Evaluation of the blunt thoracic trauma caused by solid sports ball impacts

抄録

Evaluation of the thoracic injury due to blunt impacts during the contact and collision sports activity is very crucial for the development and validation of the chest protectors for the athletes and safety balls of the sports such as cricket, baseball, lacrosse and the golf. In order to evaluate the thoracic injury due to solid sports ball impacts, a series of nonlinear transient dynamic, finite element simulations were carried out by impacting the FE model surrogate of the thorax “MTHOTA” (Mechanical THOrax for Trauma Assessment) with a baseball (both soft-core and synthetic) and a cricket ball at impact speed of 10 - 45 m/s, with an increment of 5 m/s. Only for the impact speed for which measured VC_max was 1 m/s, further simulations were carried out by introducing the ball spin (1000 - 8000 rpm, with an increment of 1000 rpm). Soft-core baseball, synthetic baseball and cricket ball impacts have caused VC_max = 1.0 m/s (25% probability for AIS3+ injuries) at impact speeds of 30.7 m/s, 27.9 m/s and 23.2 m/s respectively. For the normal impacts, spin (about impact direction and two directions perpendicular to the impact direction) of the ball has got no impact on the blunt thoracic trauma. At usual pitching speeds, soft-core baseball didn’t offer any safety and performance point of view, it was found to be as bad as synthetic baseball. Deflection response of the MTHOTA and the solid sports ball - MTHOTA energy interactions have yielded VC_max ∝ [(TE_max)¹⁷⁴⁸, (Time rate of KE_max)^0.9489, (Deformation velocity_max)^2.3227, and (Impact velocity_baseball)^2.548]. Similarly, Stored Energy Criterion and Energy Storing Rate Criterion (Wang, 1989) have yielded the relations Peak stored energy ∝ (Peak deflection MTHOTA)^1.253 and Rate of peak stored energy ∝ (Peak deflection MTHOTA × Rate of peak deflection MTHOTA)^0.5554.