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Technical Paper

Dynamic Properties of the Upper Thoracic Spine-Pectoral Girdle (UTS-PG) System and Corresponding Kinematics in PMHS Sled Tests

2012-10-29
2012-22-0003
Anthropomorphic test devices (ATDs) should accurately depict head kinematics in crash tests, and thoracic spine properties have been demonstrated to affect those kinematics. To investigate the relationships between thoracic spine system dynamics and upper thoracic kinematics in crash-level scenarios, three adult post-mortem human subjects (PMHS) were tested in both Isolated Segment Manipulation (ISM) and sled configurations. In frontal sled tests, the T6-T8 vertebrae of the PMHS were coupled through a novel fixation technique to a rigid seat to directly measure thoracic spine loading. Mid-thoracic spine and belt loads along with head, spine, and pectoral girdle (PG) displacements were measured in 12 sled tests conducted with the three PMHS (3-pt lap-shoulder belted/unbelted at velocities from 3.8 - 7.0 m/s applied directly through T6-T8).
Technical Paper

Impact Response of Restrained PMHS in Frontal Sled Tests: Skeletal Deformation Patterns Under Seat Belt Loading

2009-11-02
2009-22-0001
This study evaluated the response of restrained post-mortem human subjects (PMHS) in 40 km/h frontal sled tests. Eight male PMHS were restrained on a rigid planar seat by a custom 3-point shoulder and lap belt. A video motion tracking system measured three-dimensional trajectories of multiple skeletal sites on the torso allowing quantification of ribcage deformation. Anterior and superior displacement of the lower ribcage may have contributed to sternal fractures occurring early in the event, at displacement levels below those typically considered injurious, suggesting that fracture risk is not fully described by traditional definitions of chest deformation. The methodology presented here produced novel kinematic data that will be useful in developing biofidelic human models.
Technical Paper

Development and Design of Thor-Lx: The Thor Lower Extremity

1999-10-10
99SC09
A new lower extremity has been developed to be used with Thor, the NHTSA Advanced Frontal Dummy. The new lower extremity, known as Thor-Lx, consists of the femur, tibia, ankle joints, foot, a representation of the Achilles' tendon and the associated flash/skins, it has been designed to improve biomechanical response under axial loading of the femur during knee impacts, axial loading of the tibia, static and dynamic dorsiflexion, static plantarflexion and inversion/aversion. Instrumentation includes a standard Hybrid ill femur load cell, accelerometers, load cells, and rotary potentiometers to capture relevant kinematic and dynamic information from the foot and tibia. The design also allows the Tnor-Lx to be attached to the Hybrid III, either at the hip, or at the knee.
Technical Paper

Development of THOR-FLx: A Biofidelic Lower Extremity for Use with 5th Percentile Female Crash Test Dummies

2002-11-11
2002-22-0014
A new lower leg/ankle/foot system has been designed and fabricated to assess the potential for lower limb injuries to small females in the automotive crash environment. The new lower extremity can be retrofitted at present to the distal femur of the 5th percentile female Hybrid III dummy. Future plans are for integration of this design into the 5th percentile female THOR dummy now under development. The anthropometry of the lower leg and foot is based mainly on data developed by Robbins for the 5th percentile female, while the biomechanical response requirements are based upon scaling of 50th percentile male THOR-Lx responses. The design consists of the knee, tibia, ankle joints, foot, a representation of the Achilles tendon, and associated flesh/skins. The new lower extremity, known as THOR-FLx, is designed to be biofidelic under dynamic axial loading of the tibia, static and dynamic dorsiflexion, static plantarflexion and inversion/eversion.
Technical Paper

The Large Omnidirectional Child (LODC) ATD: Biofidelity Comparison with the Hybrid III 10 Year Old

2016-11-07
2016-22-0017
When the Hybrid III 10-year old (HIII-10C) anthropomorphic test device (ATD) was adopted into Code of Federal Regulations (CFR) 49 Part 572 as the best available tool for evaluating large belt-positioning booster seats in Federal Motor Vehicle Safety Standard (FMVSS) No. 213, NHTSA stated that research activities would continue to improve the performance of the HIII-10C to address biofidelity concerns. A significant part of this effort has been NHTSA’s in-house development of the Large Omnidirectional Child (LODC) ATD. This prototype ATD is comprised of (1) a head with pediatric mass properties, (2) a neck that produces head lag with Z-axis rotation at the atlanto-occipital joint, (3) a flexible thoracic spine, (4) multi-point thoracic deflection measurement capability, (5) skeletal anthropometry representative of a seated child, and (6) an abdomen that can directly measure belt loading.
Technical Paper

Computational Analysis of Head Impact Response Under Car Crash Loadings

1995-11-01
952718
Computational simulations are conducted for several head impact scenarios using a three dimensional finite element model of the human brain in conjunction with accelerometer data taken from crash test data. Accelerometer data from a 3-2-2-2 nine accelerometer array, located in the test dummy headpart, is processed to extract both rotational and translational velocity components at the headpart center of gravity with respect to inertial coordinates. The resulting generalized six degree-of-freedom description of headpart kinematics includes effects of all head impacts with the interior structure, and is used to characterize the momentum field and inertial loads which would be experienced by soft brain tissue under impact conditions. These kinematic descriptions are then applied to a finite element model of the brain to replicate dynamic loading for actual crash test conditions, and responses pertinent to brain injury are analyzed.
Technical Paper

Biofidelity Evaluation of the THOR and Hybrid III 50th Percentile Male Frontal Impact Anthropomorphic Test Devices

2017-11-13
2017-22-0009
The objective of this study is to present a quantitative comparison of the biofidelity of the THOR and Hybrid III 50th percentile male ATDs. Quantitative biofidelity was assessed using NHTSA’s Biofidelity Ranking System in a total of 21 test conditions, including impacts to the head, face, neck, upper thorax, lower oblique thorax, upper abdomen, lower abdomen, femur, knee, lower leg, and whole-body sled tests to evaluate upper body kinematics and thoracic response under frontal and frontal oblique restraint loading. Biofidelity Ranking System scores for THOR were better (lower) than Hybrid III in 5 of 7 body regions for internal biofidelity and 6 of 7 body regions for external biofidelity. Nomenclature is presented to categorize the quantitative results, which show overall good internal and external biofidelity of the THOR compared to the good (internal) and marginal (external) biofidelity of the Hybrid III.
Technical Paper

Comparison of Pedestrian Kinematics and Injuries in Staged Impact Tests with Cadavers and Mathematical 2D Simulations

1983-02-01
830186
The paper presents a comparison of kinematic responses between the MVMA-2D and the MAC-DAN pedestrian models and pedestrian cadaver kinematics observed in staged car/pedestrian impact tests. The paper also discusses the injuries experienced in the cadaver tests. Seven cadaver specimens in the standing posture were impacted at 25 mph by two different cars: one having a steel bumper and the other having a plastic bumper. The MVMA-2D and MAC-DAN mathematical pedestrian models were employed to simulate pedestrian impacts at 25 mph by a vehicle with a stylized geometry that is similar to the vehicles used in cadaver tests. Comparison of the simulations and the cadaver tests show that both models require further refinement to be able to more accurately simulate the kinematics of the lower legs during impacts with the vehicle bumper.
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