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Akshey, Singh TR. Analysis of the human liver model through semi-analytical and numerical techniques with non-singular kernel. Comput Methods Biomech Biomed Engin 2024:1-13. [PMID: 38556900 DOI: 10.1080/10255842.2024.2332370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 03/13/2024] [Indexed: 04/02/2024]
Abstract
This work consists of the study of the time-fractional human liver model with the Caputo-Fabrizio fractional derivative. The existence and uniqueness of the proposed model are shown using fixed point theory. Also, the stability of the considered model is shown using the Ulam Hyres theorem and the Lyapunov function. The solution of the proposed model is obtained using a semi-analytical and numerical scheme. The series solution obtained from the semi-analytical method gives the proper result at any time, similarly, the numerical scheme gives the solution for a long time. The obtained numerical results are compared with real clinical data and earlier published work and found to be very close to real data than earlier published work. Results in the graphs and tables show that the proposed fractional-order model is superior to the traditional model.
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Affiliation(s)
- Akshey
- Department of Mathematics, Sardar Vallabhbhai National Institute of Technology, Surat, Gujarat, India
| | - Twinkle R Singh
- Department of Mathematics, Sardar Vallabhbhai National Institute of Technology, Surat, Gujarat, India
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2
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Forman J, Booth G, Mergler O, Romani S, Zhang H, Roberts C, Siegmund GP, Pipkorn B, Cripton P. Variability in Body Shape, Superficial Soft Tissue Geometry, and Seatbelt Fit Relative to the Pelvis in Automotive Postures-Methods for Volunteer Data Collection With Open Magnetic Resonance Imaging. J Biomech Eng 2024; 146:031005. [PMID: 38217111 DOI: 10.1115/1.4064477] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 11/27/2023] [Indexed: 01/15/2024]
Abstract
Variability in body shape and soft tissue geometry have the potential to affect the body's interaction with automotive safety systems. In this study, we developed a methodology to capture information on body shape, superficial soft tissue geometry, skeletal geometry, and seatbelt fit relative to the skeleton-in automotive postures-using Open Magnetic Resonance Imaging (MRI). Volunteer posture and belt fit were first measured in a vehicle and then reproduced in a custom MRI-safe seat (with an MR-visible seatbelt) placed in an Open MR scanner. Overlapping scans were performed to create registered three-dimensional reconstructions spanning from the thigh to the clavicles. Data were collected with ten volunteers (5 female, 5 male), each in their self-selected driving posture and in a reclined posture. Examination of the MRIs showed that in the males with substantial anterior abdominal adipose tissue, the abdominal adipose tissue tended to overhang the pelvis, narrowing in the region of the Anterior Superior Iliac Spine (ASIS). For the females, the adipose tissue depth around the lower abdomen and pelvis was more uniform, with a more continuous layer superficial to the ASIS. Across the volunteers, the pelvis rotated rearward by an average of 62% of the change in seatback angle during recline. In some cases, the lap belt drew nearer to the pelvis as the volunteer reclined (as the overhanging folds of adipose tissue stretched). In others, the belt-to-pelvis distance increased as the volunteer reclined. These observations highlight the importance of considering both interdemographic and intrademographic variability when developing tools to assess safety system robustness.
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Affiliation(s)
- Jason Forman
- Center for Applied Biomechanics, University of Virginia Center for Applied Biomechanics, 4040 Lewis and Clark Dr., Charlottesville, VA 22911
| | - Gabrielle Booth
- MEA Forensic Engineers & Scientists, 11151 Horseshoe Way, Richmond, BC V7A 4S5, Canada
| | - Olivia Mergler
- Center for Applied Biomechanics, University of Virginia Center for Applied Biomechanics, 4040 Lewis and Clark Dr., Charlottesville, VA 22911
| | - Sarah Romani
- University of British Columbia, 2222 Health Sciences Lane, Vancouver, BC V6T 1Z3, Canada
| | - Honglin Zhang
- University of British Columbia, 798 - 2635 Laurel Street, Vancouver, BC V5Z 1M9, Canada
| | - Carolyn Roberts
- MEA Forensic Engineers & Scientists, 23281 Vista Grande Drive, Laguna Hills, CA 92653
| | - Gunter P Siegmund
- University of British Columbia, 798 - 2635 Laurel Street, Vancouver, BC V5Z 1M9, Canada; MEA Forensic Engineers & Scientists, 3281 Vista Grande Drive, Laguna Hills, CA 92653
| | - Bengt Pipkorn
- Autoliv Research and Chalmers University, Wallentinsvägen 22 Vargarda, Västergötland 44793, Sweden
| | - Peter Cripton
- School of Biomedical Engineering, University of British Columbia, 2222 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
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O'Donovan S, van den Heuvel C, Baldock M, Humphries MA, Byard RW. Seat belt injuries and external markings at autopsy in cases of lethal vehicle crashes. MEDICINE, SCIENCE, AND THE LAW 2023; 63:195-202. [PMID: 36198036 DOI: 10.1177/00258024221127845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A study was undertaken to determine what injuries are associated with the wearing of seat belts and if the presence of cutaneous seat belt markings observed on victims of lethal vehicle crashes increased the likelihood of underlying injury. Autopsy reports from the files at Forensic Science South Australia were reviewed for all fatal motor vehicle crashes from January 2014 to December 2018. A total of 173 cases were included for analysis with 127 occupants wearing seat belts at the time of impact (73.4%) (age range = 18-93; mean = 45 M:F = 81:46). Of these, only 38 had external seat belt markings (29.9%) (age range = 19-83; mean = 49 M:F = 20:18). Logistic regression modelling showed that occupants who were wearing seat belts were more likely to experience closed head injury without skull fractures in addition to mesenteric and gastrointestinal injury. Increasing body mass index increased the incidence of seat belt markings (p < 0.01) and markings were more likely to be found in the presence of bilateral pelvic fractures. Thus, external seat belt markings were observed in only a minority of seatbelt wearers, and more often in individuals with higher BMIs and with bilateral pelvic fractures (possibly associated with greater momentum and impact force).
