Definition of Peak Virtual Power Brain Trauma Variables for the use in the JSOL THUMS injury post-processor web-based estimator

Road traffic accidents and falls are catastrophic events leading to serious injury and in some cases fatality. The dichotomy is that traumatic injuries are assessed using the Abbreviated Injury Scale (AIS), which is a measurement of the probability of death, whilst the engineering tools available to support the understanding of injury causation rely on engineering measurements of stress and strain. Further to this, the problem of ageing is not adequately dealt with using existing engineering tools. The research proposes the development of a generic mathematical injury severity model, based on Peak Virtual Power (PVP), which is using the Clausius-Duhem inequality from the rate dependent form of the 2nd Law of thermodynamics, relating to degeneration and decay, to establish relationships between AIS, age and collision speed. The paper has shown that PVP was generic (global), objective (theoretical), not subjective (empirical), dimensionally meaningful (not as HIC), unique (peak values are unique) and could predict soft tissue injury severity, illustrated in this research with the case of an occipital fall. This method, newly implemented JSOL THUMS injury post-processor web-based estimator, has the ability to calculate all AIS levels of any finite element model’s white and grey matter, which are defined as a polynomial function. This paper explains the underpinning of the PVP theory, as well as provide the coefficients to calculate brain injury severity under blunt trauma impact of a THUMS4.01 head model in which material properties were modified to reflect THUMS 4.02’s latest material brain enhancements.