The stress gradient of surrounding rock and reasonable prestress of support are the keys to ensuring the stability of roadways.The elastic-plastic analytical solution for surrounding rock was derived based on unified ...The stress gradient of surrounding rock and reasonable prestress of support are the keys to ensuring the stability of roadways.The elastic-plastic analytical solution for surrounding rock was derived based on unified strength theory.A model for solving the stress gradient of the surrounding rock with the intermediate principal stress parameter b was established.The correctness and applicability of the solution for the stress gradient in the roadway surrounding rock was verified via multiple methods.Furthermore,the laws of stress,displacement,and the plastic zone of the surrounding rock with different b values and prestresses were revealed.As b increases,the stress gradient in the plastic zone increases,and the displacement and plastic zone radius decrease.As the prestress increases,the peak stress shifts toward the sidewalls,and the stress and stress gradient increments decrease.In addition,the displacement increment and plastic zone increment were proposed to characterize the support effect.The balance point of the plastic zone area appears before that of the displacement zone.The relationship between the stress gradient compensation coefficient and the prestress is obtained.This study provides a research method and idea for determining the reasonable prestress of support in roadways.展开更多
对珠子参中皂苷类成分进行定性鉴别分析,建立珠子参皂苷类多成分含量测定方法。采用超高效液相色谱-飞行时间质谱(UPLC-Q-TOF-MS/MS)技术对珠子参进行正、负离子模式扫描,使用UNIFI天然产物信息平台对珠子参所含的化学成分进行定性鉴别...对珠子参中皂苷类成分进行定性鉴别分析,建立珠子参皂苷类多成分含量测定方法。采用超高效液相色谱-飞行时间质谱(UPLC-Q-TOF-MS/MS)技术对珠子参进行正、负离子模式扫描,使用UNIFI天然产物信息平台对珠子参所含的化学成分进行定性鉴别分析;以0.1%磷酸水-乙腈溶液为流动相进行梯度洗脱,柱温30℃,流速0.3 mL/min,进行珠子参皂苷类多成分含量测定。珠子参中共鉴定出39个化学成分,包括37个皂苷类化合物和2个皂苷母核,并总结了皂苷类化合物的裂解规律,建立了UPLC同时测定珠子参中人参皂苷Rb1、人参皂苷Ro、人参皂苷Rb3、竹节参皂苷IV、竹节参皂苷IVa、人参皂苷Rd、姜状三七皂苷R1和金盏花苷E的多指标含量测定方法,该方法中8个待测成分在检测质量浓度范围内线性关系良好,精密度、重复性、稳定性的相对标准偏差(relative standard deviation,RSD)均小于3.0%,样品中人参皂苷Rb1、人参皂苷Ro、人参皂苷Rb3、竹节参皂苷IV、竹节参皂苷IVa、人参皂苷Rd、姜状三七皂苷R1和金盏花苷E的平均加样回收率分别为102.4%、103.1%、97.97%、99.42%、102.7%、102.1%、95.23%、100.5%,RSD分别为1.0%、0.98%、0.81%、2.3%、0.81%、1.9%、0.96%、1.8%。该研究建立的方法可快速、准确地对珠子参中的皂苷类成分进行定性及定量分析。展开更多
Aerocapture is one of the key technologies for low-cost transportation,with high demands of autonomy,accuracy,and robustness of guidance and control,due to its high reliability requirements for only one chance of tryi...Aerocapture is one of the key technologies for low-cost transportation,with high demands of autonomy,accuracy,and robustness of guidance and control,due to its high reliability requirements for only one chance of trying.A unified numerical predictor-corrector guidance method based on characteristic models for aerocapture is proposed.The numerical predictor-corrector guidance method is used to achieve autonomy and high accuracy,and the characteristic model control method is introduced to achieve robustness.At the same time,by transforming path constraints,characteristic model equations including apogee deviation and altitude differentiation are established.Based on the characteristic model equations,a unified guidance law which can satisfy path constraints and guidance objectives simultaneously is designed.In guidance problems,guidance deviation is not directly obtained from the output of the dynamics at present,but is calculated through integral and algebraic equations.Therefore,the method of directly discretizing differential equations cannot be used to establish characteristic models,which brings great difficulty to characteristic modeling.A method for characteristic modeling of guidance problems is proposed,and convergence analysis of the proposed guidance law is also provided.Finally,a joint numerical simulation of guidance and control considering navigation deviation and various uncertainties is conducted to verify the effectiveness of the proposed method.The proposed unified method can be extended to general aerodynamic entry guidance designs,providing theoretical and methodological support for them.展开更多
