the science of biomechanics and it’s practical application · injury research, education and...

The Science of Biomechanics and It’s Practical Application

Primerus – 2016 PPII Winter ConferenceFebruary 24-27, 2016

Delray Beach, FL

Mariusz Ziejewski, Ph.D., InżProfessor

Director of Impact Biomechanics Laboratory, College of Engineering

Director of Automotive Systems Laboratory, College of Engineering

Mechanical Engineering Department

North Dakota State University

and

Adjunct Associate Professor

Department of Neuroscience, School of Medicine

University of North Dakota

Who We Are

Founded in 2003

Mission

The mission of the NABISis to move brain injury science into practice.

VisionNABIS is the pre-eminent society for professionals involved in

state-of-the-art brain injury research, education and treatment.

A Society of Multidisciplinary Brain Injury Professionals

WHO WE ARE

Founded in 2003

MissionThe mission of the NABIS

is to move brain injury science into practice.




Who We Are

Founded in 2003

MISSION





Who We Are

Founded in 2003

Mission


VISIONNABIS is the pre-eminent society for

professionals involved in state-of-the-art brain injury research, education and treatment.



WHAT WE BRING TO THE TABLE

Continuing EducationThe largest annual conference for multidisciplinary brain injury

professionals in North America (avg. over 400 attendees)

Information ResourcesBrain Injury Professional, the largest circulation of any professional

publication on brain injury (over 6000 copies distributed per issue)

ExpertiseTransdisciplinary expertise across the lifespan to promote life quality through research, treatment, service delivery and advocacy efforts

(over 350 active members)



CONTINUING EDUCATIONThe largest annual conference for

multidisciplinary brain injury professionals in North America

(avg. over 400 attendees)

Information ResourcesBrain Injury Professional, the largest circulation of any professional publication on

brain injury (over 6000 copies distributed per issue)

ExpertiseTransdisciplinary expertise across the lifespan to promote life quality through

research, treatment, service delivery and advocacy efforts(over 350 active members)



Continuing EducationThe largest annual conference for multidisciplinary brain injury professionals in

North America (avg. over 400 attendees)

INFORMATION RESOURCESBrain Injury Professional, the largest circulation of

any professional publication on brain injury (over 6000 copies distributed per issue)

ExpertiseTransdisciplinary expertise across the lifespan to promote life quality through

research, treatment, service delivery and advocacy efforts(over 350 active members)



Continuing EducationThe largest annual conference for multidisciplinary brain injury professionals in North America

(avg. over 400 attendees)

Information ResourcesBrain Injury Professional, the largest circulation of any professional publication on brain injury

(over 6000 copies distributed per issue)

EXPERTISETransdisciplinary expertise across the

lifespan to promote life quality through research, treatment, service delivery and

advocacy efforts(over 350 active members)

Chairman

Mariusz Ziejewski, PhD

Vice Chairman

Debra Braunling-McMorrow, PhD

Secretary

Brian Greenwald, MD

Treasurer

Bruce Stern, Esq.

Family Liason

Skye MacQueen


Board of Directors

Michael Davis, CBIST

Sharon Grandinette, M.S., Ed. CBIST

Harvey E. Jacobs, PhD, CLCP

Brent Masel, MD

Jonathan Silver, MD

Louis Siracusano, Esq.

Tina Trudel, PhD

Barry Willer, PhD

Alan Weintraub, MD

THE 2015-2017 NABIS BOARD OF DIRECTORS

To learn more or to join NABIS, visit: www.nabis.org

Involvement with Department of Defense

Researcher:

1. Current, $600,000 grant, “Blast Pressure Gradients and Fragments on Ballistic Helmets and the Head and Brain Injury – Simultaneous MultiscaleModeling with Experimental Validation,” Department of the Army, US Army Research, Development and Engineering Command (2010-2013)

