In this research,the effect of the sintering and cooling process on geometry distortion and mechanical properties of PTFE/Al reactive material is investigated.Six particularly selected sintering temperatures,three dif...In this research,the effect of the sintering and cooling process on geometry distortion and mechanical properties of PTFE/Al reactive material is investigated.Six particularly selected sintering temperatures,three different cooling modes(annealing cooling,normalizing cooling and rapid cooling),three different initial cooling temperature s,as well as six different final cooling temperatures were designed to compare the effects of sintering temperature,cooling rate,initial cooling temperature and final cooling temperature on the properties of reactive materials.Geometry distortion was quantitatively analyzed by a statistic on the dimensional changes of the specimens and microscopic morphology.A mechanical response properties transition from brittle to ductile was found and analyzed.By combining the thermodynamic properties of PTFE and unsteady heat conduction theory,mechanisms of cooling induced morphology change,temperature induced distortion and strength decrease were obtained.The results showed that the cooling rate has the most significant effect on the morphology transformation,while initial cooling temperature has more significant effect on the dimensional distortion than final cooling temperature.As to the mechanical properties transition from brittle to plastic,a more prominent effect of initial cooling temperature than cooling rate and final temperature was revealed.展开更多
By applying the framework of the tangent bundle geometry to the method of Lagrange multi- pliers,a geometric description of Chetaev's nonholonomic systems subjected to unilateral nonholonomic con- straints trod un...By applying the framework of the tangent bundle geometry to the method of Lagrange multi- pliers,a geometric description of Chetaev's nonholonomic systems subjected to unilateral nonholonomic con- straints trod unilateral holonomic constraints respectively in time-independent circumstances is presented.展开更多
The description of modern differential geometry for time-dependent Chetaev nonholonomic mechanical systems with unilateral constraints is studied. By using the structure of exact contact manifold, the geometric framew...The description of modern differential geometry for time-dependent Chetaev nonholonomic mechanical systems with unilateral constraints is studied. By using the structure of exact contact manifold, the geometric framework of time- dependent nonholonomic mechanical systems subject to unilateral nonholonomic constraints and unilateral holonomic constraints respectively is presented.展开更多
In practical engineering applications,rock mass are often found to be subjected to a triaxial stress state.Concurrently,defects like joints and fractures have a notable impact on the mechanical behavior of rock mass.S...In practical engineering applications,rock mass are often found to be subjected to a triaxial stress state.Concurrently,defects like joints and fractures have a notable impact on the mechanical behavior of rock mass.Such defects are identified as crucial contributors to the failure and instability of the surrounding rock,subsequently impacting the engineering stability.The study aimed to investigate the impact of fracture geometry and confining pressure on the deformation,failure characteristics,and strength of specimens using sand powder 3D printing technology and conventional triaxial compression tests.The results indicate that the number of fractures present considerably influences the peak strength,axial peak strain and elastic modulus of the specimens.Confining pressure is an important factor affecting the failure pattern of the specimen,under which the specimen is more prone to shear failure,but the initiation,expansion and penetration processes of secondary cracks in different fracture specimens are different.This study confirmed the feasibility of using sand powder 3D printing specimens as soft rock analogs for triaxial compression research.The insights from this research are deemed essential for a deeper understanding of the mechanical behavior of fractured surrounding rocks when under triaxial stress state.展开更多
Many methods are proposed to deal with the type synthesis of parallel kinematic mechanisms（PKMs）, but most of them are less intuitive to some extent. Thus, to propose a concise and intuitive type synthesis method fo...Many methods are proposed to deal with the type synthesis of parallel kinematic mechanisms（PKMs）, but most of them are less intuitive to some extent. Thus, to propose a concise and intuitive type synthesis method for engineering application is a very challenging issue, which should be further studied in the field. Grassmann line geometry, which can investigate the dimensions of spatial line-clusters in a concise way, is taken as the mathematic foundation. Atlas method is introduced to visually describe the degrees of freedom（DOFs） and constraints of a mechanism, and the dual rule is brought in to realize the mutual conversion of the freedom-space and constraint-space. Consequently, a systematic method based on Grassmann line geometry and Atlas method is generated and the entire type synthesis process is presented. Three type 4-DOF PKMs, i.e., 1T3R, 2T2R and 3T1R（T： translational DOF; R： rotational DOF）, are classified according to the different combinations of the translational DOFs and rotational DOFs. The type synthesis of 4-DOF PKMs is carried out and the possible configurations are thoroughly investigated. Some new PKMs with useful functions are generated during this procedure. The type synthesis method based on Grassmann line geometry and Atlas method is intuitive and concise, and can reduce the complexity of the PKMs＇ type synthesis. Moreover, this method can provide theoretical guidance for other PKMs＇ type synthesis and engineering application. A novel type synthesis method is proposed, which solves the existing methods＇ problems in terms of complicated, not intuitive and unsuitable for practical application.展开更多
