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Example 3: Smoothed particle hydrodynamics (SPH) modeling for an impact problem
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EXAMPLE 3

2. Overview: SPH modeling
SPH modeling is available from Abaqus version 6.11.
Smoothed particle hydrodynamics (SPH)
A meshless Lagrangian technique, based on interpolation theory and smoothing kernel functions.
Fluid (impactor) is represented as a set of discrete interacting particles, which are independent from Lagrangian elements.
No mesh distortion of the fluid.
No solution domain to define a spatial mesh for fluid.
The method provide more accurate results than Lagrangian or coupled Eulerian-Lagrangian analyses when the deformation is too severe.
Application of SPH modeling
Effective for applications involving extreme deformation
In stead of the coupled Eulerian-Lagrangian modeling, SPH modeling can be used to reduce computational cost.
Example problems: Fluid sloshing, wave engineering, ballistics, spraying (as in paint spraying), gas flow, and obliteration and fragmentation followed by secondary impacts.
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EXAMPLE 3

3. PREPARED BY NORI. NANAMI, TEXAS A & M UNIVERSITY
Problem description
Direct impact problem
A soft body (5kg) with 50 m/sec impacts on the aluminum plate.
Aluminum plate
Dimensions: 1m× 1m× 0.002m
Material type: Linearly elastic behavior with isotropic hardening
Element : Shell elements (S4R)
Mesh size: 0.01m-0.05m
Boundary condition: Four edges are fully constrained.
Soft body impactor
Shape: cylinder with two hemispherical caps
Dimensions: 0.32 in length × 0.16 m in a diameter
Length/ diameter = 2
Material: Gelatin
Initial bird mass: 5 kg
Magnitude of initial velocity: VZ = -50 m/s
SPH particle elements (PC3D)
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EXAMPLE 3

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Part module: Target
Target structure
Model type: Shell model
Shape: Square plate
Dimensions: 1m× 1m
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EXAMPLE 3

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Part module: Impactor
Impactor
Model type: Solid model
Shape: Cylinder with hemispherical caps
Dimensions: 0.16 m in a diameter × 0.32 m in length
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EXAMPLE 3

6. Property module:Al2024 (aluminum)
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EXAMPLE 3

7. Property module: Gelatin
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EXAMPLE 3

8. PREPARED BY NORI. NANAMI, TEXAS A & M UNIVERSITY
Assembly/Step module
Coordinate
(0.5, 0.5, 0.01)
Coordinate
(0,0,0)
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EXAMPLE 3

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Interaction module
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EXAMPLE 3

10. Load module: Boundary conditions
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EXAMPLE 3

11. Load module: Initial conditions
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EXAMPLE 3

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Mesh module: Target
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EXAMPLE 3

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Mesh module: Impactor
The part with C3D8R, C3D6, or C3D4 elements or a combination of these elements can be converted to SPH particle elements (1-node PC3D element ).
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EXAMPLE 3

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Job module
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EXAMPLE 3

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Job module
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EXAMPLE 3

16. Visualization module : Velocities
Animation
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EXAMPLE 3

17. Visualization module : Displacements
Animation
Target: 0 <X < 0.8
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EXAMPLE 3

18. References: SPH modeling
SPH modeling is available from Abaqus version 6.11.
ABAQUS documentation: Abaqus Analysis User's Manual
“Smoothed particle hydrodynamic analyses,” Section 15.1
“Equations of state,” Section 25.2
“Section controls,” Section
“Particle elements,” Section 28.5
ABAQUS documentation: Abaqus Example Problems Manual
“Impact of a water-filled bottle,” Section 2.3.2
Journals/proceedings
Heimbs, S “Computational Methods for Bird Strike Simulations: a Review,” Comput. & Struct., 89(23-24):
McCallum, S.C. and C. Constantinou “The Influence of Bird-shape in Bird-strike Analysis,” presented at the 5th European LS-DYNA Users Conference, May 25-26, 2005.
Nanami, N. and O.O. Ochoa “Computational Assessment of Bird Strike on Hybrid Composite Wind Turbine Blade,” In: Proceedings of the American Society for Composites 27th Annual Technical Conference, Arlington, Texas, USA, October 1-3, 2012.
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EXAMPLE 3