2. Current, $500,000 grant, “Blast and the Consequences on Traumatic Brain Injury – Mulitscale Mechanical Modeling of Brain” Air Force Office of Scientific Research, (2007-2010)

Chair:

1. Chairman, Scientific Peer Review Panel, “Physics of Blast as it relates to Brain Injury”, Intramural proposals, DoD PTSD/TBI Research Program, Congressionally Directed Medical Research Program (CDMRP). (Nov. 2007)

2. Chairman, Scientific Peer Review Panel, “Physics of Blast as it relates to Brain Injury”, Extramural proposals, DoD PTSD/TBI Research Program, CDMRP. (Dec. 2007)

Reviewer:

1. Reviewer, Proposals for the Military Operational Medical Research Program, US Army Materiel Research Command (USAMRMC) (May 2010)

2. Reviewer, Proposals for the Military Operational Medical Research Program, US Army Materiel Research Command (USAMRMC) (April, 2010)

3. Reviewer, Intramural Proposals for the Department of Defense (DoD) Defense Medical Research and Development Program, Intramural Applied Research and Advanced Technology Development Award (Nov. 2009)

4. Reviewer, Proposals for the Military Operational Medical Research Program, US Army Materiel Research Command (USAMRMC).(Oct., 2008)

5. Reviewer, Intramural Proposals for the Department of Defense (DoD) Intramural War Supplement Program.(Nov.,2008)

6. Reviewer, Scientific Peer Review Panels, Concept Proposals related to brain injuries caused by blasts for the DoD (PTSD/TBI) Research Program, CDMRP. (Oct., 2007)

7. Reviewer, Scientific Peer Review Panels, Intramural Proposals on Clinical Diagnosis related to brain injuries caused by blasts for the DoD(PTSD/TBI) Research Program, CDMRP. (Nov., 2007)

Invited Faculty:

1. Invited Faculty, Invited by former US Air Force Surgeon General P.K. Carlton to make a presentation on the Physics of Blast Injury to a specialconference/think tank session on allocation of Department of Defense (DoD) funding for TBI/blast injuries.

2. Invited Faculty, National Veteran’s Health Administration/Department of Defense (VHA/DoD) Conference: “Visual Consequences of Traumatic Brain Injury.”

3. Invited Faculty, National Veteran’s Health Administration/Department of Defense (VHA/DoD) Conference: “Sensory Impairment Issues in Traumatic Brain Injury.”

~ 7000 Human TestsMaximum Acceleration: 80 G

Maximum Velocity: 17 m/s

Pulse Duration: 40-180 ms

AFRL/HEPA Vertical Deceleration Tower

~ 900 Tests Analyzed with Humans

Six (6) Research Contracts, 1996-2010

Biofidelity of Hybrid II head/neck research


Direction of Our Research (Sponsored by DoD)

Multiscale modeling method proposed for brain cell adhesion modeling:

(a) MD (molecular dynamics)Simulation of Cell-ECM (extracellular matrix)interaction

(b) Average traction-separation data from MD simulation

(c) Axon- ECM continuum modeling of the interface

(d) Undulated RUC (repeating cell unit) of brain material and fiber reinforced composite modeling of the tissue

(e) Micromechanics modeling of RUC under different load cases for material characterization

BIOMECHANICS

“… the application of the principles and techniques of mechanics to the structure, functions and capabilities of

living organisms.”

Webster’s New World Dictionary of the American Language Ed. David B. Guralnik. 2nd College Ed. New York: World Pub. Co., 1970

“…evaluation based on

mechanism (cause) of injury.

Such an approach relies on

knowledge of the typical

physical and psychological

sequelae associated with a

particular mechanism of injury

to guide patient assessment

and treatment.”

Scott S., H. Belanger, R. Vanderploeg, J. Massengale, J. Scholten “Mechanism-of-Injury Approach to Evaluating Patients With Blast-Related Polytrauma”,

Journal of American Osteopathic Association Vol. 106, No.5, May 2006 pp. 265-270

Injury Exceeds Juror Expectations

Some people get hurt in a collision and

others do not get hurt in the same collision.