The loads acting on the sealing elements of balanced mechanical seals are analyzed. When the balance factor approaches the back pressure factor, the spring pressure will become main part of the face pressure. The leak...The loads acting on the sealing elements of balanced mechanical seals are analyzed. When the balance factor approaches the back pressure factor, the spring pressure will become main part of the face pressure. The leakage model of balanced mechanical seals is established on the base of M-B model for rough surface. Several GY-70 type balanced mechanical seals are tested. The influences of the spring pressure both on the leakage rate and on the friction characteristic of balanced mechanical seals are investigated. The research results indicate that as spring pressure increases, both the clear-ance between two end faces and the leakage rate will decrease, and the friction will be more serious because lubrication medium between the rotating ring and the stationary ring reduces, though the increase of the spring pressure may not be enough to change the face friction state of mechanical seals. There exists an optimum spring pressure for mechanical seal operation. Under this spring pres-sure, not only leakage rate is small, but also the seal end surfaces have a fine friction characteristic. Under different operating conditions, identical type mechanical seals may possess different spring pressure. Appropriate selection of spring pressure is valuable to realize long-period and small leakage rate operating of balanced mechanical seals.展开更多
This paper describes a novel,system-level design methodology based on a genetic algorithm(GA)using freeform geometries for microelectromechanical systems(MEMS)devices.The proposed method can concurrently design and co...This paper describes a novel,system-level design methodology based on a genetic algorithm(GA)using freeform geometries for microelectromechanical systems(MEMS)devices.The proposed method can concurrently design and co-optimize the electronic and mechanical parts of a MEMS device comprising freeform geometries to achieve a better system performance,i.e.,a high sensitivity,a good system stability,and large fabrication tolerances.Also,the introduction of freeform geometries allows higher degrees of freedom in the design process,improving the diversity and potentially the performance of the MEMS devices.A MEMS accelerometer comprising a freeform mechanical motion preamplifier in a closed-loop control system is presented to demonstrate the effectiveness of the design approach.The optimization process shows the main figure-of-merit(FOM)is improved by 195%.In the mechanical component alone(open-loop system),the product of sensitivity and bandwidth has improved by 151%,with sensitivity increasing by 276%.For closed-loop performance,there is an improvement of 120%for the ratio of open and closed-loop displacements.The product of sensitivity and bandwidth is improved by 27%in the closed-loop system.Excellent immunities to fabrication errors and parameter mismatch are achieved.Experiments show that the displacement of the MEMS accelerometer in the closed-loop system decreased by 86%with 4.85 V feedback voltage compared with that in the open-loop system under a 1 g 100 Hz acceleration input.The static and dynamic nonlinearities in the closed-loop system are improved by 64%and 61%,respectively,compared with those in the open-loop system,in the±1 g acceleration input range.Besides,the closed-loop system improves the cross-axis sensitivity by 18.43%,compared with that in the open-loop system.It is the first time a closed-loop system for a MEMS accelerometer comprising a mechanical motion preamplifier is successfully implemented experimentally.展开更多
Friction stir spot welding of A6061 sheets was conducted using a tool with thread pin. The hook geometries, hook formation and mechanical properties of the joints welded with different rotary directions and speeds wer...Friction stir spot welding of A6061 sheets was conducted using a tool with thread pin. The hook geometries, hook formation and mechanical properties of the joints welded with different rotary directions and speeds were investigated. The results show that the hook in the joint welded in clockwise was curved upwards and that in anticlockwise was curved downwards. The hook formation was related to the plastic material flow in the joint. With increasing the rotary speed in clockwise direction, the hook moved upwards and far way from the center of the keyhole, resulting in an increase in the effective weld width and a decrease in the effective sheet thickness. Three types of fractuces were observed and they were affected by the hook geometries. The tensile shear load increased firstly and then decreased when the rotary speed increased in clockwise direction, which was related to the hook geometries.展开更多
