Preliminary Calibration and Validation of a Finite Element Model of THOR Mod Kit Dummy

2014 ◽  
Author(s):  
Costin D. Untaroiu ◽  
Jacob B. Putnam ◽  
Jeffrey T. Somers ◽  
Joseph A. Pellettiere
Keyword(s):  
Finite Element ◽  
Traffic Safety ◽  
Element Model ◽  
Crash Test ◽  
Fe Model ◽  
Loading Conditions ◽  
Highway Traffic ◽  
National Highway Traffic Safety ◽  
Spinal Loading ◽  
Safety Standards

New vehicles are currently being developed to transport crews to space by NASA and several commercial companies. During the takeoff and landing phase, vehicle occupants are typically exposed to spinal and frontal loading. To reduce the risk of injuries during these common impact scenarios, NASA has begun research to develop new safety standards for spaceflight. The THOR, an advanced multi-directional crash test dummy, was chosen by NASA to evaluate occupant spacecraft safety due to its improved biofidelity. Recently, a series of modifications were completed by the National Highway Traffic Safety Administration (NHTSA) to improve the bio-fidelity of the THOR dummy. The updated THOR Modification Kit (THOR-K) dummy was tested at Wright-Patterson (WP) Air Base in various impact configurations, including frontal and spinal loading. A computational finite element (FE) model of the THOR was developed in LS-DYNA software and was recently updated to match the latest dummy modifications. The main goal of this study was to calibrate and validate the FE model of the THOR-K dummy for use in future spacecraft safety studies. An optimization-based method was developed to calibrate the material properties of the pelvic flesh model under quasi-static and dynamic loading conditions. Data in a simple compression test of pelvic flesh were used for the quasi-static calibration. The whole dummy kinematic and kinetic response under spinal loading conditions was used for the dynamic calibration. The performance of the calibrated dummy model was evaluated by simulating a separate dummy test with a different crash pulse along the spinal direction. In addition, a frontal dummy test was also simulated with the calibrated model. The model response was compared with test data by calculating its correlation score using the CORA rating system. Overall, the calibrated THOR-K dummy model responded with high similarity to the physical dummy in all validation tests. Therefore, confidence is provided in the dummy model for use in predicting response in other test conditions such as those observed in the spacecraft landing.

scholarly journals Numerical Simulation of Airbag and Study on the Effect of Airbag Parameters on Head Injury Criteria

2021 ◽  
Vol 9 (9) ◽  
pp. 1654-1666
Author(s):  
Aakash R
Keyword(s):  
Finite Element ◽  
Head Injury ◽  
Traffic Safety ◽  
Critical Role ◽  
Highway Traffic ◽  
Element Analysis ◽  
National Highway Traffic Safety ◽  
Occupant Safety ◽  
Injury Criteria ◽  
Head Injury Criteria

Abstract: In the case of an accident, inflatable restraints system plays a critical role in ensuring the safety of vehicle occupants. Frontal airbags have saved 44,869 lives, according to research conducted by the National Highway Traffic Safety Administration (NHTSA).Finite element analysis is extremely important in the research and development of airbags in order to ensure optimum protection for occupant. In this work, we simulate a head impact test with a deploying airbag and investigate the airbag's parameters. The airbag's performance is directly influenced by the parameters of the cushion such as vent area and fabric elasticity. The FEM model is analysed to investigate the influence of airbag parameter, and the findings are utilised to determine an optimal value that may be employed in the construction of better occupant safety systems. Keywords: airbag, finite element method, occupant safety, frontal airbag, vent size, fabric elasticity, head injury criteria

A Comprehensive Evaluation of NHTSA Rollover Test Data for Use in Computational Model Validation

2004 ◽  
Author(s):  
Mark R. Martin ◽  
Kerry Allen
Keyword(s):  
Computational Model ◽  
Model Validation ◽  
Traffic Safety ◽  
Computational Simulation ◽  
Simulation Software ◽  
Crash Test ◽  
Motion Simulation ◽  
Highway Traffic ◽  
National Highway Traffic Safety ◽  
Vehicle Crash

