Biomechanical Analysis of Head Subjected to Blast Waves and the Role of Combat Protective Headgear Under Blast Loading: A Review

Abstract

Blast-induced traumatic brain injury (bTBI) is a rising health concern of soldiers deployed in modern-day military conflicts. For bTBI, blast wave loading is a cause, and damage incurred to brain tissue is the effect. There are several proposed mechanisms for the bTBI, such as direct cranial entry, skull flexure, thoracic compression, blast induced acceleration, and cavitation, that are not mutually exclusive. So the cause-effect relationship is not straightforward. The efficiency of protective headgears against blast waves is relatively unknown as compared with other threats. Proper knowledge about standard problem space, underlying mechanisms, blast reconstruction techniques, and biomechanical models are essential for protective headgear design and evaluation. Various researchers from cross disciplines analyze bTBI from different perspectives. From the biomedical perspective, the physiological response, neuropathology, injury scales, and even the molecular level and cellular level changes incurred during injury are essential. From a combat protective gear designer perspective, the spatial and temporal variation of mechanical correlates of brain injury such as surface overpressure, acceleration, tissue-level stresses, and strains are essential. This paper outlines the key inferences from bTBI studies that are essential in the protective headgear design context.

Cavitation in blunt impact traumatic brain injury

“…Rapid progress has been made in how helmets are tested (Rowson & Duma 2011 ) and designed (Diekfuss et al 2021 ) to minimize the risk of concussion. As attention to mild TBI has increased, attention to cavitation has decreased in the blunt impact TBI community (cavitation remains the subject of intense investigation in the blast TBI community as reviewed elsewhere (Marsh & Bentil 2021 ; Sundar & Ponnalagu 2021 )). The attitudes of researchers to the cavitation and shear strain theories of traumatic brain injury can be inferred from the parameters they use to validate models and predict injury.…”