Thoraco-Abdominal Deflection Responses of Post Mortem Human Surrogates in Side Impacts

Abstract

The objective of the present study was to determine the thorax and abdomen deflections sustained by post mortem human surrogate (PMHS) in oblique side impact sled tests and compare the responses and injuries with pure lateral tests. Oblique impact tests were conducted using modular and non-modular load-wall designs, with the former capable of accommodating varying anthropometry. Tests were conducted at 6.7 m/s velocity. Deflection responses from chestbands were analyzed from 15 PMHS tests: five each from modular load-wall oblique, non-modular load-wall oblique and non-modular load- wall pure lateral impacts. The thorax and abdomen peak deflections were greater in non-modular load-wall oblique than pure lateral tests. Peak abdomen deflections were statistically significantly different while the upper thorax deflections demonstrated a trend towards significance. Deflection angulations were statistically significantly different between pure lateral and oblique tests at all regions indicating that it is important to characterize not only the amplitude but also the angle of the vector. Injuries were confined to skeletal regions in pure lateral tests and this was in contrast to the occurrence of both skeletal and soft tissue/organ injury in oblique loading tests, again emphasizing the role of obliqueness in side impacts. Furthermore, injuries in oblique tests were primarily unilateral, paralleling real-world trauma and confirming the applicability of the experimental design to field environments. Potential injury mechanisms are discussed based on anatomical considerations. These findings, albeit from a limited sample size, underscore the need for additional studies to derive human injury tolerance and criteria in oblique side impacts.