改进型碳纤维增强复合材料筋复合式锚具的锚固性能

为了研究碳纤维增强复合材料(CFRP)筋锚具的结构形式及主要设计参数对锚固性能的影响,设计2个复合式锚具及3个改进型复合式锚具,并进行静载拉伸试验;通过对比分析不同锚具的极限荷载、金属筒测点应变以及锚具最后整体破坏形式,研究改进型CFRP筋复合式锚具的锚固性能。结果表明:在不施加预紧力前提下,改进型复合式锚具螺母纵向紧固力可以有效避免夹片滑移,黏结材料种类对锚固过程稳定性有一定影响,但并不影响最终锚固效果,筋材表面形式对锚具锚固性能影响较大;当金属筒厚度为3 mm、黏结长度为250 mm、夹片长度为100 mm时,带肋CFRP筋为中间炸裂式破坏,充分发挥了CFRP筋的抗拉特性,表明改进型CFRP筋复合式锚有良好的锚固性能。     

改进型CFRP筋黏结式锚具静载试验

研究了黏结式锚具的改进方案,对改进后的锚具进行了静载张拉试验,阐述改进型CFRP筋黏结式锚具静载试验方案和主要步骤.长度为180 mm的改进式锚具可锚固单根8 mm CFRP筋,极限拉力为115 k N;长度为280 mm的直筒式锚具可锚固单根8 mm CFRP筋,极限拉力为119 k N.改进型CFRP筋黏结式锚具静载试验表明:改进方案是有效可行的.并对黏结应力的测试方法和计算方法进行了探讨,以筋材轴力为指标,对黏结应力测试数据进行检算,当应变片间距适当时,直接在CFRP筋表面黏贴应变片,通过测点应变分析黏结应力分布的方法是可行的.在此基础上得到的试验数据经公式计算,在加载过程中误差较大,最大误差为7.20%;在极限荷载下无误差.     

CFRP筋粘结式楔型锚具锚固性能分析

为研究CFRP筋粘结式楔型锚具锚固性能及其影响因素,对12套CFRP筋粘结式楔型锚具进行静载试验,以锚具内倾角和锚固长度为变化参数,获取锚具试件荷载—滑移全过程曲线,推出锚具内部CFRP筋与环氧树脂砂浆界面粘结—滑移本构模型。研究表明:增大锚具内倾角和锚固长度可提高锚具极限荷载,平均粘结强度随锚具内倾角的增大呈增大趋势,临界锚固长度随试件锚具内倾角的增大呈减小趋势,采用回归公式计算的平均粘结强度值与试验实测值比较接近;锚固长度是影响界面粘结剪切刚度的主要因素;锚固长度和锚具内倾角可一定程度提高界面抗滑移能力,损伤发展后期,锚固长度越大,损伤速率越慢;推导出的锚具内CFRP筋与环氧树脂砂浆的粘结—滑移本构关系模型适用性较好。     

单根碳纤维(CFRP)预应力筋粘结式锚具的试验研究

本文介绍了用环氧铁砂和普通混凝土作粘结介质的粘结式锚具对碳纤维(CFRP)筋的锚固性能.通过大量试验,研究了粘结式锚具锚固CFRP筋的性能,并分析了粘结式锚具的粘结机理,为CFRP筋在结构工程中的推广应用奠定了基础.     

单根FRP筋粘结型锚具的设计与试验研究

单根FRP筋粘结型锚具组件存在两类典型的破坏形式:FRP筋在自由长度内破坏和FRP筋从锚具中被拔出。第2种破坏形式是不允许发生的,它不能很好地反映出FRP筋的材料特性。在对传统的单根FRP筋粘结型锚具进行研究的基础上,设计出一种制造简单、锚固性能好的单筋锚具,并对6组树脂封装的单根CFRP筋组装件进行单向拉伸试验,研究张拉过程中CFRP筋材的应力——应变行为,得出其极限应力、弹性模量等。试验表明,设计的单筋FRP筋锚具进行组装件的单向拉伸试验可以得到FRP筋的力学性能,试件破坏状态良好。所作工作为各种FRP筋材的材性试验以及应用提供参考。     

碳纤维筋(CFRP)夹片式锚具的有限元分析

CFRP筋要广泛地应用于工程结构中,则必须解决其锚固问题,而夹片式锚具其内部的力学性能并不能通过实验来分析,本文采用有限元方法给出了单孔锚具的分析结果,分析了摩擦系数、内壁倾角和锚具长度对锚具性能的影响。     

预应力碳板楔紧式锚具数值模拟和试验

设计了用于工程结构加固的预应力碳纤维增强复合材料(CFRP)板(碳板)楔紧式锚具,该锚具由锚杯、夹片组成,通过自锚夹持碳板。基于ANSYS软件建立了锚具的精细化有限元模型,该模型同时考虑了夹片与碳板及夹片与锚杯之间的接触。基于有限元的计算结果,进行了预应力碳板楔紧式锚具的制作和试验,试验结果表明该锚具能够可靠地锚固碳板。通过将有限元结果和试验结果进行对比,发现有限元模型能够较好地预测楔紧式锚具的受力性能,能够为预应力碳板楔紧式锚具的设计提供参考。     

CFRP筋复合型锚具的受力性能试验

为研究CFRP筋复合型锚具的主要设计参数对锚固性能的影响及锚具内部受力情况,设计了5个复合型锚具的参数静载试验,测量了锚具的极限荷载、锚环-CFRP筋间滑移变形和金属筒测点应变,通过静载试验对比分析了各设计参数对锚固效果的影响,以及金属筒表面应力的分布情况与变化规律.研究结果表明:当金属筒壁厚为2 mm,夹片夹持长度为65 mm,粘结长度为500 mm时,锚具的锚固性能较好;夹片-金属筒间锚固良好,无滑移;金属筒应力分布与变化可反映锚具内部受力情况,测点应力曲线峰值预示该位置附近的胶体与CFRP筋间的粘结破坏.     

CFRP筋在活性粉末混凝土中的锚固性能

针对碳纤维增强塑料CFRP(Carbon Fiber Reinforced Polymer/Plastics)作为预应力筋或拉索时的锚固问题,提出了以活性粉末混凝土RPC(Reactive Powder Concrete)作为粘结介质的粘结式锚具.静载试验详细研究了CFRP筋的表面形状、锚固长度、根数和间距以及套筒内壁倾角等参数的变化对RPC的锚固性能的影响.试验结果表明,CFRP筋的表面形状对锚固性能的影响最为显著;对于抗拉强度不大于3 000 MPa的表面压纹CFRP筋,其临界锚固长度约为20倍CFRP筋直径;双根压纹CFRP筋锚固时的合理筋间距不宜小于1倍CFRP筋直径;本文提出的平均粘结强度和临界锚固长度计算公式具有较好的适用性.     

水浸与周期荷载耦合下CFRP锚固系统的耐久性分析

借助光纤布拉格光栅(FBG)传感器,在不同浸润时间下,对碳纤维复合材料(CFRP)锚固结构进行周期荷载实验,探究水浸与周期荷载下CFRP锚固结构的耐久性.试验结果表明:随着循环次数的增加,环氧体塑性变形减小,并趋于稳定;水浸与周期荷载作用下,锚具内CFRP筋发生变形,但无脱锚现象发生;CFRP筋与环氧体界面受水浸环境影响小,筋材表面无腐蚀.     

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.     

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.     

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.     

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.     

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.     

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that