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Affiliation(s)
- Siobhan O'Donovan
- School of Biomedicine, The University of Adelaide, SA, Australia
- Forensic Science SA, Adelaide, SA, Australia
| | | | - Matthew Baldock
- Centre for Automotive Safety Research, The University of Adelaide, SA, Australia
| | | | - Roger W Byard
- School of Biomedicine, The University of Adelaide, SA, Australia
- Forensic Science SA, Adelaide, SA, Australia
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Robinson A, von Kleeck BW, Gayzik FS. Development and preliminary validation of computationally efficient and detailed 50th percentile female human body models. ACCIDENT; ANALYSIS AND PREVENTION 2023; 190:107182. [PMID: 37390749 DOI: 10.1016/j.aap.2023.107182] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/15/2023] [Accepted: 06/17/2023] [Indexed: 07/02/2023]
Abstract
OBJECTIVE No vehicle testing standard (physical or computational) employs a mid-sized female human surrogate, despite discrepancies related to injury outcomes for female occupants amongst all vehicle users. We detail the design and preliminary validation of 50th percentile female (F50) computational human body models (HBMs) based on Global Human Body Models Consortium (GHBMC) models. METHOD Data for the target geometry was collected as part of the initial generation of GHBMC models. Imaging, surface data, and 15 anthropomorphic measures from a living female subject (60.8 kg and 1.61 m) served as the baseline for model development. Due to the role rib cage geometry plays in biomechanical loading, rib cage morphology from secondary retrospective data was leveraged to identify an average female rib cage based on gross anatomical features. A female rib cage was selected from an existing dataset closest to the mean depth, height, and width of the set, considering only those aged 20 - 50 years. The selected subject among this secondary set also exhibited a 7th rib angle and sternum angle within 5% of the mean measurements, and within the range of previously reported studies. The GHBMC 5th percentile, small female detailed (high biofidelity) and simplified (computationally efficient) models were morphed to match the F50 subject body surface, selected bones, and mean rib cage using established thin plate spline techniques. The models were validated vs. previously published literature studies with an emphasis on rib cage response. Model data was compared to 47 channels of experimental data across four biomechanical hub simulations, two sled test simulations (one of which included all female PMHS), and two robustness simulations to test stability. Model results were mass scaled to the average of the reported corridors. Objective evaluation was conducted using CORA. IRB approval was obtained for all prospective and retrospective data collected or used. The target rib cage was selected from retrospective image data used in prior studies (n = 339 chest CT scans). RESULTS The morphed HBMs closely matched the target geometry. The detailed and simplified models had masses and element counts of 61.2 kg and 61.8 kg, and 2.8 million and 0.3 million, respectively. The mass difference is due to a coarser mesh in the simplified model. The simplified model ran 23 times faster than the detailed model on the same hardware. Each model exhibited stability in robustness tests, and the average CORA scores were 0.80 and 0.72 in the detailed and simplified models, respectively. The models performed well in frontal impacts against PMHS corridors after mass scaling. CONCLUSIONS Numerous recent studies underscore poorer injury outcomes for female vehicle occupants compared to males. While such outcomes are multifactorial, the average female models introduced in this work offer a novel tool within a widely used family of HBMs to reduce the outcome gap in terms of injury for all drivers. HBMs can be deployed in safety studies or in future regulatory requirements faster and more economically than a resized or newly designed ATDs aimed at the same target population.
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Affiliation(s)
- Andrea Robinson
- Wake Forest University School of Medicine, Department of Biomedical Engineering, United States
| | - B Wade von Kleeck
- Wake Forest University School of Medicine, Department of Biomedical Engineering, United States
| | - F Scott Gayzik
- Wake Forest University School of Medicine, Department of Biomedical Engineering, United States.
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Li X, Yuan Q, Lindgren N, Huang Q, Fahlstedt M, Östh J, Pipkorn B, Jakobsson L, Kleiven S. Personalization of human body models and beyond via image registration. Front Bioeng Biotechnol 2023; 11:1169365. [PMID: 37274163 PMCID: PMC10236199 DOI: 10.3389/fbioe.2023.1169365] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 04/28/2023] [Indexed: 06/06/2023] Open
Abstract
Finite element human body models (HBMs) are becoming increasingly important numerical tools for traffic safety. Developing a validated and reliable HBM from the start requires integrated efforts and continues to be a challenging task. Mesh morphing is an efficient technique to generate personalized HBMs accounting for individual anatomy once a baseline model has been developed. This study presents a new image registration-based mesh morphing method to generate personalized HBMs. The method is demonstrated by morphing four baseline HBMs (SAFER, THUMS, and VIVA+ in both seated and standing postures) into ten subjects with varying heights, body mass indices (BMIs), and sex. The resulting personalized HBMs show comparable element quality to the baseline models. This method enables the comparison of HBMs by morphing them into the same subject, eliminating geometric differences. The method also shows superior geometry correction capabilities, which facilitates converting a seated HBM to a standing one, combined with additional positioning tools. Furthermore, this method can be extended to personalize other models, and the feasibility of morphing vehicle models has been illustrated. In conclusion, this new image registration-based mesh morphing method allows rapid and robust personalization of HBMs, facilitating personalized simulations.
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Affiliation(s)
- Xiaogai Li
- Division of Neuronic Engineering, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Huddinge, Sweden
| | - Qiantailang Yuan
- Division of Neuronic Engineering, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Huddinge, Sweden
| | - Natalia Lindgren
- Division of Neuronic Engineering, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Huddinge, Sweden
| | - Qi Huang
- Division of Neuronic Engineering, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Huddinge, Sweden
| | | | - Jonas Östh
- Volvo Cars Safety Centre, Gothenburg, Sweden
- Division of Vehicle Safety, Department of Mechanics and Maritime Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Bengt Pipkorn
- Division of Vehicle Safety, Department of Mechanics and Maritime Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Autoliv Research, Vargarda, Sweden
| | - Lotta Jakobsson
- Volvo Cars Safety Centre, Gothenburg, Sweden
- Division of Vehicle Safety, Department of Mechanics and Maritime Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Svein Kleiven
- Division of Neuronic Engineering, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Huddinge, Sweden
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Corrales MA, Bolte J, Malcolm S, Pipkorn B, Cronin DS. Methodology to geometrically age human body models to average and subject-specific anthropometrics, demonstrated using a small stature female model assessed in a side impact. Comput Methods Biomech Biomed Engin 2022:1-12. [PMID: 35980145 DOI: 10.1080/10255842.2022.2112187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The aged population has been associated with an increased risk of injury in car-crash, creating a critical need for improved assessment of safety systems. Finite element human body models (HBMs) have been proposed, but require representative geometry of the aged population and high mesh quality. A new hybrid Morphing-CAD methodology was applied to a 26-year-old (YO) 5th percentile female model to create average 75YO and subject-specific 86YO HBMs. The method achieved accurate morphing targets while retaining high mesh quality. The three HBMs were integrated into a side sled impact test demonstrating similar kinematic response but differing rib fracture patterns.
