slopes.The characteristics of intergranular contact failure,fracture propagation,and displacement distribution are analyzed to reveal the dynamic failure evolution and instability mechanism through the discrete-element model.The dynamic instability process of slopes includes three stages:fracture initiation(0-0.2g),fracture expansion(0.2g-0.3g),and sliding instability(0.3g-0.6g).This work can provide a valuable reference for the seismic stability and reinforcement of complex slopes.
文摘This study proposes a method for calculating the probability distribution of structural responses at different intensities using the endurance time(ET)method.The results can be used to calculate the fragility curve of structural collapse.The ET method involves dynamic analysis of a structure under an intensifying record over time.While conventional ET methods can determine the median of the structural response,they lack the ability to calculate its dispersion.To address this limitation,the present study utilizes ET analysis and single-degree-of-freedom(SDOF)systems to develop a method that considers the record-to-record variability for calculating the probability distribution of structural response.The accuracy of this method is evaluated by comparing it with the incremental dynamic analysis(IDA)method using special moment frames.The results demonstrate that the proposed method achieves a reasonably accurate estimation of dispersion while significantly reducing the computational burden(by approximately 95%)compared to the IDA method.
文摘This paper aims to evaluate the stochastic response of steel columns subjected to blast loads using the modified single degree of freedom(MSDOF)method,which assessed towards the conventional single degree of freedom(SDOF)and the experimentally validated Finite Element(FE)methods(LSDYNA).For this purpose,special atten-tion is given to calculating the response of H-shaped steel columns under blast.The damage amount is determined based on the support rotation criterion,which is expressed as a function of their maximum lateral mid-span dis-placement.To account for uncertainties in input parameters and obtain the failure probability,the Monte Carlo simulation(MCS)method is employed,complemented by the Latin Hypercube Sampling(LHS)method to reduce the number of simulations.A parametric analysis is hence performed to examine the effect of several input pa-rameters(including both deterministic and probabilistic parameters)on the probability of column damage as a function of support rotation.First,the MSDOF method confirms its higher accuracy in estimating the probability of column damage due to blast,compared to the conventional SDOF.The collected results also show that un-certainties of several input parameters have significant effects on the column behavior.In particular,geometric parameters(including cross-sectional characteristics,boundary conditions and column length)have major effect on the corresponding column response,in the same way of input blast load parameters and material properties.
基金supported by the Young Scientists Fund of the National Natural Science Foundation of China(No.41304082)the China Postdoctoral Science Foundation(No.2016M590731)+2 种基金the Young Scientists Fund of the Natural Science Foundation of Hebei Province(No.D2014403011)the Program for Young Excellent Talents of Higher Education Institutions of Hebei Province(No.BJ2016046)the Geological survey project of China Geological Survey(No.1212011121197)
文摘We calculate the multicomponent responses of surface-hole transient electromagnetic method. The methods and models are unsuitable as geoelectric models of conductive surrounding rocks because they are based on regular local targets. We also propose a calculation and analysis scheme based on numerical simulations of the subsurface transient electromagnetic fields. In the modeling of the electromagnetic fields, the forward modeling simulations are performed by using the finite-difference time-domain method and the discrete image method, which combines the Gaver–Stehfest inverse Laplace transform with the Prony method to solve the initial electromagnetic fields. The precision in the iterative computations is ensured by using the transmission boundary conditions. For the response analysis, we customize geoelectric models consisting of near-borehole targets and conductive wall rocks and implement forward modeling simulations. The observed electric fields are converted into induced electromotive force responses using multicomponent observation devices. By comparing the transient electric fields and multicomponent responses under different conditions, we suggest that the multicomponent-induced electromotive force responses are related to the horizontal and vertical gradient variations of the transient electric field at different times. The characteristics of the response are determined by the varying the subsurface transient electromagnetic fields, i.e., diffusion, attenuation and distortion, under different conditions as well as the electromagnetic fields at the observation positions. The calculation and analysis scheme of the response consider the surrounding rocks and the anomalous field of the local targets. It therefore can account for the geological data better than conventional transient field response analysis of local targets.
文摘An effective optimization method for the shape/sizing design of composite wing structures is presented with satisfying weight-cutting results. After decoupling, a kind of two-layer cycled optimization strategy suitable for these integrated shape/sizing optimization is obtained. The uniform design method is used to provide sample points, and approximation models for shape design variables. And the results of sizing optimization are construct- ed with the quadratic response surface method （QRSM）. The complex method based on QRSM is used to opti- mize the shape design variables and the criteria method is adopted to optimize the sizing design variables. Compared with the conventional method, the proposed algorithm is more effective and feasible for solving complex composite optimization problems and has good efficiency in weight cutting.
