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81.
塑性损伤模型是有限元软件ABAQUS中应用广泛的一种混凝土非线性本构模型.采用CDP混凝土本构模型并针对混凝土非线性行为进行有限元模拟,结合一个现浇双向板试验对比分析,验证了在ABAQUS有限元分析中CDP模型应用到混凝土结构中可以较好的为解决实际工程提供分析参考价值. 相似文献
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The behaviour of E24 mild steel was studied by XPS analysis and electrochemical impedance spectroscopy (EIS) in a filtered solution of cement (pH 13), and an alkyl N-aminodiphosphonate aqueous solution called Aquadem® (7?pH?13). XPS results showed that the corrosion products developed in both media consisted of Fe2O3, covered by a very thin layer of goethite. The thickness of this oxide layer was estimated to be 3 nm. XPS analysis also demonstrated the adsorption of Aquadem® on the outer layer of FeOOH for pH lower than the zero charge pH of goethite (7.55). From XPS and EIS results, physical models of the E24 steel/electrolyte interface are proposed as a function of pH. For 11?pH?13, the steel is covered by a passive film, while for pH?10, pitting corrosion takes place. At pH 7, an additional mass transport phenomenon must be taken into account. The fitting procedure provided values for several physical parameters (electrolyte resistance, passive film resistance), from which the film capacitance and the dielectric constant of the oxide layer were calculated. 相似文献
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Anish Kumar Baldev Raj P. Kalyanasundaram T. Jayakumar M. Thavasimuthu 《NDT & E International》2002,35(4)
The impact echo technique is based on the use of transient stress waves for non-destructive detection of flaws in concrete structures. Impact-echo testing has been carried out for assessment of the structural integrity of the ring beam of a pressurised heavy water nuclear reactor. In order to develop the test procedure for carrying out impact echo testing, mock up calibration blocks were made. The detectability of the impact echo system has also been established in terms of the depth and the lateral dimension of the detectable flaw for the ring beam under consideration. Based on the optimised test parameters identified with the help of the studies carried out on the mock up blocks, impact echo testing was carried out on the ring beam of the reactor containment structure, for assessing its structural integrity. 相似文献
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A new technique for testing young cement paste and mortar is presented. It is based on a method, which uses unconventional prism-shaped specimens. It involves the precise measurement at fixed intervals of 24 h of the time-of-flight of both compressional and shear waves using high-frequency ultrasound. A water tank was designed that allows for easy coupling and handling of the specimens. Both waves are generated by mode conversion using the same transducer. The echoes from all the specimens were strong, and no signal processing was required. Thus, reliable and repeatable results were achieved using a very basic apparatus. Second-order elastic constants were evaluated, and correlation was made with the porosity and age of mortar. A new standard based on this method is proposed which would help in the making of prediction models for evaluating the strength of cement-based materials. 相似文献
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硫酸铵厂房和构筑物的腐蚀防护 总被引:1,自引:0,他引:1
与硫酸铵接触的部分建筑物和构筑物腐蚀严重,混凝土因腐蚀而剥落并露出钢筋,危害厂房的安全使用,通过对混凝土遭受腐蚀原因的分析,提出了相应的防护措施。 相似文献
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