The deformation energy(Wd)of soil-like tectonic coal is crucial for investigating the mechanism of coal and gas outbursts.Tectonic coal has a significant nonlinear constitutive relationship,which makes traditional ela...The deformation energy(Wd)of soil-like tectonic coal is crucial for investigating the mechanism of coal and gas outbursts.Tectonic coal has a significant nonlinear constitutive relationship,which makes traditional elastic-based models for computing Wdunsuitable.Inspired by critical state soil mechanics,this study theoretically established a new calculation model of Wdsuitable for the coal with nonlinear deformation characteristics.In the new model,the relationship between energy and stress no longer follows the square law(observed in traditional linear elastic models)but exhibits a power function,with the theoretical value of the power exponent ranging between 1 and 2.Hydrostatic cyclic loading and unloading experiments were conducted on four groups of tectonic coal samples and one group of intact coal samples.The results indicated that the relationship between Wdand stress for both intact and tectonic coal follows a power law.The exponents for intact and tectonic coal are close to 2 and 1,respectively.The stress-strain curve of intact coal exhibits small deformation and linear characteristics,whereas the stress-strain curves of tectonic coal show large deformation and nonlinear characteristics.The study specifically investigates the role of coal viscosity in the cyclic loading/unloading process.The downward bending in the unloading curves can be attributed to the time-dependent characteristics of coal,particularly its viscoelastic behavior.Based on experimental statistics,the calculation model of Wdwas further simplified.The simplified model involves only one unknown parameter,which is the power exponent between Wdand stress.The measured Wdof the coal samples increases with the number of load cycles.This phenomenon is attributed to coal's viscoelastic deformation.Within the same stress,the Wdof tectonic coal is an order of magnitude greater than that of intact coal.The calculation model of Wdproposed in this paper provides a new tool for studying the energy principle of coal and gas outbursts.展开更多
In this study, the effect of extreme laser fields on the α decay process of ground-state even–even nuclei was investigated.Using the deformed Gamow-like model, we found that state-of-the-art lasers can cause a sligh...In this study, the effect of extreme laser fields on the α decay process of ground-state even–even nuclei was investigated.Using the deformed Gamow-like model, we found that state-of-the-art lasers can cause a slight change in the α decay penetration probability of most nuclei. In addition, we studied the correlation between the rate of change of the α decay penetration probability and angle between the directions of the laser electric field and α particle emission for different nuclei. Based on this correlation, the average effect of extreme laser fields on the half-life of many nuclei with arbitrary α particle emission angles was calculated. The calculations show that the laser suppression and promotion effects on the α decay penetration probability of the nuclei population with completely random α particle-emission directions are not completely canceled.The remainder led to a change in the average penetration probability of the nuclei. Furthermore, the possibility of achieving a higher average rate of change by altering the spatial shape of the laser is explored. We conclude that circularly polarized lasers may be helpful in future experiments to achieve a more significant average rate of change of the α decay half-life of the nuclei population.展开更多
Based on the theory of superimposed deformation and the regional tectonic background,the multi-phase non-coaxial superimposed structures in Junggar Basin were systematically analyzed using seismic interpretation,field...Based on the theory of superimposed deformation and the regional tectonic background,the multi-phase non-coaxial superimposed structures in Junggar Basin were systematically analyzed using seismic interpretation,field outcrop observation,and paleo-stress field recovery methods according to the characteristics of the current tectonic framework.Moreover,the tectonic evolution process of the basin was reconstructed using sandbox analogue modelling technology.The results showed that the study area has experienced five phases of non-coaxial deformation with superimposition:The first phase of deformation(D1)is characterized by NNE-SSW extension during late Carboniferous to early Permian,which formed large graben,half graben and other extensional structure style around the basin.The second phase of deformation(D2)is represented by NE-SW compression during the middle to late Permian,and it comprised numerous contraction structures that developed based on D1.The basic form of the entire basin is alternating uplift and depression.The third phase of deformation(D3)is the NW-SE transpressional strike-slip in the Triassic-Jurassic,which produced numerous strike-slip structural styles in the middle part of the basin.The fourth phase of deformation(D4)is the uniform sedimentation during Cretaceous,and the fifth phase(D5)is the compression along NNE-SSW due to the North Tianshan northward thrust,which produced three rows of fold thrust belts and tear faults in the front of the mountain in the southern margin of the basin.The newly established three-dimensional tectonic evolution model shows that,based on the large number of NW-trending grabens and half grabens in the Carboniferous basement of Junggar Basin,multiple level NE trending uplifts have formed with the joint superposition of the late structural inversion and multiple stress fields.This has resulted in the current tectonic units of alternating uplifts and depressions in different directions in the study area.展开更多
