microstructure evolution of duplex-phase titanium does significant effects on its deformation behavior, and is sensitive to its deformation process at the same time. Approaches for microstructure numeralization, phase...
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ISBN:
(纸本)9787030338990
microstructure evolution of duplex-phase titanium does significant effects on its deformation behavior, and is sensitive to its deformation process at the same time. Approaches for microstructure numeralization, phase information mapping, efficient explicit algorithm of crystal plasticity are proposed. A grain-scale crystal plasticity finite element model is established on the platform of ABAQUS by considering the morphology and topology of grains, dual phases with different crystallographic structure, orientation and grain boundaries. Compressive test shows inhomogeneous distributions of stress and strain between grains and great effects of initial grain orientation configurations on them.
The goal of this paper is to predict how the properties of the constituent phases and microstructure of dual phase steels (consisting of ferrite and martensite) influence their fracture resistance. We focus on two com...
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The goal of this paper is to predict how the properties of the constituent phases and microstructure of dual phase steels (consisting of ferrite and martensite) influence their fracture resistance. We focus on two commercial low-carbon dual-phase (DP) steels with different ferrite/martensite phase volume fractions and properties. These steels exhibit similar flow behavior and tensile strength but different ductility. Our experimental observations show that the mechanism of ductile fracture in these two DP steels involves nucleation, growth and coalescence of micron scale voids. We thus employ microstructure-based finite element simulations to analyze the ductile fracture of these dual-phase steels. In the microstructure-based simulations, the individual phases of the DP steels are discretely modeled using elastic-viscoplastic constitutive relations for progressively cavitating solids. The flow behavior of the individual phases in both the steels are determined by homogenizing the microscale calibrated crystal plasticity constitutive relations from a previous study (Chen et al. in Acta Mater 65:133-149, 2014) while the damage parameters are determined by void cell model calculations. We then determine microstructural effects on ductile fracture of these steels by analyzing a series of representative volume elements with varying volume fractions, flow and damage behaviors of the constituent phases. Our simulations predict qualitative features of the ductile fracture process in good agreement with experimental observations for both DP steels. A 'virtual' DP microstructure, constructed by varying the microstructural parameters in the commercial steels, is predicted to have strength and ductile fracture resistance that is superior to the two commercial DP steels. Our simulations provide guidelines for improving the ductile fracture resistance of DP steels.
Fracture behavior and micro-failure mechanism in stretch-bending of dual-phase (DP) steels are still unclear. Representative volume elements (RVE) have been proved to be an applicable approach for describing microstru...
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Fracture behavior and micro-failure mechanism in stretch-bending of dual-phase (DP) steels are still unclear. Representative volume elements (RVE) have been proved to be an applicable approach for describing microstructural deformation in order to reveal the micro-failure mechanism. In this paper, 2D RVE models are built. The deformation behavior of DP steels under stretch-bending is investigated by means of RVE models based on the metallographic graphs with particle geometry, distribution, and morphology. Microstructural failure modes under different loading conditions in stretch-bending tests are studied, and different failure mechanisms in stretch-bending are analyzed. The computational results and stress-strain distribution analysis indicate that in the RVE models, the strain mostly occurs in ferrite phase, while martensite phase undertakes most stress without significant strain. The failure is the results of the deformation inhomogeneity between martensite phase and ferrite phase. The various appearance and growth of initial voids are different depending on the bending radius.
The crack growth behavior of particle-reinforced composites is determined by several factors, such as volume fraction, particle size, particle morphology, spatial distribution and particle strength. Thus, an accurate ...
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The crack growth behavior of particle-reinforced composites is determined by several factors, such as volume fraction, particle size, particle morphology, spatial distribution and particle strength. Thus, an accurate and robust numerical model must incorporate the true microstructure of the particles. It will be shown that the strength of the reinforcement particles is also an important factor. Hence, the model must be able to simulate particle fracture. In this paper, the crack growth behavior of SiC particle-reinforced Al matrix composites was modeled using actual microstructures. Linear elastic fracture mechanics principles were used to propagate the crack and obtain the local stress intensity values. The effect of particle fracture on crack growth was studied. It will be shown that spatial distribution and shape of the particles, as well as particle fracture ahead of the crack tip, significantly affect the crack trajectory and the stress distribution at the crack tip. (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
The fracture processes in cement paste at microscale are simulated by the 3D lattice fracture model based on the microstructure of hydrating cement paste. The uniaxial tensile test simulation is carried out to obtain ...
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ISBN:
(纸本)9780878492411
The fracture processes in cement paste at microscale are simulated by the 3D lattice fracture model based on the microstructure of hydrating cement paste. The uniaxial tensile test simulation is carried out to obtain the load-displacement diagram and microcracks propagation for a Portland cement paste specimen in the size of 100x100x100 mu m(3) at the degree of hydration 69%. The Young's modulus, tensile strength, strain at peak load and fracture energy are computed on the basis of the load-displacement diagram.
While it is well recognized that microstructure controls the physical and mechanical properties of a material, the complexity of the microstructure often makes it difficult to simulate by analytical or numerical techn...
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While it is well recognized that microstructure controls the physical and mechanical properties of a material, the complexity of the microstructure often makes it difficult to simulate by analytical or numerical techniques. In this paper we present a relatively new approach to incorporate microstructures into finite element modeling using an object-oriented finite element technique. This technique combines microstructural data in the form of experimental or simulated microstructures, with fundamental material data (such as elastic modulus or coefficient of thermal expansion of the constituent phases) as a basis for understanding material behavior. The object-oriented technique is a radical departure from conventional finite element analysis, where a "unit-cell" model is used as the basis for predicting material behavior. Instead, the starting point of object-oriented finite element analysis is the actual microstructure of the material being investigated. In this paper, an introduction to the object-oriented finite element approach to microstructure-based modeling is provided with two examples: SiC particle-reinforced At matrix composites and double-cemented WC particle-reinforced Co matrix composites. It will be shown that object-oriented finite element analysis is a unique tool that can be used to predict elastic and thermal constants of the composites, as well as salient effects of the microstructure on local stress state. (C) 2003 Elsevier Inc. All rights reserved.
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