1. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA 1 Summer Internship 2011 Peter M. Mancini Los Alamos National Laboratory, XTD-1 Los Alamos, New Mexico USA LA-UR-11-04080

2. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA What is LANL? Los Alamos National Laboratory Founded in 1943 in Los Alamos, New Mexico Manhattan Project 2

3. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA 3

4. First Atomic Bombs 4 Fat ManLittle Boy

5. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA What Do You Want To Do? Research - Government/University Lab - Novel topics, laboratory work environment, no right or wrong answer Industry - Quality control - Improve/develop current designs - Manufacturing 5

6. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Where Do You Live? Companies in your city/state ~ 75% of the interns at LANL are from New Mexico Cheaper for the company: no travel expenses to go out there Companies here in Florida: Lockheed Martin (Orlando) Siemens (Orlando) Pratt and Whitney (West Palm Beach) o Certain hot spots for engineering i.e. Southwest U.S. has Sandia, LANL, Lawrence-Livermore National Lab 6

7. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Who Do You Know? Networking - Find and meet people who have jobs in your desired field or at the company you would like to work for - Ask around for open positions that are often not posted on a career website With the huge amount of “John Smiths” applying for these positions, a personal recommendation to an employer can do you wonders 7

8. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Stand Out Words from my mentor (who is also the recruiter for X-Division): “I would take a student with a lower GPA from a decent, top 50 school with some research over a 4.0 from MIT with no real experience.”  Most kids weren’t exceptionally qualified  Low GPA? No worries. There are openings for you  Worked with a UF sophomore  You may feel like you don’t know enough to contribute to the research, but most of what you need for the job will be taught to you or you will have to read up on in textbooks and papers 8

9. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Government Labs Unique projects Tons of interesting, optional lectures Friendly work environment Plenty of students (undergraduate and graduate) to interact with Mentors to guide you in your research 9

10. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Adventures 10

11. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Overview of Project 11 Long Rod Penetrators (LRP) - armor-piercing ammunition generally used as anti-tank rounds  Uses high kinetic energy to penetrate target  Applies large force over small area to significantly exceed target’s yield strength  Generally use Tungsten or Uranium alloys, due to high density (~18 ) Uniqueness of problem: Semi-infinite target to model final penetration No residual velocity Due to normal impact of penetrator, simulation can be run as a quarter of the model

12. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Experimental Data 12 G. Silsby, Penetration of Semi-Infinite Steel Targets By Tungsten Long Rods at 1.3 to 4.5 km/s, Eighth International Symposium on Ballistics (October 1984)

13. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA 13 PAGOSA PAGOSA is a multi-dimensional / multi-material Eulerian hydrocode  Accurately models high strain rate deformation  Staggered mesh (U V W at vertices, P ρ e S ik at cell centers)  Multi-material (arbitrary number of materials per cell)  Young’s interface reconstruction for each material in each cell

14. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA 14 PAGOSA Equations of State Void Ideal gas analytic equation Polynomial Mie-Grüneisen ( Us / Up ) Osborne analytic Becker-Kistiakowsky-Wilson (BKW ) SESAME, tabular EOS including phase changes Jones-Wilkins-Lee (JWL ), analytic EOS for explosive materials Reactive High Explosive (HE) Burn Models : BKW-HE, JWL-HE

15. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA 15 PAGOSA Strength Models “Hydrodynamic” (no strength) Elastic-Perfectly-Plastic Johnson-Cook (JC) Modified Steinberg-Cochran-Guinan (mod SCG) Steinberg-Cochran-Guinan (SCG) Kospall (SCG with additional thermal softening terms) Preston-Tonks-Wallace (PTW) Modified Preston-Tonks-Wallace (mod PTW) Mechanical Threshold Stress (MTS)

16. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Example of Mesh…( 1mm cell size ) 16 RHA ArmorVoid Tungsten Penetrator VoVo

17. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Visual 17 Model Space Target Interface Void Penetrator

18. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Mesh Convergence 18 Decreasing cell size increases accuracy but also increases computational run time Computational cost increases nonlinearly with decreasing cell size due to several factors:  Increased number of elements  Decreased integration time steps  Increased total number of integrations performed  Communication between the parallel processors

19. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Mesh Convergence 19

20. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Equation of State Comparison 20 Maintained constant strength model: o Target – Elastic Perfectly Plastic o Projectile – Elastic Perfectly Plastic EOS Evaluated: o Target – Us/Up, Polynomial o Projectile – Us/Up, Polynomial  Results relatively insensitive to EOS

21. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Flow Stress Models 21 Elastic Perfectly Plastic:  Material is linearly elastic  After yield, stress remains constant with increasing load  2 constants required for PAGOSA Steinberg-Guinan and Johnson-Cook:  Includes strain, pressure, and thermal softening  Function of strain rate  Accounts for strain hardening  7 constants required for PAGOSA

22. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Strength Model Comparison 22

23. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Hole Diameter 23 Simulation of hole created at 3.335 km/s Differently sized hole diameters

24. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA 24 Simulation Examples Simulations Low/High Velocity Shots Wave Propagation

25. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Low velocity: 1.291 km/s 25 *Time in microseconds (µs)*

26. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA High Velocity: 4.525 km/s 26 *Time in microseconds (µs)*

27. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Wave Propagation 27

28. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA 28 Conclusions 1 mm cell size provides converged data in a reasonable run time. Simulation data are generally insensitive of EOS At low velocities, results are sensitive to strength model At high velocities (> 3 km/s), the different models converge within 2% of each other and 5% of experimental data Hydrocode simulation accurately models actual physics of the penetration, i.e. residual material and stress wave propagation Equation of State Low Velocity High Velocity Projectile: Polynomial Polynomial Target: Mie-Grüneisen (UsUp) Mie-Grüneisen (UsUp) Strength Form Low Velocity High Velocity Projectile: Johnson-Cook Steinberg-Guinan Target: Johnson-Cook Elastic Perfectly Plastic

29. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Future Work 29  Run more data points to get a smooth curve  Search for different and/or more accurate EOS, strength, and fracture models, i.e. SESAME, Osborne, Johnson-Cook Damage  Compare other experimental data.  Add different shaped tips to penetrator to see how it effects penetration geometry (depth, hole diameter, etc..)

30. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA 30 References 1.Wayne N. Weseloh, Sean P. Clancy, and James W. Painter, “PAGOSA Physics Manual,” Los Alamos National Laboratory report LA-14425-M (August 2010). 2.Wayne N. Weseloh, “PAGOSA Sample Problems,” Los Alamos National Laboratory report LA-UR-05-6514 (August 2005). 3.G. Silsby, Penetration of Semi-Infinite Steel Targets By Tungsten Long Rods at 1.3 to 4.5 km/s, Eighth International Symposium on Ballistics (October 1984) 4.Marc A. Meyers, “Dynamic Behavior of Materials,” John Wiley & Sons, Inc., 1994 5.Private communication, Shuh-Rong Chen (MST) and Wayne Weseloh (XTD-1), 8 July 2011

31. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA 31 Outline Introduction / Overview PAGOSA Mesh Convergence EOS Comparison Strength Model Comparison Simulation Examples i. Low/High Velocity Shots ii. Wave Propagation Conclusions Future Work http://www.dtc.army.mil/tts/1997/proceed/walton/walton.html

32. Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Materials 32 Experimental: Silsby (1984) Projectile: 90W-7Ni-3Fe alloy Yield Strength - 0.0119 Mbar (174 ksi) Rockwell C 40.6 hardness Density – 17.3 L/D = 23 - Initial Length (L) – 15.83 cm - Diameter (D) – 0.683 cm Target: Rolled homogeneous armor (RHA) 6 inch plate – BHN 270.4 8 inch plate – BHN 231.6 Simulation: PAGOSA Projectile: matname = “Tungsten” Yield Strength - 0.0119 Mbar (174 ksi) Shear Modulus - 1.6 Mbar Density – 17.3 L/D = 23 - Initial Length (L) – 15.83 cm - Diameter (D) – 0.683 cm Target: 6 inch plate - BNH 270.4  Yield Strength - 0.00917 (133 ksi)  Shear Modulus – 0.88 (88 GPa) 8 inch plate - BNH 231.6  Yield Strength - 0.007 (101 ksi)  Shear Modulus – 0.88 (88 GPa)