含周向裂纹管道在非对称弯矩组合载荷作用下塑性极限载荷分析

根据净截面垮塌准则 ,分别求出了含埋藏裂纹、外表面裂纹、内表面裂纹、穿透裂纹管道在非对称弯矩、内压及轴力三种载荷共同作用时的塑性极限载荷计算公式 ,并给出了穿透裂纹在纯弯曲时中性轴圆心角和无量纲弯矩系数随裂纹偏离角的变化情况。所给出的计算公式可用于管道安全评价。     

复杂载荷下含体积性缺陷弯管的塑性极限载荷

通过非线性有限元分析给出了含体积性缺陷弯管在内压、面内弯矩、面外弯矩和扭矩作用下的塑性极限载荷。对与体积型缺陷（长轴、短轴和深度)和管线（外径、壁厚和弯曲半径）有关的几何变量进行了系统的分析,并考虑了内压和面内弯矩、面外弯矩和扭矩的组合。结果表明壁厚、缺陷深度和缺陷方向对极限载荷影响较大。     

复杂载荷下弯管的极限载荷

考虑几何和材料的非线性相互作用,采用有限元方法研究复杂载荷下弯管的极限载荷。通过对比过去的研究成果,分析了内压、面内弯矩及其组合下的极限载荷规律。根据有限元结果,研究了直管强化及内压的强化对极限载荷的影响。最后提出了弯矩以及内压、弯矩联合作用下的极限压力、极限弯矩与弯管几何尺寸的定量关系。提出的计算公式扩大了弯曲系数λ的使用范围,反映了弯管强化作用。     

复杂载荷耦合协作对连续油管极限承载能力的影响研究

针对连续油管在作业过程极易发生自锁、承受高内压等极限工作载荷,且在该极限载荷下极易失效的问题,以经典塑性极限载荷力学模型为基础,基于CAE技术,建立连续油管数值计算模型;并利用实验结果验证数值计算结果的可行性。利用已验证的计算模型研究1(1/4)″和2(3/8)″型号的连续油管在拉伸载荷、弯矩载荷、内压和挤压载荷下的承载能力。研究表明,在上述四种载荷中,得出内压和弯矩载荷是造成连续油管失效的主控载荷。根据计算结果,推荐了连续油管正常服役的载荷范围;并给出了不同载荷的极限载荷值。研究拉伸载荷、弯矩载荷、内压和挤压载荷对连续油管承载能力的影响,可有效避免连续油管提前发生失效和提高连续油管使用寿命。     

含穿透裂纹碳钢管道起裂载荷的电位测试方法

含缺陷压力管道起裂载荷的确定对于石化、化工压力管道的缺陷评定具有很重要的意义.进行了含穿透裂纹碳钢管道的断裂试验,并尝试采用直流电位法实测了6根20#碳钢管试样的起裂载荷,同时,利用工程上常用的计算含缺陷压力管道起裂载荷的EPRI工程方法进行了计算,两者比较可见,所采用的测试方法是可行的.     

双材料弯曲界面裂纹尖端应力分析

探讨受纯弯载荷作用的各向同性和正交异性双材料中心穿透界面裂纹尖端附近的断裂问题,通过复变函数方法和偏微分方程组理论,构造了新的挠度函数,基于边界条件,将复合材料界面裂纹问题转化为一类偏微分方程组的边值问题,在正交异性材料的特征根判别式大于的情形下,得到了受纯弯裁荷作用的各向同性和正交异性双材料中心穿透界面裂纹尖端附近的弯矩、扭矩和应力的计算公式.当双材料变成单材料时,可以验证与各向同性单材料的应力奇异指数吻合,并用有限元验证了理论值的正确性.     

随机载荷加载下疲劳裂纹扩展速度的一种计算方法

为了揭示出随机载荷加载下,疲劳裂纹扩展速度的规律,利用临界平面方法,把多轴随机载荷等效为单轴随机载荷,并进而简化为单轴多级恒幅载荷谱,然后利用恒幅疲劳裂纹扩展的速度公式,计算裂纹的总增加量,推导出随机载荷加载下疲劳裂纹扩展速度的计算公式。通过对试件的疲劳寿命预测,验证了该公式的正确性。     

双材料纯扭界面裂纹断裂研究

对弯曲载荷作用的正交异性双材料界面裂纹尖端附近的应力场进行探讨．通过选取特别的中面挠度函数,利用复合材料断裂复变方法对受弯曲载荷作用的正交异性双材料界面断裂问题进行了研究．通过求解一类广义重调和方程组边值问题,当特征方程组的判别式△1〉0和△2〈0时推出了受纯扭曲载荷下界面裂纹尖端的弯矩、扭矩、应力的计算公式．     

双材料弯扭断裂问题

研究了正交异性双材料界面裂纹断裂的问题,根据叠加原理和偏导数的加法定理,在受弯扭载荷混合作用下,当特征方程组的判别式Δ10,Δ20时,推导出了受弯扭载荷作用下的含中心穿透双材料界面裂纹尖端附近的弯矩、扭矩、应力场的理论公式.从理论结果上可以看出双材料界面裂纹尖端附近应力场不具有振荡奇异性.此结论对于结合材料的强度和可靠性评价具有重要意义.     

含局部减薄弯管的塑性极限载荷分析

通过对有减薄缺陷弯管三维有限元模型的分析,研究了受内压弯矩联合作用时局部减薄缺陷与弯管塑性极限载荷的关系。局部减薄弯管的塑性极限载荷与减薄缺陷的形式有关,减薄的轴向尺寸、环向尺寸及深度对塑性极限载荷有不同的影响。弯矩与内压的比例对局部减薄弯管的塑性极限载荷也有影响。文中描述了局部减薄弯管的塑性极限载荷的变化规律及在不同情况下局部减薄弯管的失效模式.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.