Baseball Head Impacts to the Non-Helmeted and Helmeted Hydrid III ATD

Abstract

Traumatic brain injury may occur in baseball due to a head impact with a thrown, pitched, or batted ball. It has been shown that the average pitching speed of youth pitchers and high school pitchers is approximately 63 mph (28 m/s) and 74 mph (33 m/s), respectively. At pitching speeds of approximately 52 mph (23 m/s), the bat exit velocity (BEV) for metal bats has been shown to be approximately 100 mph (45 m/s). Head kinematics, such as linear and angular head accelerations, are often used to establish head injury risk for head impacts. With a possible ball impact velocity reaching speeds in excess of those typically tested for baseball headgear, it is necessary to understand how the head will respond to high velocity impacts in both helmeted and non-helmeted situations. In this study, head impacts were delivered to the front and side of a Hybrid III 50th percentile male anthropomorphic test device (ATD) by a baseball traveling at speeds of 60 mph (27 m/s), 75 mph (34 m/s), and 100 mph (45 m/s). Head impacts were performed on the non-helmeted ATD head and with the ATD wearing a standard batting helmet certified in accordance with the NOCSAE standard. The Hybrid III headform was instrumented with a nine accelerometer array to measure linear accelerations of the head and determine angular accelerations. Peak resultant linear head accelerations for the non-helmeted ATD were approximately 200–400 g for frontal impacts and approximately 220–480 g for lateral impacts. Peak resultant angular head accelerations for the non-helmeted condition were approximately 17,000–32,000 rad/s2 for frontal impacts and approximately 30,000–60,000 rad/s2 for lateral impacts. For the helmeted ATD, peak resultant linear accelerations of the head were approximately 70–300 g for frontal impacts and approximately 80–360 g for lateral impacts. Peak resultant angular head accelerations for the helmeted ATD were approximately 5,000–14,000 rad/s2 for frontal impacts and approximately 7,500–30,000 rad/s2 for lateral impacts. HIC values for the non-helmeted ATD were approximately 193–1,025 for frontal impacts and approximately 241–1,588 for lateral impacts. SI values for the non-helmeted ATD were approximately 235–1,267 for frontal impacts and approximately 285–1,844 for lateral impacts. HIC values for the helmeted ATD were approximately 16–415 for frontal impacts and approximately 23–585 for lateral impacts. SI values for the helmeted ATD were approximately 25–521 for frontal impacts and approximately 32–708 for lateral impacts. In comparison to the non-helmeted condition, the results demonstrate the effectiveness of a batting helmet in mitigating head accelerations for the frontal and lateral impact conditions tested.

Head Impact Severity Measures for Small Social Robots Thrown During Meltdown in Autism

“…Laboratory settings using anthropomorphic test dummies (ATD) are typically used to simulate potentially dangerous scenarios to evaluate the possible harm to a human, such as that used in car crash tests. Furthermore, similar setups have been used to quantify harm due to impacts in some sports and to evaluate protective gears, such as helmets [78,85,115]. One study used similar settings to assess the influence of taekwondo kicks and the peak velocity of the foot on the dynamics of the head [34].…”

A destructible headform for the assessment of sports impacts

“…Projectile impacts typically produce shorter contact durations, and in some circumstances have been reported to be lower than 2 ms. 7,24,25 Additionally, Raymond 26 observed skull deformation and excitation of the resonance frequency of the skull when impacting a human head with a cylindrical metal puck (diameter 38 mm, mass 103 g) at impact speeds (33.6 6 1.4 m/s) comparable to those seen in projectile sports. When assessing projectile impacts in a laboratory setting, Raymond 26 reported that the dynamic response of the Hybrid-III headform is unrealistic in impacts that produce areas of high-pressure, as the skull component is stiffer than human tissue.…”

Influence of the shape and mass of a small robot when thrown to a dummy human head

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