At the present stage, the competitive environment among enterprises in our social market is increasingly fierce, which requires strong practical ability and innovation ability for talents. Experimental teaching, as th...At the present stage, the competitive environment among enterprises in our social market is increasingly fierce, which requires strong practical ability and innovation ability for talents. Experimental teaching, as the main means to cultivate talents' problem-solving ability, practical ability and creative ability, should be reformed and innovated in time so as to improve the efficiency and quality of experimental teaching for material forming and control engineering major. Based on this, this paper mainly analyzes the importance of experimental teaching of material forming and control engineering in colleges and universities, and puts forward some methods of exploration and construction of experimental teaching for reference.展开更多
Transforming materials with evolving microstructures is one of the most important classes of smart materials that have many potential technological applications, and an unconventional phase field approach based on the...Transforming materials with evolving microstructures is one of the most important classes of smart materials that have many potential technological applications, and an unconventional phase field approach based on the characteristic functions of transforming variants has been developed to simulate the formation and evolution of their microstructures. This approach is advantageous in its explicit material symmetry and energy well structure, minimal number of ma- terial coefficients, and easiness in coupling multiple physical processes and order parameters, and has been applied successfully to study the microstructures and macroscopic prop- erties of shape memory alloys, ferroelectrics, ferromagnetic shape memory alloys, and multiferroic magnetoelectric crys- tals and films with increased complexity. In this topical re- view, the formulation of this unconventional phase field approach will be introduced in details, and its applications to various transforming materials will be discussed. Some ex- amples of specific microstructures will also be presented.展开更多
The use of ultra-high strength steels through sheet metal forming process offers a practical solution to the lightweight design of vehicles.However,sheet metal forming process not only produces desirable changes in ma...The use of ultra-high strength steels through sheet metal forming process offers a practical solution to the lightweight design of vehicles.However,sheet metal forming process not only produces desirable changes in material properties but also causes material damage that may adversely influence the service performance of the material formed.Thus,an investigation is conducted to experimentally quantify such influence for a commonly used steel(the 22MnB5 steel)based on the hot and cold forming processes.For each process,a number of samples are used to conduct a uniaxial tensile test to simulate the forming process.After that,some of the samples are trimmed into a standard shape and then uniaxially extended until fracture to simulate the service stage.Finally,a microstructure test is conducted to analyze the microdefects of the remaining samples.Based on the results of the first two tests,the effect of material damage on the service performance of 22MnB5 steel is analyzed.It is found that the material damages of both the hot and cold forming processes cause reductions in the service performance,such as the failure strain,the ultimate stress,the capacity of energy absorption and the ratio of residual strain.The reductions are generally lower and non-linear in the former process but higher and linear in the latter process.Additionally,it is found from the microstructure analysis that the difference in the reductions of the service performance of 22MnB5 by the two forming processes is driven by the difference in the micro damage mechanisms of the two processes.The findings of this research provide a useful reference in terms of the selection of sheet metal forming processes and the determination of forming parameters for 22MnB5.展开更多
Flexible roll forming is a promising manufacturing method for the production of variable cross section products. Considering the large plastic strain in this forming process which is much larger than that of uniform d...Flexible roll forming is a promising manufacturing method for the production of variable cross section products. Considering the large plastic strain in this forming process which is much larger than that of uniform deformation phase of uniaxial tensile test, the widely adopted method of simulating the forming processes with non-supplemented material data from uniaxial tensile test will certainly lead to large error. To reduce this error, the material data is supplemented based on three constitutive models. Then a finite element model of a six passes flexible roll forming process is established based on the supplemented material data and the original material data from the uniaxial tensile test. The flexible roll forming experiment of a B pillar reinforcing plate is carried out to verify the proposed method. Final cross section shapes of the experimental and the simulated results are compared. It is shown that the simulation calculated with supplemented material data based on Swift model agrees well with the experimental results, while the simulation based on original material data could not predict the actual deformation accurately. The results indicate that this material supplement method is reliable and indispensible, and the simulation model can well reflect the real metal forming process. Detailed analysis of the distribution and history of plastic strain at different positions are performed. A new material data supplement method is proposed to tackle the problem which is ignored in other roll forming simulations, and thus the forming process simulation accuracy can be greatly improved.展开更多