A new type of quantum theory known as time-dependent𝒫PT-symmetric quantum mechanics has received much attention recently.It has a conceptually intriguing feature of equipping the Hilbert space of a𝒫PT-...A new type of quantum theory known as time-dependent𝒫PT-symmetric quantum mechanics has received much attention recently.It has a conceptually intriguing feature of equipping the Hilbert space of a𝒫PT-symmetric system with a time-varying inner product.In this work,we explore the geometry of time-dependent𝒫𝒯PT-symmetric quantum mechanics.We find that a geometric phase can emerge naturally from the cyclic evolution of a PT-symmetric system,and further formulate a series of related differential-geometry concepts,including connection,curvature,parallel transport,metric tensor,and quantum geometric tensor.These findings constitute a useful,perhaps indispensible,tool to investigate geometric properties of𝒫PT-symmetric systems with time-varying system’s parameters.To exemplify the application of our findings,we show that the unconventional geometric phase[Phys.Rev.Lett.91187902(2003)],which is the sum of a geometric phase and a dynamical phase proportional to the geometric phase,can be expressed as a single geometric phase unveiled in this work.展开更多
A serial of fullerenes had been built and the optimized geome- tries had been obtained with the energy minimization of molecular mechanics calculations according to the fact that the pentagonal number is exactly 12 in...A serial of fullerenes had been built and the optimized geome- tries had been obtained with the energy minimization of molecular mechanics calculations according to the fact that the pentagonal number is exactly 12 in the fullerenes which consist of pentagons and hexagons.The fullerene geometry prediction could facilitate further theoretical and synthetical studies in the near future.展开更多
In this paper, we present our research on building computing machines consciousness about intuitive geometry based on mathematics experiments and statistical inference. The investigation consists of the following five...In this paper, we present our research on building computing machines consciousness about intuitive geometry based on mathematics experiments and statistical inference. The investigation consists of the following five steps. At first, we select a set of geometric configurations and for each configuration we construct a large amount of geometric data as observation data using dynamic geometry programs together with the pseudo-random number generator. Secondly, we refer to the geometric predicates in the algebraic method of machine proof of geometric theorems to construct statistics suitable for measuring the approximate geometric relationships in the observation data. In the third step, we propose a geometric relationship detection method based on the similarity of data distribution, where the search space has been reduced into small batches of data by pre-searching for efficiency, and the hypothetical test of the possible geometric relationships in the search results has be performed. In the fourth step, we explore the integer relation of the line segment lengths in the geometric configuration in addition. At the final step, we do numerical experiments for the pre-selected geometric configurations to verify the effectiveness of our method. The results show that computer equipped with the above procedures can find out the hidden geometric relations from the randomly generated data of related geometric configurations, and in this sense, computing machines can actually attain certain consciousness of intuitive geometry as early civilized humans in ancient Mesopotamia.展开更多
The National Strong-Motion Observation Network System of China has collected over 12 000 strong-motion recordings from 2007 to December 2020.This study assembled the source-related metadata of 1 920 earthquakes associ...The National Strong-Motion Observation Network System of China has collected over 12 000 strong-motion recordings from 2007 to December 2020.This study assembled the source-related metadata of 1 920 earthquakes associated with assembled well-processed recordings of China.The earthquake basic information,focal mechanisms,and the fault geometry were collected from various institutes and literature.We recommended the MWvalues for 900 earthquakes,the fault types for 1 064 earthquakes,and the fault geometries for 18 large earthquakes.We also performed the statistical analysis for establishing the empirical conversions of MW-MS,and ML,and providing the empirical relationships between MWand ruptured area,aspect ratio,respectively.Moreover,the ruptured fault geometries of large earthquakes were used to preliminarily divide all earthquakes considered into 1 141 mainshocks,and 779 aftershocks.The finite-fault distances(RJBand Rrup) of strong-motion recordings from the 18 large earthquakes were calculated,and then used to yield the statistic relationships between the point-source distances(Repiand Rhyp) and finite-fault distances.We finally provided the earthquake source database freely accessible at website.The source-related metadata can be directly applied to develop the ground motion prediction equations of China.展开更多
基金The authors are very grateful for the support received from the National Natural Science Foundation of China(No.11202030)State Key Laboratory of the State Key Laboratory of Explosion Science and Technology(QNKT19-03).