Blasting-induced cracks in the rock surrounding deeply buried tunnels can result in water gushing and rock mass collapse,posing significant safety risks.However,previous theoretical studies on the range of blasting-in...Blasting-induced cracks in the rock surrounding deeply buried tunnels can result in water gushing and rock mass collapse,posing significant safety risks.However,previous theoretical studies on the range of blasting-induced cracks often ignore the impact of the in-situ stress,especially that of the intermediate principal stress.The particle displacement−crack radius relationship was established in this paper by utilizing the blasthole cavity expansion equation,and theoretical analytical formulas of the stress−displacement relationship and the crack radius were derived with unified strength theory to accurately assess the range of cracks in deep surrounding rock under a blasting load.Parameter analysis showed that the crushing zone size was positively correlated with in-situ stress,intermediate principal stress,and detonation pressure,whereas negatively correlated with Poisson ratio and decoupling coefficient.The dilatancy angle-crushing zone size relationship exhibited nonmonotonic behavior.The relationships in the crushing zone and the fracture zone exhibited opposite trends under the influence of only in-situ stress or intermediate principal stress.As the in-situ stress increased from 0 to 70 MPa,the rate of change in the crack range and the attenuation rate of the peak vibration velocity gradually slowed.展开更多
A new unified analytical solution is presented for predicting the range of plastic zone and stress distributions around a deep circular tunnel in a homogeneous isotropic continuous medium. The rock mass, grouting zone...A new unified analytical solution is presented for predicting the range of plastic zone and stress distributions around a deep circular tunnel in a homogeneous isotropic continuous medium. The rock mass, grouting zone and lining are assumed as elastic-perfectly plastic and governed by the unified strength theory(UST). This new solution has made it possible to consider the interaction between seepage pressure, lining, grouting and rock mass, and the intermediate principal stress effect together. Moreover, parametric analysis is carried out to identify the influence of the related parameters on the plastic zone radius. Under the given conditions, the results show that the plastic zone radius decreases with an increasing cohesion, internal friction angle and hydraulic conductivity of lining and unified failure criterion parameter, respectively; whereas the plastic zone radius increases with the growth of elasticity modulus of lining. Comparison of results from the new solution and the other published one shows well agreement and provides confidence in the new solution proposed.展开更多
Fibre-reinforced polymer(FRP)has the advantages of high strength,light weight,corrosion resistance and convenient construction and is widely used in repairing and strengthening damaged concrete columns.Most of the exi...Fibre-reinforced polymer(FRP)has the advantages of high strength,light weight,corrosion resistance and convenient construction and is widely used in repairing and strengthening damaged concrete columns.Most of the existing strength models were built by regression analysis of experimental data;however,in this article,a new unified strength model is proposed using the Hoek-Brown failure criterion.To study the strength of FRP-confined damaged and undamaged concrete columns,900 test data were collected from the published literature and a large database that contains the cross-sectional shape of each specimen,the damage type,the damage level and the FRP-confined stiffness was established.A new strength model using the Hoek-Brown failure criterion was established and is suitable for both circular and square columns that are undamaged,load-damaged and fire-damaged.Based on the database,most of the existing strength models from the published literature and the model proposed in this paper were evaluated.The evaluation shows that the proposed model can predict the compressive strength for FRP-confined pre-damaged and undamaged concrete columns with good accuracy.展开更多
In order to study the mechanism of bearing behavior at the tip of a pile embedded in rock, the generalized nonlinear unified strength criterion and slip line principle for resolving the differential equation systems w...In order to study the mechanism of bearing behavior at the tip of a pile embedded in rock, the generalized nonlinear unified strength criterion and slip line principle for resolving the differential equation systems which govern the stress field were applied to derive the ultimate end beating capacity based on some reasonable hypothesis and failure plane model. Both numerical simulation and test results were compared with the theoretic solution. The results show good consistency with each other and verify the validity of the present approach. The depth effect with respective to embedment ratio and other influence factors like geological strength index, intermediate principal stress, overburden factor, and damage on end bearing capacity were discussed in the analytical solution. The results show that the proposed yield criterion can be much better for investigating the ultimate end bearing performance of rock-socketed pile. The end bearing capacity increases with embedment ratio and the increasing degree is influenced intensely by the above parameters. Furthermore, ignoring intermediate stress effect would underestimate the strength properties of the rock material and lead to a very conservative estimation value.展开更多
