<p>This
study is concerned with the predictive modeling of the machining and the
mechanical behaviors of additive manufactured (AMed) Ti6AlV/TiC composites and
Ti6Al4V, respectively, using microstructure-based hierarchical multiscale
modeling. The predicted results could constitute as a basis for optimizing the
parameters of machining and AM of the current materials.</p>
<p>Through
hierarchical flow of material behaviors from the atomistic, to the microscopic
and the macroscopic scales, multiscale heterogeneous models (MHMs) coupled to
the finite element method (FEM) are employed to simulate the conventional and the
laser assisted machining (LAM) of Ti6AlV/TiC composites. In the atomistic
level, molecular dynamics (MD) simulations are used to determine the
traction-separation relationship for the cohesive zone model (CZM) describing
the Ti6AlV/TiC interface. Bridging the microstructures across the scales in
MHMs is achieved by representing the workpiece by macroscopic model with the
microscopic heterogeneous structure including the Ti6Al4V matrix, the TiC
particles, and their interfaces represented by the parameterized CZM. As a
result, MHMs are capable of revealing the possible reasons of the peculiar high
thrust forces behavior during conventional machining of Ti6Al4V/TiC composites,
and how laser assisted machining can improve this behavior, which has not been
conducted before.</p>
<p>Extending MHMs to predict the mechanical
behaviors of AMed Ti6Al4V would require including the heterogeneous
microstructure at the grain level, which could be computational expensive. To
solve this issue, the extended mechanics of structure genome (XMSG) is
introduced as a novel multiscale homogenization approach to predict the
mechanical behavior of AMed Ti6Al4V in a computationally efficient manner. This
is realized by embedding the effects of microstructure heterogeneity, porosity
growth, and crack propagation in the multiscale calculations of the mechanical
behavior of the AMed Ti6Al4V using FEM. In addition, the XMSG can predict the
asymmetry in the Young’s modulus of the AMed Ti6Al4V under tensile and
compression loading as well as the anisotropy in the mechanical behaviors. The
applicability of XMSG to fatigue life prediction with valid results is
conducted by including the energy dissipations associated with cyclic
loading/unloading in the calculations of the cyclic response of the material.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/12252851 |
| Date | 07 May 2020 |
| Creators | Mohamed G Elkhateeb (8802758) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY-NC-SA 4.0 |
| Relation | https://figshare.com/articles/thesis/Multiscale_Modeling_of_the_Mechanical_Behaviors_and_Failures_of_Additive_Manufactured_Titanium_Metal_Matrix_Composites_and_Titanium_Alloys_Based_on_Microstructure_Heterogeneity/12252851 |
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