Shock absorbing frame mitigates mine blast injury for military personnel

Researchers have developed a new military vehicle shock absorbing device that could protect troops from traumatic brain injury (TBI) after a land mine blast.

Vehicle hit by IED

The elastic frame design from the University of Maryland’s School of Medicine (UMSOM) and A. James Clark School of Engineering is claimed to reduce blast acceleration by up to 80 per cent and could be adapted for vehicle bumpers and other shock absorbing devices.

Over the past 18 years of conflicts in Iraq and Afghanistan, over 250,000 troops have suffered such injuries.

Prior to this study, most research in this area focused on the effects of rapid changes in barometric pressure.

“This is the only research so far to model the effects of under-vehicle blasts on the occupants,” said Dr Gary Fiskum, Matjasko Professor for Research and Vice-Chair, Department of Anesthesiology at UMSOM. “We have produced new insights into the causes of TBI experienced by vehicle occupants, even in the absence of significant pressure changes.”

The research has led to the development of materials and vehicle frame design that greatly reduce injury caused by under-vehicle explosions.

Dr Fiskum and Dr William Fourney, Associate Dean of Engineering, Department of Aerospace Engineering, were the first to demonstrate how G-force experienced during under-vehicle blasts can cause mild to moderate TBI, even under conditions where other vital organs are unscathed.

“Intense acceleration can destroy synapses, damage nerve fibres, stimulate neuroinflammation, and damage the brain’s blood vessels,” said Dr Fiskum. The researchers also elucidated the molecular mechanisms responsible for this form of TBI.

Dr  Fourney, Ulrich Leiste, PhD, assistant research engineer in the Clark School’s Department of Aerospace Engineering, and doctoral researcher Jarrod Bonsmann, PhD, developed highly advanced shock absorber designs that incorporate polyurea-coated tubes and other structures to reduce reducing the blast acceleration experienced by vehicle occupants by up to 80 per cent.

“Essentially, it spreads out the application of force,” Dr Fourney said. “Polyurea is compressible and rebounds following compression, resulting in an excellent ability to decrease the acceleration.”

These results were combined with those of Dr Flaubert Tchantchou, UMSOM research associate, who demonstrated that mitigation of G-force by the elastic frame designs virtually eliminates the behavioural alterations in lab rats and loss of neuronal connections observed using small scale vehicles with fixed frames.

Peter Rock, MD, MBA, Martin Helrich Chair of the Department of Anaesthesiology, said: “The research team has addressed an important clinical problem by identifying a novel mechanism to explain TBI, engineered a solution to the problem, and convincingly demonstrated improvements in morphology and behaviour. This work has important implications for improving outcomes in military blast-induced TBI and might be applicable to causes of civilian TBI, such as car crashes.”

Continued collaboration between the labs of Drs. Fiskum and Fourney has the potential to lead to the next generation of armour-protected military vehicles that will further protect occupants.  An important next step will be testing a larger scale model. “If the data holds up for those, it will hold true for full scale,” Dr Fiskum said.

The findings are described in articles published in the Journal of Trauma and Acute Care Surgery, with Julie Proctor, MS, UMSOM lab manager, as primary author; Experimental Neurology, with Flaubert Tchantchou, PhD, UMSOM research associate, as primary author; and the Journal of Neurotrauma, with Rao Gullapalli, PhD, UMSOM professor of diagnostic radiology, as senior author.