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Affiliation(s)
- M A Corrales
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Canada
| | - J Bolte
- Injury Biomechanics Research Center, Ohio State University, Columbus, OH, USA
| | - S Malcolm
- Honda R&D Americas, Raymond, OH, USA
| | - B Pipkorn
- Division of Vehicle Safety, Department of Mechanics and Maritime Sciences, Chalmers University of Technology, Gothenburg, Sweden.,Autoliv Research, Vårgårda, Sweden
| | - D S Cronin
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Canada
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Naseri H, Iraeus J, Johansson H. A numerical study on the safety belt-to-pelvis interaction. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3572. [PMID: 35050534 PMCID: PMC9285376 DOI: 10.1002/cnm.3572] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/06/2022] [Accepted: 01/15/2022] [Indexed: 06/14/2023]
Abstract
The slide of the lap belt over the iliac crest of the pelvis during vehicle frontal crashes can substantially increase the risk of some occupant injuries. A multitude of factors, related to occupants or the design of belt, are associated with this phenomenon. This study investigates safety belt-to-pelvis interaction and identifies the most influential parameters. It also explores how initial lap belt position influences the interaction between lap belt and pelvis. A finite element model of the interaction between lap belt with pelvis through a soft tissue part was created. Belt angle, belt force, belt loading rate and belt-to-body friction as belt design parameters, and pelvis angle, constitute parameters of soft tissue, and soft tissue-to-pelvis friction as occupant parameters were inspected. For the soft tissue part, subcutaneous adipose tissue with different thicknesses was created and the effect initial lap belt position may have on lap belt-to-pelvis interaction was investigated. The influential parameters have been identified as: the belt angle and belt force as belt design parameters and the pelvis angle and compressibility of soft tissue as occupant parameters. The risk for the slide of lap belt over the iliac crest of the pelvis was predicted higher as the initial lap belt positions goes superior to the pelvis. Of different submarining parameters, the lap belt angle represents the most influential one. The lap belt-to-pelvis interaction is influenced by the thickness of subcutaneous adipose tissue between lap belt and pelvis indicating a higher risk for obese occupants.
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Affiliation(s)
- Hosein Naseri
- Mechanics and Maritime SciencesChalmers University of TechnologyGothenburgSweden
- Present address:
Chalmers University of TechnologyGothenburgSweden
| | - Johan Iraeus
- Mechanics and Maritime SciencesChalmers University of TechnologyGothenburgSweden
| | - Håkan Johansson
- Mechanics and Maritime SciencesChalmers University of TechnologyGothenburgSweden
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8
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Jones MLH, Ebert SM, Varban O, Hu J, Reed MP, Weerappuli P, Sundarajan S, Barbat S. Effect of Class I-III obesity on driver seat belt fit. TRAFFIC INJURY PREVENTION 2021; 22:547-552. [PMID: 34402347 DOI: 10.1080/15389588.2021.1945590] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 06/16/2021] [Accepted: 06/16/2021] [Indexed: 06/13/2023]
Abstract
OBJECTIVE Approximately 40% of the U.S. adult population are obese. An issue associated with this trend is proper seat belt fit for obese occupants. This study extends previous research, in which few individuals with high BMI (> 40 kg/m2) were included, by examining the relationship between participant and belt factors on belt fit for drivers with Class I-III obesity. METHODS Posture and belt fit of 52 men and women with BMI from 31 to 59 kg/m2 (median 38 kg/m2) were measured in a laboratory vehicle mockup. Five seat belt configurations were achieved by manipulating the belt anchorage locations. Body and belt landmark locations were recorded using a three-dimensional coordinate measuring machine. RESULTS Higher BMI was associated with a lap belt position further forward and higher relative to the pelvis. On average, the lap belt was positioned an additional 32 mm forward and 13 mm above the ASIS with each increasing level of obesity classification. Sex had a small effect after accounting for BMI and stature. The mean fore-aft location of the lap belt was 24 mm more forward for men vs. women and 12 mm higher for women vs. men at the same stature and BMI. On average, women used 50 mm more belt webbing in the lap and 92 mm more in the shoulder vs. men. CONCLUSIONS The results suggest that increasing levels of obesity class effectively introduces slack in the seat belt system by routing the belt further away from the skeleton. Because the belt is designed to engage the pelvis during a frontal crash, belt placements that are higher and further forward may increase injury risk by allowing excursions or submarining. Unique to this cohort, sex had an important effect on belt fit measures after taking into account stature and BMI. The participant and belt factors considered explained only about 40% of the variance in belt fit. The remaining variance may be due to preference or exogenous body shape effects. Further research is needed to assess methods for enhanced seat belt fit for people with obesity, including addressing sex differences in belt routing.
