1. Dr. Tom Moyer, NSWC/Carderock
Full Ship Shock Test Modeling
Dr. Tom Moyer, NSWC/Carderock
15 April, 2008
Highlight all text in each block and type in new info.

2. M&S For Ship UNDEX Response
Modeling & Simulation (M&S) Is Used By The Navy To Predict Ship Structure & Systems Response To Underwater Explosion Threats
Design & Qualification Of Ship Systems
Pre-Test Prediction Of Full Ship Shock Trial Response
M&S Being Evaluated For
More Extensive Use For Design & Qualification Of Ship Systems
Major Component In FSST Alternative(s)

3. Summary of Underwater Explosion Phenomena
Bulk Cavitation Region
Ocean Bottom
Bottom Reflected Wave
(Traveling partially through
bottom material)
(Traveling entirely
through water)
Water Surface
Surface Reflected
Wave
Spray Dome
Air
Plume SZ
Direct Shock
Waves
Burst
Bubble at first
Minimum
First Bubble
Pulse

4. DYnamic System Mechanics Advanced Simulation
DYSMAS
DYnamic System Mechanics Advanced Simulation
A fully-coupled hydrocode for simulating underwater explosion phenomena and their effects on naval structures

5. DYSMAS DYnamic System Mechanics Advanced Simulation.
GEMINI
Euler solver
Shock and Fluid Dynamics
DYNA-N &
PARADYN
Lagrange solvers
Structural Response
DFBEM
BEM solver
Bubble & Fluid Dynamics
Standard Coupler Interface
Fully Coupled Fluid-Structure Interaction
HYDROCODE FOR SIMULATION OF UNDERWATER EXPLOSION EFFECTS

6. DYSMAS V & V Approach Verification Procedure
Documentation of the DYSMAS code and its capabilities
Documentation of configuration management & model verification calculations
Documentation of laboratory and small-scale validation calculations
Comprehensive report applicable to UNDEX applications
Validation Procedure (Phase I - General Validation)
Acquire validation-quality UNDEX loading and hull response data for platform design and weapon lethality applications using surrogate ship
Pre- and post-test comparisons of DYSMAS simulations vs test data
Code validation against full-scale, realistic ship structure
Validation Procedure (Phase II - Application-specific Validation)
Design & acquire validation-quality UNDEX loading and response data for specific (local) platform structures
Code validation against design-specific concepts

7. TYPICAL DATA ANALYSIS Full Record 1/e * Pmax Shock Wave
Shock Wave (extended)
1st Bubble Pulse

8. EFSP

9. Lagrangian Model
16,165 Nodes
21,053 Elements

10. Results – Innerbottom, Vertical Velocity Below FWD STBD Mount
8976
FWD

11. Eulerian Simulation T: 5.0 msec T: 5.4 msec T: 5.9 msec T: 6.8 msec

12. Lagrangian Simulation
T: 6.2 msec
T: 10.0 msec
T: 13.2 msec
T: 50.0 msec

13. Innerbottom Vertical Acceleration DYSMAS vs EFSP Test
FWD
60 lbs HBX, 20 ft Hrz Stdf

14. DYSMAS/SUMMARY
DYSMAS Is Widely Used In Navy Community For UNDEX Simulations
2007 JASON Review Concluded
Good Agreement With Liquid Response
Good Agreement With Short-time Structural Response
Structural Response [After Initial Impulse] Can Be Improved
A validated M&S could evaluate/improve component-testing methodology

15. Beyond DYSMAS => CREATE
DYNA_N/PARADYN Lack Many Of The FEM Features Needed For Improved UNDEX Simulations
DYNA_N/PARADYN Employ Antiquated Software Constructs
Maintenance Difficult/Time Consuming
Adapting To Evolving Computer Hardware Challenging
Gemini Is Sufficiently Validated & Employs Modern Software Engineering Constructs
Standard Coupler Interface Limits Calculation Scaling On Parallel Platforms
SOLUTION: Develop Gemini/Lagrange Solver
With Parallel Coupling

16. CREATE Objectives For UNDEX
Develop Robust Computational Capability To Predict
Response Of Surface Ships & Submarines To UNDEX Loading
System/Component Environments
Structural Response & Damage
Scenarios
Stand-Off UNDEX
Close-In UNDEX
SURFEX
Interface w/ Ship State Modeling
ASAP/ARM
FASST 16