文摘In this research,the effect of the sintering and cooling process on geometry distortion and mechanical properties of PTFE/Al reactive material is investigated.Six particularly selected sintering temperatures,three different cooling modes(annealing cooling,normalizing cooling and rapid cooling),three different initial cooling temperature s,as well as six different final cooling temperatures were designed to compare the effects of sintering temperature,cooling rate,initial cooling temperature and final cooling temperature on the properties of reactive materials.Geometry distortion was quantitatively analyzed by a statistic on the dimensional changes of the specimens and microscopic morphology.A mechanical response properties transition from brittle to ductile was found and analyzed.By combining the thermodynamic properties of PTFE and unsteady heat conduction theory,mechanisms of cooling induced morphology change,temperature induced distortion and strength decrease were obtained.The results showed that the cooling rate has the most significant effect on the morphology transformation,while initial cooling temperature has more significant effect on the dimensional distortion than final cooling temperature.As to the mechanical properties transition from brittle to plastic,a more prominent effect of initial cooling temperature than cooling rate and final temperature was revealed.
基金the National Natural Science Foundation of China(No.19972010)the Qing Lan Project Foundation of Jiangsu Province of Chinathe Research Foundation of Suzhou Institute of Urban Construction & Environmental Protection of China
文摘By applying the framework of the tangent bundle geometry to the method of Lagrange multi- pliers,a geometric description of Chetaev's nonholonomic systems subjected to unilateral nonholonomic con- straints trod unilateral holonomic constraints respectively in time-independent circumstances is presented.
基金Project supported by the National Natural Science Foundation of China （Grant No 10272021）, the Natural Science Foundation of High Education of Jiangsu Province, China （Grant No 04KJA130135） and the ＂Qing Lan＂ Project Foundation of Jiangsu Province, China.
文摘The description of modern differential geometry for time-dependent Chetaev nonholonomic mechanical systems with unilateral constraints is studied. By using the structure of exact contact manifold, the geometric framework of time- dependent nonholonomic mechanical systems subject to unilateral nonholonomic constraints and unilateral holonomic constraints respectively is presented.
基金Project(2021YFC2900600)supported by the Young Scientist Project of National Key Research and Development Program of ChinaProject(52074166)supported by the National Natural Science Foundation of China+1 种基金Projects(ZR2021YQ38,ZR2020QE121)supported by the Natural Science Foundation of Shandong Province,ChinaProject(2022KJ101)supported by the Science and Technology Support Plan for Youth Innovation of Colleges and Universities in Shandong Province,China。
文摘In practical engineering applications,rock mass are often found to be subjected to a triaxial stress state.Concurrently,defects like joints and fractures have a notable impact on the mechanical behavior of rock mass.Such defects are identified as crucial contributors to the failure and instability of the surrounding rock,subsequently impacting the engineering stability.The study aimed to investigate the impact of fracture geometry and confining pressure on the deformation,failure characteristics,and strength of specimens using sand powder 3D printing technology and conventional triaxial compression tests.The results indicate that the number of fractures present considerably influences the peak strength,axial peak strain and elastic modulus of the specimens.Confining pressure is an important factor affecting the failure pattern of the specimen,under which the specimen is more prone to shear failure,but the initiation,expansion and penetration processes of secondary cracks in different fracture specimens are different.This study confirmed the feasibility of using sand powder 3D printing specimens as soft rock analogs for triaxial compression research.The insights from this research are deemed essential for a deeper understanding of the mechanical behavior of fractured surrounding rocks when under triaxial stress state.
