拼接板厚度对框架中钢梁高强螺栓拼接性能的影响

拼接板厚度是高强螺栓摩擦型连接中的一个重要参数.采用有限元分析方法,同时考虑材料、几何和接触状态3个非线性,对框架结构中钢梁高强螺栓拼接采用不同拼接板厚度时的性能,进行单调和循环荷载作用下的模拟研究.结果表明:采用较薄的拼接板时,试件的拼接区滑移出现得早,拼接板的塑性屈曲变形也变大;在设计中加大拼接板的厚度则不会对拼接区的性能造成明显影响.     

抗滑移系数对框架中钢梁高强度螺栓拼接性能的影响研究

抗滑移系数是高强螺栓摩擦型连接中的一个重要参数。本文对框架中高强螺栓拼接采用不同抗滑移系数时的性能,以及接触面的抗滑移系数大于和小于设计值时的性能,进行了单调荷载和循环荷载作用下的研究。结论表明:采用不同抗滑移系数设计的拼接节点,其性能差别很小,在设计时可不予考虑;接触面抗滑移系数大于或小于设计值,将直接导致拼接区的滑移出现和耗能性能的不同,但对拼接的极限承载能力并无影响。     

摩擦型高强螺栓连接性能的试验研究

为了了解摩擦型高强螺栓连接性能,对5个试件进行了抗滑移系数、屈服强度和极限承载能力的试验研究.结果表明,用钢丝刷清除浮锈处理的摩擦面抗滑移系数达不到规范给定的数值;连接的屈服强度和极限承载能力很接近连接板材的相应强度;加大或减小螺栓的预拉力只对连接出现滑移时的荷载有影响,对连接的其它性能并无明显影响.最后,给出了设计建议.     

新型全装配式剪力墙结构水平缝节点的机理分析

提出一种采用内嵌边框、高强螺栓以及连接钢框连接相邻层预制墙板的新型干式连接方式.为研究该连接方案的可行性及连接件的传力机理,进行了试验研究及有限元模拟;然后对节点的传力路径进行了分析,并讨论了连接件的制作误差对传力路径的影响;最后对弹性阶段及弹塑性阶段时连接件的应力分布与重分布进行了分析,得到了连接钢框应力分布的计算模型以及高强螺栓传递剪力的计算公式.试验研究及有限元分析表明,该新型连接方案可行,传力路径明确.机理分析表明:连接钢框受压区的应力大于受拉区的应力;受压区高强螺栓传递的剪力大于受拉区高强螺栓传递的剪力,受压区的高强螺栓率先发生滑移.     

铝合金构件高强螺栓牙板连接性能试验

主要对铝合金构件采用高强螺栓牙板连接进行初步试探性的理论分析和试验研究.分析结果表明:连接承载力与螺栓预压力、板件厚度、牙纹规格等因素有关,并初步得出了承载力的计算公式.进行了4组铝合金构件高强螺栓牙板连接的抗剪承载力试验,试验结果表明:高强螺栓牙板连接具有变形小、承载力高等特点,而且较普通的摩擦型高强螺栓连接承载力有明显提高,主要是因为"牙板"增大了受力方向的抗滑移系数.     

摩擦型高强螺栓连接受力性能有限元分析

利用有限元分析软件ANSYS9．0建立高强螺栓连接的简化模型,对高强螺栓连接形式进行计算分析,重点考虑几何非线性影响,在模型中建立钢板与连接板、连接板与垫圈、垫圈与螺母及螺帽之间的接触单元,对结构的非线性接触行为进行模拟。通过对有限元计算结果的分析,对摩擦型高强螺栓连接的适用性进行评价,并重点比较分析主滑动发生前后,高强螺栓的受力性能。其分析结果为工程实际提供一定意义的参考。     

基于随机有限元法的非机动车钢桥摩擦型高强螺栓可靠性分析

摩擦型高强螺栓连接是实现全拆装非机动车钢结构桥梁快速装配化建设的重要构件之一。为研究非机动车钢结构桥梁高强螺栓连接的可靠性能,首先采用有限元方法建立高强螺栓数值模型,并对模拟方法进行了准确性分析。在此基础上,利用响应面随机有限元法研究了随机变量对高强螺栓结构性能响应的影响,通过随机车流程序计算了非机动车桥梁荷载效应,最后利用可靠度设计方法研究了钢板梁高强螺栓的抗力分项系数。结果表明随机变量变异性对高强螺栓不同目标性能有不同程度影响;非机动车荷载作用下的钢桥高强螺栓设计承载力要稍高于现行规范理论公式计算值。     

摩擦型高强螺栓连接性能的试验研究

为了了解摩擦型高强螺栓连接性能，对5个试件进行了抗滑移系数、屈服强度和极限承栽能力的试验研究。结果表明，用钢丝刷清除浮锈处理的摩擦面抗滑移系数达不到规范给定的数值：连接的屈服强度和极限承栽能力很接近连接板材的相应强度；加大或减小螺栓的预拉力只对连接出现滑移时的荷栽有影响，对连接的其它性能并无明显影响。最后，给出了设计建议。     

钢结构高强螺栓连接设计的探讨

通过在施工与设计上对高强螺栓摩擦型连接设计与承压型连接进行对比,提出了按照承压型连接在其应用范围内具有的明显的优势,建议在设计中予以积极推广。另外,对于我国规范未提及的镀锌高强螺栓、具有镀锌涂层摩擦面、栓焊混合连接、在非标准孔情况下高强螺栓摩擦型连接承载力设计等问题,提供了国外的相关规范作为参考。     

冷弯薄壁型钢高强螺栓连接剪力传递性能研究

文章以28个薄壁钢板高强螺栓连接件作为试验对象,研究高强螺栓连接件在不同螺栓预紧力、直径、排列方式、钢板厚度以及不同螺栓数量下的工作状况及破坏状态,分析各参数对连接件短钢板上剪力传递值的影响.研究结果表明:对于高强螺栓连接件,螺栓排列方式不是重要影响因素,其剪力传递值随着螺栓数量、螺栓直径、螺栓间距的增大而非线性增加,...     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

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…     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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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。     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

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