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Affiliation(s)
- Monica L H Jones
- University of Michigan Transportation Research Institute, University of Michigan, Ann Arbor, Michigan
| | - Sheila M Ebert
- University of Michigan Transportation Research Institute, University of Michigan, Ann Arbor, Michigan
| | - Oliver Varban
- Adult Bariatric Surgery, University of Michigan Health System, University of Michigan, Ann Arbor, Michigan
| | - Jingwen Hu
- University of Michigan Transportation Research Institute, University of Michigan, Ann Arbor, Michigan
| | - Matthew P Reed
- University of Michigan Transportation Research Institute, University of Michigan, Ann Arbor, Michigan
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Lebarbé M, Beillas P, Janak T, Lafon Y, Richard O, Petit P. Geometrical and Mechanical Characterization of the Abdominal Fold of Obese Post Mortem Human Subjects for Use in Human Body Modelling. STAPP CAR CRASH JOURNAL 2020; 64:213-267. [PMID: 33636006 DOI: 10.4271/2020-22-0006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Obese vehicle occupants sustain specific injury patterns in case of accidents in which the interaction between the seat belt and the abdomen may play a role. This study aimed to collect geometrical characteristics and to investigate the mechanical responses of the abdomen of obese subjects. Four Post Mortem Human Subjects (PMHS) with BMI ranging from 31 to 46 kg/m2 were collected. CT-scans performed in the seated position revealed that the antero-posterior depth of the abdominal fold (from the inguinal region to the most anterior point of the abdominal surface) was much greater (170 mm max., 127 mm average) than the thickness of subcutaneous adipose tissues (85 max., 38 mm in average). Each PMHS was subjected to three infra-injurious antero-posterior belt pulls in a seated posture with a lap belt positioned (C1) superior to the umbilicus, (C2) inferior to the umbilicus, (C3) inside the abdominal fold between the abdomen and the thigh. During the C1 and C2 tests, the belt moved cranially, and the abdominal fold opened widely especially in C2. Forces remained below 1800 N, for maximum applied displacements ranging from 89 to 151 mm for C1 and C2, and 37 to 66 mm for C3. Finally, sled tests were conducted on two PMHS seated on a semi-rigid seat and restrained by a three-point belt equipped with pretensioners and a 3.5 kN force limitation at the shoulder. The first PMHS (BMI 39 kg/m2) was tested at 49 km/h (39 g peak) and sustained severe injuries (AIS 4 pelvis dislocation, AIS 3 bilateral femur fractures) attributed to the combined loading of the seat and lap belt force (about 11 kN and 7 kN, respectively). The second PMHS (BMI 46 kg/m2) was subjected to a 29 km/h test (8 g plateau) and sustained no injury. The lap belt slid inside the abdominal fold in the first case and deformed the lower abdomen in the second, providing limited restraint forces during that interaction and leading to a large body excursion for the first test. The results highlight the possible relevance of the abdominal fold at the abdomen thigh junction to model and study the restraint conditions of obese occupants using Human Body Models (HBM).
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Affiliation(s)
| | - Philippe Beillas
- Univ Lyon, Univ Claude Bernard Lyon 1, Univ Gustave Eiffel, IFSTTAR, LBMC UMR_T 9406 (F-69622 Lyon, France)
| | - Tomas Janak
- Univ Lyon, Univ Claude Bernard Lyon 1, Univ Gustave Eiffel, IFSTTAR, LBMC UMR_T 9406 (F-69622 Lyon, France)
| | - Yoann Lafon
- Univ Lyon, Univ Claude Bernard Lyon 1, Univ Gustave Eiffel, IFSTTAR, LBMC UMR_T 9406 (F-69622 Lyon, France)
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Tang J, Zhou Q, Nie B, Hu J. Obesity effects on pedestrian lower extremity injuries in vehicle-to-pedestrian impacts: A numerical investigation using human body models. TRAFFIC INJURY PREVENTION 2020; 21:569-574. [PMID: 33095068 DOI: 10.1080/15389588.2020.1821195] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 07/31/2020] [Accepted: 09/05/2020] [Indexed: 06/11/2023]
Abstract
OBJECTIVE The objectives of this study were to develop a method for modeling obese pedestrians and to investigate effects of obesity on pedestrian impact responses and injury outcomes. METHODS The GHBMC (Global Human Body Model Consortium) 50th percentile male pedestrian model was morphed into geometries with 4 body mass index (BMI) levels (25/30/35/40 kg/m2) predicted by statistical body shape models. Each of the 4 morphed models was further morphed from a standing posture into 2 other gaits (toe-off and mid-swing), which resulted in a total of 12 (4 BMIs × 3 postures) models. Each model was used to simulate vehicle-to-pedestrian impact under 2 impact velocities. Pedestrian kinematics and injury measures were analyzed focusing on lower extremities. Statistical analyses were performed to examine significance of obesity on concerned injury measures. RESULTS Peak values of the bending moment at tibia, force at medial collateral ligament (MCL), bending angle at knee joint, and contact force between vehicle and pedestrian increased significantly (P < .05) with increased BMI. By analyzing kinematics of the lower extremity, the overall vehicle-to-pedestrian impact was divided into 2 phases: "initial contact" and "tibia rebound." For obese pedestrians, the added mass caused a higher tibia bending moment in the initial contact phase, and the greater moment of inertia led to greater bending angle and MCL force in the tibia rebound phase. Statistical analyses also revealed that pre-impact posture and impact velocity had significant effects on all injury measures. CONCLUSIONS Obesity could significantly increase the risk of pedestrian lower extremity injuries due to the inertial effect from the added mass. Pre-impact posture and impact velocity also significantly affect pedestrian injury measures. Future vehicle designs for pedestrian protection should consider populations with obesity. This study demonstrated the feasibility of using parametric human modeling to account for population diversity in injury prediction.