17. CREATE USE CASE I Standoff UNDEX Response
Objective: Quantify ship response to standoff UNDEX shot geometries
Problem Characteristics:
Linear-elastic hull structure (no appreciable damage)
Point-to-point non-linear elements (e.g., shock mounts)
Linear-elastic equipment & system response
End-User Products
Quantify equipment location shock environments
Specifications for isolation systems (mounts & rafts)
Develop more-representative equipment qualification environments for component-level testing

18. CREATE USE CASE I Standoff UNDEX Response
Capabilities from CREATE program:
Integrated modal analysis capability
Integrated (implicit) static pre-calculation capability
Hydrostatic pre-stress, static bending moment
Optimized explicit code solution procedure for pure linear-elastic problems
Bulk of design cases
Improved modal characteristics of equipment & systems
Enables smoother, more accurate incorporation of vendor sub-models
Results Synthesis => Design Requirements, Performance Assessments, Design Modifications
Fully Integrated With Ship Design Tools
Includes Integration w/ ASAP/ARM
Development of “REPLAY” strategies
Meets All Requirements For FSST Replacement Calculations
Doesn’t linear elastic focus make implicit mechanics critical?

19. CREATE USE CASE II Severe UNDEX Response
Objective: Quantify equipment response and damage to more severe shot geometries
Problem Characteristics:
Non-linear hull structure response
Point-to-point non-linear elements (including shock mount bottoming)
Non-linear equipment and system response
End-User Products
Equipment and system damage and operability assessments
Hull structural performance
LFT&E Assessments (w/ limitations)

20. CREATE USE CASE II Severe UNDEX Response
Capabilities from CREATE program:
Includes list from Use Case I
Multi-length scale modeling strategies
All-up simulation capability
Telescoping analysis strategies
Applications using “REPLAY” functions
Fragility assessment capability
Enables design margins to be assessed
Enhanced Mission Effectiveness Assessment
Enhanced Results Synthesis Methodology
Quantification Of Margin & Uncertainty

21. CREATE USE CASE III LFT&E Assessments
Objective: Quantify ship structural damage due to LFT&E UNDEX scenarios
Problem Characteristics:
Extremely Non-linear hull structure response
Large hull deformations w/ Significant Contact & Significant Material Failure
Time Evolutionary Structural Degradation
End-User Products
Primary structural damage
Cascading structural damage effects
Equipment and system damage and operability assessments

22. CREATE USE CASE III LFT&E Assessments
Capabilities from CREATE program:
Improved failure models & failure criteria
Damaged based failure models
More-accurate damage progression
Energy conserving damage propagation
More-accurate damage patterns
Fracture based damage models (perhaps)
Particle methods (perhaps)
More-accurate contact algorithms
No miss contact detection
Energy/Momentum conserving forces

23. Technical Approach
Integrate Gemini Into Evolving SIERRA Architecture From SNL
Leverage Existing Substantial DOE Commitment
Evolve SIERRA To Address
More Efficient Parallel Workload Distribution
General, Scale-able Euler/Lagrange Coupling
Enhance Lagrange Capabilities In SIERRA For UNDEX Requirements
Robust Structural Element Library
Multi-Length Scale Modeling
Modal Sub-Structuring (CMS) …

24. CREATE/UNDEX Development Team Organization
CREATE UNDEX Navy Lead
CREATE UNDEX M&S Development
NSWC/CD Lead
Leveraged Related Programs
ONR
NAVSEA
OSD
Board Of Advisors
Navy Technical Authority
PEO Ships
PEO Carriers
PEO Submarines
Subject Matter Experts
Software Design Working Group
SNL Lead
Langrange Element Working Group
Euler Element Working Group
NSWC/IH Lead
Results Synthesis Working Group

25. CREATE/UNDEX Schedule

26. Summary
DYSMAS Provides Navy UNDEX Response M&S Capability Sufficient For
FSST Alternative
Limited System Design/Qualification Support
Limited Structural Damage Prediction Capability
CREATE/UNDEX Capability Will
Expand Application For System Design/Qualification
Enhance LFT&E Assessments
Support Design Of Cheaper & Safer Ships