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Influence of crack tip sharpness and radius on the strain distribution in rubbers analyzed by finite element simulation and experiments
Published in Per-Erik Austrell, Leif Kari, Constitutive Models for Rubber IV, 2017
Ch. Feichter, Z. Major, R.W. Lang
This difference occurs in a region, where the strain level is rather high. The maximum strain in pure shear measurements for the material law is, however, limited by the specimen geometry. Because of that, the exhibited strains in the full-field strain analysis exceed the completely experimentally covered strain region of the material law. The differences between the real material behavior and the predicted behavior recommend adaptations in the pure shear material law determination.
Optimum design for sustainable, ‘green’ concrete overlays. Part II: Shear failure at cracks and inadequate resistance to reflection cracking
Published in Sandra Erkens, Xueyan Liu, Kumar Anupam, Yiqiu Tan, Functional Pavement Design, 2016
Yi Xu, John N. Karadelis, Yougui Lin, Adegoke O. Olubanwo, Paul Phillips
At the first stage (Figure 3(a)), the whole ligament remains integrated to provide resistance. At the notch tip, it is subject to high shear and minimal bending moment. As crack deviates from the central line towards the boundary of the high shear zone, bending moment increases from zero to 17.6F at the boundary of the high shear zone, as shown in Figure 4(b), while shear force still equals to 173/196F. The continuous engagement of bending moment adds the weighing factor of flexure on the general performance of the specimens. It is a mix-mode problem combining mode I (opening) and mode II (shearing) with mode II being dominant. In fact, pure shear rarely exists in real engineering problems. It is always accompanied by flexure or other loading scenarios. The same applies in pavements. As the crack propagates further outside the high shear zone, as shown in Figure 4(c), the engagement of bending moment becomes dominant. It was observed in the case of steel fibre reinforced concrete beams that the peak load was reached long after the crack initiation. In other words, the load bearing capacity continued to increase after cracking. The peak load was often reached after the crack extended outside the high shear zone mainly. Multi-cracking and fibre fraction were observed before the final fracture of specimens.
Equivalent and effective strains during severe plastic deformation (SPD)
Published in Philosophical Magazine Letters, 2018
Note that γ is the shear strain accumulated along α and β slip line during time tEquations (12), (13) establish relationships between final coordinates (α, β) of the material particles and their original coordinates (α0, β0), which is based on accumulated shear γ and coefficient C. They describe distortions and finite strains of the material elements during uniform, steady and monotonic plastic flow. These equations show a strong effect of deformation mode C on the material distortion. Accumulated shear γ along slip lines together with C are the main mechanical characteristics of equivalence for large plastic strains. For various C, shear γ is associated with specific geometrical parameters of distorted elements. These properties are demonstrated by the two limit cases of pure shear and simple shear.
Phase field mechanics of residually stressed ceramic composites
Published in Philosophical Magazine, 2022
J. D. Clayton, R. B. Leavy, J. Knap
Shown in Figure 13 are normalised average shear strength versus normalised average tensile pressure at peak load in the composite, defined according to (112). Data points correspond to values of effective stress and pressure listed in Table 7 for simulations 2.1–2.18. Decreasing shear strength with increasing tensile pressure is apparent from the simulation results, in agreement with known trends for brittle solids [83, 84], including ceramics [87]. Notably, average stresses in simple shear loading (sims 2.10, 2.11, 2.12) fall beneath the quadratic fit, while those for uniaxial strain tension (sims 2.1, 2.2, 2.3) lie somewhat above it. The Lode angle is nearly the same for simple shear and pure shear (sims 2.13, 2.14, 2.15), but strength is significantly higher for pure shear. This difference in shear strength , with similar other other stress invariants and , suggests damage-induced anisotropy and/or edge effects from finite boundaries influence overall stress-strain behaviour of the composite aggregates. Anisotropic damage modelling [88, 89] may be necessary to properly account for such behaviour in a macroscopic continuum mechanical setting. Denote by the change in average between uniaxial strain and uniaxial stress loading in tension. Denote by the corresponding change in average . Results from Tables 4 and 7 produce for polycrystalline BC and for the BC-23 vol. % TiB composite. Thus, pressure sensitivity of the composite appears larger than that of the monolithic material for uniaxial tensile states. This may be a result of the more tortuous crack paths seen in the composite, and/or coupled effects of residual stress and imposed tensile pressure in the composite.