Arc far Side Impact Collaborative Research Program – Task 5b: Test Procedures Crash Tests and Sled Tests for the Far-side Environment


Effect of Center Console Height on Dummy Kinematics



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3Effect of Center Console Height on Dummy Kinematics

3.1Introduction


The objective of this task is to use the MADYMO computer simulation tool to examine the effects of center console height on occupant motion in far-side impacts.

When examining occupant motion in far-side impacts, it is apparent that few countermeasures exist to limit motion towards the far-side surface. Occupant head strikes to the far-side surface (a-pillar, door, roof, or b-pillar) are observed in real world crash investigations. This is also confirmed in cadaver testing with full vehicle to vehicle collisions.

For belted occupants, which this study limits itself to, the lap portion of a 3-point seatbelt helps to keep the occupant’s pelvis in the seat. However, the shoulder belt provides little resistance for the upper body, while the lap portion keeps the pelvis in place.

The center console also prevents the pelvis and abdomen from translating towards the impact. However, the size, shape, and even presence of a console vary among vehicle models.

This study uses MADYMO computer simulations with the human facet-model to study changes in height of the center console with belted occupant motion.

3.2Methods


A previous Task with MADYMO modeling, reported in Section 2, found the TNO human facet model placed inside a simplified vehicle model visually correlated rather well to a similar cadaver test. This grossly validated model served as the foundation for the center console experiment. The model contained on occupant seated in the normal driving position with a steering wheel, center console, transmission tunnel, and a 3 point belt system.

The lateral acceleration pulse from the cadaver test performed by Fildes et al. with a Holden Commordore was used as the input for each run (Fildes et al IRCOBI 2002). Only the y-direction acceleration was considered, ignoring x, z, roll, pitch, and yaw accelerations. Figure 1 plots the acceleration.



Figure 1: Lateral Acceleration Pulse


10 different levels for the center console were chosen. First, the center console was made flush with the driver and passenger seats. Each iteration of the model raised the center console by 25 mm (approximately 1 inch). The center console started out as flush then moved up by one inch until standing 10 inches above the seats.


3.3Results


Upon using the pulse in Figure 1 in the human facet model, the following snapshots show the model with 6 different center console height measurements.











Figure 1. Snapshots of human kinematics - six different console heights and seven time increments

Furthermore, MADYMO calculated the combined forces placed on the center console for each iteration. Figure 2 shows the peak force for each center console height.





Figure 2: Center Console to Occupant Peak Force
Figure 3 shows the lap belt forces used by MADYMO at 2 inch intervals.


Figure 3: Lap belt forces

3.4Conclusions


The model predicts that the height of the center console changed the occupant excursion slightly, perhaps not as much as would be expected. The force exerted by the occupant on the center console increased as the height of the center console increased, however, when the center console remained low, the belt restraint system restrained the pelvis rather than the center console.

It appears that as the center console height increased above 8 inches, it loaded the occupant’s abdomen and ribs. However, this was not measured on the MADYMO model due to the difficulty of using the faceted surfaces.

The plots for the lap belt force numbers are inconclusive at this point. The human facet model used has not been correlated to a test and the forces have not been checked for correctness. From the plot in figure 3 it is seen that the magnitudes of the belt forces did not change significantly as the center console height changed, especially within the first 60 milliseconds. This could be interpreted that the lap belt holds the restrains the pelvis regardless of center console height. Beyond this the shape of the plots move rather erratically. This is when the pelvis moves upward over the center console, which changes as the center console changes.

3.5References


Alonso, B., Far-side Impact Simulations with MADYMO, Report written to George Washington University – National Crash Analysis Center, October 2004.

Alonso, B., MAYDMO Human Facet Model Validation for Far-side, Memo written to George Washington University – National Crash Analysis Center, October 2004.

Fildes, B., Sparke L., Bostrom O., Pintar, F., Yoganandan N., and Morris, A. Suitability of Current Side Impact Test Dummies in Far-side Impacts, Proceedings of the 2002 International IRCOBI Conference on the Biomechanics of Impact, Munich, Germany, September 2002.

4Suitability of Square Acceleration Profile for Far-Side Impact Testing


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