文摘The aim of the present study was to optimize the supercritical CO_2 extraction conditions of icariin from Herba Epimedii by response surface method(RSM) and central composite design(CCD).A 3-factor,5-level CCD was used for the optimization.Independent variables were extraction temperature,extraction pressure and entrainer flow rate.Dependent variable was yield ratio of icariin from Herba Epimedii.A two-order polynomial equation was fitted to the data.The results showed that the optimum extraction conditions were as follows:extraction temperature 46.5℃,extraction pressure 30.6 MPa,entrainer flow rate 3.3 mL/min.CCD/ RSM is convenient and highly predictive for optimizing the extraction process of icariin from Herba Epimedii.
基金Foundation items:The National Natural Science Foundation of China(No.10472026)the Natural Science Foundation of Jiangsu Province(No.BK2003063).
文摘A new method for measuring the characteristic of electrostriction by a digital speckle correlation method （DSCM） is presented. The in-plane displacement is obtained by using the DSCM, and the out-plane displacement is obtained by the geometrical relation of the triangle theory. In this application, high field electrostrictive strains of barium titanate/polyurethane elastomer composite materials are measured. The electrostrictive strain is evaluated when the application of an electric field is repeated, and then the electrostrictive coefficient of the sample is obtained. To improve the measuring accuracy, the bilinear interpolation of gray value is used to obtain the sub-pixel gray value. The results are compared with those obtained from the surface fitting algorithm. The experimental results demonstrate that the electrostrictive response of polyurethane increases with the introduction of barium titanate into polyurethane. And by using the DSCM, the measurement of the characteristic of electrostriction can be done quickly and accurately. The DSCM provides an effective tool for the evaluation of electrostrictive response.
基金supported by the National Natural Science Foundation of China(Grant No.51579193)the Science and Technology Planning Project of Guizhou Province(Grant No.[2016]1154)
文摘Due to the size effects of rockfill materials, the settlement difference between numerical simulation and in situ monitoring of rockfill dams is a topic of general concern.The constitutive model parameters obtained from laboratory triaxial tests often underestimate the deformation of high rockfill dams.Therefore, constitutive model parameters obtained by back analysis were used to calculate and predict the long-term deformation of rockfill dams.Instead of using artificial neural networks (ANNs), the response surface method (RSM) was employed to replace the finite element simulation used in the optimization iteration.Only 27 training samples were required for RSM, improving computational efficiency compared with ANN, which required 300 training samples.RSM can be used to describe the relationship between the constitutive model parameters and dam settlements.The inversion results of the Shuibuya concrete face rockfill dam (CFRD) show that the calculated settlements agree with the measured data, indicating the accuracy and efficiency of RSM.
基金Supported by National Natural Science Foundation of China(Grant No.51375013)Anhui Provincial Natural Science Foundation of China(Grant No.1208085ME64)
文摘Tooth modification technique is widely used in gear industry to improve the meshing performance of gearings. However, few of the present studies on tooth modification considers the influence of inevitable random errors on gear modification effects. In order to investigate the uncertainties of tooth modification amount variations on system＇s dynamic behaviors of a helical planetary gears, an analytical dynamic model including tooth modification parameters is proposed to carry out a deterministic analysis on the dynamics of a helical planetary gear. The dynamic meshing forces as well as the dynamic transmission errors of the sun-planet 1 gear pair with and without tooth modifications are computed and compared to show the effectiveness of tooth modifications on gear dynamics enhancement. By using response surface method, a fitted regression model for the dynamic transmission error（DTE） fluctuations is established to quantify the relationship between modification amounts and DTE fluctuations. By shifting the inevitable random errors arousing from manufacturing and installing process to tooth modification amount variations, a statistical tooth modification model is developed and a methodology combining Monte Carlo simulation and response surface method is presented for uncertainty analysis of tooth modifications. The uncertainly analysis reveals that the system＇s dynamic behaviors do not obey the normal distribution rule even though the design variables are normally distributed. In addition, a deterministic modification amount will not definitely achieve an optimal result for both static and dynamic transmission error fluctuation reduction simultaneously.
