Development and Full Body Validation of a 5 th Percentile Female Finite Element Model. Center for Injury Biomechanics

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1 Development and Full ody Validation of a 5 th Percentile Female Finite Element Model Matthew L. Davis, harath Koya, Jeremy M. Schap, F. Scott Gayzik MES/FDA Frontiers in Medical Devices May 17, 2017 enter for njury iomechanics

2 Motor Vehicle ollisions 8 th Leading cause of death worldwide 1.2 million deaths per year million non-fatal injuries To mitigate the toll of these injuries, researchers are using a variety of tools to design and evaluate vehicle safety devices World Health Organization (WHO) 2013

3 Driving Demographics Historically, M50 ATD in mid-track position was used for frontal crash tests Real world driving population made up of different sizes, genders, and ages Limitations for designing vehicle safety devices to one demographic

4 Driving Demographics Historically, M50 ATD in mid-track position was used for frontal crash tests Real world driving population made up of different sizes, genders, and ages Limitations for designing vehicle safety devices to one demographic

5 GHM Family of Models Mission Statement: reate and maintain the world s most detailed and accurate computerized human body models Wake Forest University is the Full ody Model enter for the project Develop and validate Full ody omputational Models 13 models (10 in User Acceptance Testing, 2 in development, 1 pending) F05-O M50-O M95-O F05-P M50-P F05-OS M50-OS M95-OS 6YO-PS F05-PS M50-PS M95-PS Detailed Simplified v 3.0 v. 4.5 v. 1.1 v. α v. α v. 1.2 v v. 1.2 v. 1.3 v. 1.3 v. 1.3 v. 1.3

6 GHM Small Female Occupant Model Main focus for this presentation is on the development and validation of the detailed 5 th percentile female finite element model F05-O M50-O M95-O F05-P M50-P F05-OS M50-OS M95-OS 6YO-PS F05-PS M50-PS M95-PS Detailed Simplified v 3.0 v. 4.5 v. 1.1 v. α v. α v. 1.2 v v. 1.2 v. 1.3 v. 1.3 v. 1.3 v. 1.3

7 Development of F05-O Geometries Recruitment Multi-Modality Medical mage Set More than 14,000 medical images collected across modalities and postures External Anthropometry Model Assembly A) T High resolution segmentation of bone ) Quasi-seated T mproved placement of bone ) EA known bony landmark locations (sparse)

8 Small Female Occupant AD Dataset Used all data in multimodality approach 306 ndividual AD omponents 161 ones 35 Organs 90 Muscles 30 Ligaments, Tendons, and artilage Davis et al. (2014)

9 Small Female Mesh Development Development Goals 1. Minimize ontacts 2. Mesh Uniformity 3. Minimize ntersections and Penetrations

10 Meshing Techniques Structured Hex Mesh Structure Specific Morphing Tetrahedral Mesh

11 Element Assignment AD data used to assign muscle material properties to homogeneous flesh mesh

12 F05-O Full ody Model 92% Reduction F05-O v3.0 M50-O v4.3 Number of Parts Number of Elements 2.5 x x 10 6 Number of Nodes 1.4 x x 10 6 Model Mass (kg) Number of ontacts

13 F05-O Full ody Validation ases Regional Rigid mpacts Full ody mpacts 10 mpacts for Full ody Validation of the Small Female Occupant Model

14 Validation Approach Experimentalist: Diverse specimens are typically scaled to a target mass for corridor development Modeling: This works well if your model represents an average male, but can be a challenge for validating models of varying anthropometry M50-O F05-O Hardy et al., 2001

15 Methods for Data omparison 2 Approaches for Data omparison 1. Post-hoc scaling of output from baseline F05-O model using techniques applied to the experimental dataset 2. Geometrically morphing the model to explicitly represent the average male 1 2 Grey = M50-O lack = F05-O Time Scale Factor = Deflection Scale Factor = R m M pend + M eff ref R k M pend + M eff target R m M pend + M eff ref R k M pend + M eff target Force Scale Factor = R m R k M pend + M eff ref M pend + M eff target F05-O Morphed compared to target landmarks Mertz et al. (1984), Viano et al. (1989)

16 Rigid mpact Examples Force (kn) 4 2 Force (kn) Kroell et al Lebarbe et al Deflection (mm) Viano et al Deflection (cm) 8 12 Force (kn) Torso Force (kn) Hardy et al Deflection (%) avanaugh et al Time (ms)

17 Objective Rating Total OE Score alculated Using SO Weights Magnitude Score from ORA Total OE Score ross-orr Rating (0.6) Zhan et al., SAE , 2011 ORA orridor Rating (0.4) Gehre et al., ESV Proceedings, 2009 Phase Error (1/3) Magnitude Error (1/3) Slope Error (1/3) Recreated from SO/TR 16250, Fig. 10-1

18 Objective Rating: Rigid mpacts Objective rating scores for scaled and morphed model responses for regional hub and lateral sled impacts Legend Simulation Thoraco- Abdominal Lateral Hub Signal Force vs. Time Force vs. Time Deflection % vs. Time Lateral Plate Force vs. Time Abdominal ar Force vs. Time Lateral Sled Torso Force vs. Time Pelvis Force vs. Time Average Response For omparison orridor Slope Size* Phase SO Score Scaled Morphed Scaled Morphed Scaled Morphed Scaled Morphed Scaled Morphed Scaled Morphed Scaled Morphed Scaled Morphed *alculated using ORA magnitude score

