THOR Mod Kit Update May Human Injury and Applied Biomechanics Research Divisions

Transcription

1 THOR Mod Kit Update May 2010 Human Injury and Applied Biomechanics Research Divisions

2 THOR Short Term Modifications List of Changes Generated from SAE THOR Task Group Mod Kit updates for head/neck, thorax, knee/femur/pelvis Contracts awarded in September 2009 Contracts to complete in May 2010 Abdomen refinement ongoing under different contract Lx : NHTSA testing 3 new sets of legs One NHTSA THOR-NT will have all upgrades and be ready for initial testing by June THOR drawings, THORTEST and BOM will be modified to reflect changes 2

3 3 Head/Neck Task Review Task List 1. Investigate need for center cable 2. Revise Occipital Condyle bolt design 3. Replace neck cable guides 4. Add landmarks to skin 5. Replace head tilt sensor 6. Investigate seven accelerometer array mount vibration issues 7. Check mass properties of head

4 Head/Neck Redesign Task 1 Examine possibility of removing center cable in neck Center neck cable cannot be removed. However, a compliant neoprene spacer has been inserted in place of the Delrin spacer. This has resulted in the neck static response being closer to the Duke university requirements. Also, neck has proved to be repeatable and durable. 4

5 Neck Extension Testing 5

6 Neck Tension Tests Quasi-static Quasi-static tension response of neck neck column pulled with external 1/8 cable attached to pneumatic test machine tested cable with nylon, Neoprene spacer, and without cable peak force ~ 1100N 6

7 Neck Tension Tests Quasi-static Linearized compliances compared (mm/n) standard cable: 9.7 x 10-4 no cable: 3.3 x 10-3 Neoprene: 2.7 x 10-3 std cable => 3.4 X no cable std cable => 2.8 X Neoprene Neoprene spacer 20% stiffer than no cable Duke results (different fixture): standard cable: 6.6 x 10-4 no cable: 2.5 x 10-4 std cable => 3.7 X no cable 7

8 Neck Tension Tests Quasi-static 8

9 Head/Neck Redesign Task 2 Simplify Design of OC Bolt OC bolt is similar to H-3 bolt. All washers and nut have been removed. More robust potentiometer attachment designed. Design modification did not change A-O joint static requirements. 9

10 Task 2: Redesign of O.C Bolt 10

11 Task 2: Quasi-static AO joint test 11

12 Head/Neck Redesign Task 3 Tilt sensor replacement Current design allows use of 2 biaxial tilt sensors. MSC 260D/GP IES 1402 dual axis tilt sensor 12

13 Head/neck Redesign Task 4 Noise issues in the head assembly Source of the noise was traced to the ballast. Ballast redesigned and is currently attached to the head casting by 4 bolts instead of 2 in the original design. Design allows more contact area between the head casting and ballast. Testing is in process. 13

14 Head/Neck Redesign Task 5 Improve spring cable adjustment and cable guides 2 halves of cable guide replaced with 1 piece guide. The design has been tested and has proved to be workable and easy to insert. Cable adjustment redesign in progress. 14

15 Redesign Cable Guides Split cylinder design with top lip Samples made of Delrin and Teflon Delrin appears to be robust and secure in initial check Teflon proved to be too compliant and easily removable 5/10/2010 GESAC, Inc 15

16 Head/Neck Redesign Task 6 Measure mass properties of the head Head mass and CG are within requirements. MoI is very close to specifications and some mass may have to be taken off to get MoI in corridor. 16

17 Head/Neck Redesign Task 7 Place landmarks on head skin Nasion, infra-orbital foramen, external auditory meatus, OC location and CG location landmarks have been integrated into the head skin. 17

18 Head Skin/Skull Model NT skull and skin converted to 3D controlled skin thicknessuniform over frontal and parietal sections any existing asymmetries removed maintain existing inertial properties engagement between skull and skin at multiple locations 18

19 New Head Skin and Cap Nasion C.G EAM IOF 19

20 New Parts - 1 Head casting and head cap Head skin and cap skin Head ballast Skull accelerometer mount O-C bolt assembly and potentiometer 20

21 New Parts - 2 Head accelerometer mount plate New tilt sensor 7 accelerometer array Neck cable guides Neck center cable spacer 21

22 Thorax Task Review Task List 1. Create clavicle load cell 2. Revise T1 accelerometer mount 3. Replacement of tilt sensor 4. Replace Crux Units with IR-TRACC instrumentation 5. Thorax performance Biofidelity test at 4.3 m/s Durability test at 6.7 m/s 6. Documentation updates 22

23 Clavicle Loadcell Two load cells (left and right) Load Cell Specifications Fx: 450 lbf Fz: 450 lbf Weight:.44 lbs Comply with SAE J211 and J2570 Structural replacement is equivalent to the load cell 23