?

Each collision for each individual has its own

unique set of parameters that

control the outcomeof the impact.

We must incorporate all the significant

parameters cumulatively in a case

specific analysis.

PROVING THE CASE THROUGH

SCIENCEThe CSI Effect

Biomechanical Evaluation

ADVANTAGES:• Event specific• Unlimited resolution• Time History

DISADVANTAGES:• Accuracy of information• Accuracy of the software

To compliment the medical diagnosis of TBI

Biomechanical Engineer and

Nuclear Medicine

Top-Horizontal View

Ziejewski, M., G. Karami, W. Orrison, E. Hanson, “Dynamic Response of Head Under Vehicle Crash Loading,” 21st International Technical Conference on Enhanced Safety of Vehicles, Sponsored by Mercedes Benz and the National Highway Traffic Safety Admiistration (NHTSA), Stuttgart, Germany June 15-18th, www.nrd.nhtsa.dot.gov, SAE International, Head Injury Biomechanics, Vol. 1 P 144-187, 2011

Biomechanical MRI

http://www.nrd.nhtsa.dot.gov/

Mid-Sagittal View

Biomechanical MRI

Ziejewski, M., G. Karami, W. Orrison, E. Hanson, “Dynamic Response of Head Under Vehicle Crash Loading,” 21st International Technical Conference on Enhanced Safety of Vehicles, Sponsored by Mercedes Benz and the National Highway Traffic Safety Admiistration (NHTSA), Stuttgart, Germany June 15-18th, www.nrd.nhtsa.dot.gov, SAE International, Head Injury Biomechanics, Vol. 1 P 144-187, 2011

http://www.nrd.nhtsa.dot.gov/

What Biomechanics Can Do in Your Case

1. Explain what happened in the accident

2. Connect the collision to the injuries

3. Determine whether or not the collision was sufficient to cause traumatic brain injury (probability over 50%)

4. Case specific probability of TBI (95%???)

5. Identify the risk factors

Biomechanical EvaluationIdentify and Quantify Risk Factors

• Impact Force (Magnitude, direction, time duration)

• Gender

• Body Position

• Pre-existing Conditions

• Etc..

28


• Gender

• Body Position


• Etc..

29



• Gender

• Body Position


• Etc..

30



• Gender

• Body Position


• Etc.

31


Demonstrate the vulnerability

of the human brain

Relative Motion of the Brain


Because:

3D Dynamic Response Micro Damage

36

(Panjabi et al., 2001)


Because:


(a)(b)

Countercoup

(C, D)

Coup

(A, B)

Extremely Dynamic Oscillation of the Brain Tissue

.0002s

Ziejewski, M. and Karami, G. , “Biomechanical Perspective on Blast Injury,” in Concussive Brain Trauma: Neurobehavioral Impairment and Maladaptation by Dr. Rolland Parker, Taylor & Francis Group, Boca Raton, FL, 2012

Brain Oscillation


Because:


VEHICLEDYNAMICS ANALYSIS

HUMAN BODYDYNAMICS ANALYSIS

HUMAN TOLERANCEANALYSIS

The significant parameters of the collision include, but are not limited to:

A. Severity of Vehicle Dynamics

• Δv (Change in velocity)

• PDOF (Direction of impact)

• Δt (Duration of impact)

B. Severity of Human Body Dynamics

• Gender

• Height

• Weight

• Body position

• Vehicle interior characteristics

• Individual tolerances



INJURY MECHANISMS

Newton’s 2ND Law

(acceleration)

F = m . a(Force) (mass)

(acceleration)

F = m .(Force) (mass)

V t

What is Delta-V (V)?