To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conduc...To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conducted based on the numerical results of two mathematical models,the rigid-body model and fluid-structure interaction model.In addition,the applicable scope of the above two methods,and the structural response characteristics of the projectile have also been investigated.Our results demonstrate that:(1) The impact loads and angular motion of the projectile of the rigid-body method are more likely to exhibit periodic variations due to the periodic tail slap,its range of positive angles of attack is about α<2°.(2) When the projectile undergone significant wetting,a strong coupling effect is observed among wetting,structural deformation,and projectile motion.With the applied projectile shape,it is observed that,when the projectile bends,the final wetting position is that of Part B(cylinder of body).With the occu rrence of this phenomenon,the projectile ballistics beco me completely unstable.(3) The force exerted on the lower surface of the projectile induced by wetting is the primary reason of the destabilization of the projectile traj ectory and structu ral deformation failure.Bending deformation is most likely to appear at the junction of Part C(cone of body) and Part D(tail).The safe angles of attack of the projectile stability are found to be about α≤2°.展开更多
Estimation of the rock mass modulus of deformation(Em)is one of the most important design parameters in designing many structures in and on rock.This parameter can be obtained by in situ tests,empirical relations betw...Estimation of the rock mass modulus of deformation(Em)is one of the most important design parameters in designing many structures in and on rock.This parameter can be obtained by in situ tests,empirical relations between deformation modulus and rock mass classifcation,and estimating from laboratory tests results.In this paper,a back analysis calculation is performed to present an equation for estimation of the rock mass modulus of deformation using genetic programming(GP)and numerical modeling.A database of 40,960 datasets,including vertical stress(rz),horizontal to vertical stresses ratio(k),Poisson’s ratio(m),radius of circular tunnel(r)and wall displacement of circular tunnel on the horizontal diameter(d)for input parameters and modulus of deformation for output,was established.The selected parameters are easy to determine and rock mass modulus of deformation can be obtained from instrumentation data of any size circular galleries.The resulting RMSE of 0.86 and correlation coeffcient of97%of the proposed equation demonstrated the capability of the computer program(CP)generated by GP.展开更多
The plastic deformation behavior of new Mg-Gd-Y-Zn-Mn magnesium alloys gains great necessity to clarify and understand the mechanism deeply. In the present work,the tensile mechanical property test and visco-plastic s...The plastic deformation behavior of new Mg-Gd-Y-Zn-Mn magnesium alloys gains great necessity to clarify and understand the mechanism deeply. In the present work,the tensile mechanical property test and visco-plastic self-consistent (VPSC) model are used to investigate the activities of deformation modes of VW84M and VW94M magnesium alloys during the tensile deformation. The results show that the mechanical properties of the above extruded alloys are similar but VW94M has higher strength than VW84M after the same aging process. Compared with the extruded alloys,the as-aged alloys have significantly higher activation of pyramidal slip at the later stage of plastic deformation. In addition,the as-aged VW94M alloy with higher strength has the largest activity of pyramidal slip. In summary,the addition of Gd increases the critical resolved shear stress (CRSS)in each slip system of VW94M,while the increase in the strength and the decrease in the elongation of as-aged alloys are associated with the significant activation of pyramidal slip.展开更多
Ne and Mg isotope chains are investigated based on constrained calculations in the framework of a deformed relativistic mean-field （RMF） model with the NL075 parameter set. The calculated quadrupole deformation and ...Ne and Mg isotope chains are investigated based on constrained calculations in the framework of a deformed relativistic mean-field （RMF） model with the NL075 parameter set. The calculated quadrupole deformation and binding energy are compared with other theoretical results as well as the available experimental data. It shows that the calculated deformations of Ne and Mg with the NL075 are more accurate than those obtained with the NL-SH. It is predicted that ^19,29,32Ne and ^20,31Mg maybe have a triaxial deformation and ^25-28Ne and ^27-30Mg exhibit a shape coexistence probably. The closure effect of neutron number N=8 for ^20Mg is predicted to be very weak.展开更多
