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 This paper derives a simple formula describing the creep of metals by using the viscoelastic theory.The author makes an account of the generalized viscoelastic differential equation of stress and strain, solves n=2, i. e. Ke lvinMaxwell quaternion combined model and attains formula(5). The two creep test curves of B1900 nickelbase superalloys are used in the calculation of the examples of the formula. It is shown that the derived formula can be used to describe the creep of metals approximately.  本文用粘弹性理论导出描述金属蠕变规律的简便公式,介绍了粘弹性理论应力应变综合微分方程,并对n=2即KelvinMaxwell四元素联合模型求解,得出公式(5),然后用B—1900镍基高温合金的两条蠕变试验曲线对公式进行了举例计算。计算结果表明,所导公式可以用来近似描述金属蠕变规律,并具有一定的精度。  The complex rock foundation in large project often consists of different kinds of rocks and soft interfaces, such as interstitial layers, faults and so on. It brings about an unfavorable effect on the stability of sliding resistance, stress and displacement distribution of surface structure. Thus, the study of such problem is of great significance. In this paper, on the bases of experimental results, three models for rock and concrete are proposed, namely, 1) "Lowtension elastoplastic model" 2) "Fracture model"... The complex rock foundation in large project often consists of different kinds of rocks and soft interfaces, such as interstitial layers, faults and so on. It brings about an unfavorable effect on the stability of sliding resistance, stress and displacement distribution of surface structure. Thus, the study of such problem is of great significance. In this paper, on the bases of experimental results, three models for rock and concrete are proposed, namely, 1) "Lowtension elastoplastic model" 2) "Fracture model" 3) "Combined model". For soft interstitial layer, the "notension elastoplastic model" is proposed. Their nonlinear constitutive equations are established respectively. In the paper, the formula of F.E.M.and "The Iteration with Changeable K_ψ" are introduced. Some examples concerning practical engineering problem are analysed.  大型工程中,复杂地基(夹有夹层、节理、裂隙和断层等软弱结构面)对上部结构的抗滑稳定,应力和位移的分布等往往会带来不利的影响,因此在今天,进行复杂地基受力分析研究已受到普遍的重视,随着高速电子计算机的出现和计算技术的发展,运用有限单元法进行这种研究亦已成为可能。本文在试验资料的基础上,从弹塑性和断裂的观点出发,针对岩石和混凝土一类材料的具体情况,建议采用下列三种模型,即:1)“低抗拉弹塑性模型”,2)“断裂模型”,3)“组合模型”.而对于软弱夹层则采用“不抗拉弹塑性模型”。并分别建立了非线性本构关系,文中还介绍了有限元算式和“变Kp迭代法”,最后还附有工程计算实例。  Water model experiments were carried out to study the flow patterns developed in a ccmouldwhen submerged nozzle of different configurations were used. The relationship between particle size of nonmetallic inclusions and its floatability in a moltenmetal pool was discussed in terms of the vessel dispersion number obtained from the water modeltests. Straight nozzles were found to give a high degree of penetration which results in mixing in thelower part of the mould and beyond the mould. A combined model was... Water model experiments were carried out to study the flow patterns developed in a ccmouldwhen submerged nozzle of different configurations were used. The relationship between particle size of nonmetallic inclusions and its floatability in a moltenmetal pool was discussed in terms of the vessel dispersion number obtained from the water modeltests. Straight nozzles were found to give a high degree of penetration which results in mixing in thelower part of the mould and beyond the mould. A combined model was developed when bifurcated nozzle were used. Nozzles with four holes were found to give a dispersion model.  不同形状的浸入式水口对结晶器内流体流动状态的影响,曾在水模上进行了研究。并且根据从水模实验里得到的容器弥散准数,计算了不同大小的非金属夹杂物在融熔金属熔池中上浮的可能性。直筒水口具有很高的穿透性,旋涡区可以在结晶器下部,甚至在结晶器下面形成。使用二孔水口时,结晶器内的流动状态是混合型的。四孔水口的结晶器内的流动状态是弥散型的。   << 更多相关文摘 
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