19 Objective Rating: Rigid mpacts Objective rating scores for scaled and morphed model responses for regional hub and lateral sled impacts Legend Simulation Thoraco- Abdominal Lateral Hub Signal Force vs. Time Force vs. Time Deflection % vs. Time Lateral Plate Force vs. Time Abdominal ar Force vs. Time Lateral Sled Torso Force vs. Time Pelvis Force vs. Time Average Response For omparison orridor Slope Size* Phase SO Score Scaled Morphed Scaled Morphed Scaled Morphed Scaled Morphed Scaled Morphed Scaled Morphed Scaled Morphed Scaled Morphed *alculated using ORA magnitude score

20 Rear Seat Frontal Sled U. Shoulder elt Force (kn) adaver 1 adaver 2 F05 F05 Morphed Time (ms) Forman et al Note: No scaling applied. omparison to experimental data performed with F05-O Morphed model

21 Shaw et al. Frontal Sled Shaw et al Note: No scaling applied. omparison to experimental data performed with F05-O Morphed model

22 Shaw et al. Frontal Sled Note: No scaling applied. omparison to experimental data performed with F05-O Morphed model

23 Objective Evaluation: Full ody Sleds Legend orridor Shape Size* Phase SO Score SO Mag Weighted Score Seat elt Forces Head Kinematics Shoulder Kinematics Pelvis Kinematics Average Seat elt Forces R Knee Forces L Knee Forces Foot Forces Head Kinematics T1 Kinematics T8 Kinematics L2 Kinematics Average *alculated using ORA magnitude score

24 Simulation Summary Model was found to be robust and showed fair to good agreement with experimental biomechanical response data Quantitatively demonstrated that full body morphing can be a more effective means of model validation than post-hoc data scaling

25 Regional Validation of the F05 Model Head N = 10 Ex. rain pressure, brain marker displacement, facial impact Neck N = 15 Ex. -spine segments, lower and upper -spine, full head neck Thorax N = 8 Ex. Denuded ribs, elbow, spine, lateral thoracic impact Abdomen N = 18 Ex. elt loading, bar impact, airbag loading, oblique impact Pelvis & Lower Extremity N = 15 Ex. Ankle, foot, femoral shaft, knee-thigh-hip, pelvis

26 Future Work ncreased focus on injury risk prediction and injury differential Evaluate model in additional load cases Application of the model as a tool for the enhancement of safety devices Further development of GHM family of models F05-O M50-O M95-O F05-P M50-P F05-OS M50-OS M95-OS 6YO-PS F05-PS M50-PS M95-PS Detailed Simplified v 3.0 v. 4.5 v. 1.1 v. α v. α v. 1.2 v v. 1.2 v. 1.3 v. 1.3 v. 1.3 v. 1.3

27 Acknowledgements Funding: Wake Forest U. School of Medicine GHM hrysler LL General Motors orp. Honda R&D o. ody Regional enters of Expertise Wayne State U. (Head), U. Waterloo (Neck), U. Virginia (Thorax), FSTTAR (Abdomen), U. Virginia (Plex), Wake Forest (Full ody) Hyundai Motor o. NHTSA Nissan Motor orp. Ltd Ford Motor o. Renault s.a.s. Takata orp. PSA Peugeot-itroën PD Data appearing in this document were prepared under the support of the Global Human ody Models onsortium by the FM enter of Expertise. Any opinions or recommendations expressed in this document are those of the authors and do not necessarily reflect the views of the Global Human ody Models onsortium. Dr. Gayzik is a member of Elemance, LL. which distributes academic and commercial license for GHMowned Human ody Models.

28 Development and Full ody Validation of a 5 th Percentile Female Finite Element Model Thank You! enter for njury iomechanics

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30 Supplemental

31 Method 1: F05-O Data Scaling For each impact environment, the F05-O response was scaled using the normalization techniques applied to the experimental dataset Example: mpulse Momentum Scaling Time Scale Factor = R m R k M pend + M eff ref M pend + M eff target R k Deflection Scale Factor = R m R k M pend + M eff ref M pend + M eff target M eff i = t t 0 M pend A pend dt t = Adt t 0 i V Acceleration Scale Factor = R k R m M pend + M eff ref M pend + M eff target Force Scale Factor = R m R k M pend + M eff ref M pend + M eff target Mertz et al. (1984) Viano et al. (1989)

32 Method 2: F05-O Morphed For direct comparison to experimental data, the F05-O model was morphed to the M50-O body habitus Served as a supplement to post-hoc data scaling Morph performed with the thin-plate spline * technique with 1,871 landmarks Final model mass of 76.2 kg Grey = M50-O lack = F05-O F05-O Morphed compared to target landmarks * Vavalle et al * Schoell et al. 2015

33 Hub mpacts Force (kn) 4 2 Force (kn) Kroell et al Lebarbe et al Deflection (mm) Viano et al Deflection (cm) Hardy et al Force (kn) Deflection (%) ouquet et al Force (kn) Deflection (mm)

34 Hub mpacts 5 10 Force (kn) Thoracic Force (kn) Koh et al Time (ms) Stalnaker et al Time (ms) Force (kn) Torso Force (kn) Kemper et al Time (ms) avanaugh et al Time (ms)

35 Objective Evaluation Weighting Weight Factor = R i R x + R y + R z

36 Study Summary Developed a finite element model of a seated 5 th percentile female Developed posture specific AD model of the small female Method to develop long bone AD from clinical T scans Developed a dataset for comparing small female organ volumes Applied human body models to evaluate scaling techniques in a controlled setting omparison of OE techniques to real world interpretation