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Affiliation(s)
- Jisi Tang
- State Key Laboratory of Automotive Safety and Energy, School of Vehicle and Mobility, Tsinghua University, Beijing, China
- University of Michigan Transportation Research Institute, Ann Arbor, Michigan
| | - Qing Zhou
- State Key Laboratory of Automotive Safety and Energy, School of Vehicle and Mobility, Tsinghua University, Beijing, China
| | - Bingbing Nie
- State Key Laboratory of Automotive Safety and Energy, School of Vehicle and Mobility, Tsinghua University, Beijing, China
| | - Jingwen Hu
- University of Michigan Transportation Research Institute, Ann Arbor, Michigan
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Hu J, Zhang K, Reed MP, Wang JT, Neal M, Lin CH. Frontal crash simulations using parametric human models representing a diverse population. TRAFFIC INJURY PREVENTION 2019; 20:S97-S105. [PMID: 31381451 DOI: 10.1080/15389588.2019.1581926] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/07/2019] [Accepted: 02/08/2019] [Indexed: 06/10/2023]
Abstract
Objective: Analyses of crash data have shown that older, obese, and/or female occupants have a higher risk of injury in frontal crashes compared to the rest of the population. The objective of this study was to use parametric finite element (FE) human models to assess the increased injury risks and identify safety concerns for these vulnerable populations. Methods: We sampled 100 occupants based on age, sex, stature, and body mass index (BMI) to span a wide range of the U.S. adult population. The target anatomical geometry for each of the 100 models was predicted by the statistical geometry models for the rib cage, pelvis, femur, tibia, and external body surface developed previously. A regional landmark-based mesh morphing method was used to morph the Global Human Body Models Consortium (GHBMC) M50-OS model into the target geometries. The morphed human models were then positioned in a validated generic vehicle driver compartment model using a statistical driving posture model. Frontal crash simulations based on U.S. New Car Assessment Program (U.S. NCAP) were conducted. Body region injury risks were calculated based on the risk curves used in the US NCAP, except that scaling was used for the neck, chest, and knee-thigh-hip injury risk curves based on the sizes of the bony structures in the corresponding body regions. Age effects were also considered for predicting chest injury risk. Results: The simulations demonstrated that driver stature and body shape affect occupant interactions with the restraints and consequently affect occupant kinematics and injury risks in severe frontal crashes. U-shaped relations between occupant stature/weight and head injury risk were observed. Chest injury risk was strongly affected by age and sex, with older female occupants having the highest risk. A strong correlation was also observed between BMI and knee-thigh-hip injury risk, whereas none of the occupant parameters meaningfully affected neck injury risks. Conclusions: This study is the first to use a large set of diverse FE human models to investigate the combined effects of age, sex, stature, and BMI on injury risks in frontal crashes. The study demonstrated that parametric human models can effectively predict the injury trends for the population and may now be used to optimize restraint systems for people who are not similar in size and shape to the available anthropomorphic test devices (ATDs). New restraints that adapt to occupant age, sex, stature, and body shape may improve crash safety for all occupants.
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Affiliation(s)
- Jingwen Hu
- a University of Michigan Transportation Research Institute , Ann Arbor , Michigan
| | - Kai Zhang
- a University of Michigan Transportation Research Institute , Ann Arbor , Michigan
| | - Matthew P Reed
- a University of Michigan Transportation Research Institute , Ann Arbor , Michigan
| | - Jenne-Tai Wang
- b General Motors Research & Development , Warren , Michigan
| | - Mark Neal
- b General Motors Research & Development , Warren , Michigan
| | - Chin-Hsu Lin
- b General Motors Research & Development , Warren , Michigan
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12
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Objective Evaluation of Whole Body Kinematics in a Simulated, Restrained Frontal Impact. Ann Biomed Eng 2018; 47:512-523. [PMID: 30523467 DOI: 10.1007/s10439-018-02180-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 11/29/2018] [Indexed: 12/27/2022]
Abstract
The use of human body models as an additional data point in the evaluation of human-machine interaction requires quantitative validation. In this study a validation of the Global Human Body Models Consortium (GHBMC) average male occupant model (M50-O v. 4.5) in a restrained frontal sled test environment is presented. For vehicle passengers, frontal crash remains the most common mode, and the most common source of fatalities. A total of 55-time history traces of reaction loads and kinematics from the model were evaluated against corresponding PMHS data (n = 5). Further, the model's sensitivity to the belt path was studied by replicating two documented PMHS cases with prominent lateral and medial belt paths respectively. Results were quantitatively evaluated using open source CORA software. A tradeoff was observed; better correlation scores were achieved on gross measures (e.g. reaction loads), whereas better corridor scores were achieved on localized measures (rib deflections), indicating that subject specificity may dominate the comparison at localized anatomical regions. On an overall basis, the CORA scores were 0.68, 0.66 and 0.60 for force, body kinematics and chest wall kinematics. Belt force responses received the highest grouped CORA score of 0.85. Head and sternum kinematics earning a 0.8 and 0.7 score respectively. The model demonstrated high sensitivity to belt path, resulting in a 20-point increase in CORA score when the belt was routed closer to analogous location of data collection. The human model demonstrated overall reasonable biofidelity and sensitivity to countermeasures in frontal crash kinematics.
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Hartka TR, Carr HM, Smith BR, Melmer M, Sochor MR. Does obesity affect the position of seat belt loading in occupants involved in real-world motor vehicle collisions? TRAFFIC INJURY PREVENTION 2018; 19:S70-S75. [PMID: 29584490 DOI: 10.1080/15389588.2017.1381337] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 09/13/2017] [Indexed: 06/08/2023]
Abstract
OBJECTIVE Previous work has shown that the lap belt moves superior and forward compared to the bony pelvis as body mass index (BMI) increases. The goal of this project was to determine whether the location of lap belt loading is related to BMI for occupants who sustained real-world motor vehicle collisions (MVCs). METHODS A national MVC database was queried for vehicle occupants over a 10-year period (2003-2012) who were at least 16 years old, restrained by a 3-point seat belt, sitting in the front row, and involved in a front-end collision with a change in velocity of at least 56 km/h. Cases were excluded if there was not an available computed tomography (CT) scan of the abdomen. CT scans were then analyzed using adipose enhancement of 3-dimensional reconstructions. Scans were assessed for the presence a radiographic seat belt sign (rSBS), or subcutaneous fat stranding due to seat belt loading. In scans in which the rSBS was present, anterior and superior displacement of rSBS from the anterior-superior iliac spine (ASIS) was measured bilaterally. This displacement was correlated with BMI and injury severity. RESULTS The inclusion and exclusion criteria yielded 151 cases for analysis. An rSBS could definitively be identified in 55 cases. Cases in which occupants were older and had higher BMI were more likely to display an rSBS. There was a correlation between increasing BMI and anterior rSBS displacement (P <.01 and P <.01, right and left, respectively). There was no significant correlation between BMI and superior displacement of the rSBS (P =.46 and P =.33, right and left, respectively). When the data were examined in terms of relating increasing superior displacement of the lap belt with Injury Severity Scale (P =.34) and maximum Abbreviated Injury Score (AIS) injury severity (P =.63), there was also no significant correlation. CONCLUSION The results from this study demonstrated that anterior displacement of the radiographic seat belt sign but not superior displacement increased with higher BMI. These results suggest that obesity may worsen horizontal position but not the vertical position of the lap belt loading during real-world frontal MVCs.
