D. Friedman, G. Mattos, D. Rico Presented by Donald Friedman to the Transportation Research Board of the National Acade

3. Analysis of JRS Data Base* Parameter Sensitivity to Injury mechanisms Injury mechanisms and criteria Parameter sensitivity Prediction and Mitigation means Developing a real world protocol Lessons learned Applicability to Frontal Impact Applicability to Side Impact *In the following data, Roll 1 is at 5� and Roll 2 is at 10� pitch

4. Injury Mechanism, Criteria and Measurements In a previous series of papers CfIR identified: Correlation of residual roof crush and statistical injury potential Neck Bending as the major injury mechanism Peak Axial loading in Humans from Roof Crush is unlikely Bending Injuries occur from the extent (stroke) of roof crush Primary Injury location is in the lower neck Primary Measurement is by Lower Neck Load Cells Axial Neck Alignment and Orientation at 30�+ Flexion Development of the Integrated Bending Moment (IBM), a Momentum Injury Criteria based on duration of loading. Development of a Low Durometer Hybrid III Neck Correlation with IARV and Human Bending Injury Criteria

5. Spinal Injury Criteria and Measures Hybrid III 50th % Male Dummy Lower Neck Bending Moment and Duration The measures that proved to be the most significant indicators of injury during a rollover event were� The lower neck bending moments, measured at the C-7 vertebrae of the dummy. Although this measurement alone is not a direct indicator of injury. The duration of neck bending, combined with the resultant moment must be taken into account. you can imagine a boxer receiving a blow to the face, although this could result in a large lower neck bending moment the boxer�s head would move away and the peak moment would reduce rapidly. No lower neck injury would occur because the load was not sustained and did not cause the neck to bend. Click Lower neck bending injuries require that a large enough moment to be sustained for a duration such that the neck is bent beyond its capability. CLICK Here is a diagram showing the mechanism of a common neck bending Injury, a Bilateral Facet Dislocation. It is initiated by significant bending of the neck which dislocates the spine. It concludes with the neck contracting, pulling the spine forward and down locking the facets as shown. This, and other neck bending injuries can be predicted by looking at the area under the Lower Neck Bending Moment curve CLICK This area is akin to the Head Injury Calculation that is performed to determine the Injury potential from a head impact. It takes into account not only the peak load but also the duration of that load. Roof crush, and the loss of headroom is directly related to the bending moment measured in the neck. CLICK In a study of over 10,000 rollover accidents it was found that the probability of Spine Injury increased with increased residual Roof Crush. CLICK The tests conducted on the Jordan Rollover System included measurements of roof movement at 4 locations in the vehicle. From these measurements we were able to determine the peak dynamic roof crush and residual roof crush that occurred during each roll. It turns out that Peak axial neck force by itself is not a good indicator of injury to the spine. CLICK This is due to the very stiff vertically oriented neck of the Hybrid III dummy. The measures that proved to be the most significant indicators of injury during a rollover event were� The lower neck bending moments, measured at the C-7 vertebrae of the dummy. Although this measurement alone is not a direct indicator of injury. The duration of neck bending, combined with the resultant moment must be taken into account. you can imagine a boxer receiving a blow to the face, although this could result in a large lower neck bending moment the boxer�s head would move away and the peak moment would reduce rapidly. No lower neck injury would occur because the load was not sustained and did not cause the neck to bend. Click Lower neck bending injuries require that a large enough moment to be sustained for a duration such that the neck is bent beyond its capability. CLICK Here is a diagram showing the mechanism of a common neck bending Injury, a Bilateral Facet Dislocation. It is initiated by significant bending of the neck which dislocates the spine. It concludes with the neck contracting, pulling the spine forward and down locking the facets as shown. This, and other neck bending injuries can be predicted by looking at the area under the Lower Neck Bending Moment curve CLICK This area is akin to the Head Injury Calculation that is performed to determine the Injury potential from a head impact. It takes into account not only the peak load but also the duration of that load. Roof crush, and the loss of headroom is directly related to the bending moment measured in the neck. CLICK In a study of over 10,000 rollover accidents it was found that the probability of Spine Injury increased with increased residual Roof Crush. CLICK The tests conducted on the Jordan Rollover System included measurements of roof movement at 4 locations in the vehicle. From these measurements we were able to determine the peak dynamic roof crush and residual roof crush that occurred during each roll. It turns out that Peak axial neck force by itself is not a good indicator of injury to the spine. CLICK This is due to the very stiff vertically oriented neck of the Hybrid III dummy.

