Advances in studies of formation and accumulation mechanisms of oil and gas in marine carbonate sequences have led to continuing breakthroughs of petroleum exploration in marine carbonate sequences in Chinese sediment...Advances in studies of formation and accumulation mechanisms of oil and gas in marine carbonate sequences have led to continuing breakthroughs of petroleum exploration in marine carbonate sequences in Chinese sedimentary basins in recent years. The recently discovered giant Tahe Oil Field and Puguang Gas Field have provided geological entities for further studies of the formation and accumulation of oil and gas in marine carbonate sequences. Marine carbonate sequences in China are characterized by old age, multiple structural deformation, differential thermal evolution of source rocks, various reservoir types (i.e. reef-bank complex and paleo-weathered crust karst reservoir), uneven development of caprocks, especially gypsum seal, and multi-episodes of hydrocarbon accumulation and readjustment. As a result, the formation of hydrocarbon accumulations in the Chinese marine carbonate sequences has the following features: (i) the high-quality marine source rocks of shale and calcareous mudstone are often associated with siliceous rocks or calcareous rocks and were deposited in slope environments. They are rich in organic matter, have a higher hydrocarbon generation potential, but experienced variable thermal evolutions in different basins or different areas of the same basin. (ii) High quality reservoirs are controlled by both primary depositional environments and later modifications including diagenetic modifications, structural deformations, and fluid effects. (iii) Development of high-quality caprocks, especially gypsum seals, is the key to the formation of large-and medium-sized oil and gas fields in marine carbonate sequences. Gypsum often constitutes the caprock for most of large sized gas fields. Given that Chinese marine carbonate sequences are of old age and subject to multiple episodes of structural deformation and superposition, oil and gas tend to accumulate in the slopes and structural hinge zones, since the slopes favor the development of effective assemblage of source-reservoir-caprock, high quality so展开更多
This work provides a comprehensive review of the development and applications of bridge rotation construction methods(BRMs) and related critical construction technologies in China. A brief history of BRMs and an outli...This work provides a comprehensive review of the development and applications of bridge rotation construction methods(BRMs) and related critical construction technologies in China. A brief history of BRMs and an outline of their categories,including the rotating structural system, are given first. Subsequently, a discussion on the recent practice of BRMs in China is carried out from three types of bridges:(1) continuous beam and rigid frame bridges;(2) arch bridges;(3) cable-stayed bridges.For each group, a survey of the vital bridge cases that have adopted BRMs in China in the past two decades is provided. Key parameters, including the structure weight of rotation, maximum cantilever span, and rotation duration, are also compared and discussed. Afterward, the principles and applications of the weighing test and the spherical hinge stability, which are both related to the safety of the horizontal rotation construction process, are analyzed in the paper. Additionally, the limitations of BRMs are presented and discussed, and the article concludes with a summary of the current use and future trend of BRMs. The information and experience of BRMs provided in this work can be referenced by engineers and researchers who are devoted to the construction of bridges.展开更多
Piezoelectric actuator has high stiffness, high frequency and infinite control precision, but a short output displacement which is often 1/1 000 of its length. In order to meet the requirements that tools feeding shou...Piezoelectric actuator has high stiffness, high frequency and infinite control precision, but a short output displacement which is often 1/1 000 of its length. In order to meet the requirements that tools feeding should be long-travel, high-frequency and high-precision in non-circular precision turning, a new one-freedom flexure hinge structure is put forward to amplify the output displacement of piezoelectric actuator. Theoretical analysis is done on the static and dynamic characteristics of the structure, differential equations are presented, and it is also verified by the finite element method. It's proved by experiments that the output displacement of the structure is 293 μm and its resonant frequency is 312 Hz.展开更多
In this paper, a method of using a root hinge drive assembly （RHDA） to control the solar array deployment is provided and a multi-DOF mechanism dynamic model of the system is established. In this way, the root hinge...In this paper, a method of using a root hinge drive assembly （RHDA） to control the solar array deployment is provided and a multi-DOF mechanism dynamic model of the system is established. In this way, the root hinge torque can be calculated iteratively. Then taking the predicted torque as a reference, a RHDA is designed for a large multiple-stage packaging and deployable solar array system. The control effect of the drive assembly is validated by ground tests. The test results indicate that the solar arrays can be deployed smoothly, and the deployment velocities are restricted by the drive assembly as expected. During the tests, the RHDA output speed and output torque are obtained. In order to examine the impact force when the yoke is lock-up with a hard stop, dynamics simulations are performed according to the actual behavior. The simulation result indicates that the designed RHDA reduces the impact force significantly and improves the lock-up reliability effectively.展开更多
The design of compliant hinges has been extensively studied in the size and shape level in the literature.This paper presents a method for designing the single-axis flexure hinges in the topology level.Two kinds of hi...The design of compliant hinges has been extensively studied in the size and shape level in the literature.This paper presents a method for designing the single-axis flexure hinges in the topology level.Two kinds of hinges,that is,the translational hinge and the revolute hinge,are studied.The basic optimization models are developed for topology optimization of the translational hinge and the revolute hinge,respectively.The objective for topology optimization of flexure hinges is to maximize the compliance in the desired direction meanwhile minimizing the compliances in the other directions.The constraints for accomplishing the translational and revolute requirements are developed.The popular Solid Isotropic Material with Penalization method is used to find the optimal flexure hinge topology within a given design domain.Numerical results are performed to illustrate the validity of the proposed method.展开更多