基金supported by National Natural Science Foundation of China(Grant Nos.51175017,51245027)Innovation Foundation of Beihang University for PhD Graduates,China(Grant No.YWF-12-RBYJ008)Research Fund for the Doctoral Program of Higher Education of China(Grant No.20111102110011)
文摘Because of the randomness of many impact factors influencing the dynamic assembly relationship of complex machinery, the reliability analysis of dynamic assembly relationship needs to be accomplished considering the randomness from a probabilistic perspective. To improve the accuracy and efficiency of dynamic assembly relationship reliability analysis, the mechanical dynamic assembly reliability（MDAR） theory and a distributed collaborative response surface method（DCRSM） are proposed. The mathematic model of DCRSM is established based on the quadratic response surface function, and verified by the assembly relationship reliability analysis of aeroengine high pressure turbine（HPT） blade-tip radial running clearance（BTRRC）. Through the comparison of the DCRSM, traditional response surface method（RSM） and Monte Carlo Method（MCM）, the results show that the DCRSM is not able to accomplish the computational task which is impossible for the other methods when the number of simulation is more than 100 000 times, but also the computational precision for the DCRSM is basically consistent with the MCM and improved by 0.40-4.63% to the RSM, furthermore, the computational efficiency of DCRSM is up to about 188 times of the MCM and 55 times of the RSM under 10000 times simulations. The DCRSM is demonstrated to be a feasible and effective approach for markedly improving the computational efficiency and accuracy of MDAR analysis. Thus, the proposed research provides the promising theory and method for the MDAR design and optimization, and opens a novel research direction of probabilistic analysis for developing the high-performance and high-reliability of aeroengine.
基金supported by the National Basic Research Program of China (No. 2006CB705401)the National Natural Science Foundation of China (No.51075270)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (No.10KJD460003)
文摘A modified cellular automata （CA） model of dynamic recrystallization （DRX） and a flow stress-based nucleation parameter identification method have been developed. In the method, the modified CA model, which takes the role of deformation degree on nucleation behavior into consideration, is coupled with an adaptive response surface model （ARSM） to search for the optimum nucleation parameter. The DRX behavior of an oxygen free high conductivity （OFHC） copper with different initial grain sizes has been taken as an example to validate the model. Good agreement is found between the simulated and the experimental results, which demonstrates that the new method can effectively improve the simulation accuracy.
文摘A response surface method was employed to study the effect of α-amylase concentration, hydrolysis temperature and time on the production of high protein glutinous rice flour(HPGRF). The suspension of glutinous rice flour(15%) that contained 6.52% protein was gelatinized and subsequently hydrolyzed by thermostable α-amylase. The hydrolysis yielded 0.144–0.222 g/g HPGRF with 29.4%–45.4% protein content. Hydrolysis time exerted a significant effect, while enzyme concentration and hydrolysis temperature showed insignificant effect on the protein content and production yield of HPGRF. The result of response surface method showed that the optimum condition for the production of HPGRF that contained at least 36% protein was treating gelatinized 15% glutinous rice flour suspension with 0.90 Kilo Novo α-amylase Unit(KNU)/g α-amylase at 80 oC for 99 min. By carrying out the predicted hydrolysis condition, HPGRF with 35.9% protein and 61.8% carbohydrates was resulted. The process yielded 0.172 g/g HPGRF. HPGRF contained higher amount of essential amino acids compared to glutinous rice flour. HPGRF had higher solubility and lower swelling power, and also showed no pasting peak compared with glutinous rice flour.
基金The project supported by the National Outstanding Youth Science Foundation of China (10425208)the National Natural Science Foundation of ChinaInstitute of Engineering Physics of China (10376002) The English text was polished by Keren Wang
文摘Two non-probabilistic, set-theoretical methods for determining the maximum and minimum impulsive responses of structures to uncertain-but-bounded impulses are presented. They are, respectively, based on the theories of interval mathematics and convex models. The uncertain-but-bounded impulses are assumed to be a convex set, hyper-rectangle or ellipsoid. For the two non-probabilistic methods, less prior information is required about the uncertain nature of impulses than the probabilistic model. Comparisons between the interval analysis method and the convex model, which are developed as an anti-optimization problem of finding the least favorable impulsive response and the most favorable impulsive response, are made through mathematical analyses and numerical calculations. The results of this study indicate that under the condition of the interval vector being determined from an ellipsoid containing the uncertain impulses, the width of the impulsive responses predicted by the interval analysis method is larger than that by the convex model; under the condition of the ellipsoid being determined from an interval vector containing the uncertain impulses, the width of the interval impulsive responses obtained by the interval analysis method is smaller than that by the convex model.
