A hull structure is prone to local deformation and damage due to the pressure load on the surface.How to simulate surface pressure is an important issue in ship structure test.The loading mode of hydraulic actuator co...A hull structure is prone to local deformation and damage due to the pressure load on the surface.How to simulate surface pressure is an important issue in ship structure test.The loading mode of hydraulic actuator combined with high-pressure flexible bladder was proposed,and the numerical model of the loading device based on flexible bladder was established.The design and analysis method of high-pressure flexible bladder based on aramid-fiber reinforced thermoplastic polyurethane was proposed to break through the surface pressure loading technology of ship structures.The surface pressure loading system based on flexible bladder was developed.The ultimate strength verification test of the box girder under the combined action of bending moment and pressure was carried out to systematically verify the feasibility and applicability of the loading system.The results show that the surface pressure loading technology can be used well for applying uniform pressure to ship structures.Compared with the traditional surface loading methods,the improved device can be applied with horizontal constant pressure load,with rapid response and safe process,and the pressure load is always stable with the increase of the bending moment load during the test.The requirement for uniform loading in the comprehensive strength test of large structural models is satisfied and the accuracy of the test results is improved by this system.展开更多
A nonlinear finite element model of the nut post reinforced concrete （RC） structure of the safety mechanism in the Three Gorges Project （TGP） ship lift was built by ANSYS software. Some irregular structures such a...A nonlinear finite element model of the nut post reinforced concrete （RC） structure of the safety mechanism in the Three Gorges Project （TGP） ship lift was built by ANSYS software. Some irregular structures such as the nut post and the rotary rod were divided by curved surface into a series of regular parts, and the structures were all meshed to hexahedron. Constraint equations were defined between two interfaces with different element sizes and mesh patterns. PRETS179 elements were used to simulate the preload in the tendons and the pre-stressed screws, and the loss of prestressing force was calculated. Five extreme load cases were analyzed. The stress of each part in the structure was obtained. The results indicate that the maximum compressive stress of concrete C35 is 24.13 MPa, so the concrete may be partially crushed; the maximum tensile stress of the grouting motar is 6.73 MPa, so the grouting motar may partially fracture; the maximum yon Mises stress of the rotary rod is 648.70 MPa, therefore the rotary rod may partially yield.展开更多
There have been a great demand for a suitable and convenient method in the field of buckling analysis of stiffened ship structures, which is essential to structural safety assessment and is significantly time-consumin...There have been a great demand for a suitable and convenient method in the field of buckling analysis of stiffened ship structures, which is essential to structural safety assessment and is significantly time-consuming. Modeling, buckling behaviors and ultimate strength prediction of stiffened panels were investigated. The modeling specification including nonlinear finite element model and imperfections generation, and post-buckling analysis procedure of stiffened plates were demonstrated. And a software tool using set-based finite element method was developed and executed in the MSC. Marc environment. Different types of stiffen panels of marine structures have been employed to investigate the buckling behavior and assess the validity in the estimation of ultimate strength. A comparison between results of the generally accepted methods, experiments and the software tool developed was demonstrated. It is shown that the software tool can predict the ultimate capacity of stiffened panels with imperfections with a good accuracy.展开更多
