X型钢管相贯节点抗弯极限承载力的影响因素分析

为解决钢管结构设计中相贯节点设计问题,采用三维四节点弹塑性壳单元shell 181单元和理想弹塑性材料在ANSYS有限元程序中建立X型钢管相贯节点的有限元模型,分析了支管直径与主管直径比β、主管直径与壁厚比γ对X型钢管节点的极限抗弯承载力的影响,并给出各影响因素对X型钢管相贯节点抗弯极限承载力的影响规律.     

圆钢管混凝土T型节点在轴向作用力下静力性能研究

T型圆管节点在支管轴向力作用下,破坏位置一般出现在主管表面的焊趾处.主要是因为主管的径向刚度远小于支管的轴向刚度,并且节点部位存在较大的应力集中.为提高T型管节点的静力强度,可通过在主管中填充混凝土以提高其径向刚度来实现.为了研究主管填充混凝土对T型管节点静力强度的影响,用有限元分析软件(ABAQUS)首先对6个模型分...     

平面内弯矩作用下主圆支方K型节点的应力集中系数研究

文中采用有限元与试验方法系统地分析了主圆支方K型管节点在平面内弯矩作用下的应力集中系数。使用ABAQUS软件进行了125组在平面内弯矩作用下节点的数值模拟,得到了K型管节点在平面内弯矩作用下焊缝区域的应力集中系数,并且对主管和支管的应力集中系数进行了系统研究,分析了节点几何参数对主管和支管的应力集中系数的影响。结果表明,β(支管与主管直径比值)和2γ(主管直径与壁厚比值)值对节点的应力集中系数影响较大,而τ(支管与主管壁厚比值)对主管和支管的应力集中系数影响较小。主管的应力集中系数值主要出现在鞍点的附近,而支管的应力集中系数值出现的位置主要由β、2γ和τ等几何参数来决定。根据有限元模型的分析结果,通过曲线拟合提出了计算平面内弯矩作用下主圆支方K型管节点应力集中系数的参数方程,并对该方程的准确性进行了评价。最后,通过节点平面内弯曲试验再次验证了本文提出的应力集中系数公式的可靠性和安全性。     

X型方钢管相贯节点抗弯刚度的影响因素

分析相贯节点几何参数对刚度的影响,有助于了解相贯节点的抗弯机理。以X型方钢管相贯节点为研究对象,利用ANSYS有限元软件,通过节点弯矩-转角曲线分析相贯节点支管与主管宽度比β、主管宽厚比γ以及支管与主管厚度比τ对平面内抗弯刚度的影响。结果表明:γ和τ一定时,节点抗弯刚度随着β的增加逐渐增大,在线性段增加幅度较大;τ和β一定时,节点抗弯刚度随着γ的降低而增大,在线性段增加明显;γ和β一定时,随着τ的变化,节点抗弯刚度基本不变。影响节点抗弯刚度的主要几何参数是β和γ,τ的影响不显著,但随着β的增加,τ的影响有所提高。     

不同搭接率时主方支圆钢管节点的承载力分析

K形搭接节点是空间结构中经常使用的一种连接方式.为深入了解K形搭接节点的特性,使用ANSYS软件,对一系列不同搭接率下的主方支圆K形钢管节点进行数值模拟,并将有限元分析结果绘制成曲线.分析支主管径宽比β,支主管厚度比τ,主管宽厚比γ支主管夹角θ等几何参数对此类节点极限承载力的影响.分析结果显示,当τ较小时,搭接率Ov对...     