A unified semi-analytical solution is presented for elastic-plastic stress of a deep circular hydraulic tunnel with support yielding under plane strain conditions.The rock mass is assumed to be elastic-perfectly plast...A unified semi-analytical solution is presented for elastic-plastic stress of a deep circular hydraulic tunnel with support yielding under plane strain conditions.The rock mass is assumed to be elastic-perfectly plastic and governed by the unified strength theory (UST).Different major principal stresses in different engineering situations and different support yielding conditions are both considered.The unified solution obtained in this work is a series of results,rather than one specific solution,hence it is suitable for a wide range of rock masses.In addition,parametric study is conducted to investigate the effect of intermediate principal stress.The result shows the major principal stress should be rationally chosen according to different engineering conditions.Finally,the applicability of the unified solution is discussed according to the critical pressures.展开更多
At first, the paper reviews, analyses and discusses uplifting mechanism and history, current situation of Tibet plateau. Coal\|bearing strata and coal seam were discovered by surveying and many rocks samples and struc...At first, the paper reviews, analyses and discusses uplifting mechanism and history, current situation of Tibet plateau. Coal\|bearing strata and coal seam were discovered by surveying and many rocks samples and structural samples were collected, which established the foundation for further studying. From all above, the paper has studied strata system, time\|spatial evolution, magma activity and its regularity of continental collision of Tibet plateau and rock’s mechanical features under high temperature and pressure. The paper has also summerized tectonic features, studied geological process by time coordinate and proposed multidisciplinary geological model. The paper has proposed evolutinal model of modern structural stress field in early quaternary, modern structural stress field and crustal deformation and explored geophysical field features and deep structures from man\|mad earthquake, regional gravity field and electrical structures, thus established geophysical field model. In addition, the paper proposed overall dynamic model according to stress field, displacement orientation and velocity restriction condition, indoplate collision to Eurasia.Thoroughly, the paper has studied and stated mechanical system, non\|stability, multibody collision mechanics and mantle plume mechanical model and established mechanical model. Finally, the paper has studied numeral simulation about spheric inter\|acting during continental collision of Tibet plateau, from this, analysed and inferred its evolution history.展开更多
For the interaction relation between geological object and engineering object in some fields related to water conservancy and hydropower, a unified modeling idea was proposed. On the basis of summarizing both advantag...For the interaction relation between geological object and engineering object in some fields related to water conservancy and hydropower, a unified modeling idea was proposed. On the basis of summarizing both advantages and disadvantages of existing modeling methods, an automatic unified modeling method of both engineering and geological objects based on tri-prism(TP) model was presented. Through the lossless correction algorithm of deviated drill holes contained in this method, the real deviated drill holes could be corrected into the equivalent virtual vertical ones. And the correction accuracy fully meets the requirements of unified modeling. With the virtual vertical drilling data, TIN construction of both cover layer and other stratums would be built in order to obtain the 3D geological model. Then, the engineering design data would be introduced into the 3D geological model for achieving unified modeling. For this process, the volume subdividing and restructuring principles were introduced to deal with the spatial relationships between engineering object and geological object. In order to improve the efficiency of unified modeling, the reconstruction of TIN based on constraint information was also applied in this method. At last, the feasibility and validation of the unified modeling method as well as its relevant key algorithms were verified by specific experiments and analysis of results.展开更多