基金supported by National Natural Science Foundation of China(Grant No.51135008)National Basic Research Program of China(973 Program,Grant No.2013CB035400)China Postdoctoral Science Foundation(Grant Nos.2012M520256,2013T60107)
文摘Many methods are proposed to deal with the type synthesis of parallel kinematic mechanisms（PKMs）, but most of them are less intuitive to some extent. Thus, to propose a concise and intuitive type synthesis method for engineering application is a very challenging issue, which should be further studied in the field. Grassmann line geometry, which can investigate the dimensions of spatial line-clusters in a concise way, is taken as the mathematic foundation. Atlas method is introduced to visually describe the degrees of freedom（DOFs） and constraints of a mechanism, and the dual rule is brought in to realize the mutual conversion of the freedom-space and constraint-space. Consequently, a systematic method based on Grassmann line geometry and Atlas method is generated and the entire type synthesis process is presented. Three type 4-DOF PKMs, i.e., 1T3R, 2T2R and 3T1R（T： translational DOF; R： rotational DOF）, are classified according to the different combinations of the translational DOFs and rotational DOFs. The type synthesis of 4-DOF PKMs is carried out and the possible configurations are thoroughly investigated. Some new PKMs with useful functions are generated during this procedure. The type synthesis method based on Grassmann line geometry and Atlas method is intuitive and concise, and can reduce the complexity of the PKMs＇ type synthesis. Moreover, this method can provide theoretical guidance for other PKMs＇ type synthesis and engineering application. A novel type synthesis method is proposed, which solves the existing methods＇ problems in terms of complicated, not intuitive and unsuitable for practical application.
基金This project is supported by Provincial Natural Science Foundation of Educa-tion Office of Jiangsu, China (No. 04KJD530090)Innovating Founda-tion for Doctoral Dissertation of Nanjing University of Technology, China (No. BSCX200510).
文摘The loads acting on the sealing elements of balanced mechanical seals are analyzed. When the balance factor approaches the back pressure factor, the spring pressure will become main part of the face pressure. The leakage model of balanced mechanical seals is established on the base of M-B model for rough surface. Several GY-70 type balanced mechanical seals are tested. The influences of the spring pressure both on the leakage rate and on the friction characteristic of balanced mechanical seals are investigated. The research results indicate that as spring pressure increases, both the clear-ance between two end faces and the leakage rate will decrease, and the friction will be more serious because lubrication medium between the rotating ring and the stationary ring reduces, though the increase of the spring pressure may not be enough to change the face friction state of mechanical seals. There exists an optimum spring pressure for mechanical seal operation. Under this spring pres-sure, not only leakage rate is small, but also the seal end surfaces have a fine friction characteristic. Under different operating conditions, identical type mechanical seals may possess different spring pressure. Appropriate selection of spring pressure is valuable to realize long-period and small leakage rate operating of balanced mechanical seals.
基金supported by The Science and Technology Development Fund,Macao SAR(FDCT),004/2023/SKLThe Science and Technology Development Fund,Macao SAR(FDCT),0087/2023/ITP2.
文摘This paper describes a novel,system-level design methodology based on a genetic algorithm(GA)using freeform geometries for microelectromechanical systems(MEMS)devices.The proposed method can concurrently design and co-optimize the electronic and mechanical parts of a MEMS device comprising freeform geometries to achieve a better system performance,i.e.,a high sensitivity,a good system stability,and large fabrication tolerances.Also,the introduction of freeform geometries allows higher degrees of freedom in the design process,improving the diversity and potentially the performance of the MEMS devices.A MEMS accelerometer comprising a freeform mechanical motion preamplifier in a closed-loop control system is presented to demonstrate the effectiveness of the design approach.The optimization process shows the main figure-of-merit(FOM)is improved by 195%.In the mechanical component alone(open-loop system),the product of sensitivity and bandwidth has improved by 151%,with sensitivity increasing by 276%.For closed-loop performance,there is an improvement of 120%for the ratio of open and closed-loop displacements.The product of sensitivity and bandwidth is improved by 27%in the closed-loop system.Excellent immunities to fabrication errors and parameter mismatch are achieved.Experiments show that the displacement of the MEMS accelerometer in the closed-loop system decreased by 86%with 4.85 V feedback voltage compared with that in the open-loop system under a 1 g 100 Hz acceleration input.The static and dynamic nonlinearities in the closed-loop system are improved by 64%and 61%,respectively,compared with those in the open-loop system,in the±1 g acceleration input range.Besides,the closed-loop system improves the cross-axis sensitivity by 18.43%,compared with that in the open-loop system.It is the first time a closed-loop system for a MEMS accelerometer comprising a mechanical motion preamplifier is successfully implemented experimentally.
基金This work was sponsored by the National Natural Science Foundation of China （51364037）, the Landed Plan of Science and Technology in Colleges and Universities of Jiangxi Province （KJLD12074）, the Aerospace Science Foundation of China （20111156004）.
