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21.
The concept that plasticity index of soils can be defined as a range of water contents producing a 100-fold variation in undrained shear strength has been experimentally verified with the help of a large number of tests on soils of diverse nature. This has led to the redefinition of the plastic limit as the water content at which undrained shear strength is around 170 kN/m2. Undrained shear strength of a soil at the liquid limit can be considered to be around 1.7 kN/m2. Accordingly, both the liquid limit and the plastic limit have been determined in the present work by a single consistent method, i.e., the Swedish fall cone method. The undrained shear strength-water content relationship has been found to be log-linear for a wide range of water contents beginning from lower than the plastic limit to higher than the liquid limit. This resulted in the formulation of an expression for predicting undrained shear strength of a remolded soil at any water content based solely on its liquid limit and plastic limit. 相似文献
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To find the exact probability distribution of the global maximum or minimum of a random field within a bounded domain is a pending problem even for Gaussian fields. Except for very special examples of fields, recourse must be taken to approximate reasoning or asymptotic considerations to be judged with respect to accuracy by simulations. In this paper, the problem is addressed through a functional equation that leads to the definition of a class of distribution functions that depend solely on process or field characteristics and domain quantities that can be calculated explicitly. This distribution function class is studied for Gaussian processes in earlier works by the author and it has been obtained explicitly for Gaussian fields on rectangular domains in the plane. Simulation studies show that rather good predictions are obtained for sufficiently smooth wide band Gaussian processes and fields. In this paper, the distribution function is obtained in general for Gaussian fields over arbitrary bounded domains with piecewise continuous and differentiable boundaries, and as in earlier works the distribution function is tested against empirical distribution functions obtained by simulation of sample functions of a smooth approximately Gaussian field, herein called a broken line Hino field. For completeness this particular field type is defined in appendix a and appendix b. The paper concludes with a statistical application on data for plain concrete tensile strength. 相似文献
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The object of study is a stationary Gaussian white noise excited multi-degree-of-freedom (MDOF) linear elastic, ideal plastic, linearly damped, statically determinate oscillator with several potential elements of ideal plastic yielding. Specifically the study is exemplified for a plane multistory shear frame with rigid traverses where all the connecting columns except the columns in one or more of the bottom floors have finite symmetrical yield limits. The white noise excitation acts on the mass of the first floor making the movement of the elastic bottom floors simulate a ground motion that interacts with the structure above the bottom floors. The method of study is so-called Slepian model simulation and is in principle the same for other statically determinate MDOF elasto-plastic oscillators of the considered type. The method is fast as compared to direct simulation and provides results that give good insight in the behavior of the plastic displacement response process. 相似文献
26.
织物-树脂复合材料层压板的准静态侵彻机理 总被引:4,自引:1,他引:3
本文利用MTS得到了芳纶和高强维纶织物复合材料层压板受尖头侵彻体穿孔的准静态侵彻曲线 ,比较和分析了不同类型纤维集合体与热固性树脂和热塑性树脂复合材料的破坏模式 ,并考察了芳纶织物复合材料层压板侵彻的逐步破坏过程 ,揭示了复合材料层压板的准静态侵彻机理。 相似文献
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微合金化高强度钢轧制采用的工艺技术 总被引:1,自引:0,他引:1
本文综述微合金化高强度钢轧制采用的工艺技术,其中包括热装热送、板坯加热、控轧控冷、快速冷却、采用的新设备等工艺技术。重点是生产低碳、高韧性、高强度、易焊接的造船用钢采用形变热处理技术,以提高产量和质量,节省昂贵的Ni、Cr、Mo等合金,降低生产成本。 相似文献
28.
Ionic Strength Effects on Heat-induced Gelation of Myofibrils and Myosin from Fast- and Slow-twitch Rabbit Muscles 总被引:1,自引:0,他引:1
The effects of ionic strength on myofibrils and myosin from rabbit fast-twitch Psoas major (PM) and slow-twitch Semimembranosus proprius (SMp) muscles before and after heating were studied by electron microscopy and thermal scanning rheometry. The direct suspension of proteins in low ionic strength (0.2M KCl; pH 6.0) led to very weak gels, whereas a gradual lowering of the ionic strength (by dialysis against 0.2M KCl; pH 6.0) of 0.6M KCl protein solutions induced strand-type networks at low temperature and strong heat-induced gels. As shown by transmission and scanning electron micrographs, in low ionic strength, SMp myosins formed shorter filaments before heating and thinner and shorter structures in heat-induced gels, as well as a lower gel porosity than PM myosins. 相似文献
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