基金supported by the National Basic Research Program of China (Grant No. 2005CB422108)
文摘Advances in studies of formation and accumulation mechanisms of oil and gas in marine carbonate sequences have led to continuing breakthroughs of petroleum exploration in marine carbonate sequences in Chinese sedimentary basins in recent years. The recently discovered giant Tahe Oil Field and Puguang Gas Field have provided geological entities for further studies of the formation and accumulation of oil and gas in marine carbonate sequences. Marine carbonate sequences in China are characterized by old age, multiple structural deformation, differential thermal evolution of source rocks, various reservoir types (i.e. reef-bank complex and paleo-weathered crust karst reservoir), uneven development of caprocks, especially gypsum seal, and multi-episodes of hydrocarbon accumulation and readjustment. As a result, the formation of hydrocarbon accumulations in the Chinese marine carbonate sequences has the following features: (i) the high-quality marine source rocks of shale and calcareous mudstone are often associated with siliceous rocks or calcareous rocks and were deposited in slope environments. They are rich in organic matter, have a higher hydrocarbon generation potential, but experienced variable thermal evolutions in different basins or different areas of the same basin. (ii) High quality reservoirs are controlled by both primary depositional environments and later modifications including diagenetic modifications, structural deformations, and fluid effects. (iii) Development of high-quality caprocks, especially gypsum seals, is the key to the formation of large-and medium-sized oil and gas fields in marine carbonate sequences. Gypsum often constitutes the caprock for most of large sized gas fields. Given that Chinese marine carbonate sequences are of old age and subject to multiple episodes of structural deformation and superposition, oil and gas tend to accumulate in the slopes and structural hinge zones, since the slopes favor the development of effective assemblage of source-reservoir-caprock, high quality so
基金the National Natural Science Foundation of China(Grant No.51808056)Hunan Provincial Natural Science Foundation of China(Grant No.2020JJ5583)+1 种基金the Research Project of Hunan Provincial Department of Education(Grant No.19B012)the China Scholarship Council(Grant No.201808430232)。
文摘This work provides a comprehensive review of the development and applications of bridge rotation construction methods(BRMs) and related critical construction technologies in China. A brief history of BRMs and an outline of their categories,including the rotating structural system, are given first. Subsequently, a discussion on the recent practice of BRMs in China is carried out from three types of bridges:(1) continuous beam and rigid frame bridges;(2) arch bridges;(3) cable-stayed bridges.For each group, a survey of the vital bridge cases that have adopted BRMs in China in the past two decades is provided. Key parameters, including the structure weight of rotation, maximum cantilever span, and rotation duration, are also compared and discussed. Afterward, the principles and applications of the weighing test and the spherical hinge stability, which are both related to the safety of the horizontal rotation construction process, are analyzed in the paper. Additionally, the limitations of BRMs are presented and discussed, and the article concludes with a summary of the current use and future trend of BRMs. The information and experience of BRMs provided in this work can be referenced by engineers and researchers who are devoted to the construction of bridges.
文摘Piezoelectric actuator has high stiffness, high frequency and infinite control precision, but a short output displacement which is often 1/1 000 of its length. In order to meet the requirements that tools feeding should be long-travel, high-frequency and high-precision in non-circular precision turning, a new one-freedom flexure hinge structure is put forward to amplify the output displacement of piezoelectric actuator. Theoretical analysis is done on the static and dynamic characteristics of the structure, differential equations are presented, and it is also verified by the finite element method. It's proved by experiments that the output displacement of the structure is 293 μm and its resonant frequency is 312 Hz.
基金Ph.D. Programs Foundation of Ministry of Education of China (200800060009)
文摘In this paper, a method of using a root hinge drive assembly （RHDA） to control the solar array deployment is provided and a multi-DOF mechanism dynamic model of the system is established. In this way, the root hinge torque can be calculated iteratively. Then taking the predicted torque as a reference, a RHDA is designed for a large multiple-stage packaging and deployable solar array system. The control effect of the drive assembly is validated by ground tests. The test results indicate that the solar arrays can be deployed smoothly, and the deployment velocities are restricted by the drive assembly as expected. During the tests, the RHDA output speed and output torque are obtained. In order to examine the impact force when the yoke is lock-up with a hard stop, dynamics simulations are performed according to the actual behavior. The simulation result indicates that the designed RHDA reduces the impact force significantly and improves the lock-up reliability effectively.
基金supported by the National Natural Science Foundation of China(Grant No.91223201)the Natural Science Foundation of Guangdong Province(Grant No.S2013030013355),Project GDUPS(2010)the Fundamental Research Funds for the Central Universities(Grant No.2012ZP0004)
文摘The design of compliant hinges has been extensively studied in the size and shape level in the literature.This paper presents a method for designing the single-axis flexure hinges in the topology level.Two kinds of hinges,that is,the translational hinge and the revolute hinge,are studied.The basic optimization models are developed for topology optimization of the translational hinge and the revolute hinge,respectively.The objective for topology optimization of flexure hinges is to maximize the compliance in the desired direction meanwhile minimizing the compliances in the other directions.The constraints for accomplishing the translational and revolute requirements are developed.The popular Solid Isotropic Material with Penalization method is used to find the optimal flexure hinge topology within a given design domain.Numerical results are performed to illustrate the validity of the proposed method.