s Western Yunnan is located at the boundary of collision or underthrusting zone of Eurasian plate and is influenced by many times tectonic movements. With very complex geological environment and tectonic background, i...s Western Yunnan is located at the boundary of collision or underthrusting zone of Eurasian plate and is influenced by many times tectonic movements. With very complex geological environment and tectonic background, it is one of the seismically active areas. In the paper, the teleseismic records were selected from 16 national, local and mo-bile stations, including 4 very-wide-band mobile stations of PASSCAL. And nearly 2 000 receiver functions were extracted. Two measuring lines are 650 km and 450 km, respectively and across some major tectonic units in Western Yunnan. It is indicated that Nujiang might be a seam characterized by underthrusting. The western and eastern boundaries of Sichuan-Yunnan rhombus block, i.e., Honghe and Xiaojiang faults, might be an erection seam or collision belt. Panxi tectonic zone still has the characteristics of continental rift valley, that is, the surface is hollow and the upper mantle is upwarping. The tectonic situation in Western Yunnan is of certain regulation with the interlacing distribution of orogenic zone and seam. The crustal thickness decreases gradually from the north to the south and the S wave velocity is globally lower here.展开更多
2023年12月18日甘肃积石山发生M_(S)6.2地震,该地震造成了严重的地质灾害,属国内近些年来6级以上地震所罕见.基于多阶段定位方法对2023年积石山M_(S)6.2地震序列进行了重定位,根据gCAP(generalized Cut And Paste)方法反演了序列中M_(S)...2023年12月18日甘肃积石山发生M_(S)6.2地震,该地震造成了严重的地质灾害,属国内近些年来6级以上地震所罕见.基于多阶段定位方法对2023年积石山M_(S)6.2地震序列进行了重定位,根据gCAP(generalized Cut And Paste)方法反演了序列中M_(S)≥3.0以上地震的震源机制及矩心深度,并对震源机制节面进行聚类分析,获取了地震序列的主要断层面形状,计算了积石山地震序列震源区的构造应力场,研究了其应力场与震源机制节面及断层面的关系,最后结合地质构造、地壳形变等资料综合探讨和推测了积石山地震序列可能的发震构造.结果显示:(1)重定位结果表明,积石山M_(S)6.2地震序列震中区的长轴主要沿着拉脊山北缘断裂南段呈NNW向的优势展布,整个序列长约15km、宽约6km,北端、南端各分别止于大河家镇南侧及积石山县西侧,且存在显著的丛集分区特征,主要划分为大河家镇到刘集乡之间的北段余震稀疏区,以及刘集乡到积石山县西侧之间的南段余震密集区,其中南段余震密集区呈现为NW-SE向的分支和NNW-SSE向的分支,且两个分支形成了NW端分叉且SE端汇聚的分布特征,大部分余震主要集中在NW-SE向分支而积石山M_(S)6.2主震位于NNW-SSE向分支的NE侧.整个序列的平均震源深度约为11.4km,大多数地震主要集中在9~14km深度范围,其中主震的初始破裂深度为13.6km.震源深度剖面清晰勾勒出地震序列的主要发震断层面倾向为NE向,积石山M_(S)6.2主震则位于倾向NE的断层面底端,余震基本位于M_(S)6.2主震的上方,大体呈现为单侧破裂的特征.(2)gCAP波形反演表明,积石山M_(S)6.2主震震源机制节面I的走向/倾角/滑动角为304°/55°/65°,节面II的走向/倾角/滑动角为163°/42°/121°,P轴方位51°和其倾伏角7°,矩心深度10km,矩震级M_(W)5.95.主震及M_(S)3.0以上余震的震源机制主要表现以逆冲为主且略带少量的走滑分量,震源机制的P轴主要呈现近NE-SW向的水平挤压,矩心深度介于9~12km之间,平均矩心深度10.7km.(3)震源机制节面聚类分析得出两簇聚类中心节面,其中NE倾向的聚类中心节面走向311°及倾角43°,其形状和重定位的深度剖面大体一致.震源区应力场反演结果显示,积石山震源区的最优压应力轴走向、倾伏角分别为57°和15°,表明积石山震源区应力场表现为NE向的近水平挤压,并以逆冲为主的应力状态.通过将其反演得到的应力场投影到积石山地震序列震源机制节面及其聚类中心节面,发现积石山应力体系在这些震源机制节面和聚类中心节面上均更容易产生逆冲破裂的地震事件.(4)结合已有区域地质构造、地壳形变等研究,综合分析认为积石山M_(S)6.2地震序列的发震构造和拉脊山北缘主断裂南段(积石山东缘断裂)与其至少两条走向略不同的反冲断层组成的“y”型冲断构造所在的复杂逆冲推覆环境有关,其中积石山M_(S)6.2主震位于NNW-SSE走向、SW倾向拉脊山北缘主断裂南段与其NW-SE走向、NNW-SSE走向及NE倾向的次级反冲断层形成的背冲式构造“y”形汇合部位,并在拉脊山北缘主断裂南段上的反冲断层上发生了相对密集的积石山余震序列.展开更多
Based on the biological prototype characteristics of shark’s gill jet orifice,the flexible driving characteristics of ionic exchange polymer metal composites(IPMC)artificial muscle materials and the use of sleeve fle...Based on the biological prototype characteristics of shark’s gill jet orifice,the flexible driving characteristics of ionic exchange polymer metal composites(IPMC)artificial muscle materials and the use of sleeve flexible connector,the IPMC linear driving unit simulation model is built and the IPMC material-driving dynamic control structure of bionic gill unit is developed.Meanwhile,through the stress analysis of bionic gill plate and the motion simulation of bionic gill unit,it is verified that various dynamic control and active control of the jet orifice under the condition of different mainstream field velocities will be taken by using IPMC material-driving.Moreover,the large-deflection deformation of bionic gill plate under dynamic pressure and the comparative analysis with that of a rigid gill plate is studied,leading to the achievement of approximate revised modifier from real value to theoretical value of the displacement control of IPMC.展开更多
This paper used the modern evaluation method of DEA （Data Envelopment Analysis） to assess the comparative efficiency and then on the basis of this among multiple schemes chose the optimal scheme of agricultural prod...This paper used the modern evaluation method of DEA （Data Envelopment Analysis） to assess the comparative efficiency and then on the basis of this among multiple schemes chose the optimal scheme of agricultural production structure adjustment. Based on the results of DEA model, we dissected scale advantages of each discretionary scheme or plan. We examined scale advantages of each discretionary scheme, tested profoundly a definitive purpose behind not-DEA efficient, which elucidated the system and methodology to enhance these discretionary plans. At the end, another method had been proposed to rank and select the optimal scheme. The research was important to guide the practice if the modification of agricultural production industrial structure was carded on.展开更多