It is difficult to determine the effective reservoir rock compressibility,aquifer volume and water influx of high pressure and ultra-high pressure gas reservoirs,so when the traditional apparent reservoir pressure and...It is difficult to determine the effective reservoir rock compressibility,aquifer volume and water influx of high pressure and ultra-high pressure gas reservoirs,so when the traditional apparent reservoir pressure and cumulative gas production curve extrapolation method and its modified version are used to calculate the initial gas in-place of such gas reservoirs,the calculation accuracy is lower.The material balance equation in the form of power function for such gas reservoirs was established based on Gonzalez method to improve the accuracy and reliability of reserve evaluation.Then,based on 20 high pressure and ultra-high pressure reservoirs that had been developed abroad,the empirical value of the power exponent was defined,and the influences of the depletion degree of apparent reservoir pressure and the degree of reserve recovery on the reliability of reserve calculation were analyzed.Besides,the critical value of the key parameter affecting the reliability of reserve evaluation(depletion degree of apparent reservoir pressure)was determined and compared with the critical value of the two-linear trends.Finally,an example calculation was carried out.And the following research results were obtained.First,the empirical value of the power exponent calculated using the material balance method in the form of power function is 1.02847,with an upper limit of 1.11567.Second,the depletion degree of apparent reservoir pressure corresponding to the inflection point of the classical two-linear trends ranges from 0.14 to 0.38 with an average of 0.23,while that corresponding to the extrapolation point of the second straight line is between 0.23 and 0.50 with an average of 0.33,and the corresponding degree of reserve recovery is in the range of 33%-65%with an average of 45%.Third,the reserves of such high pressure gas reservoirs calculated with this new method has an error rate less than 10%if the depletion degree of apparent reservoir pressure is greater than 0.33.In conclusion,for such high pressure gas reservoirs and the stress-sensitive fractured gas reservoirs,the material balance method in the form of power function proposed in this paper can avoid the uncertainty parameters(e.g.effective reservoir rock compressibility,aquifer volume and water influx)and it is advantageous with simple calculation process,better practicability and small error.展开更多
Lunar in-situ construction using additive manufacturing(AM)technology has emerged as a critical pathway for sustainable extraterrestrial exploration.This review systematically evaluates two dominant AM paradigms for l...Lunar in-situ construction using additive manufacturing(AM)technology has emerged as a critical pathway for sustainable extraterrestrial exploration.This review systematically evaluates two dominant AM paradigms for lunar regolith processing:low-temperature deposition forming(material extrusion and binder jetting),and high-energy beam additive manufacturing(powder bed fusion and directed energy deposition).Low-temperature methods achieve moderate compressive strength with low energy consumption but face challenges such as binder dependency and vacuum instability.By contrast,high-energy beam techniques enable binder-free fabrication with better compatibility for in-situ resource utilization,though they suffer from porosity,high energy intensity,and geometric limitations.In the context of lunar in-situ resource utilization(ISRU),low-temperature methods offer near-term feasibility for small-scale infrastructure,while high-energy approaches show promise for large-scale,autonomous construction by leveraging solar energy and raw regolith.Future advancements will hinge on hybrid systems that integrate material efficiency,energy sustainability,and robotic adaptability to overcome extreme environmental challenges.This review consolidates technological progress,identifies interdisciplinary synergies,and provides strategic insights into guiding the transition from Earth-dependent prototypes to self-sufficient lunar habitats,ultimately advancing the capability of humanity for a long-term extraterrestrial presence.展开更多
Three dimensional(3D)tubes,which possess the characteristics of space saving,lightweight and high strength,are widely used in many high-end industries such as aviation,aerospace,automobile and shipbuilding.However,whe...Three dimensional(3D)tubes,which possess the characteristics of space saving,lightweight and high strength,are widely used in many high-end industries such as aviation,aerospace,automobile and shipbuilding.However,when manufacturing a 3D tube in flexible bending process,springback is a big obstacle for improving the forming quality.In this paper,a new comprehensive strategy for springback control of 3D tubes is proposed.The strategy can be described as follows:(1)define the desired shape and manufacture shape;(2)optimize the manufacture shape using two tooling design methods(e.g.DA(displacement adjustment)method and B&T(bending and twisting)method presented in this paper);(3)make a discretization of the manufacture shape to acquire the optimized forming parameters.Additionally,experiment is implemented to validate the effectiveness of the new strategy.Results show that forming parameters acquired by the new strategy are partially effective.The new strategy also demonstrates that,during 3D tubes forming,the deviation caused by over-bent elements can be counteracted by the deficient-bent elements.This principle is helpful to reduce the difficulty of parameter determination in future.展开更多