TIME

VEL

OC

ITY

Pre-Impact

Post-Impact

Severity of Collision for Specific Δt

Impact (Delta V, ΔV)

Linder, A., et al. “Change of Velocity and Pulse Characteristics in Rear Impacts: Real World and Vehicle

Tests Data.” 18th ESV Conference, Paper #285, 2003.

100 – 120 ms

Heinrichs, B., J. Lawrence, B. Allin, J. Bowler, C. Wilkinson, K. Ising and D. King. Low-Speed Impact Testing of Pickup Truck

Bumpers Society of Automotive Engineers, Inc. 2001.

7.5 mph

60 ms

100 ms

A

t = 2.5 ms

Simulation Test

Dynamic Progressive Buckling

•Ziejewski, M., B. Anderson, M. Rao and M. Hussain, “Energy Absorption for Short Duration Impacts,” SAE Paper #961851, Indianapolis, IN, 1996•Ziejewski, M., B. Anderson, “The Effect of Structural Stiffness on Occupant Response For A -Gx Acceleration Impact,” SAE Paper #962374, São Paulo, SP, Brazil, 1996•Ziejewski, M., H. Goettler, “Effect of Structural Stiffness and Kinetic Energy on Impact Force,” SAE Paper #961852, Indianapolis, IN, 1996•Anderson, B., M. Ziejewski, H. Goettler, “Method to Predict the Energy Absorption Rate Characteristics for a Structural Member,” Society of Automotive Engineers (SAE) Paper #982388, Detroit, MI, 1998•Pan, X., M. Ziejewski, H. Goettler, “Force Response Characteristics of Square Columns for Selected Materials at Impact Loading Combinations Based on FEA,” SAE Paper #982418, Detroit, MI., 1998

Uniqueness of the Loading Conditions

μs

(kPa

)

• Supersonic overpressurization shockwave• Timescale in μs (microseconds) • 1atm ≈ 100 kPa

Uniqueness of the Loading Conditions

(kP

a)

μs

(kP

a)

• Supersonic overpressurization shockwave• Timescale in μs (microseconds) • 1atm ≈ 100 kPa

Time Matters

∆V = 7.5 mph

∆t = 120 ms aaverage= 2.8 g apeak= 5.7 g

∆t = 60 ms aaverage= 5.7 g apeak= 11.4 g

∆t = 2.5 ms aaverage= 136.6 g apeak= 273.2 g



INJURY MECHANISMS

RAPID HEAD VELOCITY CHANGE

BRAIN DEFORMATION

BRAIN DAMAGE

→LINEAR→ANGULAR

→LINEAR→ANGULAR

→CHANGE IN SHAPE→CHANGE IN VOLUME

→STRESS→STRAIN→INTERCRANIAL PRESSURE

APPLICATION OF FORCE

54

ENGINEERING PARAMETERS

INJURY QUANTIFICATION

YESYES

YESYES

--

--YES

Mechanical Properties of Brain Tissue

• Incompressible (High resistance to change in size, high bulk modulus)

• Deformable (Low resistance to change in shape, low shear modulus)

• Heterogeneous (Different properties within the brain)

• Anisotropic (Different properties in different directions)

• Viscoelastic (Time dependent properties: magnitude, duration, rate of change)

B.R. Donnelly and J. Medige, “Shear Properties of Human Brain Tissue,” Journal of Biomechanical Engineering, Nov. 1997, Vol. 119, 423-432. Shames, I.H. and Cozzarelli, F.A., 1992, Elastic and Inelastic Stress Analysis, New Jersey: Prentice Hall, Englewood Cliffs, NJ

Incompressible/Deformable

• Bulk modulus is approximately 105 (100,000) times larger than shear modulus.

• Deformation of brain tissue can be assumed to depend on shear modulus only.