Large-scale gypsum rocks associated with world-class Pb-Zn ore formations are widely distributed in the Lanping Basin,Sowthwest China.Geochemical studies alongside field investigations were conducted in this study to ...Large-scale gypsum rocks associated with world-class Pb-Zn ore formations are widely distributed in the Lanping Basin,Sowthwest China.Geochemical studies alongside field investigations were conducted in this study to determine the source and evolutionary processes of the gypsum rocks in this area.The gypsum sequences in the Lanping Basin developed in two formations:the Triassic Sanhedong Formation and the Paleogene Yunlong Formation.The gypsum hosted in the former displays a primary thick-banded structure withδ34SV-CDT values in the range of 14.5‰−14.8‰.Combined with the 87Sr/86Sr values(0.707737−0.707783)of limestone,it can be suggested that the Sanhedong Formation is of marine origin.In contrast,the gypsum from the Paleogene Yunlong Formation is characterized by the dome,bead and diapiric salt structures,wider range of both 87Sr/86Sr(0.707695−0.708629)andδ34SV-CDT values(9.6‰−17‰),thus indicating a marine source but with the input of continental materials.The initial layered salt formations were formed by chemical deposition in a basin and were later intensely deformed by collisional orogeny during the Himalaya period.As a result,variable salt structures were formed.We hereby propose an evolutionary model to elucidate the genesis of the gypsum formations in the Lanping Basin.展开更多
Considering the serious coal and rock dynamic disasters around the main slip plane called F16 in the coal mining area) of Henan Yima(China) thrust nappe structure,the mechanical genesis of the Yima thrust nappe struct...Considering the serious coal and rock dynamic disasters around the main slip plane called F16 in the coal mining area) of Henan Yima(China) thrust nappe structure,the mechanical genesis of the Yima thrust nappe structure was studied comprehensively using geomechanics,fault mechanics,elastic mechanics,and Coulomb's law of friction.First,using the centrifugal inertia force of Earth's rotation as a source,a mechanical model of N-S compression superimposed with W-E reverse torsion was established to explain the formation of the early Yima coal basin and Jurassic Yima Group coal measures.Second,an equation for the ultimate stress in the forming stage of F16 was derived using the plastic slip-line field theory and the parabolic Mohr failure criterion.Moreover,the distribution of ultimate stress and the geometric characteristics of the fault profile were obtained using the field model parameters.Finally,the stress field of F16 and the mechanical genesis of the large-scale reverse thrust sheet were discussed based on elastic mechanics theory and Coulomb's law of friction.The results show that the tectonic framework of the early Yima coal basin and the formation pattern of Jurassic Yima Group coal measures given by the model are consistent with the in-situ explorations.The geometric characteristics of the fault profile obtained by numerical calculation can better reflect the shape of F16 in its forming stage,and the mechanical genesis of the large-scale reverse thrust sheet also concurred with the field situations.Thus,this work can provide a foundation for further studies on the genesis of the thrust nappe structure,the mechanism of rock bursts induced by F16,and the characteristics of the residual stress field in the Yima mining area.展开更多
文摘A hull structure is prone to local deformation and damage due to the pressure load on the surface.How to simulate surface pressure is an important issue in ship structure test.The loading mode of hydraulic actuator combined with high-pressure flexible bladder was proposed,and the numerical model of the loading device based on flexible bladder was established.The design and analysis method of high-pressure flexible bladder based on aramid-fiber reinforced thermoplastic polyurethane was proposed to break through the surface pressure loading technology of ship structures.The surface pressure loading system based on flexible bladder was developed.The ultimate strength verification test of the box girder under the combined action of bending moment and pressure was carried out to systematically verify the feasibility and applicability of the loading system.The results show that the surface pressure loading technology can be used well for applying uniform pressure to ship structures.Compared with the traditional surface loading methods,the improved device can be applied with horizontal constant pressure load,with rapid response and safe process,and the pressure load is always stable with the increase of the bending moment load during the test.The requirement for uniform loading in the comprehensive strength test of large structural models is satisfied and the accuracy of the test results is improved by this system.
