起重机吊钩横梁的疲劳剩余寿命预测

以某桥式起重机的吊钩横梁为研究对象,通过有限元分析确定其疲劳危险部位及危险部位应力与起升载荷的关系;并通过应力测试验证有限元分析结果的正确性。提出起升载荷监测与应力计算相结合的新方法,获取吊钩横梁疲劳危险部位的全程应力谱;并采用名义应力法预测吊钩横梁的疲劳剩余寿命。     

800t铸造起重机双钩式吊钩结构优化分析

应用有限单元法和优化设计理论,对某铸造起重机吊钩设计参数进行大量的数据分析研究,探索了这种双钩型吊钩设计参数与结构力学特性,以及吊钩工作时设计参数与吊钩应力分布规律的关系,从而达到优化设计,减少重量的目的。     

考虑吊钩组升降的伸缩臂起重机动力学模型研究

建立了一种模拟伸缩臂起重机转台回转,吊臂变幅、伸缩,吊钩升降的运动学、动力学模型.利用光滑连续的正余弦函数描述伸缩臂起重机的运动,使用拉格朗日方法列出吊钩组的动力学方程,并用时变约束方程描述吊钩钢丝绳的升降长度,最终组成微分代数方程,使用约束稳定化方法进行求解.通过算例验证了伸缩臂起重机动力学模型的正确性.该模型可以为伸缩臂起重机的复合动作控制研究及虚拟吊装方案设计提供参考.     

起重量限制器在电动单梁起重机上的设置及检验

本文主要讨论了起重量限制器的原理和特点及起重量限制器在电动单梁起重机上的安装形式,结合起重机检验中发现的问题,对起重量限制器的相关问题的解决进行探讨。     

关于起重机钢丝绳摆幅与干涉的研究

起重机在起吊重物时,主要采用钢丝绳来承受载荷,随着起重机大小车的启动和停止,在惯性载荷作用下,吊钩或重物由于自身的惯性属性会带动钢丝绳有一定的摆幅,若摆幅过大,钢丝绳会与其他部件干涉,造成起重机不能安全工作。通过分析起重机钢丝绳的摆幅与干涉,指出起重机吊钩在启制动时的偏摆角度与吊钩所在的位置无关,与起升高度无关,只与加速度有关,随着加速度的增大而增大。随着钢丝绳长度的增加,在固定加速度的情况下,吊钩或重物的摆幅会越来越大。     

起重机械安全技术管理浅谈

0引言起重机械是现代化工业生产中必不可少的设备,对于减轻繁重的体力劳动、节省人力、提高劳动生产率和实现生产过程的机械化、自动化以及改善人民的物质、文化生活需要都有重大的意义。起重机是一种间歇作业的搬运设备,通过起重吊钩或其他吊具的升降与运移,从而实现重物的空间位移。从安全角度看,起重机特殊的功能和特殊的结构形式,使起重机和起重作业方式本身就存在着诸多危险因素,从     

不同工况下螺栓连接梁有限元仿真分析与强度校核研究

为研究螺栓连接梁在不同危险工况下的结构强度及安全性，本文采用了仿真和理论相结合的方法，对受偏心载荷的螺栓连接梁危险工况进行综合分析。并针对仿真结果中应力较大的螺栓部分采用了建立子模型的方法进一步仿真分析，以确保横梁结构安全可靠。使用了力线平移定理对横梁所受载荷进行简化，并对横梁进行强度校核。研究结果表明：（1）横梁在危险工况下各结构均满足强度要求，且不同危险工况对横梁结构的变形及应力影响较小；（2）螺栓预紧力是导致螺栓结构产生较大应力的原因，而外载荷对螺栓结构的影响较小；（3）在忽略螺栓结构对横梁结构的影响后，横梁强度校核结果与仿真结果近似相同，且均满足材料的强度要求。综上所述，通过仿真分析及理论强度校核均可证明该螺栓连接梁在各工况下均能满足强度需求。同时该研究也为后续研究该类型横梁提供一定的仿真及理论依据。     

100/32t铸造起重机主梁受损分析及加固处理

某台100/32t渣罐桥式起重机在使用时,因主小车的起升机构上升时极限失灵,吊钩横梁撞击辅梁,导致该吊车辅梁箱形结构的下翼缘板及腹板严重受损变形,无法安全运行。为了解箱形辅梁损坏程度,进行了检测、分析,并拿出了加固处理方案。     

吊钩桥式起重机主梁的有限元计算

目的在过载条件下,对吊钩桥式起重机的主梁进行分析计算,确保作业安全.方法选用壳单元SHELL63对主梁进行有限元分析,施加均布载荷和集中载荷后,在正常吊重、1.1倍吊重、1.25倍吊重情况下,对整体结构的应力发布进行计算,并与根据《起重机设计手册》计算出的刚度、强度结果进行对比.结果在正常吊重、1.1倍吊重、1.25倍吊重情况下,许用变形均小于27.5 mm,许用应力均小于202.6 M Pa.结论起重机主梁的刚度、强度均有足够的剩余,满足要求,可以安全使用.     

子模型技术在精轧机机架强度分析中的应用

采用有限元方法对热轧精轧机机架进行应力分析.通过子模型技术对机架上横梁压下螺母孔顶部过渡圆弧处应力最大的部位进行精确计算,比较了整体模型和子模型计算结果差异,结果表明子模型方法更适合于机架应力集中处强度分析的精确计算.     

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).     

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.     

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.