• This behavior is common with viscoelasticmaterials (Shames and Cozzarelli, 1992)

Mechanical Properties of Brain Tissue

• Incompressible (High resistance to change in size, high bulk modulus)

• Deformable (Low resistance to change in shape, low shear modulus)

• Heterogeneous (Different properties within the brain)

• Anisotropic (Different properties in different directions)

• Viscoelastic (Time dependent properties: magnitude, duration, rate of change)

Demonstration

Slow Application of Force

Rapid Application of Force

• macro scale (mm) (10-3 m) – MRI detection limit – Fig. A, B, C• Diffusion Tensor Imaging (DTI) – 1x1x5 mm3

• Susceptibility Weighted Imaging (SWI) – 0.2x0.2x0.2 mm3

• micro scale (μm) (10-6 m) – the cell – Fig. D• MR Microscopy (MRM) – 100 μm3, 7 – 9.4 Tesla• Performed only on autopsied brain

• nano scale (nm) (10-9 m) – the axon neural filaments – Fig. E• Electron microscope to visualize

Invisible Injury – Why?

•Carpenter, M., Human Neuroanatomy. Baltimore, MD: Williams and Wilkins, 1976•Williams TH, Gluhbegovic N. Jew JY. The human brain: dissections of the real brain. Virtual Hospital, University of Iowa, 1997; www.vh.org/Providers/Textbooks/BrainAnatomy and www.brain-iniversity.com [21/10/22]•Callot, et. al, Short-scan-time multi-slice diffusion MRI of the mouse cervical spinal cord using echo planar imaging, NMR in Biomedicine, 2008

http://www.vh.org/Providers/Textbooks/BrainAnatomy

http://www.brain-iniversity.com/

Accelerometer

TYPES OF ACCELERATION

Ax = Linear Acceleration, Forward-Backward DirectionAy = Linear Acceleration, Side to Side Direction

Az = Linear Acceleration, Vertical Direction

a x = Rotational Acceleration, About Forward-Backward Axis

a y = Rotational Acceleration, About Side to Side Axis

a z = Rotational Acceleration, About Vertical Axis

Linear Acceleration

Rotational Acceleration

Y

X

Z







Linear Acceleration


Z

Y

X







Linear Acceleration


Y

Z

X







Linear Acceleration


Y

X

Z







Linear Acceleration


Y

Z

X

4. External vs. Internal Injuries

Comparison of Pressure Contours on Brain and Skull

T=3.2ms

T=4.2ms

A. Angular Acceleration (1 of 3):

B. Linear Acceleration (1 of 3):

+

-

Angular Acceleration of the head has an effect on the entire brain

Equipment

Skull/Gel Model• Skull: A20/1

(Anatomical Chart Company; Hagerstown, MD)

• Gel: Sylgard 527 A&B Silicon Dielectric Gel(Dow Corning Corporation; Midland, MI)

Subject Seat• 1997 Ford F250

(VIN: 1FT HW26F 8 VE A67707)

Accelerometer• Type: ICSensors 3028

• Range: +/- 100g

• Serial Number: 0021-029

High Speed Camera• MotionScope®, Redlake Imaging

• Model: PCI 2000

• Model Number: 1108-0004

• Serial Number: 98P-0095

Skull: A20/1(Anatomical Chart Company; Hagerstown, MD)

Equipment

9hr cure 14hr cure

12hr cure

Silicon Gel PropertiesSylgard 5-27 A&B Silicon Dielectric Gel

(Dow Corning Corporation; Midland, MI)

Equipment

Brands, D., P. Bovendeered, G. Peter, et al. “Comparison of the Dynamic Behaviour of Brain Tissue and Two Model Materials”, SAE

99C21, Society of Automotive Engineers, Inc. 1999.

