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Eshelby-FEM Shear Stress (τ) Summary

Anisotropic continuum simulations of Magnesium twin embryos: Pure Elliptical, Hexagonal Faceted, Circular, and 3D Spherical Twin Models.

Solver: ANSYS MAPDL 2025 R2 Applied Shear: 2.0% (γ = 0.02)

Infinite Matrix Limit τ (Ellipse)

-121.84 MPa

Pure Ellipse (AR 4:1) asymptotic shear stress as Ltwin / Lbox → 0

Infinite Matrix Limit τ (Circle)

-472.52 MPa

Circular twin asymptotic shear stress as Dtwin / Lbox → 0

Geometric Scaling Invariance

< 0.01% Δτ

Invariant τ across 2.0 μm, 4.0 μm, and 10.0 μm boxes at constant size ratio

3D 105nm Spherical Twin τ

-979.79 MPa

3D spherical inclusion under 2.0% applied shear strain

Shear Stress (τ) vs. Twin Size (2.0 μm Box)

Volume-averaged shear stress τ [MPa] plotted across geometries (12 nm to 520 nm).

Multi-Box Size Scaling of τ (Ellipse)

Boundary decay of τ across 2.0 μm, 4.0 μm, and 10.0 μm boxes.

1. 2D Shear Stress (τ) Results (2.0 μm x 2.0 μm Box)

Comparison of internal shear stress τ [MPa] across twin geometries under 2% applied shear (γ = 0.02, utop = 0.04 μm).

Twin Size Hexagonal Faceted Twin τ [MPa] Pure Elliptical Twin (AR 4:1) τ [MPa] Circular Twin τ [MPa]
12 nm-170.0425-121.8586-472.5684
25 nm-170.0848-121.9028-472.7451
36 nm-170.1584-121.9644-472.9916
50 nm-170.2816-122.0749-473.4338
75 nm-170.5965-122.3614-474.5813
105 nm-171.1404-122.8552-476.5628
210 nm-174.4351-125.8468-488.6676
340 nm-181.3553-132.1235-514.6526
520 nm-195.3888-144.8637-570.1479

2. Multi-Box Size Scaling & Geometric Invariant of τ

Applied shear displacement scales proportionally with domain box size (utop = γ × Lbox).

Twin Size Pure Ellipse τ (2.0 μm Box) Pure Ellipse τ (4.0 μm Box) Pure Ellipse τ (10.0 μm Box) Circular Twin τ (2.0 μm Box) Circular Twin τ (4.0 μm Box) Circular Twin τ (10.0 μm Box)
12 nm-121.8586-121.8487-472.5684-472.5287
25 nm-121.9028-121.8597-472.7451-472.5729
36 nm-121.9644-121.8751-472.9916-472.6345
50 nm-122.0749-121.9027-473.4338-472.7451
75 nm-122.3614-121.9745-474.5813-473.0321
105 nm-122.8552-122.0984-476.5628-473.5279
210 nm-125.8468-122.8552-488.6676-476.5628
340 nm-132.1235-124.4790-514.6526-483.1116
520 nm-144.8637-127.9382-122.8361-570.1479-497.2350-476.4862

• Geometric Invariance Highlight:

Holding the normalized ratio Ltwin / Lbox = 0.0525 constant yields identical shear stress across all scales:

• 105nm in 2.0 μm Box: τellipse = -122.8552 MPa, τcircle = -476.5628 MPa

• 210nm in 4.0 μm Box: τellipse = -122.8552 MPa, τcircle = -476.5628 MPa

• 520nm in 10.0 μm Box: τellipse = -122.8361 MPa, τcircle = -476.4862 MPa

3. 3D Spherical Twin Simulation (105 nm in 2.0 μm x 2.0 μm x 2.0 μm Box)

High-order 3D solid elements (SOLID186/SOLID187), 3D periodic boundary conditions, 2% applied shear.

Volume-Averaged Shear Stress τ

-979.7880 MPa

3D Sphere

Volume Conservation Accuracy

99.998%

Simulated V = 6.0612e-4 μm3