Abstract： Landslide is one of natural catastrophes affecting national economy and people＇s livelihood. There are many reports on the forming mechanism and control of landslide, but the studies on micromorphology of ...Abstract： Landslide is one of natural catastrophes affecting national economy and people＇s livelihood. There are many reports on the forming mechanism and control of landslide, but the studies on micromorphology of landslide soil are few. There are many potential landslides in the Three Gorges Region in China. In this paper, the micromorphologic features of the Jibazi landslide soil in Yunyang in the Three Gorges Region of the Yangtze River were studied using routine methods, that is, soil micromorphology, X-ray diffraetometer and scanning electron microscope. The main conclusions are as follow： （1） The basic micromorphologic characteristics of the landslide soil are that the fine soil particles are commonly cohesive matrix, finer and lower content of skeleton grains, the microstructures are mainly types of phenocrystal gelatinization, densely chap and fissure structure. As a result, these micromorphologic features affect the discharging of soil water, favor the movement of landslide body and provide an internal basis of materials for the formation of landslide. （2） The concept on the forming material of landslide was proposed, and types of optical beamed clay aggregates, Fe-Mn isolates and glassy material were found in landslide-belt soil, which were remarkably different from the natural soil formation, and had some scientific significance in analyzing the forming mechanism of landslide and distinguishing me landslide-belt soil. （3） Some special micromorphologic and sub-micromorphologic characteristics, such as fingerprint microstructure, clay beamed bedding microstructure, oppressive microstructure, moulage microstructure and extending hole microstncture, could bring useful micromorphologic evidences for the observation and forecasting of landslide. The results mentioned above will bring helpful micromorphologic evidences for distinguishing slide soil, analyzing the formation mechanism of landslide, and monitoring and forecasting the occurrence of landslide.展开更多
In the field of optical computing and parallel information processing, several number systems have been used for different arithmetic and algebraic operations. Therefore an efficient conversion scheme from one number ...In the field of optical computing and parallel information processing, several number systems have been used for different arithmetic and algebraic operations. Therefore an efficient conversion scheme from one number system to another is very important. Modified trinary number （MTN） has already taken a significant role towards carry and borrow free arithmetic operations. In this communication, we propose a tree-net architecture based all optical conversion scheme from binary number to its MTN form. Optical switch using nonlinear material （NLM） plays an important role.展开更多
文摘At the present stage, the competitive environment among enterprises in our social market is increasingly fierce, which requires strong practical ability and innovation ability for talents. Experimental teaching, as the main means to cultivate talents' problem-solving ability, practical ability and creative ability, should be reformed and innovated in time so as to improve the efficiency and quality of experimental teaching for material forming and control engineering major. Based on this, this paper mainly analyzes the importance of experimental teaching of material forming and control engineering in colleges and universities, and puts forward some methods of exploration and construction of experimental teaching for reference.
基金supported by the NSF (DMR-1006194 and CMMI1100339)NSFC (10972189 and 11102175)NSC(100-2628-E-002-034-MY3)
文摘Transforming materials with evolving microstructures is one of the most important classes of smart materials that have many potential technological applications, and an unconventional phase field approach based on the characteristic functions of transforming variants has been developed to simulate the formation and evolution of their microstructures. This approach is advantageous in its explicit material symmetry and energy well structure, minimal number of ma- terial coefficients, and easiness in coupling multiple physical processes and order parameters, and has been applied successfully to study the microstructures and macroscopic prop- erties of shape memory alloys, ferroelectrics, ferromagnetic shape memory alloys, and multiferroic magnetoelectric crys- tals and films with increased complexity. In this topical re- view, the formulation of this unconventional phase field approach will be introduced in details, and its applications to various transforming materials will be discussed. Some ex- amples of specific microstructures will also be presented.