大曲率主管的圆钢管X型节点轴压承载力研究

为研究大曲率主管的圆钢管X型节点轴压性能,采用数值模拟方法对96个不同支、主管外径比β、主管径厚比2γ和主管曲率半径R的圆钢管节点进行有限元参数分析。有限元参数分析结果表明:支、主管外径比β对节点的破坏模式影响较大;曲率半径R对节点破坏模式影响较小。小β值节点主管出现局部凹陷之后产生一定薄膜效应导致承载力出现一定回升;大β值节点试件主管仅出现椭圆化变形无承载力回升现象。当β=0.8时,随着曲率变化节点极限承载力变化较小。当β=0.2、0.4和0.6时,主管曲率半径大于12倍主管直径时,极限承载力变化较小;主管曲率半径小于12倍主管直径时,极限承载力随曲率增大而有所提高。对于相同的主管径厚比2γ,主管曲率半径大于12倍主管直径时,极限承载力变化较小;主管曲率半径小于12倍主管直径时,极限承载力随曲率增大而有所提高。在欧洲钢结构规范(Eurocode3 Design of Steel Structures)中的主管平直的圆钢管X型节点极限承载力计算公式的基础上,采用乘以修正系数的方式拟合出大曲率主管的圆钢管X型节点轴压承载力计算公式,为该类节点的设计提供参考。     

圆钢管混凝土K型焊接管板节点试验研究和有限元分析

以组成K型焊接管板节点的塔柱径厚比γ、腹杆与塔柱管径比β和壁厚比τ,节点板厚度与腹杆壁厚比t_g/t_i为参数,对4个圆钢管混凝土K型焊接管板节点和1个空心圆钢管K型焊接管板节点进行试验,研究该类型节点的破坏模式、承载能力以及节点区的受力特点,并采用有限元方法分析各参数对圆钢管混凝土K型焊接管板节点受力性能的影响规律。研究结果表明:随着所取参数的变化,圆钢管混凝土K型焊接管板节点存在腹杆失效和节点板失效2种破坏模式;而空心圆钢管K型焊接管板节点的破坏模式为塔柱管壁过度塑性变形失效。说明钢管中混凝土的填充改变了节点的受力特点和破坏模式,有利于材料承载能力的充分发挥。节点板厚度与腹杆壁厚比t_g/t_i是影响圆钢管混凝土K型焊接管板节点破坏模式和极限承载力的关键因素。在实际工程中,为避免出现节点失效,t_g/t_i的取值宜大于2。     

矩形钢管偏心相贯节点的平面外抗弯性能研究

为了研究十字形矩形钢管偏心相贯节点的平面外抗弯性能,进行了节点试验.根据试验的破坏特征建立了节点承载力的屈服线模型并推导出理论式,通过有限元参数分析对理论式进行改进,结合回归分析,建立节点平面外抗弯承载力的实用参数化计算式.结果表明:节点试验的破坏模式为主管表面屈服,节点承载力与主管截面高度和主管壁厚的平方成正比,支主管截面高度比对节点承载力的影响较大,支主管壁厚比和主管截面高宽比对节点承载力的影响较小,参数化计算式所得承载力与试验结果相差3.4%、与有限元结果的相差大多小于10%.     

圆钢管平面K型间隙节点极限承载力及其影响因素

以圆钢管平面K型间隙节点为对象,利用非线性有限元对其极限承载力进行了研究.分析了主、支管轴线间角度θ,支、主管直径比β（d/D）,主管径厚比γ（D/T）以及不同的边界条件及加载方式对节点极限承载力的影响.通过有限元计算值pu与规范公式计算值pcu的比值发现,规范公式对K型间隙节点承载力的计算偏向保守,且未考虑边界条件对节点承载力的影响.     

内置加劲环T型管节点抗冲击承载力分析

以内置加劲环宽度和厚度为参数,采用有限元分析法,建立内置加劲环T型钢管节点有限元分析模型.通过分析主管跨中变形、冲击力、惯性力、支座反力时程曲线,得到内置加劲环T型管节点的抗冲击破坏模态和抗冲击作用机理.结果表明:内置加劲环可以提高T型管节点的抗冲击承载力,而且加劲环厚度对提高T型管节点抗冲击承载力的效果要强于宽度,冲击力峰值大小和波形持续时间可以反映T型管节点的刚度大小.内置加劲环提高T型管节点抗冲击性能,为钢管结构抗冲击设计和加强维护提供参考.     

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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.