In this research,mechanical stress,static strain and deformation analyses of a cylindrical pressure vessel subjected to mechanical loads are presented.The kinematic relations are developed based on higherorder sinusoi...In this research,mechanical stress,static strain and deformation analyses of a cylindrical pressure vessel subjected to mechanical loads are presented.The kinematic relations are developed based on higherorder sinusoidal shear deformation theory.Thickness stretching formulation is accounted for more accurate analysis.The total transverse deflection is divided into bending,shear and thickness stretching parts in which the third term is responsible for change of deflection along the thickness direction.The axisymmetric formulations are derived through principle of virtual work.A parametric study is presented to investigate variation of stress and strain components along the thickness and longitudinal directions.To explore effect of thickness stretching model on the static results,a comparison between the present results with the available results of literature is presented.As an important output,effect of micro-scale parameter is studied on the static stress and strain distribution.展开更多
The evolution of faults within the same stress field is frequently influenced by numerous factors,involving the reactivation of pre-existing structures,stress transmission through ductile detachment layers,and the gro...The evolution of faults within the same stress field is frequently influenced by numerous factors,involving the reactivation of pre-existing structures,stress transmission through ductile detachment layers,and the growth,interaction,as well as linkage of new fault segments.This study analyses a complex multi-phase oblique extension fault system in the Nanpu Sag(NPS)of the Bohai Bay Basin(BBB),China.High-resolution three-dimensional(3D)seismic data and analogue modelling indicate that the oblique extensional reactivation of pre-existing structures governs the sequential arrangement of fault segments in the caprock,and they dip synthetically to the reactivated fault at depth.During the NW-SE extension in the Eocene,the predominant movement of the pre-existing fault is strike-slip.Subsequently,during the N-S extension since the Oligocene,inclined at 20.to the pre-existing fault,forming splay fault segments and ultimately creating large en-echelon arcuate faults linked by relay ramps.Using fault throw-distance(T-D)and laser scanning,we reconstructed the fault evolution model of oblique extension reactivation in the presence of a ductile detachment basement.Our study illustrates that the arcuate faults can be categorized into linear master fault segments controlled by pre-existing structures,bending splay faults in the termination zone,and normal fault segments responding to the regional stress field.The interaction between faults occurs among normal faults and strike-slip faults,and the kinematic unification of the two fault systems is accomplished in the intersection zone.As the faults continue to evolve,the new fault segments tend to relinquish the control of pre-existing structures and concentrate more on the development of planar and continuous major faults.The ductile detachment layer significantly contributes to the uniform distribution of strain,resulting in narrow shear zones and discontinuous normal faults in its absence.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(No.2024QN11072)National Natural Science Foundation of China(Nos.52404264 and 52174217)State Key Program of the National Natural Science Foundation of China(No.52034008)。
文摘The deformation energy(Wd)of soil-like tectonic coal is crucial for investigating the mechanism of coal and gas outbursts.Tectonic coal has a significant nonlinear constitutive relationship,which makes traditional elastic-based models for computing Wdunsuitable.Inspired by critical state soil mechanics,this study theoretically established a new calculation model of Wdsuitable for the coal with nonlinear deformation characteristics.In the new model,the relationship between energy and stress no longer follows the square law(observed in traditional linear elastic models)but exhibits a power function,with the theoretical value of the power exponent ranging between 1 and 2.Hydrostatic cyclic loading and unloading experiments were conducted on four groups of tectonic coal samples and one group of intact coal samples.The results indicated that the relationship between Wdand stress for both intact and tectonic coal follows a power law.The exponents for intact and tectonic coal are close to 2 and 1,respectively.The stress-strain curve of intact coal exhibits small deformation and linear characteristics,whereas the stress-strain curves of tectonic coal show large deformation and nonlinear characteristics.The study specifically investigates the role of coal viscosity in the cyclic loading/unloading process.The downward bending in the unloading curves can be attributed to the time-dependent characteristics of coal,particularly its viscoelastic behavior.Based on experimental statistics,the calculation model of Wdwas further simplified.The simplified model involves only one unknown parameter,which is the power exponent between Wdand stress.The measured Wdof the coal samples increases with the number of load cycles.This phenomenon is attributed to coal's viscoelastic deformation.Within the same stress,the Wdof tectonic coal is an order of magnitude greater than that of intact coal.The calculation model of Wdproposed in this paper provides a new tool for studying the energy principle of coal and gas outbursts.
基金This work was supported by the National Nature Science Foundation of China(Nos.12375244,12135009)the Science and Technology Innovation Program of Hunan Province(No.2020RC4020)+1 种基金the Hunan Provincial Innovation Foundation for Postgraduate(No.CX20210007)Natural Science Research Project of Yichang City(No.A23-2-028).
