VEHICLE TECHNOLOGY DIRECTORATE Crash Simulation of a Vertical Drop Test of a B737 Fuselage Section...

VEHICLE TECHNOLOGY DIRECTORATE

Crash Simulation of a Vertical Drop Test of a B737 Fuselage Section with Overhead Bins

Karen E. Jackson and Edwin L. FasanellaUS Army Research Laboratory

Vehicle Technology DirectorateNASA Langley Research Center

Hampton, VA 23681

Third Triennial Aircraft Fire and Cabin Safety ConferenceAtlantic City, New Jersey

October 22-25, 2001

• In November of 2000, the FAA performed a 30-ft/s vertical drop test of a 10-ft. long fuselage section of a Boeing 737 (B737) transport aircraft

• The fuselage section was outfitted with two different commercial overhead stowage bins and luggage

• The objective of the test was to evaluate the dynamicThe objective of the test was to evaluate the dynamic response of the overhead bins in a narrow-body response of the overhead bins in a narrow-body transport fuselage section subjected to a severe, but transport fuselage section subjected to a severe, but survivable, impact eventsurvivable, impact event

• This test also provided a unique opportunity to evaluateThis test also provided a unique opportunity to evaluate the capabilities of computational tools for crash the capabilities of computational tools for crash simulation simulation

Introduction and Background InformationVEHICLE TECHNOLOGY DIRECTORATE

• To develop a finite element model of the fuselage section suitable for execution in a crash simulation

• Perform a crash simulation using the nonlinear, explicit transient dynamic code, MSC.Dytran, and generate pre-test predictions of fuselage and overhead bin dynamic responses

• Validate the model through extensive analytical and experimental correlation

• Assess simulation accuracy and suggest changes to the model for improved correlation

ObjectivesVEHICLE TECHNOLOGY DIRECTORATE


Vertical Drop Test of a B737 Fuselage Section

Pre-test photographPre-test photograph

• 10-ft. long section of a B737-100 transport aircraft from FS 380 to FS 500, weighing 1, 360-lbs.

• Six triple-occupant passenger seats with test dummies and mannequins

• 3,229-lbs. of luggage

• Two different commercial overhead stowage bins loaded with wood

• 14-ft. drop test onto wooden platform for 30-ft/s vertical velocity

• ≈140 channels of data collected at 10,000 samples per second



Heath Tecna Overhead Bin

Forward

FS 400 FS 420 FS 440 FS 460 FS 480



Hitco Overhead Bin

Forward

FS 440FS 460FS 480 FS 420 FS 400


Asymmetry in the Test Article

Seat rails

Seats

Rear

Front

RightLeft

Floor Plan View Schematic Photograph of the Cargo Door



Post-test Photographs

Right-sideRight-sideseat failureseat failure

Asymmetric deformationof the lower fuselage


MSC.Dytran Model Development

Crash Simulation of the Vertical DropTestof the B737 Fuselage Section

• Model geometry was developed from hand measurements, i.e. no engineering drawings available

• Model contains 9, 759 nodes and 13,638 elements, including 9, 322 shell and 4, 316 beam elements

• Seats, dummies, cameras, luggage, and plywood in bins modeled using concentrated masses

• Material properties were estimated using engineering judgementFront view of model


MSC.Dytran Model of the Heath Tecna Bin


Three-quarter view

Side view

Front view


MSC.Dytran Model of the Hitco Bin


Side view

Front viewThree-quarter view



• Rigid impact surface was added to represent the wooden platform

• 3 master-surface to slave-node contact surfaces were defined between: - the impact surface and lower fuselage structure - the Heath Tecna bin and the upper fuselage structure - the Hitco bin and the upper fuselage structure

• The model was executed for 0.2 seconds of simulation time, requiring 36 hours of CPU on a Sun Ultra Enterprise 450 workstation computer

MSC.Dytran Model Execution

Three-quarter viewof model


Analytical and Experimental Correlation

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Exp. (ch 218)Dytran (node 3974)

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Acceleration, gAcceleration, g

Time, s Time, sLeft outer seat track Left inner seat track

Vertical Acceleration Responses of the Left-Side Inner and Outer Seat Track at FS 484



Vertical Acceleration Responses of the Right-Side Inner and Outer Seat Track at FS 484

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Acceleration, g Acceleration, g

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Right outer seat track Right inner seat track



Vertical Velocity Responses of the Left- and Right-Side Outer Seat Track at FS 418

Left outer seat track Right outer seat track

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Left outer seat trackMSC.Dytran

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Right outer seat trackMSC.Dytran

Velocity, ft/s

Time, s

Velocity, ft/s

Time, s



Vertical Acceleration Responses of the Left- and Right-Side Lower Side Wall at FS 480

Left-side lower side wall Right-side lower side wall

Acceleration, g

Time, s

Acceleration, g

Time, s

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ExperimentAnalysis

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ExperimentAnalysis


Axial Force Responses of the Vertical SupportRods HT-1 and HT-3 of the Heath Tecna Bin

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Axial Force, lbs.

Time, s

Axial Force, lbs.

Time, s

Forward support rod, HT-1 Rear support rod, HT-3

Measured tensile failure load = 1,656 lbs.


Axial Force Responses of the .616-in. DiameterSupport Rods H-1 and H- of the Hitco Bin

Axial Force, lbs.

Time, s

Axial Force, lbs.

Time, s

Support rod, H-1 Support rod, H-2

Measured tensile failure load = 5,350 lbs.

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ExperimentAnalysis

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ExperimentAnalysis



Predicted Structural Deformation

Time = 0.0 s Time = 0.06 s Time = 0.09 s

Time = 0.12 s Time = 0.15 s Time = 0.18 s

Concluding Remarks

• A finite element model of the B737 fuselage section with overhead bins and luggage was developed and pre-test predictions of fuselage and bin responses were generated

• The model was generated from hand measurements of fuselage geometry (no engineering drawings were available)

• Predicted floor-level acceleration responses compared favorably with experimental data with peak acceleration values with ±5-g

• Integrated velocity comparisons indicate that the model is too stiff and removes velocity more quickly that the test

• Deformed plots of the model indicate excessive deformation of the lower fuselage structure into the cargo hold


Ongoing ResearchVEHICLE TECHNOLOGY DIRECTORATE

• Incorporate platform model

• Model luggage physically using solid elements

• Add rotation springs at joints between bin linkages

• Modify material properties

• Rediscretize model in certain regions

• Examine the effect of the contact penalty factor

Suggested Model Improvements

Fuselage Model with Platform

Fuselage Model with Luggage

AcknowledgementsVEHICLE TECHNOLOGY DIRECTORATE

• This research was performed under an Inter Agency Agreement DTFA03-98-X-90031, established in 1998, between the US Army Research Laboratory, Vehicle Technology Directorate and the FAA William J. Hughes Technical Center.

• The technical support and contributions provided by Gary Frings, Tong Vu, and Allan Abramowitz of the FAA are gratefully acknowledged.

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