dyna caeassociates
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LS-D naat
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Overview
z Experience with LS-Dyna for Dynamics Modeling CAE Associates engineers have nearly 30 years of experience using explicit dynamics
finite element codes for complex design and analysis applications. Their experiencewith these codes began in 1975 at Pratt and Whitney Aircraft when the WHAMcode was first used to model jet engine foreign object damage and containment. Atthat time, WHAM only supported shell elements and did not have any contactcapabilities. Dr. Kenneth Brown, currently working with CAE Associates, developedand implemented contact capabilities for WHAM, as well as adding a membraneelement for analysis of Kevlar containment designs.
In the early 1990s DYNA3D superseded WHAM as the impact software of choice forthese applications, due to its more complete library of elements and contact
capabilities. Dr. Brown was one of several developers nationwide to use the publicdomain, Lawrence-Livermore version of DYNA. He continued to provide codeimprovements, including development of a PC version of DYNA and a fabricconstitutive model for Kevlar containment applications. This model was included inthe Livermore version of Dyna (LS-Dyna) as Material Type 41 (Fabric with Damage).
He also calculated numerous material coefficients from test data using regressionfitting techniques for a variety of applications, including:
Bammann model coefficients for Titanium containment applications, including strain rate and thermalsoftening effects.
Johnson-Cook models for ballistic impact applications.
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Mooney-Rivlin and Ogden models for sporting goods applications.
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Overview
ANSYS for use with LS-Dyna. Particular areas of expertise include brick-only meshing techniques,mesh distribution methods considering
definition, element type selection, load curve application,and
hourglass control methods. Other strengths include the ability toidentify and correct several common problems associated with highspeed impact analysis in LS-Dyna, including the following:
Over-penetration of one body into another
Excessive run times
High hourglass energies
Initial contact penetration
Solution instabilities often associated with out-of-range velocities errors
z CAE Associates has also provided consulting and training in explicitd namics finite element methods for man ears.
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Overviewz Training in LS-Dyna, Finite Element Analysis, Dynamics, and other
CAE Associates provides training classes in the following areas: ANSYS/LS-Dyna for Explicit Dynamics Analysis
ANSYS Dynamics Modal, Harmonic, Transient, and Random Vibration Methods
Finite Element Best Practices
Introduction to ANSYS
Advanced ANSYS Nonlinear Analysis, Contact, and Bolt Pretension
ANSYS Parametric Design Language (APDL)
ANSYS Heat Transfer
ssoc a es eng neers ave rece ve ra n ng rom e eve opers o - yna vermoreSoftware Technology Corporation) in the application of ALE (Arbitrary Lagrangian Eulerian),SPH (Smooth Particle Hydrodynamics), and manufacturing simulation methods. CAEA engineers
have also received training in the use of LS-Dyna for general transient modeling applications,includin im act anal ses.
All CAE Associates engineers have M.S. and/or Ph.D. degrees in Mechanical Engineering. Theyhave received training in general materials science, dynamics, and finite element analysisthrough a range of undergraduate and graduate level courses, including the following:
Materials Science Fatigue and Fracture of Materials
Advanced Mechanics of Materials
Advanced Dynamics
Finite Element Methods
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Plasticity
Advanced Fluid Mechanics
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Overview
z Partial List of Consulting Projects Utilizing LS-Dyna
eve ope numerous pro ec e mpac mo e s or e . . rmy us ng agrang an,
multimaterial ALE, and SPH modeling methods. Numerous material models wereinvestigated for the projectiles, soft targets, and hard targets.
Performed LS-Dyna analyses of a helicopter clutch assembly to predict the potentialfor slipping during torque application.
Provided drop test simulations of a nuclear spent fuel cask using ANSYS/LS-Dyna topredict the potential for loss of containment at several different drop orientations
. ,and they were reviewed and approved by the NRC.
Developed LS-Dyna models for Pratt & Whitney Aircraft to simulate fan bladeloss,containment, and bird ingestion. These included pre-stress, complex contact
e n ons, an g s ra n ra e ma er a mo e s. ese mo e s were use opredict failure in existing and proposed containment case, blade, and disk designs.
Provided sporting goods design analyses of golf balls, basketballs, soccer balls, golf
clubs, and softball bats. These allowed for predictions of dynamic behavior of
existing and proposed designs to reduce prototype testing.
