In modern day industry, an emphasis of lean engineering has taken place in order to save time and resources while delivering better products than competitors. Furthermore, great strides in production and manufacturing have raised efficiency and saved companies time and money. However, testing and certification, although essential, can be a costly procedure in between the stages of design and production. In an effort to enhance and supplement the structural testing methods, specifically crash analysis, a simplified yet accurate FEA modeling method is developed to better understand a design performance during physical testing. However, the methodology will not be a substitute for real world certification testing, but rather a means to save time and money so as to offer performance and design insight. A critical area of performance is crash test analysis. The modeling method in this presentation was based upon crash conditions referenced from FAR 25.562 as well as physical test methods for crash analysis. Furthermore, this modeling method was directly compared to real world test data. The crash modeling utilizes HyperMesh, HyperCrash, and LS-DYNA so as to offer insight into structural performance.

1. Finite Element Modeling and Testing of
Aerospace Seats Under Crash Conditions
2012 Americas HyperWorks Technology Conference
Fady Barsoum Ph.D
Benjamin Walke (presenting)
Aditya Gupte
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2. Talking Points
 Motivation
 Simulation Standards
 Process Flowchart
 Key Functions
 Results
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3. Motivation
 Step-by-Step modeling method for effective
crash simulation
 Save time required to simulate a high-g crash
in conjunction with testing
 Allow for simulation of design changes to
improve safety
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4. Aircraft Seats
 Gulfstream
aircraft seats
 Pilot &
Passenger
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5. Simulation Standards
 Simplify the structure
and crash conditions with
the aim of a basic model
 Cushions removed
 2-point buckle
 Head on crash
 16G in 90ms
 170 lb Dummy
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6. Simulations Standards
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7. Flowchart
CAD
Pre-Processing
Explicit Dynamic
*Defeaturing
*Mesh HyperMesh
*BC HyperCrash
*Prescribed Motion
Solver
LS-DYNA
Post-
Processing
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8. Geometry
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9. Geometry
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10. 2D Geometry Integration
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11. Initial Mid-Surface
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12. Pre-Procesing in HyperMesh
Hole
Removal
Fillet and
Round
Defeaturing
Automatic
MidSurface
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13. Mesh
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14. HyperCrash
 Contact Modeling
 Dummy and Seat
 Belt and Dummy
 Seat Components
 Boundary Conditions
 Prescribed Motion
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15. Contact Modeling
Tied Surface to Surface
Automatic Surface to Surface
Automatic Nodes to Surface
Tied Shell Edge to Surface
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16. Boundary Conditions
Boundary Conditions set to allow only for translational
motion in the aft facing direction
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17. Sled Acceleration
0 50 100 150 200
-1 Time (milliseconds)
-3
-5
-7
G -9
-11
-13
-15
-17
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18. Post-Processing
0 ms 50 ms 100 ms
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19. Testing
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20. Future Analysis and Testing
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21. Conclusion
 Functions in HyperMesh and HyperCrash
greatly reduced our time to pre-process.
 We are close to the validation of simulation
data with test data, however more work must
be done.
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22. References
 Bala, Suri. Jim Daly. “General Guidelines for Crash Analysis in LS-
DYNA”
 Bhonge, Prasannakumar. “A Methodology for Aircraft Seat Certification
By Dynamic Finite Element Analysis.”
 “Getting Started with LS-DYNA.” (LSTC)
 LS-DYNA Keyword User’s Manual (LSTC)
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