CFDRC is developing multiscale computational tools, CoBi, for the blast wave human body injury, protection, and treatment. It is a challenging task involving modeling tools for: explosion gas dynamics, human body dynamics, body tissue biomechanics and primary injury, hemodynamics, autoregulation, organ perfusion, oxygen/glucose metabolism, all secondary injury pathophysiology events, injury prevention and therapeutic treatment.

Traumatic Brain Injury and Pulmonary Lung Blast Injury (TBI and PLBI)

America's armed forces are sustaining attacks by rocket-propelled grenades, improvised explosive devices, and land mines almost daily in Iraq and Afghanistan.
Over 50% of wounded soldiers suffer from “Traumatic Brain Injuries (TBI)” and Pulmonary Lung Blast Injury (PLBI).
Blast injuries result from the complex pressure waves generated by an explosion.  Pressure waves interact with different body parts and organs differently.
Brain and other bone-surrounded, fluid-filled organs and air-filled organs (e.g. ear, lung, and gastrointestinal tract) are especially susceptible to primary blast injury.

CoBi integrates explosion gas dynamics, human body dynamics (translocation in air), FEM biomechanics of primary blast injury, and the human body trauma injury and treatment. Multiscale human body injury can be analyzed using 3D FEM based models, distributed compartmental tools, or their combination. The 3D human body injury model couples FEM body biomechanics with the quasi-3D whole body hemodynamics.  The hemodynamics model includes 3D topology of major arterial and venous vessels and major organs (heart, lung, brain, liver, etc.) solving coupled blood flow-vessel elasticity equations coupled to organ perfusion and metabolism models. FEM biomechanics and hemodynamics models can be solved in a coupled mode e.g. to analyze blast loading or tissue compression/occlusion. Such coupled 3D high fidelity model is computationally very demanding. Alternative approach is to use distributed compartmental models, which have less anatomic and spatial information, but provide huge computational advantage (speed, rate of model development, ease of model calibration, parametric simulations, easy adaptation to specific human and animal models, etc).

We are using this technology for the optimal design of next generation military helmets and body armor. Our work on body armor has been featured in Scientific Computing Magazine. The image below shows a blast wave on the soldier’s head and helmet.

High-Fidelity Modeling Tools for Bone Conduction Communication Systems
A joint CFDRC and Georgia Tech collaboration is developing bone conduction (BC) listening technology, where sound is transmitted/received through vibration transducers attached to the human head. Existing BC technology is not mature enough to provide high fidelity devices required for military operations. We are continuing to develop and validate anatomy and physics based modeling tools for analysis and design of cranial BC communication systems. These tools are used to optimize the design, attachment, and anatomical location of BC speakers and microphones for best communication clarity in various military environments. CFDRC’s high-fidelity Acoustic-Structures-Interaction software is used to model the filtering effects of the skull, brain, fluids, and other tissues as vibrations transit from points on the head surface to the cochlea. Resulting transfer functions will be used to predict speech intelligibility and evaluated empirically at Georgia Tech’s Sonification Lab through validation studies involving human listeners. Image shows Gaussian pulse stimulation at forehead, inner ear zone, and extracted 3D cochlea geometry

Medical Imaging and Image Based Model Generation

All biomechanics simulations require realistic and accurate 3D human models. CFDRC has developed in collaboration with Columbia University an imaging and model generation pipeline. The figure below shows the imaging and model generation pipeline for blast wave simulation involving human head and helmet.

The MRI scans are taken from NIH’s visible human model. The images are segmented and a 3D model is reconstructed. We have special software to improve the surface mesh quality, so that the surfaces meshes are suitable for volumetric mesh generation. The volumetric mesh can be used for any CAE analysis.

Please contact us for more information about computational medicine and biology research activities.