基金Project (SPKJ 016-06) supported by the Key Research Project of State Power CorporationProject (2004AC101D31) supported the Key Scientific Research Project of Hubei Province, China
文摘A nonlinear finite element model of the nut post reinforced concrete （RC） structure of the safety mechanism in the Three Gorges Project （TGP） ship lift was built by ANSYS software. Some irregular structures such as the nut post and the rotary rod were divided by curved surface into a series of regular parts, and the structures were all meshed to hexahedron. Constraint equations were defined between two interfaces with different element sizes and mesh patterns. PRETS179 elements were used to simulate the preload in the tendons and the pre-stressed screws, and the loss of prestressing force was calculated. Five extreme load cases were analyzed. The stress of each part in the structure was obtained. The results indicate that the maximum compressive stress of concrete C35 is 24.13 MPa, so the concrete may be partially crushed; the maximum tensile stress of the grouting motar is 6.73 MPa, so the grouting motar may partially fracture; the maximum yon Mises stress of the rotary rod is 648.70 MPa, therefore the rotary rod may partially yield.
基金Projects(51575535,51805551)supported by the National Natural Science Foundation of ChinaProject(ZZYJKT2018-15)supported by the of State Key Laboratory of High Performance Complex Manufacturing,China+1 种基金Project(2015CX002)supported by the Innovation-driven Plan in Central South University,ChinaProject(2018BB30501)supported by the Key R&D Program of Liuzhou City,China
文摘There have been a great demand for a suitable and convenient method in the field of buckling analysis of stiffened ship structures, which is essential to structural safety assessment and is significantly time-consuming. Modeling, buckling behaviors and ultimate strength prediction of stiffened panels were investigated. The modeling specification including nonlinear finite element model and imperfections generation, and post-buckling analysis procedure of stiffened plates were demonstrated. And a software tool using set-based finite element method was developed and executed in the MSC. Marc environment. Different types of stiffen panels of marine structures have been employed to investigate the buckling behavior and assess the validity in the estimation of ultimate strength. A comparison between results of the generally accepted methods, experiments and the software tool developed was demonstrated. It is shown that the software tool can predict the ultimate capacity of stiffened panels with imperfections with a good accuracy.
基金State Key Basic Research Development and Programming Project of China (G1998040700).
文摘s Western Yunnan is located at the boundary of collision or underthrusting zone of Eurasian plate and is influenced by many times tectonic movements. With very complex geological environment and tectonic background, it is one of the seismically active areas. In the paper, the teleseismic records were selected from 16 national, local and mo-bile stations, including 4 very-wide-band mobile stations of PASSCAL. And nearly 2 000 receiver functions were extracted. Two measuring lines are 650 km and 450 km, respectively and across some major tectonic units in Western Yunnan. It is indicated that Nujiang might be a seam characterized by underthrusting. The western and eastern boundaries of Sichuan-Yunnan rhombus block, i.e., Honghe and Xiaojiang faults, might be an erection seam or collision belt. Panxi tectonic zone still has the characteristics of continental rift valley, that is, the surface is hollow and the upper mantle is upwarping. The tectonic situation in Western Yunnan is of certain regulation with the interlacing distribution of orogenic zone and seam. The crustal thickness decreases gradually from the north to the south and the S wave velocity is globally lower here.
