The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Xinquan Liang - One of the best experts on this subject based on the ideXlab platform.
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Synthetic Slip Plane, a hybrid kind of calcite twin data in dynamic analysis
MethodsX, 2019Co-Authors: Yehua Shan, Jian Zheng, Xinquan LiangAbstract:This paper defines a synthetic Slip Plane as the linear combination of a pair of twinned and untwinned e-Planes in a single calcite crystal. This auxiliary Slip Plane is dependent upon neither the twinned e-Plane nor the untwinned e-Plane. It can be used together with the twinned e-Plane either to further constrain the extents of the compression and tension axes in graphic dynamic analysis or to better estimate the reduced stress in numerical dynamic analysis. Highlights •The linear combination of twinned and untwinned e-Planes in a calcite crystal defines the synthetic Slip Plane.•The synthetic Slip Plane can be incorporated into graphic and numerical dynamic analysis.
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Synthetic Slip Plane, the combination of a pair of twinned and untwinned e-Planes in a single calcite crystal: Application in dynamic analysis
Journal of Structural Geology, 2019Co-Authors: Yehua Shan, Jian Zheng, Xinquan LiangAbstract:Abstract This paper defines a synthetic Slip Plane as the linear combination of a pair of twinned and untwinned e-Planes in a single calcite crystal. This auxiliary Slip Plane can be used together with the twinned e-Plane either to further constrain the extents of the compression and tension axes in graphic dynamic analysis or to better estimate the reduced stress in numerical dynamic analysis. In this paper we proposed the novel method that solves for the reduced stress by maximizing the sum of the shear stress along the Slip line on each twinned e-Plane or synthetic Slip Plane under the constraint of the 1-valued second stress invariant. This new method yields an analytical solution of stress. It is applied to a series of artificial examples without any measurement error generated under the prescribed stresses. The estimated stresses are generally accurate and robust, which illustrates the feasibility of this new method.
J. Weertman - One of the best experts on this subject based on the ideXlab platform.
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The double Slip Plane model for the study of short cracks
Mechanics of Materials, 1995Co-Authors: C.a. Caracostas, Hossein M. Shodja, J. WeertmanAbstract:Abstract Apart from crack closure which has been employed extensively to explain apparent differences in the behaviour of short and long cracks, dislocation crack tip shielding is investigated as an additional contributing factor. The double Slip Plane (DSP) crack model is employed and a numerical approach is followed for the calculation of the dislocation density distributions on the crack and the Slip Planes and the plastic zone size. By accounting for dislocation crack tip shielding, the critical stress σ cr and applied stress intensity factor K A,cr which define the onset of crack advance, exhibit a crack length dependence which is a manifestation of the anomalous short crack behaviour. It is shown, that below a critical crack length K A,cr is not constant, but rather decreases with decreasing crack length. Furthermore, a critical stress smaller than that predicted by linear elastic fracture mechanics is found. A method to calculate crack propagation rates based on dislocation density distributions is also presented. It is shown that under cyclic loading, a short crack propagates below the threshold stress intensity of a long crack and exhibits faster crack growth rates for the same nominal crack driving force. For the mild crack growth regime, Paris power-law exponents of 2 and 2.7 are predicted, depending on the value of an adjustable parameter in the configuration of the DSP model.
Yehua Shan - One of the best experts on this subject based on the ideXlab platform.
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Synthetic Slip Plane, a hybrid kind of calcite twin data in dynamic analysis
MethodsX, 2019Co-Authors: Yehua Shan, Jian Zheng, Xinquan LiangAbstract:This paper defines a synthetic Slip Plane as the linear combination of a pair of twinned and untwinned e-Planes in a single calcite crystal. This auxiliary Slip Plane is dependent upon neither the twinned e-Plane nor the untwinned e-Plane. It can be used together with the twinned e-Plane either to further constrain the extents of the compression and tension axes in graphic dynamic analysis or to better estimate the reduced stress in numerical dynamic analysis. Highlights •The linear combination of twinned and untwinned e-Planes in a calcite crystal defines the synthetic Slip Plane.•The synthetic Slip Plane can be incorporated into graphic and numerical dynamic analysis.
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Synthetic Slip Plane, the combination of a pair of twinned and untwinned e-Planes in a single calcite crystal: Application in dynamic analysis
Journal of Structural Geology, 2019Co-Authors: Yehua Shan, Jian Zheng, Xinquan LiangAbstract:Abstract This paper defines a synthetic Slip Plane as the linear combination of a pair of twinned and untwinned e-Planes in a single calcite crystal. This auxiliary Slip Plane can be used together with the twinned e-Plane either to further constrain the extents of the compression and tension axes in graphic dynamic analysis or to better estimate the reduced stress in numerical dynamic analysis. In this paper we proposed the novel method that solves for the reduced stress by maximizing the sum of the shear stress along the Slip line on each twinned e-Plane or synthetic Slip Plane under the constraint of the 1-valued second stress invariant. This new method yields an analytical solution of stress. It is applied to a series of artificial examples without any measurement error generated under the prescribed stresses. The estimated stresses are generally accurate and robust, which illustrates the feasibility of this new method.