基金Supported by National Natural Science Foundation of China(Grant No.51375201)CSAE(Beijing)Automotive Lightweight Technology Research Institute Development Fund Project of China
文摘The use of ultra-high strength steels through sheet metal forming process offers a practical solution to the lightweight design of vehicles.However,sheet metal forming process not only produces desirable changes in material properties but also causes material damage that may adversely influence the service performance of the material formed.Thus,an investigation is conducted to experimentally quantify such influence for a commonly used steel(the 22MnB5 steel)based on the hot and cold forming processes.For each process,a number of samples are used to conduct a uniaxial tensile test to simulate the forming process.After that,some of the samples are trimmed into a standard shape and then uniaxially extended until fracture to simulate the service stage.Finally,a microstructure test is conducted to analyze the microdefects of the remaining samples.Based on the results of the first two tests,the effect of material damage on the service performance of 22MnB5 steel is analyzed.It is found that the material damages of both the hot and cold forming processes cause reductions in the service performance,such as the failure strain,the ultimate stress,the capacity of energy absorption and the ratio of residual strain.The reductions are generally lower and non-linear in the former process but higher and linear in the latter process.Additionally,it is found from the microstructure analysis that the difference in the reductions of the service performance of 22MnB5 by the two forming processes is driven by the difference in the micro damage mechanisms of the two processes.The findings of this research provide a useful reference in terms of the selection of sheet metal forming processes and the determination of forming parameters for 22MnB5.
基金Supported by National Natural Science Foundation of China(Grant Nos.51205004,51475003)Beijing Municipal Natural Science Foundation of China(Grant No.3152010)Beijing Municipal Education Committee Science and Technology Program,China(Grant No.KM201510009004)
文摘Flexible roll forming is a promising manufacturing method for the production of variable cross section products. Considering the large plastic strain in this forming process which is much larger than that of uniform deformation phase of uniaxial tensile test, the widely adopted method of simulating the forming processes with non-supplemented material data from uniaxial tensile test will certainly lead to large error. To reduce this error, the material data is supplemented based on three constitutive models. Then a finite element model of a six passes flexible roll forming process is established based on the supplemented material data and the original material data from the uniaxial tensile test. The flexible roll forming experiment of a B pillar reinforcing plate is carried out to verify the proposed method. Final cross section shapes of the experimental and the simulated results are compared. It is shown that the simulation calculated with supplemented material data based on Swift model agrees well with the experimental results, while the simulation based on original material data could not predict the actual deformation accurately. The results indicate that this material supplement method is reliable and indispensible, and the simulation model can well reflect the real metal forming process. Detailed analysis of the distribution and history of plastic strain at different positions are performed. A new material data supplement method is proposed to tackle the problem which is ignored in other roll forming simulations, and thus the forming process simulation accuracy can be greatly improved.
基金Project supported by Major Special Science and Technology Project of PetroChina Company Limited“Study and application of key technologies for developing deepeultra-deep gas in Kuqa depression”(No.:2018E-1803).
文摘It is difficult to determine the effective reservoir rock compressibility,aquifer volume and water influx of high pressure and ultra-high pressure gas reservoirs,so when the traditional apparent reservoir pressure and cumulative gas production curve extrapolation method and its modified version are used to calculate the initial gas in-place of such gas reservoirs,the calculation accuracy is lower.The material balance equation in the form of power function for such gas reservoirs was established based on Gonzalez method to improve the accuracy and reliability of reserve evaluation.Then,based on 20 high pressure and ultra-high pressure reservoirs that had been developed abroad,the empirical value of the power exponent was defined,and the influences of the depletion degree of apparent reservoir pressure and the degree of reserve recovery on the reliability of reserve calculation were analyzed.Besides,the critical value of the key parameter affecting the reliability of reserve evaluation(depletion degree of apparent reservoir pressure)was determined and compared with the critical value of the two-linear trends.Finally,an example calculation was carried out.And the following research results were obtained.First,the empirical value of the power exponent calculated using the material balance method in the form of power function is 1.02847,with an upper limit of 1.11567.Second,the depletion degree of apparent reservoir pressure corresponding to the inflection point of the classical two-linear trends ranges from 0.14 to 0.38 with an average of 0.23,while that corresponding to the extrapolation point of the second straight line is between 0.23 and 0.50 with an average of 0.33,and the corresponding degree of reserve recovery is in the range of 33%-65%with an average of 45%.Third,the reserves of such high pressure gas reservoirs calculated with this new method has an error rate less than 10%if the depletion degree of apparent reservoir pressure is greater than 0.33.In conclusion,for such high pressure gas reservoirs and the stress-sensitive fractured gas reservoirs,the material balance method in the form of power function proposed in this paper can avoid the uncertainty parameters(e.g.effective reservoir rock compressibility,aquifer volume and water influx)and it is advantageous with simple calculation process,better practicability and small error.
