Advanced Human Modeling

The Advanced Human Modeling Laboratory (AHML) of the Bioengineering Center is equipped with two high-speed clusters linked by Myrinet network for high performance computing and a range of RAID devices for real-time back-up. Models developed at AHML include human component models from head to toe and a number of animal head models for head injury investigations.

Current Projects:

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ANSIR: The project code-named ANSIR (Anthropomorphic Numerical Surrogate for Injury Reduction) is aimed to develop a range of whole body and component human models for improved occupant safety. The current paradigm of designing a safer vehicle is to conduct biomechanical studies in order to obtain human response data to design anthropomorphic crash dummies, which in turn are used to develop and evaluate new concepts for vehicular safety systems. Unfortunately, significant differences exist between the dummy and the human. For instance, dummies are designed to emulate human responses in a handful of impact directions and are unable to fully simulate bony fractures. Nonetheless, dummies have become part of the regulations set forth by governmental agencies , and as a result, while modern day cars are much safer than their predecessors, one may say that today's cars are designed to be safe for dummies. With the rapid advancement in computing technology, modeling the human occupant has become an achievable goal and the present aim of this laboratory is to develop a family of numerical surrogates to investigate human injury mechanisms and tolerances.

MRMC Pig Head Modeling: The aim of this work is to develop and validate a computer model of the pig brain simulating the effects of a blast overpressure. Based on our prior work on the development of a computer model of the rat brain subjected to a shock wave, a similar approach will be taken to develop a model of the minipig. In the first step, we shall need to model the shock wave generation from a free field explosion and then its propagation in the air. The next step is to develop a detailed model of the minipig’s head and brain. Using MRI data of the minipig, we will construct a mesh to represent the entire head and neck of the minipig that is detailed enough for the calculation of intracranial responses for comparison with biomechanical measurements and with the injury data obtained from our blast experiments, including histological data. A fluid/solid interface (FSI) algorithm will be used to compute the forces acting on the head of the minipig and the reflection of the pressure wave from the skull and transmission of the pressure pulse into the brain.

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MRMC Blast Modeling:As a part of the three-year project “Prevention of blast-related injuries” supported by the US Army Medical Research and Materiel Command (MRMC), this study aims to simulate the blast effect on the brain with a pig head computer model. The head model was developed based on medical images (CT and MRI) and included sufficient anatomic details. The blast wave was modeled with an Arbitrary Lagrangian Eulerian approach and the interaction of blast and head was computed based on solid/fluid coupling algorithms. The model predictions (e.g. intracranial pressures and accelerations) were validated against experimental data. A 3D injury map within brain will be further established to link the response parameters and injuries.

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Rat and Mouse Brain modeling: Human brain injury is very complex and heterogeneous. As a result, various laboratory brain injury experiments were developed to investigate brain injury mechanisms and therapeutic strategies. The most used animals in the laboratory were rat and mouse. We developed anatomically-detailed high quality rat and mouse brain finite element models to investigate intracranial biomechanics during the laboratory-controlled in vivo brain injury experiments, and correlate intracranial biomechanics to physiological, neurological, and morphological alterations in the brain. These numerical models provided a unique opportunity to comprehensively describe intracranial tissue stretch/stress/pressure, for focal impact, diffuse impact, and inertial loading (linear/rotational accelerations. Results demonstrated that brain contusion was related to tissue stretch (30% strain), rather than traditionally-perceived positive brain pressure. Also, there were positive relations between neuronal cell loss percentages and maximum principal strain. The numerical simulations further provided a biomechanical answer for a long-lasting question that why CA3, which is positioned deep inside the brain, was more injured during controlled cortical impact. Currently, the rat and mouse brain models are being used to investigate biomechanics of mild traumatic brain injury, especially concussion and blast injuries. The new experimental designs are being developed with the aid of virtual experiments being performed in the computer. (Part of the above descriptions were edited from Dr. Haojie Mao's PhD thesis and papers)

Anthropometric test device modeling: Anthropometric test devices (ATD’s), such as Hybrid-III crash test dummy, have been applied to simulate the lower extremity response of mounted soldiers under anti-vehicular (AV) mine blast loading conditions. Numerical simulations such as finite element (FE) analysis of such high-speed vertical loading on the ATD parts require accurate strain rate-dependent material parameters. This study presents a combined experimental and computational study to calibrate the rate-dependent properties of three materials on the Hybrid-III dummy lower extremity, i.e. heel pad foam, foot skin and lower leg flesh, which can greatly affect the force and moment transferred to the lower extremity. The heel pad foam was tested through a standard uniaxial compressive testing protocol at a wide range of strain rates, and its material parameters could be directly determined using the stress-strain curves obtained. Since the foot skin and lower leg flesh were of irregular shape, component level tests, i.e. axial impact and dynamic three-point bending tests were performed on the foot and lower leg components, respectively. Based on experimental data, an optimization-based methodology was used to calibrate the material parameters. The processes combined computations with a set of optimization procedures to systematically adjust the material input parameters until the calculated mechanical responses optimally matched those measured experimentally. Results indicate that optimized material models generated from these procedures reasonably replicates the experimentally obtained response data and outperform the non-optimized counterparts.