Properties Comparison Silicon Gel & Brain Tissue

0

2

4

6

8

10

12

14

0 0.01 0.02 0.03 0.04 0.05

Time(Sec)

Lin

ea

r A

cc

ele

rati

on

(G)

14.09g 10.55g

A. SEVERITY OF IMPACT

B. POSITION OF HEAD

75º

Simulation Experimental

Simulation Experimental 75º75º

Test Conditions (per ATB Simulation)

Skull/Gel Model Testing

• Severity of Impact (X = 10.10g, Y = 14.09g, Z = 4.02)•Tested at Y = 10.55g •Position of Head (Yaw 75º, Pitch 7º, Roll 6º)

Test Conditions (per ATB Simulation) :

Video Parameters:• Capture rate: 10,000 frames/sec• Slow motion (1/60th of actual velocity)


• Severity of Impact (X = 10.10g, Y = 14.09g, Z = 4.02)•Tested at Y = 10.55g• Position of Head (Yaw 75º, Pitch 7º, Roll 6º)



Transformed MRI Data

Source of Original Data:

• Dr. Orrison, Nevada Imaging Centers


• Severity of Impact (X = 10.10g, Y = 14.09g, Z = 4.02)•Tested at Y = 10.55g• Position of Head (Yaw 75º, Pitch 7º, Roll 6º)



Transformed MRI Data

Source of Original Data:

• Dr. Orrison, Nevada Imaging Centers

Approach

Rebound

Dynamic Pattern at Impact

The Head Model simulates all essential anatomical features of a male head, including the brain, falx and tentorium, CSF, dura mater, pia mater, skull and scalp.

Finite Element Modeling of the Human Head- Continuum Scale(Model currently used in Military Brain Trauma Analysis)

(US Department of Defense Research)

M Sotudeh Chafi, V Dirisala, G Karami, and M Ziejewski, A finite element method parametric study of the dynamic response of the human brain with different

cerebrospinal fluid constitutive properties, Proc. IMechE Part H: J. Engineering in Medicine, 2009; 223, 1003-101984

Variation of ICP and Shear Stress on the Brain with time

ICP

Shear

Stress

2.9

ms4.9

ms

4 ms

7 ms4.9

ms

3 ms

(kPa

)

• Supersonic overpressurization shockwave (>300m/s)

• Pressure increased to 10-100 MPa (1atm ≈ 100 kPa)

• Timescale in μs (microseconds)

Automotive Blast

Cavitation

Scanning Electron Micrograph

Crater

Brass Plate

Cavitation

Liquid Jet

~ 1 mm

CAVITATION DAMAGE

Macroscale

A. Spherical Bubble Collapse

B. Non-Spherical Bubble Collapse

Bubble Collapse

(Classical Approach)NanoscaleBubble Inception

(New Brain Injury Mechanism)

Liquid Jet

MassSpring

Fracture Point

Recoil pressure waves

MassSpring



INJURY MECHANISMS

Human Tolerance to Impact Conditions as Related to Motor Vehicle Design, SAE International, Revised Dec. 2003, SAE J885, Temporo-Parietal Bone p13.

Mean: 1910 lb Min: 1050 lb

Skull Fracture Research

Prasad, P., et al., (1985). The Position of the United States Delegation to the ISO Working Group on the Use of HIC in the

Automotive Environment. Ford Motor and G M Corp. SAE 851246

16%

25%

Prasad, P., et al., (1985). The Position of the United States Delegation to the ISO Working Group on the Use of HIC in the Automotive Environment. Ford Motor and G M Corp. SAE 851246

•Depreitere, B., Van Lierde, C., Vander Sloten, J., Van Audekercke, R., Van Der Perre, G., Plets, C., Goffin, J. (2006). Mechanics of acute subdural hematomas resulting from bridging vein rupture, Journal fo Neurosurgery, Vol. 104, J Neurosurg 104.

10,000rad/sec2

Tolerance Level:

Subdural Hematoma

Pulse Duration:

Shorter than: 10 ms

•Bandak, F., Eppinger, R. (1994). A Three-Dimensional Finite Element Analysis of The Human Brain Under Combined Rotational and Translational Accelerations, National Highway Traffic Safety Administration (NHTSA), SAE 942215.