The yield behavior of metallic glasses was studied. Three yield criteria, including von Mises yield criterion, Mohr-Coulomb yield criterion and the unified yield criterion were used to describe the yield phenomena of ...The yield behavior of metallic glasses was studied. Three yield criteria, including von Mises yield criterion, Mohr-Coulomb yield criterion and the unified yield criterion were used to describe the yield phenomena of the metallic glasses. Two classes of the experimental data were chosen to draw the yield loci using the unified yield criterion. It is shown that the unified yield criterion can be used to describe the yield behavior of the metallic glasses no matter whether the metallic glasses show strength- different effect or non-strength-different effect. Almost all the widely accepted yield criteria are the subsets of the unified yield criterion if the intermediate principle stress and/or the intermediate principle shear stress are not considered at all.展开更多
Initiated three decades ago,integrated design of controllers and fault detectors has continuously attracted research attention.The recent development of the unified control and detection framework with an observer-bas...Initiated three decades ago,integrated design of controllers and fault detectors has continuously attracted research attention.The recent development of the unified control and detection framework with an observer-based residual generator in its core gives a more general form of the previous works.Its applications to residual centred modelling of uncertain control systems,fault detection in feedback control systems with uncertainties,fault-tolerant control(FTC)as well as control performance degradation monitoring,detection and recovery are introduced.In conclusion,some future perspectives are proposed.展开更多
1. IntroductionHumans have the ability (or competence) to think logically, and this is an undeniable fact. However,what this ability consists in is a difficult question. It might be said that logical ability consists ...1. IntroductionHumans have the ability (or competence) to think logically, and this is an undeniable fact. However,what this ability consists in is a difficult question. It might be said that logical ability consists in theknowledge of a set of logic rules. But what are those logic rules? For centuries logicians have devel-展开更多
基金Project(52274130)supported by the National Natural Science Foundation of ChinaProject(ZR2024ZD22)supported by the Major Basic Research Project of the Shandong Provincial Natural Science Foundation,China+2 种基金Project(2023375)supported by the Guizhou University Research and Innovation Team,ChinaProject(Leading Fund(2023)09)supported by the Natural Science Research Fund of Guizhou University,ChinaProject(JYBSYS2021101)supported by the Open Fund of Key Laboratory of Safe and Effective Coal Mining,Ministry of Education,China。
文摘The stress gradient of surrounding rock and reasonable prestress of support are the keys to ensuring the stability of roadways.The elastic-plastic analytical solution for surrounding rock was derived based on unified strength theory.A model for solving the stress gradient of the surrounding rock with the intermediate principal stress parameter b was established.The correctness and applicability of the solution for the stress gradient in the roadway surrounding rock was verified via multiple methods.Furthermore,the laws of stress,displacement,and the plastic zone of the surrounding rock with different b values and prestresses were revealed.As b increases,the stress gradient in the plastic zone increases,and the displacement and plastic zone radius decrease.As the prestress increases,the peak stress shifts toward the sidewalls,and the stress and stress gradient increments decrease.In addition,the displacement increment and plastic zone increment were proposed to characterize the support effect.The balance point of the plastic zone area appears before that of the displacement zone.The relationship between the stress gradient compensation coefficient and the prestress is obtained.This study provides a research method and idea for determining the reasonable prestress of support in roadways.