文摘2023年12月18日甘肃积石山发生M_(S)6.2地震,该地震造成了严重的地质灾害,属国内近些年来6级以上地震所罕见.基于多阶段定位方法对2023年积石山M_(S)6.2地震序列进行了重定位,根据gCAP(generalized Cut And Paste)方法反演了序列中M_(S)≥3.0以上地震的震源机制及矩心深度,并对震源机制节面进行聚类分析,获取了地震序列的主要断层面形状,计算了积石山地震序列震源区的构造应力场,研究了其应力场与震源机制节面及断层面的关系,最后结合地质构造、地壳形变等资料综合探讨和推测了积石山地震序列可能的发震构造.结果显示:(1)重定位结果表明,积石山M_(S)6.2地震序列震中区的长轴主要沿着拉脊山北缘断裂南段呈NNW向的优势展布,整个序列长约15km、宽约6km,北端、南端各分别止于大河家镇南侧及积石山县西侧,且存在显著的丛集分区特征,主要划分为大河家镇到刘集乡之间的北段余震稀疏区,以及刘集乡到积石山县西侧之间的南段余震密集区,其中南段余震密集区呈现为NW-SE向的分支和NNW-SSE向的分支,且两个分支形成了NW端分叉且SE端汇聚的分布特征,大部分余震主要集中在NW-SE向分支而积石山M_(S)6.2主震位于NNW-SSE向分支的NE侧.整个序列的平均震源深度约为11.4km,大多数地震主要集中在9~14km深度范围,其中主震的初始破裂深度为13.6km.震源深度剖面清晰勾勒出地震序列的主要发震断层面倾向为NE向,积石山M_(S)6.2主震则位于倾向NE的断层面底端,余震基本位于M_(S)6.2主震的上方,大体呈现为单侧破裂的特征.(2)gCAP波形反演表明,积石山M_(S)6.2主震震源机制节面I的走向/倾角/滑动角为304°/55°/65°,节面II的走向/倾角/滑动角为163°/42°/121°,P轴方位51°和其倾伏角7°,矩心深度10km,矩震级M_(W)5.95.主震及M_(S)3.0以上余震的震源机制主要表现以逆冲为主且略带少量的走滑分量,震源机制的P轴主要呈现近NE-SW向的水平挤压,矩心深度介于9~12km之间,平均矩心深度10.7km.(3)震源机制节面聚类分析得出两簇聚类中心节面,其中NE倾向的聚类中心节面走向311°及倾角43°,其形状和重定位的深度剖面大体一致.震源区应力场反演结果显示,积石山震源区的最优压应力轴走向、倾伏角分别为57°和15°,表明积石山震源区应力场表现为NE向的近水平挤压,并以逆冲为主的应力状态.通过将其反演得到的应力场投影到积石山地震序列震源机制节面及其聚类中心节面,发现积石山应力体系在这些震源机制节面和聚类中心节面上均更容易产生逆冲破裂的地震事件.(4)结合已有区域地质构造、地壳形变等研究,综合分析认为积石山M_(S)6.2地震序列的发震构造和拉脊山北缘主断裂南段(积石山东缘断裂)与其至少两条走向略不同的反冲断层组成的“y”型冲断构造所在的复杂逆冲推覆环境有关,其中积石山M_(S)6.2主震位于NNW-SSE走向、SW倾向拉脊山北缘主断裂南段与其NW-SE走向、NNW-SSE走向及NE倾向的次级反冲断层形成的背冲式构造“y”形汇合部位,并在拉脊山北缘主断裂南段上的反冲断层上发生了相对密集的积石山余震序列.