Biomechanical Analysis Outcomes

1. Visualization of injury (beyond MRI’s)

• Resolution for MRI 0.25mm macroscale (10-3 m)• Details of biomechanic modeling nanoscale (10-9 m)

2. Mechanism of injury (beyond the current understanding)• Extremely dynamic oscillation of the brain tissue• Nanoscale Cavitation (New Brain Injury Mechanism)

3. Benefits• Current patients (location, extent of injury)• Prevention (protective systems, helmet)

6. Male vs.

Female

Quinlan, K., J. Annest, B. Myers, et.al. “Neck strains and sprains among motor vehicle occupants”,

Accident Analysis and Prevention 36, 2004.

~ 7000 Human TestsMaximum Acceleration: 80 G

Maximum Velocity: 17 m/s

Pulse Duration: 40-180 ms


M. Ziejewski and E.M. Yliniemi, “Prediction of Head Acceleration and Neck Loading in Vertical Impact”, The Impact of Technology on Sport III, 2009.

1.4 x

138 Tests

Female

Male

6.8 g

5.0 g

1.8 X

6mph

Female

Male

12g

6.5g

Hell W., S. Schick, and K. Langwieder “Biomechanics of Cervical Spine Injuries in Rear End Car Impacts: Influence of Car Seats and Possible Evaluation Criteria”, Traffic Injury Prevention, 2002.

2.5 XVan den Kroomerberg, M. Philippens, H. Cappon, J. Wismans, “Human Head-Neck Response During Low-Speed Rear Impacts”

SAE 983158.

6 mph

7. Humanvs.

Hybrid III

Kleinberger, M., R. Eppinger, M. Haffner, and M. Beebe, “Enhancing Safety with an Improved Cervical Test Device” Safety in Football, ASTM 1997.

3.5X5X

3X

2X

Stiffness in Neck

Stiffness in Neck

Human - Max

Human - Min

Hybrid III

Hybrid III

Human - Max

Human - Min

100°

80°

75°

55°

25°

20°


2X3X

2X1.5X

Human - Max

Human - Min

Hybrid III

Human - Max

Human - Min

Hybrid III

Stiffness in Neck

Stiffness in Neck

105°

85°

35°

90°

70°

45°


Gender: M Initial Head Angle: -9.0°

Weight: 175 Human Head Rotation: Forward

Human/Manikin Curve Matching

Gender: F Initial Head Angle: -28.9°

Weight: 136 Human Head Rotation: Forward

Human/Manikin Curve Matching

Headgear

Underwash: Fluid Flow Dynamics

Streamlines around unprotected and helmeted heads

0

100

200

300

400

500

600

700

800

-0.002 1E-17 0.002 0.004 0.006 0.008

Pre

ssu

re (

kP

a)

Time (s)

Helmeted

Velocity vectors- Top view

1) CPSC Headform 3) Human Head 4) Hybrid III2) Test Area

5) Human Head 6) Injury Diagram

7) Hybrid III with Exemplar Helmet

Impact Site Location

Temporal Bone Fracture

5) Human Head 6) Injury Diagram

7) Surrogate with Exemplar Helmet

Approximate impact site elevation for test to back of the helmet (1 in above the test line for the back impact)

1) DOT Headform 3) Human Head 4) Hybrid III2) Test Area

Impact Site Location

SNELL M2005 ECE 22.05

•Scheer, D., Karami, G., Ziejewski, M. (2015). An Evaluation of the Riddell IQ HITS System in Prediction of an Athlete’s Head Acceleration, 7th Asia-Pacific Congress on Sports Technology, SAE 942215.

Lateral Plane

•Scheer, D., Karami, G., Ziejewski, M. (2015). Effects of Helmet Surface Geometry on Head Acceleration in High Velocity Water Sports, 7th Asia-Pacific Congress on Sports Technology, SAE 942215.

the science of biomechanics and it’s practical application · injury research, education and...

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