文摘对珠子参中皂苷类成分进行定性鉴别分析,建立珠子参皂苷类多成分含量测定方法。采用超高效液相色谱-飞行时间质谱(UPLC-Q-TOF-MS/MS)技术对珠子参进行正、负离子模式扫描,使用UNIFI天然产物信息平台对珠子参所含的化学成分进行定性鉴别分析;以0.1%磷酸水-乙腈溶液为流动相进行梯度洗脱,柱温30℃,流速0.3 mL/min,进行珠子参皂苷类多成分含量测定。珠子参中共鉴定出39个化学成分,包括37个皂苷类化合物和2个皂苷母核,并总结了皂苷类化合物的裂解规律,建立了UPLC同时测定珠子参中人参皂苷Rb1、人参皂苷Ro、人参皂苷Rb3、竹节参皂苷IV、竹节参皂苷IVa、人参皂苷Rd、姜状三七皂苷R1和金盏花苷E的多指标含量测定方法,该方法中8个待测成分在检测质量浓度范围内线性关系良好,精密度、重复性、稳定性的相对标准偏差(relative standard deviation,RSD)均小于3.0%,样品中人参皂苷Rb1、人参皂苷Ro、人参皂苷Rb3、竹节参皂苷IV、竹节参皂苷IVa、人参皂苷Rd、姜状三七皂苷R1和金盏花苷E的平均加样回收率分别为102.4%、103.1%、97.97%、99.42%、102.7%、102.1%、95.23%、100.5%,RSD分别为1.0%、0.98%、0.81%、2.3%、0.81%、1.9%、0.96%、1.8%。该研究建立的方法可快速、准确地对珠子参中的皂苷类成分进行定性及定量分析。
基金The National Key R&D Program of China(2018YFA0703800)。
文摘Aerocapture is one of the key technologies for low-cost transportation,with high demands of autonomy,accuracy,and robustness of guidance and control,due to its high reliability requirements for only one chance of trying.A unified numerical predictor-corrector guidance method based on characteristic models for aerocapture is proposed.The numerical predictor-corrector guidance method is used to achieve autonomy and high accuracy,and the characteristic model control method is introduced to achieve robustness.At the same time,by transforming path constraints,characteristic model equations including apogee deviation and altitude differentiation are established.Based on the characteristic model equations,a unified guidance law which can satisfy path constraints and guidance objectives simultaneously is designed.In guidance problems,guidance deviation is not directly obtained from the output of the dynamics at present,but is calculated through integral and algebraic equations.Therefore,the method of directly discretizing differential equations cannot be used to establish characteristic models,which brings great difficulty to characteristic modeling.A method for characteristic modeling of guidance problems is proposed,and convergence analysis of the proposed guidance law is also provided.Finally,a joint numerical simulation of guidance and control considering navigation deviation and various uncertainties is conducted to verify the effectiveness of the proposed method.The proposed unified method can be extended to general aerodynamic entry guidance designs,providing theoretical and methodological support for them.
基金Project(2021JJ10063)supported by the Natural Science Foundation of Hunan Province,ChinaProject(202115)supported by the Science and Technology Progress and Innovation Project of Hunan Provincial Department of Transportation,ChinaProject(2021K094-Z)supported by the Science and Technology Research and Development Program of China Railway Guangzhou Group Co.,Ltd。
文摘Blasting-induced cracks in the rock surrounding deeply buried tunnels can result in water gushing and rock mass collapse,posing significant safety risks.However,previous theoretical studies on the range of blasting-induced cracks often ignore the impact of the in-situ stress,especially that of the intermediate principal stress.The particle displacement−crack radius relationship was established in this paper by utilizing the blasthole cavity expansion equation,and theoretical analytical formulas of the stress−displacement relationship and the crack radius were derived with unified strength theory to accurately assess the range of cracks in deep surrounding rock under a blasting load.Parameter analysis showed that the crushing zone size was positively correlated with in-situ stress,intermediate principal stress,and detonation pressure,whereas negatively correlated with Poisson ratio and decoupling coefficient.The dilatancy angle-crushing zone size relationship exhibited nonmonotonic behavior.The relationships in the crushing zone and the fracture zone exhibited opposite trends under the influence of only in-situ stress or intermediate principal stress.As the in-situ stress increased from 0 to 70 MPa,the rate of change in the crack range and the attenuation rate of the peak vibration velocity gradually slowed.
