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 Physics , 2014, Abstract: Molecular Dynamics (MD) simulations have been carried out to investigate the deformation behaviour of <110>/{111} body centered cubic (BCC) Fe nanowires under tensile and compressive loading. An embedded atom method (EAM) potential was used to describe the interatomic interactions. The simulations were carried out at 10 K with a constant strain rate of $1\times10^{8}$ $s^{-1}$. The results indicate a significant differences in deformation mechanisms under tensile and compressive loading. Under tensile loading, the deformation occurs by the slip of full dislocations, While under compressive loading twinning was observed as the dominant mode of deformation. The tension-compression asymmetry in deformation mechanisms of BCC Fe nanowires is attributed to twinning-antitwinning asymmetry of 1/6<111> partial dislocation on {112} planes. We further explain the mechanism of dislocation pile up in tensile loading and twin growth in compressive loading.
 材料科学技术学报 , 1992, Abstract: Results indicate that under cyclic tension the growth rate of short fatigue crack from notch root will be lowered greatly by tensile pre-loading,but only a little change by compressive pre-loading. The effect of tensile pre-loading will decrease with the increase of stress ratio.The variation of short fatigue crack growth rate is related to the residual stress distribution around notch root.
 Applied Physics Research , 2012, DOI: 10.5539/apr.v4n3p8 Abstract: The structural stability and theoretical strength of BCC crystals Fe, V, Nb and Ta under hydrostatic loading have been investigated by using the modified analytical embedded atom method (MAEAM). For all the calculated BCC crystals, the failures occur while the relation m >0 is violated in compression and k >0 is violated in tension. It found that the stable regions are 0.9269~1.1495, 0.9270~1.1545, 0.9268~1.1449 and 0.9268 ~ 1.1427 in the lattice stretch l or the corresponding -408.89 ~ 123.54, -186.96 ~ 131.43, -259.07 ~ 152.53 and -283.92 ~137.04eV/nm3 in the theoretical strength for Fe, V, Nb and Ta, respectively. The calculated maximum tensile stresses smax of Fe, V, Nb and Ta are 123.57, 131.74, 154.45 and 137.85eV/nm3 and the corresponding lattice stretch lmax ??are 1.1527, 1.1617, 1.1661 and 1.1545. The calculated maximum tensile stress smax and the corresponding lattice stretch lmax ??of Fe are consistent well with the results of Ab initio calculation.
 Journal of Engineering and Applied Sciences , 2012, DOI: 10.3923/jeasci.2012.108.112 Abstract: This study presents the compressive strength and crack propagation of cement composites reinforced coconut fibre. The development of cement composites in this research were done by substituting coconut fibre to the portion of sand based on the ratio of cement to sand. Cement composites were mixed with 3, 6, 9, 12, 15 wt. % of coconut fibre and amount of water per cement ratio was fixed at 0.55. They were then cured in water for 7, 14 and 28 days of curing. The result obtained that the cement composite with 9 wt. % of coconut fibre gives highest compressive strength and the crack propagation is controlled by coconut fibre addition.
 International Journal of Materials Engineering , 2012, DOI: 10.5923/j.ijme.20120205.02 Abstract: In this paper, in order to predict the crack growth trajectory and to evaluate the SIF under mixed modes (I & II), one proposes a new finite element program for crack growth using the source code written in FORTRAN. The finite element mesh is generated using an advancing front method, where the generation of the background mesh and the construction of singular elements are also added to this developed programme to facilitate the crack process and the fracture analysis. Displacement Extrapolation Technique (DET) was employed to evaluate the SIFs under mixed mode loading conditions. Therefore, the accuracy of both SIF`s values and the crack path predictions results are compared and validated with other relevant published research work. However, the assessment indicated that this developed finite element programme is reliable and robust to evaluate the SIFs and predicts the crack trajectories successfully based on the applied loading conditions.
 岩石力学与工程学报 , 2008, Abstract: Microcrack development patterns in Westerly granite specimens stressed immediately before their ultimate failure by uniaxial compressive loading are observed using the fluorescent method proposed by Nishiyama and Kusuda(1994). Applying this method,the microscopic crack growth patterns,such as cleavage cracks within feldspar grains and intracrystalline cracks in quartz grains,and the wide-area distributions of these cracks are simultaneously confirmed with accuracy and ease. As a result of the observations,the elongated contiguous cracks estimated to have a direct impact on the final failure of granite are identified;and these cracks are roughly classified into three types. It is inferred that these three types of cracks do not develop at the same time;and each type has a different mechanism of generation. The mechanism of crack development under uniaxial compression is suggested to occur as follows. Firstly,many microcracks running parallel to the loading direction are induced by loading. Next,long cracks are induced by the elongation and coalescence of these microcracks located near the sides of the specimen. Then,the sides move outward due to further loading,generating the fault plane. The cracks within the relatively less damaged remaining parts are linked and propagated;and finally,these cracks induce the failure of specimen.
 金属学报 , 1996, Abstract: Studies of the fatigue crack initiation and propagation show that there is the loading frequency effect for the quenched and tempered or normalized 40Cr steel, but no the loading frequency effect for the solution treated ICr18Ni9Ti. The essential reason that causes the loading frequency effect is due to decrease in the plastic deformation propagation speed with the inereasing loading frequency. The decrease in plastic strain amplitude and the increase in residual compressive stress play a main role for the delaying fatigue crack initiation and the retarding crack propagation. The study of the loading frequency effect on the fatigue behaviour of the metals with the lower plastic deformation propagation speed possesses important engineering signification.