scholarly journals A Hierarchical Multiscale Modeling Investigation on the Behavior of Microtextured Regions in Ti-6242 α/β Processing

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 233
Author(s):  
Ran Ma ◽  
Timothy Truster
Keyword(s):  
Multiscale Modeling ◽  
Multiscale Model ◽  
Orientation Distribution ◽  
Initial Orientation ◽  
Modeling Framework ◽  
Initial Microstructure ◽  
Loading Direction ◽  
Creep Fatigue ◽  
Strain Paths ◽  
Hierarchical Multiscale

Ti-6242 is a near alpha titanium alloy, which has excellent high-temperature creep resistance and is widely used in jet engine compressors. This alloy is susceptible to creep fatigue failure under dwell loading below 473 K. The existence of microtextured regions (MTRs) contributes significantly to this fast crack propagation. Mechanical processing in the alpha + beta region has been employed to eliminate MTRs, but the efficiency depends significantly on the applied strain path. Previous investigations based on crystal plasticity finite element (CPFE) simulations have demonstrated the relationship between breakdown efficiency and loading direction. Therein, MTRs with regular geometry and pure initial orientation were used to isolate the effect of loading direction from initial microstructure. In this paper, the behavior of MTRs with realistic initial microstructure was investigated using a hierarchical multiscale modeling framework, and the microscale results were analyzed in detail to understand the behavior of MTRs under different loading conditions. It was shown that a hierarchical multiscale model with realistic initial microstructure at the microscale can reflect the influences from different strain paths, initial orientation distributions, and positions of the region simultaneously. The combined effect of initial orientation distribution and loading direction on the MTR breakdown efficiency is discussed in detail.

A PERIDYNAMICS FORMULATION BASED HIERARCHICAL MULTISCALE MODELING APPROACH BETWEEN CONTINUUM SCALE AND ATOMISTIC SCALE

2012 ◽  
Vol 01 (03) ◽  
pp. 1250029 ◽  
Author(s):  
R. RAHMAN ◽  
A. HAQUE
Keyword(s):  
Multiscale Modeling ◽  
Continuum Model ◽  
Molecular Model ◽  
Multiscale Simulation ◽  
Coupling Method ◽  
Fine Scale ◽  
Modeling Framework ◽  
Multiscale Modeling Framework ◽  
Hierarchical Multiscale ◽  
Nonlocal Force

In this paper, a multiscale modeling framework has been established between peridynamics and atomistic models. Peridynamics (PD) formulation is based on continuum theory implying nonlocal force based interactions. Peridynamics (PD) and molecular dynamics (MD) have similarities since both use nonlocal force based interaction. It means continuum points in PD and MD atoms are separated by finite distance and exert force upon each other. In this work PD based continuum model of epoxy polymer is defined by meshless Lagrangian particles. MD is coupled with PD based continuum model through a hierarchical multiscale modeling framework. In this framework, PD particles at coarse scale interact with fine scale PD particles by transferring pressure, displacements and velocities among each other. Based on the same hierarchical coupling method, fine scale PD model is seamlessly interfaced with molecular model through an intermediate mesoscale region i.e. coarse-grain atomic model. At the end of this hierarchical downscaling, the information — such as deformation, energy and other important parameters — were captured in the atomistic region under the applied force at micro and macro regions. A two-dimensional plate of neat epoxy was considered for demonstration of such multiscale simulation platform. The region of interest in the 2D plate was interfaced with atomistic model by applying the proposed hierarchical coupling method. The results show reasonable consistency between PD and MD simulations.

scholarly journals Hierarchical multiscale model for biomechanics analysis of microfilament networks

2013 ◽  
Vol 113 (19) ◽  
pp. 194701 ◽  
Author(s):  
Tong Li ◽  
Y. T. Gu ◽  
Xi-Qiao Feng ◽  
Prasad K. D. V. Yarlagadda ◽  
Adekunle Oloyede
Keyword(s):  
Multiscale Model ◽  
Hierarchical Multiscale

A Multiscale Approach to Modeling the Passive Mechanical Contribution of Cells in Tissues

