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A combined experimental and modeling research is performed to study the anisotropic elastoplastic and damage responses of SiC particle-reinforced Al composite sheets. To investigate the effects of the composite processing, two sets of specimens cut from the heat-treated and as-rolled composite sheets are tested under uniaxial loading. The dependenc...
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The present paper deals with the interfacial debonding processes in Al/SiC metal matrix composites, by using 3D finite element calculations on representative cells. The reinforcements are considered as elastic, while the behaviour of the matrix is described by an elastoviscoplastic law. The debonding of the reinforcement is allowed for by using a n...
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Citations
... Alternatively we could use the notation introduced in[69], namely e.g. instead of (Ĉ) ijkm we could writeĈ IJKM with the annotation that upper-case indices take on the same numbers as the corresponding lower-case ones but are not summed up -see also[70]. ...
The considerations are addressed to the notion of implicit nonlocality in the
mechanical models. The term implicit means that there is no direct measure of
nonlocal action in a model (like classical or fractional gradients etc. in the explicit
nonlocal models) but some phenomenological material parameters can be interpreted
as one that maps some experimentally observed phenomena responsible
for the scale effects.
The overall discussion is conducted in the framework of the Perzyna Theory
of Viscoplasticity where the role of the implicit length scale parameter plays the
relaxation time of the mechanical disturbance. In this sense, in the viscoplastic
range of the material behaviour, the deformation at each material point contributes
from finite surrounding. The important consequence is that the solution of the
IBVP described by the Perzyna’s theory is unique - the relaxation time is the
regularizing parameter.
... However, the results depend on the mesh unless adaptive remeshing algorithms are used. Alternatively, continuum damage-plasticity models were used for this type of problems (Hao et al., 2003; Bielski et al., 2006; Dorgan and Voyiadjis, 2006; Murzewski, 2006; Voyiadjis and Abd Al-Rub, 2006; Chow et al., 2007; Massart et al., 2007; Ricci and Brunig, 2007; Thakkar and Panley, 2007; Bogard et al., 2008; Skolnik et al., 2008). However, they are not capable of capturing discrete cracks that can be important for concrete. ...
Fracture in concrete is determined by excessive cracking. Numerical analysis of concrete fracture is either based on smeared crack method or discrete crack method. Smeared crack method is easier to implement than the discrete crack method but is therefore less accurate and applicable only for specific problems. We study fracture of concrete by a simplified meshless discrete crack method. The method exploit the advantages of smeared crack method and maintains the accuracy of discrete crack method. The discrete crack is modeled by set of crack segments that can be arbitrarily placed in the meshless discretization. Neo-Hooke material is used in the bulk material and cohesive zone model once the discrete crack occurs. We demonstrate for mode-I and mixed mode failure the accuracy of the meshless discrete crack method.
... Upon cooling from the processing temperature there is a residual tensile stress field that remains in the composite ( Fernández et al., 2004) resulting in a lower tensile yield strength. The compression testing in the forging direction and perpendicular to the forging direction for all three plates show anisotropic behavior that can be explained by the anisotropic microstructure that results during deformation (Skolnik et al., 2008). ...
The addition of ceramic particulate reinforcement via cryomilling can significantly increase the physical and mechanical properties of Al alloys. In the present study, boron carbide (B4C) was cryomilled with Al 5083 to form a nano-grained metal matrix powder. This powder was blended with unmilled Al 5083 to increase ductility and was then consolidated into plates by three methods: (1) hot isostatic pressing (HIPping) followed by high strain rate forging (HSRF), (2) HIPping followed by two-step quasi-isostatic forging (QIF), and (3) three-step QIF. The effects of process method on microstructure and mechanical behavior for the final consolidated nano-composite plates were investigated.
... 5 Alternatively we could use the notation introduced in [72], namely e.g. instead of (Ĉ) ijkm we could writeĈ IJKM with the annotation that upper-case indices take on the same numbers as the corresponding lower-case ones but are not summed up -see also [124]. ...
The geometric model of extruding SiCp/Al composites was established by means of solidworks, and the hot extrusion process was simulated by using DEFORM finite element software. The changes of metal streamline, effective strain and damage under different extrusion angles, friction coefficients, sleeve thicknesses and initial temperatures were investigated. The results show that there is no obvious linear relationship between the extrusion angle and the extrusion characteristics, and the best extrusion angle is 45°. With the increase in friction coefficient, the effective strain and damage increase gradually. The higher the initial temperature, the smaller the effective strain produced during extrusion. When the extrusion angle is 45°, the friction coefficient is 0.2, and the initial temperature is 450 ℃, the extruded specimen has the best comprehensive performance and uniform internal deformation. In addition, under the protection of the sleeve, the damage will be greatly reduced. When the bottom thickness is 25 mm, the specimen has the least damage. The results of this paper can provide effective guidance for the development of the actual extrusion process and the design of the extrusion mold.
IntroductionCharacterization of Interfaces in Macro- and MicrocompositesMicromechanics-Based AnalysisInterfacial Damage ModelingSummaryReferences
This article demonstrates a novel parameter identification of a rate-dependent damage constitutive model using self-optimizing inverse method. In the self-optimizing inverse method, an implicit–explicit objective function is formulated as a function of two sets of full-field stresses/strains (implicit non-measurable variables) from two nonlinear finite element analyses, that is, force-driven and displacement-driven simulations, respectively, and global boundary displacements and forces (explicit measurable variables) from experimental tests. The self-optimizing inverse method can self-correct the damage parameter set through optimization procedures referring to global responses measured in laboratory tests. A micromechanics and fracture mechanics based damage constitutive law that accounts for the microcrack nucleation and growth is adopted. Synthetic data from impact tension test simulations were used to demonstrate successful performances of the self-optimizing inverse method in identifying the nonlinear constitutive and damage-related parameters. Comparative studies were conducted using two different optimization techniques – the simplex method and the steady-state genetic algorithm. The identified parameters proved to be identical to the reference values. Finally, in order to further verify the inverse identification method, self-optimizing inverse method analyses were conducted to identify the damage parameter set based on real experimental data from impact tension tests at different strain rates.
