Subject-specific rib finite element models with material data derived from coupon tests under bending loading.

Rib fractures are common thoracic injuries in motor vehicle crashes. Several human finite element (FE) human models have been created to numerically assess thoracic injury risks. However, the accurate prediction of rib biomechanical response has shown to be challenging due to human variation and modeling approaches.

Development and validation of a finite element model of a small female pedestrian.

Pedestrians are the most vulnerable road user and represent about 23% of the road traffic deaths in the world. A finite element (FE) model corresponding to a 5 percentile female pedestrian (F05-PS) was developed by morphing the Global Human Body Models Consortium (GHBMC) 50 percentile male pedestrian (M50-PS) model to the reconstructed geometry of a recruited small female subject. The material properties of the pedestrian model were assigned based on GHBMC M50-PS model.

Evaluation of finite element human body models for use in a standardized protocol for pedestrian safety assessment.

Finite element human body models (HBMs) must be certified for use within the EuroNCAP pedestrian safety assessment protocol. We demonstrate that the Global Human Body Model Consortium (GHBMC) simplified pedestrian series of HBMs meet all criteria set forth in Technical Bulletin (TB) 024 (v 1.1 Jan.

A finite element model of an anthropomorphic test device lower limb to assess risk of injuries during vertical accelerative loading.

Improvised explosive devices (IEDs) were used extensively to target occupants of military vehicles during the conflicts in Iraq and Afghanistan (2003-2011). War fighters exposed to an IED attack were highly susceptible to lower limb injuries. To appropriately assess vehicle safety and make informed improvements to vehicle design, a novel Anthropomorphic Test Device (ATD), called the Warrior Injury Assessment Manikin (WIAMan), was designed for vertical loading.

A Review of Pediatric Lower Extremity Data for Pedestrian Numerical Modeling: Injury Epidemiology, Anatomy, Anthropometry, Structural, and Mechanical Properties.

Pedestrian injuries are the fourth leading cause of unintentional injury-related death among children aged 1 to 19. The lower extremity represents the most frequently injured body region in car-to-pedestrian accidents. The goal of this study was to perform a systematic review of the data related to pedestrian lower extremity injuries, anatomy, anthropometry, structural, and mechanical properties, which can be used in the development of new pediatric computational models.

Finite element modeling of the human kidney for probabilistic occupant models: Statistical shape analysis and mesh morphing.

Statistical shape analysis was conducted on 15 pairs (left and right) of human kidneys. It was shown that the left and right kidney were significantly different in size and shape. In addition, several common modes of kidney variation were identified using statistical shape analysis.

Validation of a booted finite element model of the WIAMan ATD lower limb in component and whole-body vertical loading impacts with an assessment of the boot influence model on response.

Objective: A novel anthropomorphic test device (ATD) representative of the 50th percentile male soldier is being developed to predict injuries to a vehicle occupant during an underbody blast (UBB). The main objective of this study was to develop and validate a finite element (FE) model of the ATD lower limb outfitted with a military combat boot and to insert the validated lower limb into a model of the full ATD and simulate vertical loading experiments.

Methods: A Belleville desert combat boot model was assigned contacts and material properties based on previous experiments.

A Finite Element Model of a Midsize Male for Simulating Pedestrian Accidents.

Pedestrians represent one of the most vulnerable road users and comprise nearly 22% the road crash-related fatalities in the world. Therefore, protection of pedestrians in car-to-pedestrian collisions (CPC) has recently generated increased attention with regulations involving three subsystem tests. The development of a finite element (FE) pedestrian model could provide a complementary component that characterizes the whole-body response of vehicle-pedestrian interactions and assesses the pedestrian injuries.

Mechanical characterization and finite element implementation of the soft materials used in a novel anthropometric test device for simulating underbody blast loading.

Soft materials (e.g. polymers) are widely used in biomechanical devices to represent the nonlinear viscoelastic properties inherent in biological soft tissues.

A finite element model of a six-year-old child for simulating pedestrian accidents.

Child pedestrian protection deserves more attention in vehicle safety design since they are the most vulnerable road users who face the highest mortality rate. Pediatric Finite Element (FE) models could be used to simulate and understand the pedestrian injury mechanisms during crashes in order to mitigate them. Thus, the objective of the study was to develop a computationally efficient (simplified) six-year-old (6YO-PS) pedestrian FE model and validate it based on the latest published pediatric data.

Statistical shape analysis of the human spleen geometry for probabilistic occupant models.

Statistical shape models are an effective way to create computational models of human organs that can incorporate inter-subject geometrical variation. The main objective of this study was to create statistical mean and boundary models of the human spleen in an occupant posture. Principal component analysis was applied to fifteen human spleens in order to find the statistical modes of variation, mean shape, and boundary models.

Development and evaluation of a finite element model of the THOR for occupant protection of spaceflight crewmembers.

New vehicles are currently being developed to transport humans to space. During the landing phases, crewmembers may be exposed to spinal and frontal loading. To reduce the risk of injuries during these common impact scenarios, the National Aeronautics and Space Administration (NASA) is developing new safety standards for spaceflight.

A statistical geometrical description of the human liver for probabilistic occupant models.

Realistic numerical assessments of liver injury risk for the entire occupant population require incorporating inter-subject variations into numerical models. Statistical shape models of the abdominal organs have been shown to be useful tools for the investigation of the organ variations and could be applied to the development of statistical computational models. The main objective of this study was to establish a standard procedure to quantify the shape variations of a human liver in a seated posture, and construct three-dimensional (3D) statistical shape boundary models.

