A mathematical model of a new rear-end impact dummy neck was implemented using MADYMO. The main goal was to design a model with a human-like response of the first extension motion in the crash event. The new dummy neck was modelled as a series of rigid bodies (representing the seven cervical vertebrae and the uppermost thoracic element, T1) connected by pin joints, and supplemented by two muscle substitutes. The joints had non-linear stiffness characteristics and the muscle elements possessed both elastic stiffness and damping properties. The new model was compared with two neck models with the same number of vertebrae, but without muscle substitutes. The properties of the muscle substitutes and the need of these were evaluated by using three different modified neck models. The motion of T1 in the simulations was prescribed using displacement data obtained from volunteer tests. In a sensitivity analysis of the mathematical model the influence of different factors on the head-neck kinematics was evaluated. The neck model was validated against kinematics data from volunteer tests: linear displacement, angular displacement, and acceleration of the head relative to the upper torso at 7 km/h velocity change. The response of the new model was within the corridor of the volunteer tests for the main part of the time history plot. This study showed that a combination of elastic stiffness and damping in the muscle substitutes, together with a non-linear joint stiffness, resulted in a head-neck response similar to human volunteers, and superior to that of other tested neck models.

To assess the protective performance of seats and head restraints, occupant models able to mimic the motion of a human in a crash are needed. Hence, a new mechanical dummy neck for low-velocity rear collision tests was developed. The dummy neck consists of seven cervical elements connected by pin joints. The stiffness properties of the neck were represented by rubber blocks mounted between each pair of vertebrae, as well as by muscle substitutes between the head and the first thoracic vertebra (T1). The muscle substitutes consist of cables connected to a unit containing springs and a damper. The neck was validated against volunteer test data (Δv of 7 km/h) and compared with the kinematics of the Hybrid III dummy. The new neck was tested as a part of a new dummy (BioRID) that produced a human-like motion of the T1. The kinematics of the new neck was within the corridor of the volunteers, during the major part of the first 250 ms of the crash event, for both displacement of the head relative to T1 and for the acceleration of the head. This applies to both duration and peak values. When compared with the new neck, the Hybrid III showed an earlier decrease of the horizontal acceleration of the head, less maximum horizontal displacement, and an earlier increase of the rearward angular displacement of the head relative to T1.

The aim of the study was to validate the BioRID P3, an improvement of the BioRID I, in regular car seats against rear-end impact volunteer test data and compared it to PMHS data collected previously. The performance of the BioRID P3 was also compared to the performance of a Hybrid III equipped with a TRID neck. The volunteer tests were performed at a change of velocity (Δv) of 10 km/h and a maximum acceleration of 3.5 g. The PMHS (Post Mortem Human Subject) tests were run at Δv of 10 and 15 km/h. The BioRID P3 acceleration and displacement data correlated well with the volunteer and PMHS data. Comparison of the head and chest horizontal displacement and the horizontal neck forces data showed differences between the dummies. 

Crash test dummies able to mimic the motion of a human are needed to assess the protective performance of seats and head restraints in crash tests. This study evaluates both a newly developed dummy for rear impacts (BioRID P3) and the Hybrid III dummy by means of a recently available set of human subject data. The study also meets the need for validation of the BioRID P3 at a higher impact severity than that previously achieved. The BioRID P3 and the Hybrid III were evaluated by means of pendulum impacts to the back and compared with data from previously run cadaver tests. Seated dummies were struck with a pendulum with a mass of 23 kg and an impact velocity of 4.6 m/s at the level of the 6th thoracic vertebra. The results showed that peak values and temporal responses of the BioRID P3 was closer to that of the corridor of the cadavers than the Hybrid III in terms of horizontal, vertical, and angular displacement of the head and of the head relative to T1.

Dummy responses in a crash test can vary depending not only on the change of velocity but also on how the impact was generated. Literature reporting how acceleration pulses can vary in cars impacted in different configurations is limited. The aim of this study was to collect and categorise different acceleration pulses in 3 different types of rear collision. The acceleration pulse resulting from a solid, 1000 kg, mobile barrier test at 40% overlap and an impact velocity of 15 km/h was studied for 33 different cars. Seven cars were impacted at 100% overlap at higher impact velocities using the same mobile barrier. Acceleration pulses from two different car types in real-world collisions producing a similar change of velocity were also analysed.

The results from the barrier tests show that a similar change of velocity can be generated by a large variety of pulse shapes in low velocity rear impacts. The results from real-world collisions showed that a similar change of velocity was generated in different ways both in terms of peak and mean acceleration. The results of this study highlight the importance of knowing the acceleration pulse both when evaluating the severity of a real world crash and when designing test methods for evaluating vehicle safety performance in low velocity rear-end impacts, particularly in respect of soft tissue neck injuries. 

There is good evidence that seat design and impact severities in terms of delta-V and acceleration plays a role in AIS 1 neck injury outcomes in the event of a rear impact. This study evaluates a number of current production seats to assess the AIS 1 neck injury protection potential at different impact severities. Five different seat designs were exposed to four different impact severities in a sled simulating a rear impact. The same delta-V produced with different peak accelerations generated very different dummy responses. Head restraint position influenced the angular and horizontal displacement of the head relative to torso and the time of head to head restraint contact. The lowest motion of the head relative to the torso was found in the two anti-whiplash seats tested. The results of the study can be used for the design of future vehicle seats and anti-whiplash systems.