基金Project(51378309)supported by National Natural Science Foundation of China
文摘A new unified analytical solution is presented for predicting the range of plastic zone and stress distributions around a deep circular tunnel in a homogeneous isotropic continuous medium. The rock mass, grouting zone and lining are assumed as elastic-perfectly plastic and governed by the unified strength theory(UST). This new solution has made it possible to consider the interaction between seepage pressure, lining, grouting and rock mass, and the intermediate principal stress effect together. Moreover, parametric analysis is carried out to identify the influence of the related parameters on the plastic zone radius. Under the given conditions, the results show that the plastic zone radius decreases with an increasing cohesion, internal friction angle and hydraulic conductivity of lining and unified failure criterion parameter, respectively; whereas the plastic zone radius increases with the growth of elasticity modulus of lining. Comparison of results from the new solution and the other published one shows well agreement and provides confidence in the new solution proposed.
基金Project(2017M622540)supported by the China Postdoctoral Science FoundationProject(51808419)supported by the National Natural Science Foundation of China+1 种基金Project(2019CFB217)supported by the National Natural Science Foundation of Hubei Province,ChinaProject(201623)supported by the Science and Technology Project of Wuhan Urban and Rural Construction Committee,China。
文摘Fibre-reinforced polymer(FRP)has the advantages of high strength,light weight,corrosion resistance and convenient construction and is widely used in repairing and strengthening damaged concrete columns.Most of the existing strength models were built by regression analysis of experimental data;however,in this article,a new unified strength model is proposed using the Hoek-Brown failure criterion.To study the strength of FRP-confined damaged and undamaged concrete columns,900 test data were collected from the published literature and a large database that contains the cross-sectional shape of each specimen,the damage type,the damage level and the FRP-confined stiffness was established.A new strength model using the Hoek-Brown failure criterion was established and is suitable for both circular and square columns that are undamaged,load-damaged and fire-damaged.Based on the database,most of the existing strength models from the published literature and the model proposed in this paper were evaluated.The evaluation shows that the proposed model can predict the compressive strength for FRP-confined pre-damaged and undamaged concrete columns with good accuracy.
基金Project(2007AA11Z134) supported by the National High-tech Research and Development Program of ChinaProject(10JJ4035) supported by Hunan Provincial Natural Science Foundation of ChinaProject(04SK2008) supported by Hunan Provincial Science and Technology Department,China
文摘In order to study the mechanism of bearing behavior at the tip of a pile embedded in rock, the generalized nonlinear unified strength criterion and slip line principle for resolving the differential equation systems which govern the stress field were applied to derive the ultimate end beating capacity based on some reasonable hypothesis and failure plane model. Both numerical simulation and test results were compared with the theoretic solution. The results show good consistency with each other and verify the validity of the present approach. The depth effect with respective to embedment ratio and other influence factors like geological strength index, intermediate principal stress, overburden factor, and damage on end bearing capacity were discussed in the analytical solution. The results show that the proposed yield criterion can be much better for investigating the ultimate end bearing performance of rock-socketed pile. The end bearing capacity increases with embedment ratio and the increasing degree is influenced intensely by the above parameters. Furthermore, ignoring intermediate stress effect would underestimate the strength properties of the rock material and lead to a very conservative estimation value.
基金Project(50969007)supported by National Natural Science Foundation of ChinaProject(GJJ13753)supported by the Scientific and Technological Research Fund,Department of Education,Jiangxi Province,China
文摘A unified semi-analytical solution is presented for elastic-plastic stress of a deep circular hydraulic tunnel with support yielding under plane strain conditions.The rock mass is assumed to be elastic-perfectly plastic and governed by the unified strength theory (UST).Different major principal stresses in different engineering situations and different support yielding conditions are both considered.The unified solution obtained in this work is a series of results,rather than one specific solution,hence it is suitable for a wide range of rock masses.In addition,parametric study is conducted to investigate the effect of intermediate principal stress.The result shows the major principal stress should be rationally chosen according to different engineering conditions.Finally,the applicability of the unified solution is discussed according to the critical pressures.