基金supported in part from the Fundamental Research Project funded by the Ministry of Industry and Information Technology of the People’s Republic of China
文摘Many variables affect the sealing performance, and their distribution characteristics are difficult to obtain with probabilistic methods owing to the high cost involved. Numerous problems in engineering are similar due to the appearance of small-sample parameters. In this study, the sealing reliability of an aviation seal was defined as the research object, and an interval uncertainty method and multidimensional response surface were proposed to calculate the sealing reliability.Based on this, we first analyzed the failure mechanism of the aviation seal and established a leakage rate model. Then, based on the non-probabilistic interval model, an interval uncertainty method was proposed to construct the analytical model. With reference to the limit state equation from the structural reliability theory, the multidimensional response surface was used for fast calculation.Then, we chose the single-cylinder gas steering gear used in aircraft as the case study, its sealing reliability in working and non-working statuses were calculated, and the results were verified with the actual maintenance records. By analyzing the sensitivity of some variables, we can improve the sealing reliability of the aviation seal by improving the surface roughness only if the cost allows.Finally, we consider that the method proposed in this study realizes the application of smallsample uncertainty analysis in reliability analysis, and could provide a feasible way to solve the similar problems in engineering with multidimensional and small-sample parameters.
基金Ministry of Science and Technology of China Under Grant No.SLDRCE10-B-04the National Natural Science Foundation Under Grant No.50621062
文摘Wind loading is one of the most important loads for controlling the design of large-span roof structures. Equivalent static wind loads, which can generally aim at determining a specific response, are widely used by structural designers. A method for equivalent static wind loads applicable to multi-responses is proposed in this paper. A modified load- response-correlation （LRC） method corresponding to a particular peak response is presented, and the similarity algorithm implemented for the group response is described. The main idea of the algorithm is that two responses can be put into one group if the value of one response is close to that of the other response, when the structure is subjected to equivalent static wind loads aiming at the other response. Based on the modified LRC, the grouping response method is put forward to construct equivalent static wind loading. This technique can simultaneously reproduce peak responses for some grouped responses. To verify its computational accuracy, the method is applied to an actual large-span roof structure. Calculation results show that when the similarity of responses in the same group is high, equivalent static wind loads with high accuracy and reasonable magnitude of equivalent static wind distribution can be achieved.
基金Sponsored by National Science and Technology Major Project of the Ministry of Science and Technology of China(2009ZX04014-074)Doctor Science Research Foundation of the Education Ministry of China(20120006110017)
文摘The effect of hot stamping parameters on the mechanical properties of 22MnB5 steel sheet with thickness of 1.1 mm is studied. The considered parameters are austenization temperature （800- 1 000 ℃ ）, austenitizing soa king time （60-540 s）, initial deformation temperature （560-800 C） and tool temperature （20-220 ℃）. In order to obtain hot stamped parts with optimal mechanical properties, response surface methodology based on the central composite design has been employed to design the experiment matrix. Tensile strength of hot stamped parts is deter- mined as the relation in the mathematical model. The optimal condition and objective effects of parameters are deter mined via this relation. The statistical analysis showed that all four factors significantly affect the tensile strength of the hot stamped parts. The optimum austenization temperature is found to be 918.89 ℃ with the austenitizing soa- king time, initial deformation temperature and tool temperature of 279.45 s, 684.69 C and 21.85 ℃, respectively. These optimal hot stamping parameters prove to have high tensile strength （1 631.84 MPa） where deviation between predicted and actual response falls within 2 %.
基金supported by the National Basic Research Program of China (Nos. 2007CB714107 and 90510018)the Trans-Century Training Programme Foundation for the Talents by the State Education Com-mission (No. NCET-06-0270),China
文摘The aim of this study was to design and construct an improved response surface method(RSM) based on weighted regression for the anti-slide reliability analysis of concrete gravity dam.The limitation and lacuna of the traditional RSM were briefly analyzed.Firstly,based on small experimental points,research was devoted to an improved RSM with singular value decomposition techniques.Then,the method was used on the basis of weighted regression and deviation coefficient correction to reduce iteration times and experimental points and improve the calculation method of checking point.Finally,a test example was given to verify this method.Compared with other conventional algorithms,this method has some strong advantages:this algorithm not only saves the arithmetic operations but also greatly enhances the calculation efficiency and the storage efficiency.