6. Illustration of IBM Results Results. It is clear from the videos of the dummy motion that the roof of the production vehicles interact with the head of he dummy in a much more severe manner. The reinforced roofs provided much more protection by maintaining the occupant survival space. CLICK This video shows the interior views of the production and reinforced 1998 Crown Victoria as tested on the CRIS. The production vehicle is shown in the top screen. Dummy movement up to the point of initial roof contact is nearly identical. The deformation of the roof in the production vehicle applies a force to the head of the dummy and causes the neck to bend significantly. No neck bending was observed in the reinforced vehicles. Estimated Roof crush is 2� for reinforced and more than 10 inches for the production vehicle CLICK In the tests performed on the JRS the production vehicles sustained up to 6 times more residual roof crush than the reinforced vehicles. This equates to an average of 5� more dynamic roof crush during the event. CLICK The peak lower neck bending moments measured in the production vehicles was 30 to 56% greater than what was measured in the reinforced vehicle. CLICK Along with this the duration of neck bending in the production vehicle was 150% greater for the production vehicles. CLICK Dummies in the production vehicles were trapped 2 out of the 5 times in injurious positions that could limit breathing and inhibit safe evacuation. Results. It is clear from the videos of the dummy motion that the roof of the production vehicles interact with the head of he dummy in a much more severe manner. The reinforced roofs provided much more protection by maintaining the occupant survival space. CLICK This video shows the interior views of the production and reinforced 1998 Crown Victoria as tested on the CRIS. The production vehicle is shown in the top screen. Dummy movement up to the point of initial roof contact is nearly identical. The deformation of the roof in the production vehicle applies a force to the head of the dummy and causes the neck to bend significantly. No neck bending was observed in the reinforced vehicles. Estimated Roof crush is 2� for reinforced and more than 10 inches for the production vehicle CLICK In the tests performed on the JRS the production vehicles sustained up to 6 times more residual roof crush than the reinforced vehicles. This equates to an average of 5� more dynamic roof crush during the event. CLICK The peak lower neck bending moments measured in the production vehicles was 30 to 56% greater than what was measured in the reinforced vehicle. CLICK Along with this the duration of neck bending in the production vehicle was 150% greater for the production vehicles. CLICK Dummies in the production vehicles were trapped 2 out of the 5 times in injurious positions that could limit breathing and inhibit safe evacuation.

8. The SWR = 6.8, Scion Xb broke the Neck

26. R2 Correlation and Slope of Roof Crush vs. Parameters 5 � / 10� pitch Major radius (of 41 to 50 inches) 0.793 / 0.830 Elasticity 0.873 / 0.861 Dynamic Dummy Injury Measure (IBM) 0.746 / 0.233 Residual Dummy Injury Measure (IBM) 0.792 / 0.289 Peak Dynamic Headroom and Injury Measure (IBM) 0.642 / 0.427 Residual Headroom and Injury Measure (IBM) 0.659 / ----- Peak Dynamic Headroom and Injury Measure (IARV) 0.289 / 0.252 Road speed and proportional roll rate ----- / 0.371 Road speed and average residual crush ----- / 0.951 Road speed independent of roll rate (20% increase) 0.985 / ~15% Roll rate independent of road speed (20% increase) ----- / ~35% Strength to weight ratio (SWR) 0.410 / 0.068 Curb Weight 0.257 / 0.034 Roll Moment of Inertia 0.274 / 0.166 Major/minor radius difference 0.005 / 0.0002 CG vs A-Pillar location ----- / 0.659

27. Prediction and Mitigation Means CfIR previously showed that residual crush and ejection potential decrease with SWR greater than 3.0 and increase with 10� pitch. This analysis indicates that: Momentum derived hybrid III dummy injury measures correlate with one roll residual crush injury potential. Increased major radius results in increased injury potential independent of SWR, Elastic structures reduce injury potential. Increasing road speed increases injury potential Increased roll rate has more substantial effect than road speed Shifting CG Rearward (Rear seat passengers or load) reduces injury potential by reducing pitch propensity.

28. Developing a real world protocol

29. Lessons learned 

30. Applicability to Neck Comparison in 15 mph Frontal Impact

31. Applicability to Deploying Side Impact Airbag

32. Please contact: Susie Bozzini susie@centerforinjuryresearch.org What are the 3 points we want to make? 1. Injury is associated with roof collapse. 2. Roof collapse is associated with vehicle impact orientation. 3. Weak roofs, not diving, are the cause of head and neck injury. Four things we found from dolly rollover testing and NASS. Flat ground rollovers. Dummies hit the roof at 3-4000 N casually with no likely injury, orientation of the vehicle at serious impact is rolled 145 pitched 10 and speed at 20 mph and roof panels buckle. See the next slides.What are the 3 points we want to make? 1. Injury is associated with roof collapse. 2. Roof collapse is associated with vehicle impact orientation. 3. Weak roofs, not diving, are the cause of head and neck injury. Four things we found from dolly rollover testing and NASS. Flat ground rollovers. Dummies hit the roof at 3-4000 N casually with no likely injury, orientation of the vehicle at serious impact is rolled 145 pitched 10 and speed at 20 mph and roof panels buckle. See the next slides.

33. What are the 3 points we want to make? 1. Injury is associated with roof collapse. 2. Roof collapse is associated with vehicle impact orientation. 3. Weak roofs, not diving, are the cause of head and neck injury. Four things we found from dolly rollover testing and NASS. Flat ground rollovers. Dummies hit the roof at 3-4000 N casually with no likely injury, orientation of the vehicle at serious impact is rolled 145 pitched 10 and speed at 20 mph and roof panels buckle. See the next slides.What are the 3 points we want to make? 1. Injury is associated with roof collapse. 2. Roof collapse is associated with vehicle impact orientation. 3. Weak roofs, not diving, are the cause of head and neck injury. Four things we found from dolly rollover testing and NASS. Flat ground rollovers. Dummies hit the roof at 3-4000 N casually with no likely injury, orientation of the vehicle at serious impact is rolled 145 pitched 10 and speed at 20 mph and roof panels buckle. See the next slides.