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1.
In this paper, by capturing the atomic information and reflecting the behaviour governed by the nonlinear potential function,
an analytical molecular mechanics approach is proposed. A constitutive relation for single-walled carbon nanotubes (SWCNT’s)
is established to describe the nonlinear stress-strain curve of SWCNT’s and to predict both the elastic properties and breaking
strain of SWCNT’s during tensile deformation. An analysis based on the virtual internal bond (VIB) model proposed by P. Zhang
et al. is also presented for comparison. The results indicate that the proposed molecular mechanics approach is indeed an
acceptable analytical method for analyzing the mechanical behavior of SWCNT’s.
The project supported by the National Natural Science Foundation of China (10121202, 90305015 and 10328203), the Key Grant
Project of Chinese Ministry of Education (0306) and the Research Grants Council of the Hong Kong Special Administrative Region,
China (HKU 7195/04E). 相似文献
2.
Nonlinear Dynamics - The continuation and stability analysis methods for quasi-periodic solutions of nonlinear systems are proposed. The proposed continuation method advances the... 相似文献
3.
Experimental and theoretical study of the nonlinear response of agiant magnetostrictive rod 总被引:1,自引:0,他引:1
In this paper, a magnetomechanical coupling constitutive relation of the giant magnetostrictive material was investigated
experimentally and theoretically. A grain-oriented magnetostrictive rod of iron and rare earth was tested under a combined
magnetomechanical loading. Two types of experimental curves were obtained, i.e., the magnetostrictive curve of the extensional
strain vs the magnetic field, and the curve of the magnetic polarization intensity vs the pre-stress. A new theoretical constitutive
model, based on the density of domain switching, is developed. Comparison of the theoretical predictions with the experimental
results indicates that this model can capture the main characteristics of the magnetoelastic coupling deformation of a giant
magnetostrictive rod.
The project supported by the National Natural Science Foundation of China (10025209, 10132010, 10102007) 相似文献
4.
Yongmao Pei Daining Fang Faxin Li 《Journal of magnetism and magnetic materials》2009,321(18):2783-2787
The axial and transversal linear magnetostrictions (λ∥ and λ⊥) in [1 1 0] oriented polycrystalline Tb0.3Dy0.7Fe1.95 alloys were measured simultaneously under uniaxial magnetomechanical loading to get the forced volume magnetostriction (ω=λ∥+2λ⊥). Despite the almost zero ω observed in Terfenol-D single crystals, it reaches up to 1000×10−6 in polycrystalline Tb0.3Dy0.7Fe1.95 alloys near the saturation magnetic field under a stress above 50 MPa. 相似文献
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6.
This paper is concerned with the dynamic behaviors of wave propagation in layered periodic composites consisting of piezoelectric and piezomagnetic phases. The dispersion relations of Lamb waves axe derived. Dispersion curves and displacement fields are calculated with different piezoelectric volume fractions. Numerical results for BaTiO3/CoFe2O4 composites show that the dispersion curves resemble the symmetric Lamb waves in a plate. Exchange between the longitudinal (i.e. thickness) mode and coupled mode takes place at the crossover point between dispersion curves of the first two branches. With the increase of BaTiO3 volume fraction, the crossover point appears at a lower wave number and wave velocity is higher. These findings are useful for magnetoelectric transducer applications. 相似文献
7.
Mechanical properties of lattice grid composites 总被引:1,自引:0,他引:1
An equivalent continuum method only considering the stretching deformation of struts was used to study the in-plane stiffness and strength of planar lattice grid com- posite materials. The initial yield equations of lattices were deduced. Initial yield surfaces were depicted separately in different 3D and 2D stress spaces. The failure envelope is a polyhedron in 3D spaces and a polygon in 2D spaces. Each plane or line of the failure envelope is corresponding to the yield or buckling of a typical bar row. For lattices with more than three bar rows, subsequent yield of the other bar row after initial yield made the lattice achieve greater limit strength. The importance of the buckling strength of the grids was strengthened while the grids were relative sparse. The integration model of the method was used to study the nonlinear mechanical properties of strain hardening grids. It was shown that the integration equation could accurately model the complete stress-strain curves of the grids within small deformations. 相似文献
8.
Phase-field modeling approach has been used to study the oxidation behavior of pure Ni when considering heat conduction. In this calculation, the dependence of the coefficient of the Cahn–Hilliard equation Lc on the temperature T was considered. To this end, high-temperature oxidation experiments and phase-field modeling for pure Ni were performed in air under atmospheric pressure at 600,700, and 800?C. The oxidation rate was measured by thermogravimetry and Lc at these temperatures was determined via interactive algorithm. With the Lc-T relationship constructed, oxidation behavior of Ni when considering heat conduction was investigated. The influence of temperature boundaries on the oxidation degree, oxide film thickness, and specific weight gain were discussed. The phase-field modeling approach proposed in this study will give some highlights of the oxidation resistance analysis and cooling measures design of thermal protection materials. 相似文献
9.
综述了近几十年, 特别是近十几年来铁磁材料的力磁耦合变形与断裂行为的研究概况.
传统铁磁弹性问题的研究已经有较长时间的积累, 文献中已有大量的研究结果发表. 近些年
来, 随着智能材料及结构应用与研究的兴起, 功能铁磁材料如稀土超磁致伸缩材料、铁磁相
变材料以及铁磁复合材料等的力学行为越来越受到重视, 人们在功能铁磁材料的变形与断裂
以及铁磁复合材料的有效性质等方面开展了大量的研究工作. 本文在简单介绍了经典铁磁弹
性和传统铁磁结构的力磁性能的研究背景基础上, 结合作者近年来在铁磁材料变形与断裂方
面所开展的工作, 着重评述了功能软铁磁材料在变形与断裂的实验研究,如实验设备和技术,
以及铁磁复合材料细观力学、软铁磁材料、铁磁功能材料的变形与断裂理论等方面的研究进
展, 并指出了需要进一步研究的方向. 相似文献
10.