基金supported by National Key Research and Development Program of China(Grant Nos.2023YFB3711300,2021YFF0500300)Space Application System of China Manned Space ProgramStrategic Research and Consulting Project of the Chinese Academy of Engineering(Grant No.2023-JB-09-10)。
文摘Lunar in-situ construction using additive manufacturing(AM)technology has emerged as a critical pathway for sustainable extraterrestrial exploration.This review systematically evaluates two dominant AM paradigms for lunar regolith processing:low-temperature deposition forming(material extrusion and binder jetting),and high-energy beam additive manufacturing(powder bed fusion and directed energy deposition).Low-temperature methods achieve moderate compressive strength with low energy consumption but face challenges such as binder dependency and vacuum instability.By contrast,high-energy beam techniques enable binder-free fabrication with better compatibility for in-situ resource utilization,though they suffer from porosity,high energy intensity,and geometric limitations.In the context of lunar in-situ resource utilization(ISRU),low-temperature methods offer near-term feasibility for small-scale infrastructure,while high-energy approaches show promise for large-scale,autonomous construction by leveraging solar energy and raw regolith.Future advancements will hinge on hybrid systems that integrate material efficiency,energy sustainability,and robotic adaptability to overcome extreme environmental challenges.This review consolidates technological progress,identifies interdisciplinary synergies,and provides strategic insights into guiding the transition from Earth-dependent prototypes to self-sufficient lunar habitats,ultimately advancing the capability of humanity for a long-term extraterrestrial presence.
基金supported by Key Research and Development Program of Shaanxi of China(No.2020ZDLGY01-05)。
文摘Three dimensional(3D)tubes,which possess the characteristics of space saving,lightweight and high strength,are widely used in many high-end industries such as aviation,aerospace,automobile and shipbuilding.However,when manufacturing a 3D tube in flexible bending process,springback is a big obstacle for improving the forming quality.In this paper,a new comprehensive strategy for springback control of 3D tubes is proposed.The strategy can be described as follows:(1)define the desired shape and manufacture shape;(2)optimize the manufacture shape using two tooling design methods(e.g.DA(displacement adjustment)method and B&T(bending and twisting)method presented in this paper);(3)make a discretization of the manufacture shape to acquire the optimized forming parameters.Additionally,experiment is implemented to validate the effectiveness of the new strategy.Results show that forming parameters acquired by the new strategy are partially effective.The new strategy also demonstrates that,during 3D tubes forming,the deviation caused by over-bent elements can be counteracted by the deficient-bent elements.This principle is helpful to reduce the difficulty of parameter determination in future.
基金supported by the National Science Foundation of 0utstanding Youth of China(40025103)
文摘Abstract： Landslide is one of natural catastrophes affecting national economy and people＇s livelihood. There are many reports on the forming mechanism and control of landslide, but the studies on micromorphology of landslide soil are few. There are many potential landslides in the Three Gorges Region in China. In this paper, the micromorphologic features of the Jibazi landslide soil in Yunyang in the Three Gorges Region of the Yangtze River were studied using routine methods, that is, soil micromorphology, X-ray diffraetometer and scanning electron microscope. The main conclusions are as follow： （1） The basic micromorphologic characteristics of the landslide soil are that the fine soil particles are commonly cohesive matrix, finer and lower content of skeleton grains, the microstructures are mainly types of phenocrystal gelatinization, densely chap and fissure structure. As a result, these micromorphologic features affect the discharging of soil water, favor the movement of landslide body and provide an internal basis of materials for the formation of landslide. （2） The concept on the forming material of landslide was proposed, and types of optical beamed clay aggregates, Fe-Mn isolates and glassy material were found in landslide-belt soil, which were remarkably different from the natural soil formation, and had some scientific significance in analyzing the forming mechanism of landslide and distinguishing me landslide-belt soil. （3） Some special micromorphologic and sub-micromorphologic characteristics, such as fingerprint microstructure, clay beamed bedding microstructure, oppressive microstructure, moulage microstructure and extending hole microstncture, could bring useful micromorphologic evidences for the observation and forecasting of landslide. The results mentioned above will bring helpful micromorphologic evidences for distinguishing slide soil, analyzing the formation mechanism of landslide, and monitoring and forecasting the occurrence of landslide.
文摘In the field of optical computing and parallel information processing, several number systems have been used for different arithmetic and algebraic operations. Therefore an efficient conversion scheme from one number system to another is very important. Modified trinary number （MTN） has already taken a significant role towards carry and borrow free arithmetic operations. In this communication, we propose a tree-net architecture based all optical conversion scheme from binary number to its MTN form. Optical switch using nonlinear material （NLM） plays an important role.