Modeling the biomechanical and injury response of human liver parenchyma under tensile loading.

The rapid advancement in computational power has made human finite element (FE) models one of the most efficient tools for assessing the risk of abdominal injuries in a crash event. In this study, specimen-specific FE models were employed to quantify material and failure properties of human liver parenchyma using a FE optimization approach. Uniaxial tensile tests were performed on 34 parenchyma coupon specimens prepared from two fresh human livers.

A numerical investigation on the variation in hip injury tolerance with occupant posture during frontal collisions.

Objective: More than half of occupant lower extremity (LEX) injuries during automotive frontal crashes are in the knee-thigh-hip (KTH) complex. The objective of this study is to develop a detailed and biofidelic finite element (FE) occupant LEX model that may improve current understanding of mechanisms and thresholds of KTH injuries.

Methods: Firstly, the pelvis, thigh-knee-hip, and foot models developed in our previous studies were connected into an occupant lower limb model.

Statistical modeling of human liver incorporating the variations in shape, size, and material properties.

The liver is one of the most frequently injured abdominal organs during motor vehicle crashes. Realistic numerical assessments of liver injury risk for the entire occupant population require incorporating inter-subject variations into numerical models. The main objective of this study was to quantify the shape variations of human liver in a seated posture and the statistical distributions of its material properties.

Development, calibration, and validation of a head-neck complex of THOR mod kit finite element model.

Introduction/objective: In an effort to continually improve upon the design of the test device for human occupant restraint (THOR) dummy, a series of modifications have recently been applied. The first objective of this study was to update the THOR head-neck finite element (FE) model to the specifications of the latest dummy modifications. The second objective was to develop and apply a new optimization-based methodology to calibrate the FE head-neck model based on experimental test data.

Effect of storage on tensile material properties of bovine liver.

Cadaveric tissue models play an important role in the assessment and optimization of novel restraint systems for reducing abdominal injuries. However, the effect of tissue preservation by means of freezing on the material properties of abdominal tissues remains unknown. The goal of this study was to investigate the influence of frozen storage time on the material responses of the liver parenchyma in tensile loading.

The influence of the specimen shape and loading conditions on the parameter identification of a viscoelastic brain model.

The mechanical properties of brain under various loadings have been reported in the literature over the past 50 years. Step-and-hold tests have often been employed to characterize viscoelastic and nonlinear behavior of brain under high-rate shear deformation; however, the identification of brain material parameters is typically performed by neglecting the initial strain ramp and/or by assuming a uniform strain distribution in the brain samples. Using finite element (FE) simulations of shear tests, this study shows that these simplifications have a significant effect on the identified material properties in the case of cylindrical human brain specimens.

Biomechanical and injury response of human foot and ankle under complex loading.

Ankle and subtalar joint injuries of vehicle front seat occupants are frequently recorded during frontal and offset vehicle crashes. A few injury criteria for foot and ankle were proposed in the past; however, they addressed only certain injury mechanisms or impact loadings. The main goal of this study was to investigate numerically the tolerance of foot and ankle under complex loading which may appear during automotive crashes.

Statistical shape analysis of clavicular cortical bone with applications to the development of mean and boundary shape models.

During car collisions, the shoulder belt exposes the occupant's clavicle to large loading conditions which often leads to a bone fracture. To better understand the geometric variability of clavicular cortical bone which may influence its injury tolerance, twenty human clavicles were evaluated using statistical shape analysis. The interior and exterior clavicular cortical bone surfaces were reconstructed from CT-scan images.

Material characterization of liver parenchyma using specimen-specific finite element models.

The liver is one of the most frequently injured abdominal organs during motor vehicle crashes. Realistic car crash simulations require incorporating strain-rate dependent mechanical properties of soft tissue in finite element (FE) material models. This study presents a total of 30 tension tests performed on fresh bovine liver parenchyma at various loading rates in order to characterize the biomechanical and failure properties of liver parenchyma.

Effect of storage methods on indentation-based material properties of abdominal organs.

To investigate the possible changes in material properties of cadaveric abdominal organs due to the preservation methods, the indentation data obtained from porcine abdominal organs (kidney, liver, and spleen) preserved by cooling and freezing are analyzed statistically in this study. Indentation tests were first conducted on fresh specimens. One half of the specimens of each organ were then frozen (preserved at - 12 degrees C), and the other half of the specimens were cooled (preserved at 4 degrees C).

A finite element model of the lower limb for simulating automotive impacts.

A finite element (FE) model of a vehicle occupant's lower limb was developed in this study to improve understanding of injury mechanisms during traffic crashes. The reconstructed geometry of a male volunteer close to the anthropometry of a 50th percentile male was meshed using mostly hexahedral and quadrilateral elements to enhance the computational efficiency of the model. The material and structural properties were selected based on a synthesis of current knowledge of the constitutive models for each tissue.

Freezing and decay effects on material properties of porcine kidney and liver.

Abdominal injuries caused by traffic accidents have severe consequences and are major causes of death in the United States. Several experiments were performed in the past on post-mortem human surrogate (PMHS) to quantify the abdominal tolerance under impact loading. However, some concerns were raised regarding the PMHS storage and its influence on the biomechanical response of internal organs.