基金Project(51275102)supported by the National Natural Science Foundation of ChinaProject(HEUCF140713)supported by the Fundamental Research Funds for the Central Universities,China
文摘Based on the biological prototype characteristics of shark’s gill jet orifice,the flexible driving characteristics of ionic exchange polymer metal composites(IPMC)artificial muscle materials and the use of sleeve flexible connector,the IPMC linear driving unit simulation model is built and the IPMC material-driving dynamic control structure of bionic gill unit is developed.Meanwhile,through the stress analysis of bionic gill plate and the motion simulation of bionic gill unit,it is verified that various dynamic control and active control of the jet orifice under the condition of different mainstream field velocities will be taken by using IPMC material-driving.Moreover,the large-deflection deformation of bionic gill plate under dynamic pressure and the comparative analysis with that of a rigid gill plate is studied,leading to the achievement of approximate revised modifier from real value to theoretical value of the displacement control of IPMC.
文摘This paper used the modern evaluation method of DEA （Data Envelopment Analysis） to assess the comparative efficiency and then on the basis of this among multiple schemes chose the optimal scheme of agricultural production structure adjustment. Based on the results of DEA model, we dissected scale advantages of each discretionary scheme or plan. We examined scale advantages of each discretionary scheme, tested profoundly a definitive purpose behind not-DEA efficient, which elucidated the system and methodology to enhance these discretionary plans. At the end, another method had been proposed to rank and select the optimal scheme. The research was important to guide the practice if the modification of agricultural production industrial structure was carded on.
基金Project(41362008)supported by the National Natural Science Foundation of China。
文摘Large-scale gypsum rocks associated with world-class Pb-Zn ore formations are widely distributed in the Lanping Basin,Sowthwest China.Geochemical studies alongside field investigations were conducted in this study to determine the source and evolutionary processes of the gypsum rocks in this area.The gypsum sequences in the Lanping Basin developed in two formations:the Triassic Sanhedong Formation and the Paleogene Yunlong Formation.The gypsum hosted in the former displays a primary thick-banded structure withδ34SV-CDT values in the range of 14.5‰−14.8‰.Combined with the 87Sr/86Sr values(0.707737−0.707783)of limestone,it can be suggested that the Sanhedong Formation is of marine origin.In contrast,the gypsum from the Paleogene Yunlong Formation is characterized by the dome,bead and diapiric salt structures,wider range of both 87Sr/86Sr(0.707695−0.708629)andδ34SV-CDT values(9.6‰−17‰),thus indicating a marine source but with the input of continental materials.The initial layered salt formations were formed by chemical deposition in a basin and were later intensely deformed by collisional orogeny during the Himalaya period.As a result,variable salt structures were formed.We hereby propose an evolutionary model to elucidate the genesis of the gypsum formations in the Lanping Basin.
基金Project(2010CB226805) supported by the National Basic Research Program of ChinaProject(CXLX13-949) supported by the Research and Innovation Project for College Graduates of Jiangsu Province,China+1 种基金Project(51174285) supported by the National Natural Science Foundation of ChinaProject(SZBF2011-6-B35) supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Considering the serious coal and rock dynamic disasters around the main slip plane called F16 in the coal mining area) of Henan Yima(China) thrust nappe structure,the mechanical genesis of the Yima thrust nappe structure was studied comprehensively using geomechanics,fault mechanics,elastic mechanics,and Coulomb's law of friction.First,using the centrifugal inertia force of Earth's rotation as a source,a mechanical model of N-S compression superimposed with W-E reverse torsion was established to explain the formation of the early Yima coal basin and Jurassic Yima Group coal measures.Second,an equation for the ultimate stress in the forming stage of F16 was derived using the plastic slip-line field theory and the parabolic Mohr failure criterion.Moreover,the distribution of ultimate stress and the geometric characteristics of the fault profile were obtained using the field model parameters.Finally,the stress field of F16 and the mechanical genesis of the large-scale reverse thrust sheet were discussed based on elastic mechanics theory and Coulomb's law of friction.The results show that the tectonic framework of the early Yima coal basin and the formation pattern of Jurassic Yima Group coal measures given by the model are consistent with the in-situ explorations.The geometric characteristics of the fault profile obtained by numerical calculation can better reflect the shape of F16 in its forming stage,and the mechanical genesis of the large-scale reverse thrust sheet also concurred with the field situations.Thus,this work can provide a foundation for further studies on the genesis of the thrust nappe structure,the mechanism of rock bursts induced by F16,and the characteristics of the residual stress field in the Yima mining area.