2013 ◽  
Author(s):  
Victor K. Lai ◽  
Mohammad F. Hadi ◽  
Robert T. Tranquillo ◽  
Victor H. Barocas
Keyword(s):  
Extracellular Matrix ◽  
Soft Tissues ◽  
Multiscale Model ◽  
Tissue Mechanics ◽  
Multiscale Approach ◽  
Cellular Solids ◽  
Comprehensive Model ◽  
Modeling Framework ◽  
Tissue Biomechanics ◽  
Tensegrity Model

In addition to their obvious biological roles in tissue function, cells often play a significant mechanical role through a combination of passive and active behaviors. Phenomenological and continuum modeling approaches to understand tissue biomechanics have included improved constitutive laws that incorporate anisotropy in the extracellular matrix (ECM) and/or cellular phenomenon, e.g, [1]. The lack of microstructural detail in these models, however, limits their ability to explore the respective contributions and interactions between different components within a tissue. In contrast, structural approaches attempt to understand tissue biomechanics by incorporating microstructural details directly into the model, e.g., the tensegrity model [2], cellular solids models [3], or biopolymer models [4]. Research in our group focuses on developing a comprehensive model to predict the mechanical behavior of soft tissues via a multiscale approach, a technique that allows integration of the microstructural details of different components into the modeling framework. A significant gap in our previous models, however, is the absence of cells. The current work represents an improvement of the multiscale model via the addition of cells, and investigates the passive mechanical contribution of cells to overall tissue mechanics.

Effect of Strain Path and the Magnitude of Prestrain on the Formability of a Low Carbon Steel: On the Textural and Microtextural Developments

2004 ◽  
Vol 126 (1) ◽  
pp. 53-61 ◽  
Author(s):  
S. K. Yerra ◽  
H. V. Vankudre ◽  
P. P. Date ◽  
I. Samajdar
Keyword(s):  
Carbon Steel ◽  
First Generation ◽  
Biaxial Tension ◽  
True Strain ◽  
Low Carbon Steel ◽  
Orientation Distribution ◽  
Deformation Texture ◽  
Low Carbon ◽  
Normal Anisotropy ◽  
Strain Paths

A low carbon steel (0.07-wt % carbon) sheet metal was deformed in five different strain paths, from equi-biaxial tension to plane strain to near uniaxial tension, by in-plane stretching. Textural developments were characterized by X-ray Orientation Distribution Function (ODFs) and the same were simulated using different Taylor type deformation texture models. A strong difference in bulk texture developments was observed at respective strain paths. The textural differences largely explain the changes observed in normal anisotropy values obtained by mechanical testing. The new deformation texture simulation model, Lamel, was quite successful in predicting quantitatively such textural differences. Microscopically, the significant features of the substructures were “strain localizations”—first generation dense dislocation walls (DDWs) and micro bands (MBs). Both in-grain rotations and estimated stored energies did depend on the relative appearance of such strain localizations. These, on the other hand, were distinctly related to the textural softening or dM/dε, where M and ε are the Taylor factor and true strain, respectively.

Review of Hierarchical Multiscale Modeling to Describe the Mechanical Behavior of Amorphous Polymers

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
J. L. Bouvard ◽  
D. K. Ward ◽  
D. Hossain ◽  
S. Nouranian ◽  
E. B. Marin ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Multiscale Modeling ◽  
Coarse Graining ◽  
Amorphous Polymers ◽  
Multiscale Methods ◽  
Structure Property ◽  
Lightweight Materials ◽  
Structure Property Relationships ◽  
Modeling Strategy ◽  
Hierarchical Multiscale

Modern computational methods have proved invaluable for the design and analysis of structural components using lightweight materials. The challenge of optimizing lightweight materials in the design of industrial components relates to incorporating structure-property relationships within the computational strategy to incur robust designs. One effective methodology of incorporating structure-property relationships within a simulation-based design framework is to employ a hierarchical multiscale modeling strategy. This paper reviews techniques of multiscale modeling to predict the mechanical behavior of amorphous polymers. Hierarchical multiscale methods bridge nanoscale mechanisms to the macroscale/continuum by introducing a set of structure-property relationships. This review discusses the current state of the art and challenges for three distinct scales: quantum, atomistic/coarse graining, and continuum mechanics. For each scale, we review the modeling techniques and tools, as well as discuss important recent contributions. To help focus the review, we have mainly considered research devoted to amorphous polymers.

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