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Affiliation(s)
- Thomas R Hartka
- a Department of Emergency Medicine , University of Virginia Health Sciences Center , Charlottesville , Virginia
| | - Hannah M Carr
- b School of Medicine, University of Virginia Health Sciences Center , Chartlottesville , Virginia
| | - Brittany R Smith
- b School of Medicine, University of Virginia Health Sciences Center , Chartlottesville , Virginia
| | - Monica Melmer
- a Department of Emergency Medicine , University of Virginia Health Sciences Center , Charlottesville , Virginia
| | - Mark R Sochor
- a Department of Emergency Medicine , University of Virginia Health Sciences Center , Charlottesville , Virginia
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14
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Naseri H, Johansson H, Brolin K. A Nonlinear Viscoelastic Model for Adipose Tissue Representing Tissue Response at a Wide Range of Strain Rates and High Strain Levels. J Biomech Eng 2018; 140:2658263. [DOI: 10.1115/1.4038200] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Indexed: 11/08/2022]
Abstract
Finite element human body models (FEHBMs) are nowadays commonly used to simulate pre- and in-crash occupant response in order to develop advanced safety systems. In this study, a biofidelic model for adipose tissue is developed for this application. It is a nonlinear viscoelastic model based on the Reese et al.'s formulation. The model is formulated in a large strain framework and applied for finite element (FE) simulation of two types of experiments: rheological experiments and ramped-displacement experiments. The adipose tissue behavior in both experiments is represented well by this model. It indicates the capability of the model to be used in large deformation and wide range of strain rates for application in human body models.
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Affiliation(s)
- Hosein Naseri
- Mechanics and Maritime Sciences, Chalmers University of Technology, Gothenburg SE-412 96, Sweden e-mail:
| | - Håkan Johansson
- Mechanics and Maritime Sciences, Chalmers University of Technology, Gothenburg SE-412 96, Sweden e-mail:
| | - Karin Brolin
- Mechanics and Maritime Sciences, Chalmers University of Technology, Gothenburgkarin SE-412 96, Sweden e-mail:
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Zhang K, Cao L, Wang Y, Hwang E, Reed MP, Forman J, Hu J. Impact Response Comparison Between Parametric Human Models and Postmortem Human Subjects with a Wide Range of Obesity Levels. Obesity (Silver Spring) 2017; 25:1786-1794. [PMID: 28815943 DOI: 10.1002/oby.21947] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 06/25/2017] [Accepted: 06/27/2017] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Field data analyses have shown that obesity significantly increases the occupant injury risks in motor vehicle crashes, but the injury assessment tools for people with obesity are largely lacking. The objectives of this study were to use a mesh morphing method to rapidly generate parametric finite element models with a wide range of obesity levels and to evaluate their biofidelity against impact tests using postmortem human subjects (PMHS). METHODS Frontal crash tests using three PMHS seated in a vehicle rear seat compartment with body mass index (BMI) from 24 to 40 kg/m2 were selected. To develop the human models matching the PMHS geometry, statistical models of external body shape, rib cage, pelvis, and femur were applied to predict the target geometry using age, sex, stature, and BMI. A mesh morphing method based on radial basis functions was used to rapidly morph a baseline human model into the target geometry. The model-predicted body excursions and injury measures were compared to the PMHS tests. RESULTS Comparisons of occupant kinematics and injury measures between the tests and simulations showed reasonable correlations across the wide range of BMI levels. CONCLUSIONS The parametric human models have the capability to account for the obesity effects on the occupant impact responses and injury risks.
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Affiliation(s)
- Kai Zhang
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan, China
- University of Michigan Transportation Research Institute, Ann Arbor, Michigan, USA
| | - Libo Cao
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan, China
| | - Yulong Wang
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan, China
- University of Michigan Transportation Research Institute, Ann Arbor, Michigan, USA
| | - Eunjoo Hwang
- University of Michigan Transportation Research Institute, Ann Arbor, Michigan, USA
| | - Matthew P Reed
- University of Michigan Transportation Research Institute, Ann Arbor, Michigan, USA
| | - Jason Forman
- Center for Applied Biomechanics, University of Virginia, Charlottesville, Virginia, USA
| | - Jingwen Hu
- University of Michigan Transportation Research Institute, Ann Arbor, Michigan, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, USA
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Klein KF, Hu J, Reed MP, Schneider LW, Rupp JD. Validation of a parametric finite element human femur model. TRAFFIC INJURY PREVENTION 2017; 18:420-426. [PMID: 28095035 DOI: 10.1080/15389588.2016.1269172] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 12/02/2016] [Indexed: 06/06/2023]
Abstract
OBJECTIVE Finite element (FE) models with geometry and material properties that are parametric with subject descriptors, such as age and body shape/size, are being developed to incorporate population variability into crash simulations. However, the validation methods currently being used with these parametric models do not assess whether model predictions are reasonable in the space over which the model is intended to be used. This study presents a parametric model of the femur and applies a unique validation paradigm to this parametric femur model that characterizes whether model predictions reproduce experimentally observed trends. METHODS FE models of male and female femurs with geometries that are parametric with age, femur length, and body mass index (BMI) were developed based on existing statistical models that predict femur geometry. These parametric FE femur models were validated by comparing responses from combined loading tests of femoral shafts to simulation results from FE models of the corresponding femoral shafts whose geometry was predicted using the associated age, femur length, and BMI. The effects of subject variables on model responses were also compared with trends in the experimental data set by fitting similarly parameterized statistical models to both the results of the experimental data and the corresponding FE model results and then comparing fitted model coefficients for the experimental and predicted data sets. RESULTS The average error in impact force at experimental failure for the parametric models was 5%. The coefficients of a statistical model fit to simulation data were within one standard error of the coefficients of a similarly parameterized model of the experimental data except for the age parameter, likely because material properties used in simulations were not varied with specimen age. In simulations to explore the effects of femur length, BMI, and age on impact response, only BMI significantly affected response for both men and women, with increasing BMI producing higher impact forces. CONCLUSIONS Impactor forces from simulations, on average, matched experimental values at the time of failure. In addition, the simulations were able to match the trends in the experimental data set.
