基于有限元的差速器齿轮动态啮合特性分析

针对汽车行驶过程中差速器的2种典型工况,计算某轿车差速器行星齿轮和半轴齿轮的转速和转矩分配.基于有限元动态仿真方法,建立差速器齿轮接触有限元模型,进行动态啮合仿真,研究了齿轮啮合时的应力分布情况.分析了齿轮接触面间的摩擦系数对应力分布的影响,发现随着摩擦系数的增大,齿轮接触应力有所上升.基于名义应力法,以动态啮合时的最大接触应力作为载荷输入,计算齿轮的接触和弯曲疲劳寿命,齿轮的疲劳危险位置发生在齿轮齿面接触区域和齿轮齿根,齿轮寿命符合设计要求.结果表明所开发的结合齿轮动态仿真与疲劳寿命分析方法可以有效地预测差速器齿轮寿命.     

斜齿轮齿向修形对承载能力的影响

以某钢厂1580热连轧机减速机斜齿轮为研究对象,建立减速机斜齿轮的Pro/E参数化三维模型,根据斜齿轮啮合原理,对三维模型实现了无干涉装配。利用有限元分析软件,得到啮合齿接触带中心位于不同位置时齿轮的齿根最大弯曲应力和齿面最大接触应力。通过对比不同齿向修形参数下斜齿轮的应力值,确定了最佳齿向修形长度,为硬齿面斜齿轮的设计加工提供有价值的参考。     

渐开线直齿圆柱齿轮有限元仿真分析

利用ANSYS软件对齿轮变形和齿根应力进行了有限元计算,建立了一对齿轮接触仿真分析的模型,利用ANSYS的面面接触单元进行齿轮接触仿真分析,计算了齿轮啮合中的接触应力和接触变形,说明了ANSYS在齿轮计算尤其在接触分析上的有效性,为齿轮的优化设计和可靠性设计及CAE奠定了基础.     

少齿数齿轮副的有限元分析

结合渐开线斜齿轮和少齿数齿轮设计理论,对少齿数齿轮副各参数进行选取,建立少齿数齿轮副的三维模型,进行少齿数齿轮副的接触有限元分析,得到了少齿数齿轮副传动过程中接触区域和轮齿接触应力。通过对比两种齿面接触强度计算方法,初步验证了以下界点作为齿面接触强度计算点的合理性,为少齿数齿轮副的优化设计和齿面接触强度公式的建立提供参考依据。     

基于ABAQUS的碟式太阳能方位角驱动机构蜗轮蜗杆接触强度分析

蜗轮蜗杆是碟式太阳能方位角驱动机构的重要部件,为确保方位角驱动机构能够安全平稳的工作,要求蜗轮蜗杆工作时的接触应力小于材料许用应力.本文采用参数化建模法建立了蜗轮蜗杆实体模型并导入ABAQUS中得到多齿对蜗轮蜗杆接触有限元模型;基于非线性接触分析法,探索了蜗轮蜗杆啮合瞬间接触齿面的应力分布状况.结果表明:基于ABAQUS的蜗轮蜗杆接触应力结果与赫兹接触应力理论计算结果之间误差仅为1%,蜗轮蜗杆接触应力均远低于相应材料的许用应力,但齿根处最大应力值达到了258.3 MPa,且有明显应力集中现象,而增大齿根过渡圆半径能有效降低齿根应力,增大齿轮接触强度,但当过渡圆半径大于5 mm以后,蜗轮蜗杆难以正常啮合甚至已不能正常工作.     

考虑摩擦力影响的风电齿轮接触问题数值分析

针对风电齿轮在实际应用中由于应力过大导致的失效率高的问题,采用参数化方法精确建立了风电增速齿轮模型,应用ANSYS Workbench软件,在考虑摩擦力影响的情况下,分析了摩擦因数对风电增速齿轮接触应力和接触变形的影响.结果表明:在齿轮啮合过程中,齿根附近出现应力集中,并且出现最大应力值;当摩擦因数小于0.3时,接触应力和接触变形随着摩擦因数的增大而急剧增大,并呈现出线性变化趋势;当摩擦因数大于0.3时,接触应力随着摩擦因数的增大而缓慢增大,而接触变形随着摩擦因数的增大略有减小,呈现出非线性变化趋势.该研究结果对提高风电齿轮强度的分析、改进和优化设计具有一定的参考价值.     

燃气轮机用人字齿轮副接触应力及稳态热分析

为了获得人字型齿轮副齿面接触应力和本体温度的分布特征,利用参数化设计语言,建立了齿轮副的三维模型,结合传热学、摩擦学及啮合原理,对齿轮副的接触应力场及稳态温度场进行了数值模拟,分析了齿轮副的接触应力、本体温度及啮合齿面热流密度的分布情况.分析结果显示,载荷沿各条接触线的分布具有规律性;摩擦热流密度沿齿高方向呈现出先减小后增大的变化趋势;齿体本身的传导散热作用强于齿顶的对流换热作用.结论表明有限元模拟方法可用于评价此种传动副的传动性能.     

传动齿轮接触应力的有限元分析

在SolidWorks环境下建立齿轮三维实体模型,将生成的一对齿轮模型进行齿轮啮合标准安装生成啮合模型.通过COSMOS/Works软件网格化成由节点元素组成的有限元模型,施加载荷,进行了齿轮接触应力计算分析,获得了齿轮的接触应力云图,并通过赫兹压力理论验证了基于COSMOS/Works进行有限元分析的正确性,从而实现CAD与CAE的一体化.     

风机维修平台用齿轮齿条机构的动力学分析方法

目的对所设计的风机内部维修平台的齿轮齿条运行机构的平台进行动力学分析,解决风机维护问题.方法利用三维绘图软件Solid Works建立了齿轮齿条的三维实体模型,在Ansys Workbench中建立了有限元模型,利用瞬态动力学模块分析风载大小的变化对平台运行机构的影响.结果通过对平台运行机构在强风,高空的工作环境下的有限元分析和电机突然启制动对齿轮齿条的瞬态动力学分析,得出风机内部维修平台运行机构在风机特定工况下,接触应力随时间变化的仿真曲线.齿轮齿条的最大接触应力在144.9~146.5 MPa波动,并在约0.2s以后稳定在145.7 MPa,符合所选取齿轮齿条材料的许用应力要求.结论平台齿轮齿条运行机构在选定的特殊工况下都能安全工作,当风场风速与所吊重物尺寸存在指定关系时可以进行吊装作业,所选取的运行机构的结构形式也为同类风机内部维修平台的设计与优化提供参考.     

大型模锻压机工装桁架结构设计与分析

针对目前世界上最大的800 MN模锻压机安装过程中的辅助工装桁架,进行钢结构设计计算与有限元分析研究.首先运用三维设计软件Solidworks,设计建立桁架的三维实体模型,然后根据模型结构和几何参数在ANSYS中建立简化的有限元分析模型,对桁架工作过程中的最不利工况进行载荷分析,并运用ANSYS软件对其进行有限元强度、刚度以及稳定性分析,进而得出最不利工况的应力云图、位移云图以及位移-载荷曲线.分析结果表明:工装桁架最大应力和最大挠度均分别小于许用应力和许用挠度,工作稳定安全系数远大于许用稳定安全系数;模锻压机的成功安装,证明了桁架设计的合理性、安全性和可靠性.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

A computer generator for randomly layered structures

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

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

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。     

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.     

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

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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