文摘Friction stir spot welding of A6061 sheets was conducted using a tool with thread pin. The hook geometries, hook formation and mechanical properties of the joints welded with different rotary directions and speeds were investigated. The results show that the hook in the joint welded in clockwise was curved upwards and that in anticlockwise was curved downwards. The hook formation was related to the plastic material flow in the joint. With increasing the rotary speed in clockwise direction, the hook moved upwards and far way from the center of the keyhole, resulting in an increase in the effective weld width and a decrease in the effective sheet thickness. Three types of fractuces were observed and they were affected by the hook geometries. The tensile shear load increased firstly and then decreased when the rotary speed increased in clockwise direction, which was related to the hook geometries.
基金supported by Singapore Ministry of Education Academic Research Fund Tier I(WBS No.R-144-000-353-112)by the Singapore NRF Grant No.NRFNRFI2017-04(WBS No.R-144-000-378-281)supported by Singapore Ministry of Education Academic Research Fund Tier I(WBS No.R-144-000-352-112)。
文摘A new type of quantum theory known as time-dependent𝒫PT-symmetric quantum mechanics has received much attention recently.It has a conceptually intriguing feature of equipping the Hilbert space of a𝒫PT-symmetric system with a time-varying inner product.In this work,we explore the geometry of time-dependent𝒫𝒯PT-symmetric quantum mechanics.We find that a geometric phase can emerge naturally from the cyclic evolution of a PT-symmetric system,and further formulate a series of related differential-geometry concepts,including connection,curvature,parallel transport,metric tensor,and quantum geometric tensor.These findings constitute a useful,perhaps indispensible,tool to investigate geometric properties of𝒫PT-symmetric systems with time-varying system’s parameters.To exemplify the application of our findings,we show that the unconventional geometric phase[Phys.Rev.Lett.91187902(2003)],which is the sum of a geometric phase and a dynamical phase proportional to the geometric phase,can be expressed as a single geometric phase unveiled in this work.
文摘A serial of fullerenes had been built and the optimized geome- tries had been obtained with the energy minimization of molecular mechanics calculations according to the fact that the pentagonal number is exactly 12 in the fullerenes which consist of pentagons and hexagons.The fullerene geometry prediction could facilitate further theoretical and synthetical studies in the near future.
文摘In this paper, we present our research on building computing machines consciousness about intuitive geometry based on mathematics experiments and statistical inference. The investigation consists of the following five steps. At first, we select a set of geometric configurations and for each configuration we construct a large amount of geometric data as observation data using dynamic geometry programs together with the pseudo-random number generator. Secondly, we refer to the geometric predicates in the algebraic method of machine proof of geometric theorems to construct statistics suitable for measuring the approximate geometric relationships in the observation data. In the third step, we propose a geometric relationship detection method based on the similarity of data distribution, where the search space has been reduced into small batches of data by pre-searching for efficiency, and the hypothetical test of the possible geometric relationships in the search results has be performed. In the fourth step, we explore the integer relation of the line segment lengths in the geometric configuration in addition. At the final step, we do numerical experiments for the pre-selected geometric configurations to verify the effectiveness of our method. The results show that computer equipped with the above procedures can find out the hidden geometric relations from the randomly generated data of related geometric configurations, and in this sense, computing machines can actually attain certain consciousness of intuitive geometry as early civilized humans in ancient Mesopotamia.
基金supported by the National Key R&D Program of China(Grant No.2019YFE0115700).
文摘The National Strong-Motion Observation Network System of China has collected over 12 000 strong-motion recordings from 2007 to December 2020.This study assembled the source-related metadata of 1 920 earthquakes associated with assembled well-processed recordings of China.The earthquake basic information,focal mechanisms,and the fault geometry were collected from various institutes and literature.We recommended the MWvalues for 900 earthquakes,the fault types for 1 064 earthquakes,and the fault geometries for 18 large earthquakes.We also performed the statistical analysis for establishing the empirical conversions of MW-MS,and ML,and providing the empirical relationships between MWand ruptured area,aspect ratio,respectively.Moreover,the ruptured fault geometries of large earthquakes were used to preliminarily divide all earthquakes considered into 1 141 mainshocks,and 779 aftershocks.The finite-fault distances(RJBand Rrup) of strong-motion recordings from the 18 large earthquakes were calculated,and then used to yield the statistic relationships between the point-source distances(Repiand Rhyp) and finite-fault distances.We finally provided the earthquake source database freely accessible at website.The source-related metadata can be directly applied to develop the ground motion prediction equations of China.