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Toyota 10YO modeling:Because human bodies change with age, injuries sustained in vehicular crashes by children differ in important ways from adult. Existing computer models of the human body used to study how vehicular occupants move and interact with a vehicle in a simulated crash event do not adequately account for age differences. Toyota’s CSRC and Wayne State University Bioengineering Center have partnered to expand the available FE tools in order to empower engineers to design vehicle safety systems that take into account differences in body characteristics, in effort to reduce the injuries of children. The project aims to develop a new FE model representing the body structure of a 10-year-old child. Based on the FE model, numerical simulations are conducted to identify occupant kinematics and loads sustained during impact events. Age specific material properties of biological tissues (i.e. bone and organs) are adopted to increase the accuracy of the simulated occupant, and help correlate the measured forces to injury probability.

75-year old Female Modeling:Elderly small female occupants are at greater risk of death and serious injuries in motor-vehicle crashes than the mid-size, young, male occupants. However, current injury assessment tools, including crash test dummies and finite element (FE) human models, generally do not account for different body shape and composition variations among the population. This study aims to develop the FE model for the elderly female which will help to close the gap between current safety testing and the actual injuries sustained by this vulnerable population.

Infant Brain Model:Head injury is the leading cause of pediatric death and child abuse is the leading cause of head injury in infants. Short falls are also extremely common events in infants and young children as they learn to roll, climb, and walk. The injury potential of short falls in infants and young children is a question often debated in the courts, and rigorous injury biomechanics research is still needed to provide more objective and definitive answers. To accurately figure out whether a pediatric head injury is consistent with the cause stated by the caregivers, accurate tools and associated head injury criteria are needed. Given the limitations of current pediatric assessment tools, the overall goal of this research is to develop a new concept of using subject-specific pediatric head FE models to help provide more accurate head injury assessment in specific cases.

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Personnel:

King, Albert
Distinguished Professor, Biomedical Engineering
313-577-1347 
king@eng.wayne.edu
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Yang, King H.
Professor of Biomedical Engineering & Director of Bioengineering Center
313-577-0252
king.yang@wayne.edu
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Zhang, Liying
Research Associate Professor, Biomedical Engineering
313-993-9434 
zhang@eng.wayne.edu
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Begeman, Paul C.
Research Associate, Biomedical Engineering
313-993-8393 
begeman@wayne.edu
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Zhu, Feng
Assistant Professor - Research, Biomedical Engineering
Research Interest: Applied impact mechanics,Traumatic biomechanics,Dynamic behavior and energy absorption of advanced materials and structures, CAD/CAM/optimization of energy absorbers.
313-577-8577 
fengzhume@gmail.com

Jin, Xin
Postdoctoral Fellow
Research Interest: Experimental and finite element study on biological tissues properties and whole body impact biomechanics
313-577-8577
xin.jin@wayne.edu

Jiang, Binhui
Postdoctoral Fellow
Research Interest: Human body FE modeling and Vehicle satety
eq2294@wayne.edu

Shen,Ming
Graduate Research Assistant
Research Interest: Impact Biomechanics and Motor Vehicle Saftey.
ex9034@wayne.edu

Kalra, Anil
Graduate Research Assistant
Research Interest: Impact Biomechanics,Vehicle Safety,Blast Modeling.
anil.kalra@wayne.edu

Zhou, Runzhou
Graduate Research Assistant
Graduate Research Interest: Traumatic brain injury: Rat brain diffuse axonal injury
eb8173@wayne.edu

Saif, Tal
Graduate Research Assistant
Research Interest: Impact Biomechanics.
eg8215@wayne.edu

Fan, Haonan
Graduate Research Assistant
Research Interest: Finite Element Modeling,Brain Injury Mechanism.
fc6278@wayne.edu

Raut, Rohit
Student Assistant
Research Interest: Crashworthiness and occupant protection and human body FE modeling
rohit.raut@wayne.edu

Manjrekar, Vinit
Student Assistant
Research Interest:Injury analysis of head using Human FE model,Crashworthiness and occupant protection in transportation systems
fg4598@wayne.edu