container impact in water using ls-dyna
DESCRIPTION
Container Impact in Water Using LS-DYNA. Matt Wesley [email protected] University of Hawaii at Manoa 7/6/12. Outline. Beginning stages Model setups Results so far Future work. Beginning Steps. Learning to use LS-DYNA Running SMP or MPP - PowerPoint PPT PresentationTRANSCRIPT
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Container Impact in Water Using LS-DYNAMatt [email protected] of Hawaii at Manoa7/6/12
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Outline
• Beginning stages
• Model setups
• Results so far
• Future work
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Beginning Steps
• Learning to use LS-DYNA
• Running SMP or MPP• shared memory parallel or massive parallel processing
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Model Setup
• Need an accurate model to test in air and in water
• 1:5 scale of a 20ft shipping container
• Made from acrylic
48 in
Side view
48.5 in
20.4 in
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Solid or Shell Elements• Shell elements yield even at low velocities
• Solid elements hold up much better
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Acrylic Box Model• Material: PLASTIC_KINEMATIC• E=3.2 GPa• ρ=1200 kg/m3
• ν=0.37
• Dimensions:• Base: modeled as solid elements, thickness of 0.024 m• Base also has a lip, this is where the contact will be made
• Top: modeled as shell elements, thickness of 0.012 m
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Contact • First, created a wall with the same width as the
box• Used rigid material • Set it to be stationary
• Next, created a ‘load cell’• Used the same rigid material and made it stationary
• Varied the speed at which the box impacted
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Model verification• *A*v
• When contact area is the whole base:• Fact = 39800N • Fest = 39504N
• This is using an adjusted density of 3560 kg/m3
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Impact forces on a 0.1016m diameter cylinder
Estimation uses adjusted density of 5893 kg/m3
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.50
20000400006000080000
100000120000140000160000180000200000 Force vs Velocity
SimulationEstimation
Velocity (m/s)
Forc
e (N
)
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OSU test setup
• Viscous flow with an initial velocity
• BIG!!!
• Need to add a column with a ‘load cell’ and the acrylic box model
• Just using basic properties for now until the model works
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Problems• Need to void the interior of the box• *INITIAL_VOLUME_FRACTION_GEOMETRY
• What is the best ratio of ALE nodes per Lagrangian node
• Long run times!!!
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Timeframes
9 10 11 12 13 16 17 18 19 20 23 24 25 26 27 30 31 1 2
OSU test setup
empty inside of box
correct constraints on column and box
compare forces for in air and in water
final report
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Conclusion• Starting out with LS-DYNA
• Results so far
• Future work and problems
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Sources• Paczkowski, K. Riggs, H.R. Naito, C.J. Lehmann, A. A one-
dimensional model for impact forces resulting from high mass, low velocity debris. Structural Engineering and Mechanics. Vol. 42. No. 6. 2012. Pages 831-847.
• http://www.encyclopedia2.thefreedictionary.com/MPP
• LS-DYNA Theory Manual