24 T1 Accelerometer Mount Original design T1 accelerometer mount is far below the anatomic T1 location New design T1 accelerometer mount is close to anatomic T1 location Original design located under shoulder joint New Design 24

25 Replace Tilt Sensor Tilt sensor mount accommodate both IES and MSC tilt sensor. Top View ISO View 25

26 IR-TRACC Instrumentation All four IR-TRACCs are identical design. Two potentiometers are coupled with each IR-TRACC to measure the rotation along Y and Z rotations. Lower two IR-TRACCs have longer mounting extension to provide the same amount of range of motion as the upper two. Upper IR-TRACC and Pots Lower IR-TRACC and Pots 26

27 Pot Zeroing Fixture Potentiometer zeroing fixture compatible L/R, Upper/Lower IR-TRACC mounts Upper IR-TRACC Assembly Lower IR-TRACC Assembly 27

28 Upper IR-TRACCs IRTRACC can move 24º inboard without contact. Mounting point at sternum can move over 60 mm inboard along Y axis. NHTSA test data showed 58 mm lateral deflection maximum under a pure lateral loading condition. Position w/o Deformation 24º contact location 28

29 25 mm standoff used Lower IR-TRACCs Allows 60 mm inward lateral movement Position w/o Deformation Position at Contact 29

30 Comparison of Thorax Test with CRUX and 4.3 m/s Force (N) Calibration Corridor Left IR-TRACC Right IR-TRACC Left IR-TRACC Right IR-TRACC CRUX-1 CRUX-2 Spec Displacement (mm) 30

31 Durability Tests Five Tests were conducted at 6.7 m/s Tests were very repeatable No damage was observed after each tests Data was overlaid in the next few slides 31

32 Summary Double-Gibaled IRTRACC provides equivalent measurements to the CRUX. Weight and Center of Gravity of the thorax remains unchanged. Dummy performance remains unchanged. The design is robust and durable under 6.7 m/s impact test condition. Deliverables Dummy Parts installed on the dummy 3D CAD model and 2D drawing package Updated User s Manual Convert Kit Manual 32

33 Knee/Femur/Pelvis Task List Task 1: New 2-axis(Fx & My) ASIS load cell Task 2: Pelvis Flesh Revisions and Updates and retain mass properties Task 3: Revise Femur Puck and Knee Slider Stiffness Task 4: CAD Drawings and Final Report Task 5: Provide Hardware Kit for THOR 33

34 Developed Smallest Iliac Wing Load cell to date + The load cell measures the contact force (FX) of the belt against the iliac as well as the bending moment about the center of the load cell. The bending moment is an indicator of the belt position on the iliac. A positive moment indicates a belt position above center of the iliac and a negative moment indicates a belt position below the center of the iliac J ASIS Load Cell AXIS FX MY Capacity (Metric) 13 kn 325 Nm The FX force capacity was chosen to be 13 kn. This capacity is the same as for seat belt load cells typically used with Hybrid III 50th ATDs. The moment capacity was chosen based on the geometry of the iliac. The maximum moment that can be applied by the belt is the force x distance from the iliac center to the end of the bone. A distance of.025 M (25 mm) x 13 kn force capacity equals the moment capacity of 325 NM. 34

35 Modified Iliac Wings to fit Load Cell 35

36 Iliac Wing Load Cell Final Assembly 36

37 Revised Pelvic Flesh vs Original 37

38 THOR Femur Revisions 38

39 Target Femur Force-Deflection Response Force (kn) 16X stiffer 3X stiffer 0.5 kn/mm Hybrid III knee/femur THOR-NT knee/femur Upper bound TARGET Cadaver response corridor 3X 2X F 0.75 kn/mm Deflection (mm) From Rupp et al. (2003)

40 Revised Design Square Bearing 50mm Rubber Element Square Shaft WorldSID load cell 40

41 Femur Test Set Up 41

42 Final Results Force vs Displacement 60 Shore A Natural Rubber Femur Puck Compensated Force (N) Upper Corridor Lower Corridor Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test Displacement (mm) 42

43 Part Kits to update a current NT Pelvis flesh Pelvic Base Module (Illac wing mounting) Accelerometer/tilt sensor block R & L Illac Wings w/structural replacements L & R Upper leg flesh L & R Upper Leg Assemblies L & R Knee Flesh L & R Knee assemblies L & R Knee Slider Assemblies 44

44 Summary: THOR Mod Kit Status Mod Kit Project Completed all deliverables from Short Term Task list Improved biofidelity, durability and usability Next Steps NHTSA to evaluate modified dummy (June-Sept. 2010) Component, sled, vehicle (possibly) tests Communicate results to SAE THOR Task Group Develop plans to modify additional dummies Develop test plan for R&R Develop THOR FE model to match modifications Need to determine model maintenance process 45