The influence of impact location and angle on the dynamic impact response of a Hybrid III headform

Abstract

To properly assess sports helmet performance, it is important to select impact conditions that yield high peak linear or angular accelerations. This was done by measuring the kinematic response of a Hybrid III headform when impacted with a modified Wayne State University linear impactor with special consideration for impact locations and angles. The 20 impact conditions (five locations and four angles) were then compared to published thresholds to identify the conditions, which were linked to an increased risk of head injury. These conditions were the following: 1A (linear 121.3g; angular 3.84 krad s -2 ), 2A (linear 102.1g; angular 9.28 krad s -2 ), 2C (linear 94.4g; angular 8.67 krad s -2 ), 3A (linear 132.8g; angular 9.38 krad s -2 ), 4A (linear 92.8g; angular 11.49 krad s -2 ), 4D (linear 113.3g; angular 12.86 krad s -2 ), 5A (linear 116.9g; angular 9.01 krad s -2 ) and 5D (linear 87.5g; angular 8.81 krad s -2 ). The results presented in this study were specific to the test rig used as well as the tested conditions; however, it is believed that a test protocol using the above impact conditions could identify the ability of sports helmets to reduce risk of head injuries.

An examination of American football helmets using brain deformation metrics associated with concussion

“…These results suggest that it may be possible to affect not only the magnitude of the deformation but also the region of the brain in which the peak is incurred using helmet show that these helmets perform differently from each other. The impact sites used in this method were based upon risks of injury using reconstructive research and until now have not been examined for their appropriateness for helmet testing [15]. The present results show that these impact sites do serve to test the performance of the helmet for centric and non-centric conditions in a sensitive and robust manner.…”

“…Nine different impact sites (Figures 1 and 2), representing both centric and noncentric loading conditions, were used to evaluate the performance of the three helmets models [15]. Three of each helmet types were tested under these conditions to provide data to analyse statistical variability without repeatedly impacting each helmet at the same location, which would have induced progressive degradation.…”

The Influence of Impactor Mass on the Dynamic Response of the Hybrid III Headform and Brain Tissue Deformation

“…impact site based on the University of Ottawa Testing Protocol (uOTP) [35] (Table 3). A centric and a non-centric impact condition were chosen, as the direction of the applied force was shown to have an effect on the dynamic impact response [43] and risks to injury [35].…”

“…The left-hand rule is used to define the coordinate system for the head form. The positive axis is directed anteriorly towards the right ear, and caudally for the x, y and z, respectively [35]. pressure [16] and relative brain motion [36].…”

Evaluation of Dynamic Response and Brain Deformation Metrics for a Helmeted and Non-Helmeted Hybrid III Headform Using a Monorail Centric/Non-Centric Protocol

“…Three impact conditions were chosen for preliminary investigation of non-centric impacts using the monorail drop rig and are shown/listed in Figure 5 and Table 1 [25].…”