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多孔水泥基混凝土疲劳方程的建立及应用 总被引:2,自引:0,他引:2
作为水泥混凝土或沥青路面基层的多孔混凝土和面层一起受到荷载和温度的反复作用,因此,在路面应力分析和结构设计中需考虑它的疲劳性能。在多孔混凝土小梁弯拉疲劳实验的基础上,通过分析疲劳寿命实验数据的概率分布,得出其疲劳寿命服从双参数Weibull分布,并依次回归出不同应力水平和等效应力水平下两种形式的疲劳方程。根据疲劳方程提出了以多孔混凝土作为水泥混凝土路面下面层应力计算的荷载疲劳应力系数,沥青路面基层层底拉应力验算的抗拉强度结构系数,建立了进行路面结构设计的轴载换算模型。 相似文献
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利用Gleeble-1500热/力模拟试验机,研究了不同变形温度(250~350℃)和应变速率(0.01~1s-1)条件下铸态ZK30镁合金的热压缩变形行为。结合真应力-真应变曲线特征,分析了热压缩试验过程中的变形条件对合金流变应力及其变化规律的影响。结果显示,随着变形过程中应变量的逐渐增大,受热变形条件的影响真应力-真应变曲线展现了由硬化作用主导的变形机制到动态回复或动态再结晶为特征的软化机制变化过程。在变形温度恒定不变的情况下,当应变速率由0.01s-1增大到1s-1时流变应力水平明显增大;在应变速率为一定值时,当变形温度由250℃增大到350℃时流变应力水平显著减小。 相似文献
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采用有限元软件ANSYS中生死单元技术对压力容器筒体与平封头单面焊焊接过程进行数值模拟,得出焊缝焊接残余应力、温度场及位移场的分布情况。经过分析可以得出:在焊缝区及熔合区温度极高;远离焊缝,温度峰值急剧下降。在熔舍区焊接残余应力达最大值;焊根处残余应力较小;在热影响区,沿焊缝方向多为拉应力,垂直焊缝方向多为压应力。 相似文献
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基于DIC技术对玄武岩纤维混凝土在单轴受压过程中的全场位移和应变进行采集,分析混凝土在不同纤维掺量、不同受力阶段下应变云图的变化特征和变形参数的变化规律,并拟合出玄武岩纤维混凝土单轴受压的应力应变曲线.结果 表明:掺入玄武岩纤维可减小混凝土的变形,0.2%纤维掺量的混凝土整体变形性能更好.不同玄武岩纤维掺量混凝土的应力-应变曲线上升段几乎重合,下降段表现出不同的变形性能.掺入纤维可以降低峰值应变到极限应变下降斜率,掺入0.2%玄武岩纤维更有利于提高本试验条件下混凝土的延性性能. 相似文献
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乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。 相似文献
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D. G. Gordeev L. F. Gudarenko M. V. Zhernokletov V. G. Kudel’kin M. A. Mochalov 《Combustion, Explosion, and Shock Waves》2008,44(2):177-189
A semi-empirical equation of state for metals is described. Its capabilities are demonstrated by the example of the equation
of state for aluminum. New experimental data are presented on the location of the isentrope of aluminum for unloading from
the state at p = 229.71 GPa on the shock adiabat to an aerogel (SiO2) of density 0.08 g/cm3.
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Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 2, pp. 61–75, March–April, 2008. 相似文献
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Jorge Marcelo Romero Soledad Bustillo Hugo Enrique Ramirez Maisuls Nelly Lidia Jorge Manuel Eduardo Gómez Vara Eduardo Alberto Castro Alicia H. Jubert 《International journal of molecular sciences》2007,8(7):688-694
A thermochemical rather simple experimental technique is applied to determine the enthalpy of formation of Diperoxide of ciclohexanone. The study is complemented with suitable theoretical calculations at the semiempirical and ab initio levels. A particular satisfactory agreement between both ways is found for the ab initio calculation at the 6–311G basis This set level. Some possible extensions of the present procedure are pointed out. 相似文献
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A perturbation viscometer is a differential capillary viscometer that measures the logarithmic viscosity gradient of the viscosity-composition curve for gas mixtures. Measurements are made at different gas mixture compositions. Integration of the logarithmic viscosity gradients measured over the full composition range gives the mixture viscosity relative to the viscosity of one of the pure components of the gas mixture. This method is attractive because, for measurements of equal precision, integration of the gradients is potentially an order of magnitude more precise than measurement of the viscosities directly. It can also work at high and low temperatures and perhaps high pressures.The perturbation viscometer has been used to make measurements on ideal gas mixtures at ambient and elevated temperatures. The situation is more complicated when the gas mixtures are non-ideal. Extra effects due to density differences, molar volume change on mixing and differential thermal expansion may be measured in addition to the desired viscosity change producing systematic errors in the results. Thus, a more sophisticated apparatus is required. The standard perturbation viscometer has been modified to separate out the extra effects to permit measurement of the true change in viscosity. In addition, the theoretical operation of the modified apparatus has been revised to account for the design changes to permit calculation of the viscosity-composition profiles from the results.The apparatus has been tested using helium-HFC-125 mixtures and two new viscosity-composition profiles are presented for these mixtures at 23 and . Internal consistency tests have been used to confirm that the data produced are of high quality with an estimated uncertainty in the viscosity ratio data at of 0.9% and at of 1.5%. 相似文献
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塔设备改造选型的分析 总被引:2,自引:0,他引:2
就当前扩产增容中塔设备设计和改造时板式塔和填料塔的选型问题加以分析。在评述目前国内常用的几种塔板和新型填料之后,着重介绍一种新型塔板(导向梯形浮阀塔板)和一种新型填料(波环填料——乾隆帕克)。 相似文献