文摘In this study, the effect of extreme laser fields on the α decay process of ground-state even–even nuclei was investigated.Using the deformed Gamow-like model, we found that state-of-the-art lasers can cause a slight change in the α decay penetration probability of most nuclei. In addition, we studied the correlation between the rate of change of the α decay penetration probability and angle between the directions of the laser electric field and α particle emission for different nuclei. Based on this correlation, the average effect of extreme laser fields on the half-life of many nuclei with arbitrary α particle emission angles was calculated. The calculations show that the laser suppression and promotion effects on the α decay penetration probability of the nuclei population with completely random α particle-emission directions are not completely canceled.The remainder led to a change in the average penetration probability of the nuclei. Furthermore, the possibility of achieving a higher average rate of change by altering the spatial shape of the laser is explored. We conclude that circularly polarized lasers may be helpful in future experiments to achieve a more significant average rate of change of the α decay half-life of the nuclei population.
基金supported by the National Natural Science Foundation of China,(Grant No.42072144)Shengli Oilfield,SINOPEC,China(Nos.30200018-21-ZC0613-0030 and 30200018-20-ZC0613-0116)。
文摘Based on the theory of superimposed deformation and the regional tectonic background,the multi-phase non-coaxial superimposed structures in Junggar Basin were systematically analyzed using seismic interpretation,field outcrop observation,and paleo-stress field recovery methods according to the characteristics of the current tectonic framework.Moreover,the tectonic evolution process of the basin was reconstructed using sandbox analogue modelling technology.The results showed that the study area has experienced five phases of non-coaxial deformation with superimposition:The first phase of deformation(D1)is characterized by NNE-SSW extension during late Carboniferous to early Permian,which formed large graben,half graben and other extensional structure style around the basin.The second phase of deformation(D2)is represented by NE-SW compression during the middle to late Permian,and it comprised numerous contraction structures that developed based on D1.The basic form of the entire basin is alternating uplift and depression.The third phase of deformation(D3)is the NW-SE transpressional strike-slip in the Triassic-Jurassic,which produced numerous strike-slip structural styles in the middle part of the basin.The fourth phase of deformation(D4)is the uniform sedimentation during Cretaceous,and the fifth phase(D5)is the compression along NNE-SSW due to the North Tianshan northward thrust,which produced three rows of fold thrust belts and tear faults in the front of the mountain in the southern margin of the basin.The newly established three-dimensional tectonic evolution model shows that,based on the large number of NW-trending grabens and half grabens in the Carboniferous basement of Junggar Basin,multiple level NE trending uplifts have formed with the joint superposition of the late structural inversion and multiple stress fields.This has resulted in the current tectonic units of alternating uplifts and depressions in different directions in the study area.
基金supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX24_0714).
文摘To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conducted based on the numerical results of two mathematical models,the rigid-body model and fluid-structure interaction model.In addition,the applicable scope of the above two methods,and the structural response characteristics of the projectile have also been investigated.Our results demonstrate that:(1) The impact loads and angular motion of the projectile of the rigid-body method are more likely to exhibit periodic variations due to the periodic tail slap,its range of positive angles of attack is about α<2°.(2) When the projectile undergone significant wetting,a strong coupling effect is observed among wetting,structural deformation,and projectile motion.With the applied projectile shape,it is observed that,when the projectile bends,the final wetting position is that of Part B(cylinder of body).With the occu rrence of this phenomenon,the projectile ballistics beco me completely unstable.(3) The force exerted on the lower surface of the projectile induced by wetting is the primary reason of the destabilization of the projectile traj ectory and structu ral deformation failure.Bending deformation is most likely to appear at the junction of Part C(cone of body) and Part D(tail).The safe angles of attack of the projectile stability are found to be about α≤2°.
文摘Estimation of the rock mass modulus of deformation(Em)is one of the most important design parameters in designing many structures in and on rock.This parameter can be obtained by in situ tests,empirical relations between deformation modulus and rock mass classifcation,and estimating from laboratory tests results.In this paper,a back analysis calculation is performed to present an equation for estimation of the rock mass modulus of deformation using genetic programming(GP)and numerical modeling.A database of 40,960 datasets,including vertical stress(rz),horizontal to vertical stresses ratio(k),Poisson’s ratio(m),radius of circular tunnel(r)and wall displacement of circular tunnel on the horizontal diameter(d)for input parameters and modulus of deformation for output,was established.The selected parameters are easy to determine and rock mass modulus of deformation can be obtained from instrumentation data of any size circular galleries.The resulting RMSE of 0.86 and correlation coeffcient of97%of the proposed equation demonstrated the capability of the computer program(CP)generated by GP.