K.p.d. Lagerlöf - One of the best experts on this subject based on the ideXlab platform.
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On basal Slip and basal twinning in sapphire (α-Al2O3)—I. Basal Slip revisited
Acta Materialia, 1996Co-Authors: Jørgen Bilde-sørensen, A. H. Heuer, B.f. Lawlor, T. Geipel, Pirouz Pirouz, K.p.d. LagerlöfAbstract:Abstract The motion of partial dislocations (b = 1/3 [011¯0〉 and 1/3 [101¯0〉) uvtw〉 refers to the direction [uvtw] and the two equivalent directions related by the 3-fold rotational symmetry about [0001]. 1/3 〈112¯0〉) in sapphire (α-Al2O3 is analysed. Crystallographic arguments suggest that the basal Slip Plane should be a Plane passing through the normally-vacant octahedral sites defined by the anion sublattice. This definition of the basal Slip Plane implies that half of the cations lying between two adjacent anion layers are above and the other half are below the Slip Plane. The stacking faults that would be created by the motion of a dissociated basal dislocation differs in structure and energy, depending on whether the 1/3 [101¯0〉 partial is leading or trailing. Thus, the motion of a 1/3 [101¯0〉 partial in its favorable (lower energy) direction creates a stacking fault with a stacking sequence in which the cations are in a localized twin symmetry, whereas the motion of a 1/3 [101¯0〉 partial in its unfavorable (higher energy) direction is “forbidden”. Furthermore, the motion of a 1/3 [101¯0〉 partial in its favorable direction can take place without the need for synchroshear.
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On Basal Slip and basal twinning in sapphire (α-Al2O3)—II. A new model of basal twinning
Acta Materialia, 1996Co-Authors: Pirouz Pirouz, A. H. Heuer, Jørgen Bilde-sørensen, B.f. Lawlor, T. Geipel, K.p.d. LagerlöfAbstract:Abstract Based on a new model for basal Slip in sapphire developed in Part I of this series of papers, the formation of a basal twin is considered. It is shown that deformation twinning is a natural outgrowth of the present model of Slip when the material is deformed in a particular regime of temperature and stress. The model is based on the glide of a leading partial dislocation on a basal Slip Plane and double-cross-Slip to the next-but-one Slip Plane. The model predicts a Type-II twin, i.e. a twin related to the matrix by a 2-fold axis along the direction of shear, η 1 = [101¯0〉, and lying in the twin/matrix interface.
Jian Zheng - One of the best experts on this subject based on the ideXlab platform.
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Synthetic Slip Plane, a hybrid kind of calcite twin data in dynamic analysis
MethodsX, 2019Co-Authors: Yehua Shan, Jian Zheng, Xinquan LiangAbstract:This paper defines a synthetic Slip Plane as the linear combination of a pair of twinned and untwinned e-Planes in a single calcite crystal. This auxiliary Slip Plane is dependent upon neither the twinned e-Plane nor the untwinned e-Plane. It can be used together with the twinned e-Plane either to further constrain the extents of the compression and tension axes in graphic dynamic analysis or to better estimate the reduced stress in numerical dynamic analysis. Highlights •The linear combination of twinned and untwinned e-Planes in a calcite crystal defines the synthetic Slip Plane.•The synthetic Slip Plane can be incorporated into graphic and numerical dynamic analysis.
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Synthetic Slip Plane, the combination of a pair of twinned and untwinned e-Planes in a single calcite crystal: Application in dynamic analysis
Journal of Structural Geology, 2019Co-Authors: Yehua Shan, Jian Zheng, Xinquan LiangAbstract:Abstract This paper defines a synthetic Slip Plane as the linear combination of a pair of twinned and untwinned e-Planes in a single calcite crystal. This auxiliary Slip Plane can be used together with the twinned e-Plane either to further constrain the extents of the compression and tension axes in graphic dynamic analysis or to better estimate the reduced stress in numerical dynamic analysis. In this paper we proposed the novel method that solves for the reduced stress by maximizing the sum of the shear stress along the Slip line on each twinned e-Plane or synthetic Slip Plane under the constraint of the 1-valued second stress invariant. This new method yields an analytical solution of stress. It is applied to a series of artificial examples without any measurement error generated under the prescribed stresses. The estimated stresses are generally accurate and robust, which illustrates the feasibility of this new method.