Numerous experimental evidences show that the grain size may significantly alter the yield strength of metals.Similarly,innickel-based superalloys,the precipitate size also influences their yield strength.Then,how to ...Numerous experimental evidences show that the grain size may significantly alter the yield strength of metals.Similarly,innickel-based superalloys,the precipitate size also influences their yield strength.Then,how to describe such two kinds of size effects on the yield strength is a very practical challenge.In this study,according to experimental observations,a collinear micro-shear-bands model is proposed to explore these size effects on metal materials’yield strength.An analytical solution for the simple model is derived.It reveals that the yield strength is a function of average grain-size or precipitate-size,which is able to reasonably explain size effects on yield strength.The typical example validation shows that the new relationship is not only able to precisely describe the grain-size effect in some cases,but also able to theoretically address the unexplained Hall-Petch relationship between theprecipitate size and the yield strength of nickel-based superalloys.展开更多
纤维含量是影响加筋土的重要参数,现有研究中纤维含量的取值范围一般较小,纤维含量较高的加筋土物理力学性能尚不清楚。为了研究较高纤维含量对稻草纤维加筋土的影响,设置10个纤维质量分数,采用直剪试验进行研究,探讨不同纤维含量对加...纤维含量是影响加筋土的重要参数,现有研究中纤维含量的取值范围一般较小,纤维含量较高的加筋土物理力学性能尚不清楚。为了研究较高纤维含量对稻草纤维加筋土的影响,设置10个纤维质量分数,采用直剪试验进行研究,探讨不同纤维含量对加筋土强度特性的影响,并通过扫描电镜(scanning electron microscope,SEM)试验和核磁共振(nuclear magnetic resonance,NMR)测试对纤维加筋土的微观结构特征进行分析。结果表明,加入纤维能有效提高土体的抗剪强度。纤维加筋土的增强机理与纤维含量有关,较低的纤维含量对土体孔隙率影响不大,加筋土以土骨架为基础;当纤维含量较高时,孔隙率明显增大,加筋土的主体结构将由土骨架和纤维骨架组成。展开更多
基金supported by the National Natural Science Foundation of China (41630634)the China Postdoctoral Science Foundation (2017M623213)
文摘Numerous experimental evidences show that the grain size may significantly alter the yield strength of metals.Similarly,innickel-based superalloys,the precipitate size also influences their yield strength.Then,how to describe such two kinds of size effects on the yield strength is a very practical challenge.In this study,according to experimental observations,a collinear micro-shear-bands model is proposed to explore these size effects on metal materials’yield strength.An analytical solution for the simple model is derived.It reveals that the yield strength is a function of average grain-size or precipitate-size,which is able to reasonably explain size effects on yield strength.The typical example validation shows that the new relationship is not only able to precisely describe the grain-size effect in some cases,but also able to theoretically address the unexplained Hall-Petch relationship between theprecipitate size and the yield strength of nickel-based superalloys.
文摘纤维含量是影响加筋土的重要参数,现有研究中纤维含量的取值范围一般较小,纤维含量较高的加筋土物理力学性能尚不清楚。为了研究较高纤维含量对稻草纤维加筋土的影响,设置10个纤维质量分数,采用直剪试验进行研究,探讨不同纤维含量对加筋土强度特性的影响,并通过扫描电镜(scanning electron microscope,SEM)试验和核磁共振(nuclear magnetic resonance,NMR)测试对纤维加筋土的微观结构特征进行分析。结果表明,加入纤维能有效提高土体的抗剪强度。纤维加筋土的增强机理与纤维含量有关,较低的纤维含量对土体孔隙率影响不大,加筋土以土骨架为基础;当纤维含量较高时,孔隙率明显增大,加筋土的主体结构将由土骨架和纤维骨架组成。