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Affiliation(s)
- Katelyn F Klein
- a University of Michigan Transportation Research Institute , Ann Arbor , Michigan
| | - Jingwen Hu
- a University of Michigan Transportation Research Institute , Ann Arbor , Michigan
- b Department of Mechanical Engineering , University of Michigan , Ann Arbor , Michigan
| | - Matthew P Reed
- a University of Michigan Transportation Research Institute , Ann Arbor , Michigan
- c Center for Ergonomics, Industrial and Operations Engineering, University of Michigan , Ann Arbor , Michigan
| | - Lawrence W Schneider
- a University of Michigan Transportation Research Institute , Ann Arbor , Michigan
- d Department of Biomedical Engineering , University of Michigan , Ann Arbor , Michigan
| | - Jonathan D Rupp
- a University of Michigan Transportation Research Institute , Ann Arbor , Michigan
- d Department of Biomedical Engineering , University of Michigan , Ann Arbor , Michigan
- e Department of Emergency Medicine , University of Michigan Medical School , Ann Arbor , Michigan
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Hwang E, Hu J, Chen C, Klein KF, Miller CS, Reed MP, Rupp JD, Hallman JJ. Development, Evaluation, and Sensitivity Analysis of Parametric Finite Element Whole-Body Human Models in Side Impacts. STAPP CAR CRASH JOURNAL 2016; 60:473-508. [PMID: 27871104 DOI: 10.4271/2016-22-0014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Occupant stature and body shape may have significant effects on injury risks in motor vehicle crashes, but the current finite element (FE) human body models (HBMs) only represent occupants with a few sizes and shapes. Our recent studies have demonstrated that, by using a mesh morphing method, parametric FE HBMs can be rapidly developed for representing a diverse population. However, the biofidelity of those models across a wide range of human attributes has not been established. Therefore, the objectives of this study are 1) to evaluate the accuracy of HBMs considering subject-specific geometry information, and 2) to apply the parametric HBMs in a sensitivity analysis for identifying the specific parameters affecting body responses in side impact conditions. Four side-impact tests with two male post-mortem human subjects (PMHSs) were selected to evaluate the accuracy of the geometry and impact responses of the morphed HBMs. For each PMHS test, three HBMs were simulated to compare with the test results: the original Total Human Model for Safety (THUMS) v4.01 (O-THUMS), a parametric THUMS (P-THUMS), and a subject-specific THUMS (S-THUMS). The P-THUMS geometry was predicted from only age, sex, stature, and BMI using our statistical geometry models of skeleton and body shape, while the S-THUMS geometry was based on each PMHS's CT data. The simulation results showed a preliminary trend that the correlations between the PTHUMS- predicted impact responses and the four PMHS tests (mean-CORA: 0.84, 0.78, 0.69, 0.70) were better than those between the O-THUMS and the normalized PMHS responses (mean-CORA: 0.74, 0.72, 0.55, 0.63), while they are similar to the correlations between S-THUMS and the PMHS tests (mean-CORA: 0.85, 0.85, 0.67, 0.72). The sensitivity analysis using the PTHUMS showed that, in side impact conditions, the HBM skeleton and body shape geometries as well as the body posture were more important in modeling the occupant impact responses than the bone and soft tissue material properties and the padding stiffness with the given parameter ranges. More investigations are needed to further support these findings.
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Affiliation(s)
- Eunjoo Hwang
- University of Michigan Transportation Research Institute
| | - Jingwen Hu
- University of Michigan Transportation Research Institute
| | - Cong Chen
- University of Michigan Transportation Research Institute
| | | | - Carl S Miller
- University of Michigan Transportation Research Institute
| | - Matthew P Reed
- University of Michigan Transportation Research Institute
| | | | - Jason J Hallman
- Collaborative Safety Research Center, Toyota Technical Center USA
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Wang Y, Cao L, Bai Z, Reed MP, Rupp JD, Hoff CN, Hu J. A parametric ribcage geometry model accounting for variations among the adult population. J Biomech 2016; 49:2791-2798. [DOI: 10.1016/j.jbiomech.2016.06.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 06/14/2016] [Accepted: 06/18/2016] [Indexed: 11/29/2022]
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Cao L, Zhang K, Lv X, Yan L. Comparison of current ATDs with Chinese adults in anthropometry. TRAFFIC INJURY PREVENTION 2016; 17:430-433. [PMID: 26508539 DOI: 10.1080/15389588.2015.1101077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
OBJECTIVE Crash test dummies are full-scale anthropomorphic test devices (ATDs) that simulate the dimensions, weight proportions, and articulation of the human body and are used to measure human injury potential in vehicle crashes. The Hybrid III dummy family, which is widely used currently, takes selected percentiles of anthropometry dimensions of U.S. adults as design references. The objective of this study was to assess the difference in anthropometry between Chinese adults and the currently used dummy. METHODS Based on the Chinese National Physical Fitness Surveillance of the year 2000, 2005, 2010 and National Standard of China GB/T 10000-1988, a series of anthropometric parameters for Chinese adults were obtained, and data analysis was conducted between Chinese adults and ATDs that are currently used. RESULTS The comparison revealed distinct anthropometric difference between ATDs and Chinese adults. Based on the latest data, median Chinese females were about 2.6% lower in stature and about 8.03% lower in body weight than the ATD design targets. Similarly, median Chinese males were about 3.48% shorter and weighed 11.89% less than the ATD design targets. CONCLUSIONS Although the anthropometric differences between Chinese adults and the Hybrid III ATD specifications were modest and growing smaller, it is advisable to take the differences in anthropometry between ATDs and Chinese adults into consideration when developing new vehicles in China to provide effective protection specifically for Chinese occupants.