文摘The plastic deformation behavior of new Mg-Gd-Y-Zn-Mn magnesium alloys gains great necessity to clarify and understand the mechanism deeply. In the present work,the tensile mechanical property test and visco-plastic self-consistent (VPSC) model are used to investigate the activities of deformation modes of VW84M and VW94M magnesium alloys during the tensile deformation. The results show that the mechanical properties of the above extruded alloys are similar but VW94M has higher strength than VW84M after the same aging process. Compared with the extruded alloys,the as-aged alloys have significantly higher activation of pyramidal slip at the later stage of plastic deformation. In addition,the as-aged VW94M alloy with higher strength has the largest activity of pyramidal slip. In summary,the addition of Gd increases the critical resolved shear stress (CRSS)in each slip system of VW94M,while the increase in the strength and the decrease in the elongation of as-aged alloys are associated with the significant activation of pyramidal slip.
基金Project supported by the Major State Basic Research Development Program of China （Grant No G2000077404）, the National Natural Science Foundation of China （Grant Nos 10125521, 10475108, 10405032 and 10328259）, the Fund of the Education Ministry of China （Grant No 20010284036） and the Shanghai Phosphor Program （Grant No 03 QA 14066）.
文摘Ne and Mg isotope chains are investigated based on constrained calculations in the framework of a deformed relativistic mean-field （RMF） model with the NL075 parameter set. The calculated quadrupole deformation and binding energy are compared with other theoretical results as well as the available experimental data. It shows that the calculated deformations of Ne and Mg with the NL075 are more accurate than those obtained with the NL-SH. It is predicted that ^19,29,32Ne and ^20,31Mg maybe have a triaxial deformation and ^25-28Ne and ^27-30Mg exhibit a shape coexistence probably. The closure effect of neutron number N=8 for ^20Mg is predicted to be very weak.
文摘In this research,mechanical stress,static strain and deformation analyses of a cylindrical pressure vessel subjected to mechanical loads are presented.The kinematic relations are developed based on higherorder sinusoidal shear deformation theory.Thickness stretching formulation is accounted for more accurate analysis.The total transverse deflection is divided into bending,shear and thickness stretching parts in which the third term is responsible for change of deflection along the thickness direction.The axisymmetric formulations are derived through principle of virtual work.A parametric study is presented to investigate variation of stress and strain components along the thickness and longitudinal directions.To explore effect of thickness stretching model on the static results,a comparison between the present results with the available results of literature is presented.As an important output,effect of micro-scale parameter is studied on the static stress and strain distribution.
基金funded by the National Natural Science Foundation of China (grant No.41472116)the Jidong Oil Company of China National Petroleum Corporation (grant No.JDYT-2017-JS-308)the Beijing Research Centre of China National Offshore Oil Company (grant No.CCL2022RCPS2017XNN)。
文摘The evolution of faults within the same stress field is frequently influenced by numerous factors,involving the reactivation of pre-existing structures,stress transmission through ductile detachment layers,and the growth,interaction,as well as linkage of new fault segments.This study analyses a complex multi-phase oblique extension fault system in the Nanpu Sag(NPS)of the Bohai Bay Basin(BBB),China.High-resolution three-dimensional(3D)seismic data and analogue modelling indicate that the oblique extensional reactivation of pre-existing structures governs the sequential arrangement of fault segments in the caprock,and they dip synthetically to the reactivated fault at depth.During the NW-SE extension in the Eocene,the predominant movement of the pre-existing fault is strike-slip.Subsequently,during the N-S extension since the Oligocene,inclined at 20.to the pre-existing fault,forming splay fault segments and ultimately creating large en-echelon arcuate faults linked by relay ramps.Using fault throw-distance(T-D)and laser scanning,we reconstructed the fault evolution model of oblique extension reactivation in the presence of a ductile detachment basement.Our study illustrates that the arcuate faults can be categorized into linear master fault segments controlled by pre-existing structures,bending splay faults in the termination zone,and normal fault segments responding to the regional stress field.The interaction between faults occurs among normal faults and strike-slip faults,and the kinematic unification of the two fault systems is accomplished in the intersection zone.As the faults continue to evolve,the new fault segments tend to relinquish the control of pre-existing structures and concentrate more on the development of planar and continuous major faults.The ductile detachment layer significantly contributes to the uniform distribution of strain,resulting in narrow shear zones and discontinuous normal faults in its absence.