Predicted knuckle pullout strength of concrete decking in support of NISTs WorldTrade Center investigation.
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eve ope - yna mo e s o attery eep raw ng processes, arter a stentinsertion, drop-testing of surgical devices, accident simulations.
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LS-Dyna Analyses at CAE Associates
Lagrange and multi-material ALE gelatin block models
Many different gelatin material models were investigated:
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Strain-rate dependent plasticity
Fluid
Simplified rubber (Ogden hyperelastic)
Piecewise linear plasticity
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LS-Dyna Analyses at CAE Associates
Lagrange gelatin block and bullet
Eroding gelatin elements
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LS-Dyna Analyses at CAE Associates
A Multi-material Arbitrary Lagrange-Eulerian (ALE) method was used forthe copper block. This allows the copper to flow at impact.
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LS-Dyna Analyses at CAE Associates
A Multi-material ALE method was used for the projectile.
A Johnson-Cook material model was used for the lead
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LS-Dyna Analyses at CAE Associates
High velocity impact of a copper cylinder onto a lagrange steel plate.
A Johnson-Cook material model was used for the copper.
hydrodynamics) to evaluate the ability of this method for predictingfragmentation.
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LS-Dyna Analyses at CAE Associates
CAE Associates developed a LS-Dyna model to simulate the dynamics of abullet traveling through a barrel. Meshing methods were developed to
enerate riflin rooves in the barrel. Pressure curves were a lied to thebase of the bullet and to the interior of the barrel. The copper jacket of
the bullet was modeled with a plasticity material law to allow for theformation of grooves as it enters the barrel.
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LS-Dyna Analyses at CAE Associates
z eren a on o me- s ory resu s o o a n u e ve oc es
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LS-Dyna Analyses at CAE Associates
Johnson-Cook and Bamman material models were investigated.
This model was used to calibrate the material laws and showed the correct.
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LS-Dyna Analyses at CAE Associates
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LS-Dyna Analyses at CAE Associates
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LS-Dyna Analyses at CAE Associates
model
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LS-Dyna Analyses at CAE Associates
A shape memory material model was used for the Nitinol
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LS D A l CAE A i
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LS-Dyna Analyses at CAE Associates
Looking at backspin and sidespin for a toe hit
Multilayer molded golf ball models were generated using Mooney-Rivlin-.
clubs were developed to predict their dynamic behavior with the goal of
reducing prototype testing.
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LS D A l t CAE A i t
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LS-Dyna Analyses at CAE Associates
Spent fuel shipping and storage casks must go through a detailedanalytical evaluation to gain certification.
casks using ANSYS/LS-DYNA explicit dynamics software.
The analyses include a simulation of the slapdown effect with materialmodels that include crushing of the concrete pad. Experimental data wasused to validate the finite element models.
The analyses performed by CAE Associates for their client were reviewed
by the NRC and approved without any follow-up required.
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LS D A l t CAE A i t
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LS-Dyna Analyses at CAE Associates
Cask Model for End Drop
Soil
Concrete Pad
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LS D A l t CAE A i t
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LS-Dyna Analyses at CAE Associates
End cask drop: Displacements after impact
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LS D A l t CAE A i t
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LS-Dyna Analyses at CAE Associates
Side impact with slapdown
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Stress results after impact: Simplified model of internals
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LS D na Anal ses at CAE Associates
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LS-Dyna Analyses at CAE Associates
Quasi-static analysis using critical damping to minimize dynamic effects Alpha damping applied to minimize local oscillations in the flexible spring
(some Beta dam in also added)
Mass scaling used to speed up the run time
Torque applied as pressures to the spline faces Cylinder pushed over the spring with a sine wave velocity curve
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LS Dyna Analyses at CAE Associates
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LS-Dyna Analyses at CAE Associates
Quasi-static analysis
Plasticity material model with considerable strain
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LS Dyna Analyses at CAE Associates
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LS-Dyna Analyses at CAE Associates
Quasi-static analyses
Material models included cracking and crushing in the concrete, and
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LS Dyna Analyses at CAE Associates
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LS-Dyna Analyses at CAE Associates
Modeled walls both with and without rebar.
An air blast load was applied based on an equivalent weight of TNT.
used.