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Affiliation(s)
- Libo Cao
- a State Key Laboratory of Advanced Design and Manufacture for Vehicle Body, Hunan University , Changsha , Hunan , China
| | - Kai Zhang
- a State Key Laboratory of Advanced Design and Manufacture for Vehicle Body, Hunan University , Changsha , Hunan , China
| | - Xin Lv
- a State Key Laboratory of Advanced Design and Manufacture for Vehicle Body, Hunan University , Changsha , Hunan , China
| | - Lingbo Yan
- a State Key Laboratory of Advanced Design and Manufacture for Vehicle Body, Hunan University , Changsha , Hunan , China
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Hu J, Flannagan CA, Bao S, McCoy RW, Siasoco KM, Barbat S. Integration of Active and Passive Safety Technologies--A Method to Study and Estimate Field Capability. STAPP CAR CRASH JOURNAL 2015; 59:269-296. [PMID: 26660747 DOI: 10.4271/2015-22-0010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The objective of this study is to develop a method that uses a combination of field data analysis, naturalistic driving data analysis, and computational simulations to explore the potential injury reduction capabilities of integrating passive and active safety systems in frontal impact conditions. For the purposes of this study, the active safety system is actually a driver assist (DA) feature that has the potential to reduce delta-V prior to a crash, in frontal or other crash scenarios. A field data analysis was first conducted to estimate the delta-V distribution change based on an assumption of 20% crash avoidance resulting from a pre-crash braking DA feature. Analysis of changes in driver head location during 470 hard braking events in a naturalistic driving study found that drivers' head positions were mostly in the center position before the braking onset, while the percentage of time drivers leaning forward or backward increased significantly after the braking onset. Parametric studies with a total of 4800 MADYMO simulations showed that both delta-V and occupant pre-crash posture had pronounced effects on occupant injury risks and on the optimal restraint designs. By combining the results for the delta-V and head position distribution changes, a weighted average of injury risk reduction of 17% and 48% was predicted by the 50th percentile Anthropomorphic Test Device (ATD) model and human body model, respectively, with the assumption that the restraint system can adapt to the specific delta-V and pre-crash posture. This study demonstrated the potential for further reducing occupant injury risk in frontal crashes by the integration of a passive safety system with a DA feature. Future analyses considering more vehicle models, various crash conditions, and variations of occupant characteristics, such as age, gender, weight, and height, are necessary to further investigate the potential capability of integrating passive and DA or active safety systems.
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Affiliation(s)
- Jingwen Hu
- University of Michigan Transportation Research Institute
| | | | - Shan Bao
- University of Michigan Transportation Research Institute
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Zhu F, Jiang B, Hu J, Wang Y, Shen M, Yang KH. Computational Modeling of Traffic Related Thoracic Injury of a 10-Year-Old Child Using Subject-Specific Modeling Technique. Ann Biomed Eng 2015; 44:258-71. [PMID: 26126484 DOI: 10.1007/s10439-015-1372-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 06/19/2015] [Indexed: 11/24/2022]
Abstract
Traffic injuries have become a major health-related issue to school-aged children. To study this type of injury with numerical simulations, a finite element model was developed to represent the full body of a 10-year-old (YO) child. The model has been validated against test data at both body-part and full-body levels in previous studies. Representing only the average 10-YO child, this model did not include subject-specific attributes, such as the variations in size and shape among different children. In this paper, a new modeling approach was used to morph this baseline model to a subject-specific model, based on anthropometric data collected from pediatric subjects. This mesh-morphing method was then used to rapidly morph the baseline mesh into the subject-specific geometry while maintaining a good mesh quality. The morphed model was subsequently applied to simulate a real-world motor vehicle crash accident. A lung injury observed in the accident was well captured by the subject-specific model. The findings of this study demonstrate the feasibility of the proposed morphing approach to develop subject-specific human models, and confirm their capability in prediction of traffic injuries.
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Affiliation(s)
- Feng Zhu
- Bioengineering Center, Wayne State University, Detroit, USA.
| | - Binhui Jiang
- Bioengineering Center, Wayne State University, Detroit, USA.,Key State Lab of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, China
| | - Jingwen Hu
- University of Michigan Transportation Research Institute, Ann Arbor, USA.,Department of Mechanical Engineering, University of Michigan, Ann Arbor, USA
| | - Yulong Wang
- Key State Lab of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, China.,University of Michigan Transportation Research Institute, Ann Arbor, USA
| | - Ming Shen
- Bioengineering Center, Wayne State University, Detroit, USA
| | - King H Yang
- Bioengineering Center, Wayne State University, Detroit, USA
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Wang Y, Bai Z, Cao L, Reed MP, Fischer K, Adler A, Hu J. A simulation study on the efficacy of advanced belt restraints to mitigate the effects of obesity for rear-seat occupant protection in frontal crashes. TRAFFIC INJURY PREVENTION 2015; 16 Suppl 1:S75-S83. [PMID: 26027978 DOI: 10.1080/15389588.2015.1010722] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
OBJECTIVE Recent field data analyses have shown that the safety advantages of rear seats relative to the front seats have decreased in newer vehicles. Separately, the risks of certain injuries have been found to be higher for obese occupants. The objective of this study is to investigate the effects of advanced belt features on the protection of rear-seat occupants with a range of body mass index (BMI) in frontal crashes. METHODS Whole-body finite element human models with 4 BMI levels (25, 30, 35, and 40 kg/m2) developed previously were used in this study. A total of 52 frontal crash simulations were conducted, including 4 simulations with a standard rear-seat, 3-point belt and 48 simulations with advanced belt features. The parameters varied in the simulations included BMI, load limit, anchor pretensioner, and lap belt routing relative to the pelvis. The injury measurements analyzed in this study included head and hip excursions, normalized chest deflection, and torso angle (defined as the angle between the hip-shoulder line and the vertical direction). Analyses of covariance were used to test the significance (P <.05) of the results. RESULTS Higher BMI was associated with greater head and hip excursions and larger normalized chest deflection. Higher belt routing increased the hip excursion and torso angle, which indicates a higher submarining risk, whereas the anchor pretensioner reduced hip excursion and torso angle. Lower load limits decreased the normalized chest deflection but increased the head excursion. Normalized chest deflection had a positive correlation with maximum torso angle. Occupants with higher BMI have to use higher load limits to reach head excursions similar to those in lower BMI occupants. DISCUSSION AND CONCLUSION The simulation results suggest that optimizing load limiter and adding pretensioner(s) can reduce injury risks associated with obesity, but conflicting effects on head and chest injuries were observed. This study demonstrated the feasibility and importance of using human models to investigate protection for occupants with various BMI levels. A seat belt system capable of adapting to occupant size and body shape will improve protection for obese occupants in rear seats.
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Affiliation(s)
- Yulong Wang
- a State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body , Hunan University , Changsha , Hunan , China
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Park H, Park W, Kim Y. Manikin Families Representing Obese Airline Passengers in the US. JOURNAL OF HEALTHCARE ENGINEERING 2014; 5:479-504. [DOI: 10.1260/2040-2295.5.4.479] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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