文摘At first, the paper reviews, analyses and discusses uplifting mechanism and history, current situation of Tibet plateau. Coal\|bearing strata and coal seam were discovered by surveying and many rocks samples and structural samples were collected, which established the foundation for further studying. From all above, the paper has studied strata system, time\|spatial evolution, magma activity and its regularity of continental collision of Tibet plateau and rock’s mechanical features under high temperature and pressure. The paper has also summerized tectonic features, studied geological process by time coordinate and proposed multidisciplinary geological model. The paper has proposed evolutinal model of modern structural stress field in early quaternary, modern structural stress field and crustal deformation and explored geophysical field features and deep structures from man\|mad earthquake, regional gravity field and electrical structures, thus established geophysical field model. In addition, the paper proposed overall dynamic model according to stress field, displacement orientation and velocity restriction condition, indoplate collision to Eurasia.Thoroughly, the paper has studied and stated mechanical system, non\|stability, multibody collision mechanics and mantle plume mechanical model and established mechanical model. Finally, the paper has studied numeral simulation about spheric inter\|acting during continental collision of Tibet plateau, from this, analysed and inferred its evolution history.
基金Project(BK2012812)supported by the Natural Science Foundation of Jiangsu Province,ChinaProject(51079053)supported by the National Natural Science Foundation of China+2 种基金Project(KYLX_0493)supported by the Scientific Research and Innovation Program for College Graduates of Jiangsu Province,ChinaProject(2014B38814)supported by the Fundamental Research Funds for Central Universities,ChinaProject(2014.1526)supported by the Open Research Fund Program of Key Laboratory of Geological Information of Ministry of Land and Resources,China
文摘For the interaction relation between geological object and engineering object in some fields related to water conservancy and hydropower, a unified modeling idea was proposed. On the basis of summarizing both advantages and disadvantages of existing modeling methods, an automatic unified modeling method of both engineering and geological objects based on tri-prism(TP) model was presented. Through the lossless correction algorithm of deviated drill holes contained in this method, the real deviated drill holes could be corrected into the equivalent virtual vertical ones. And the correction accuracy fully meets the requirements of unified modeling. With the virtual vertical drilling data, TIN construction of both cover layer and other stratums would be built in order to obtain the 3D geological model. Then, the engineering design data would be introduced into the 3D geological model for achieving unified modeling. For this process, the volume subdividing and restructuring principles were introduced to deal with the spatial relationships between engineering object and geological object. In order to improve the efficiency of unified modeling, the reconstruction of TIN based on constraint information was also applied in this method. At last, the feasibility and validation of the unified modeling method as well as its relevant key algorithms were verified by specific experiments and analysis of results.
基金Projects(51011120053, 50823006, 50825102) supported by the National Natural Science Foundation of China
文摘The yield behavior of metallic glasses was studied. Three yield criteria, including von Mises yield criterion, Mohr-Coulomb yield criterion and the unified yield criterion were used to describe the yield phenomena of the metallic glasses. Two classes of the experimental data were chosen to draw the yield loci using the unified yield criterion. It is shown that the unified yield criterion can be used to describe the yield behavior of the metallic glasses no matter whether the metallic glasses show strength- different effect or non-strength-different effect. Almost all the widely accepted yield criteria are the subsets of the unified yield criterion if the intermediate principle stress and/or the intermediate principle shear stress are not considered at all.
基金This work was supported by the National Natural Science Foundation of China(62020106003,62073029)the Beijing Natural Science Foundation(4202045)the Fundamental Research Funds for the Central Universities(FRF-TP-20-012A3).
文摘Initiated three decades ago,integrated design of controllers and fault detectors has continuously attracted research attention.The recent development of the unified control and detection framework with an observer-based residual generator in its core gives a more general form of the previous works.Its applications to residual centred modelling of uncertain control systems,fault detection in feedback control systems with uncertainties,fault-tolerant control(FTC)as well as control performance degradation monitoring,detection and recovery are introduced.In conclusion,some future perspectives are proposed.
文摘1. IntroductionHumans have the ability (or competence) to think logically, and this is an undeniable fact. However,what this ability consists in is a difficult question. It might be said that logical ability consists in theknowledge of a set of logic rules. But what are those logic rules? For centuries logicians have devel-