Increased computational power and new software have brought occupant motion simulation into the mainstream for vehicle accident reconstructionists. Using programs available today, investigators are able to achieve numerical results that match actual physical results with a high degree of accuracy. It should therefore be possible to validate the performance of a software simulation using instrument data collected from a real vehicle test. For valid results, however, one must have valid data upon which to base the simulation. We attempted to validate MADYMO occupant motion simulation software by using data from the National Highway Traffic Safety Administration (NHTSA) vehicle crash test database for vehicle rollovers. In the course of our work, we discovered flaws in the NHTSA database that rendered it useless for both validating and disputing a computational simulation. These flaws included data that did not match the descriptions of vehicle travel in the written reports, entire channels of missing data, and others. NHTSA crash tests are often cited as reliable sources of data in vehicle crash situations. While not disputing the limited scientific value of these tests, this paper documents the problems with NHTSA test reports and concludes that the data contained therein can be unintentionally misleading and of little value for computational model validation of rollover simulations. This paper also presents testing improvement procedures that should allow a greater correlation of computational and testing data.

Study of Occupant Safety and Airbag Deployment Time

2015 ◽  
Author(s):  
Steven Yang ◽  
Kristian Lardner ◽  
Moustafa El-Gindy
Keyword(s):  
Traffic Safety ◽  
Impact Test ◽  
Crash Test ◽  
Passenger Vehicle ◽  
Highway Traffic ◽  
Element Analysis ◽  
National Highway Traffic Safety ◽  
Hybrid Iii ◽  
Airbag Deployment ◽  
Deployment Time

This paper presents the use of Finite Element Analysis (FEA) software in recreating a full frontal barrier impact test with a 50th percentile male hybrid III dummy to investigate various passenger vehicle airbag deployment times for the development of an airbag trigger sensor. Results for the physical full frontal barrier impact test where prepared by MGA Research Corporation with a 2007 Toyota Yaris. Using a nonlinear transient dynamic FEA software, a virtual full frontal barrier impact test was created to reproduce the physical results and trends experienced in the physical crash test found in a report by the National Highway Traffic Safety Administration (NHTSA) 5677. The results of the simulation were compared to the results of the physical crash which produced similar trends, but not the same values. The simulation was then used in testing different passenger vehicle airbag deployment times to see its results on specific occupant injury criteria’s; Head Injury Criterion (HIC), Chest Compression Criterion (CC). Four different vehicle speeds where used; 20 km/h, 40 km/h, 56 km/h, and 90 km/h in conjunction with a range of +/− 6 milliseconds in the airbag deployment timing. Results of the airbag deployment timing showed that trends of faster airbag deployment times resulted in lower values for HIC and CC. Following these trends, suggestions for airbag deployment trigger distances were developed to aid in creation of an advanced airbag deployment sensor or crash sensor. While the simulation has yet to be validated, the trends may be assessed and actual values may differ.

Evaluation of Automotive Roof Strength and Pretensioner Performance on the Occupant Neck Load

2010 ◽  
Author(s):  
Chandrashekhar K. Thorbole ◽  
Stephen A. Batzer ◽  
David A. Renfroe
Keyword(s):  
Traffic Safety ◽  
Injury Risk ◽  
Element Model ◽  
Neck Injury ◽  
Highway Traffic ◽  
National Highway Traffic Safety ◽  
Hybrid Iii ◽  
The Subject ◽  
Roof Strength ◽  
Modest Level

Roof intrusion is a major cause of neck injury to belted occupants during rollover accidents. The correlation of reduced head room with increased injury risk has been demonstrated by the National Highway Traffic Safety Administration (NHTSA) and others such as the Insurance Institute of Highway Safety (IIHS). The current FMVSS 216 standard requires the vehicle roof, when loaded with a platen of prescribed geometry and application vector, to resist 1.5 times the vehicle empty weight before deforming 127mm. This standard was developed to ensure a modest level of safety of the vehicle in rollover. This paper demonstrates the relation between roof intrusions, available head room and belt pretension on occupant neck loads. A validated finite element model of a 2001 Ford Taurus is used to conduct an inverted drop simulation. The vehicle’s roof impacts an ideally rigid surface with 5 deg of roll and 10 deg of pitch. A 95th percentile Hybrid III ATD (Anthropomorphic Test Device) is used to simulate a large occupant. The simulations are conducted both for a production roof and a modified stiffer, stronger roof. The production roof is modified by addition of extra material in the B-pillars and A-pillars to enhance strength. A seatbelt pretensioner is also modeled to demonstrate the effectiveness of belt pretension in attenuating neck loads. This study demonstrates the inadequate performance of the subject production roof in preventing neck injury. The stronger roof in association with the belt pretensioner reduces the magnitude of the neck loads sufficiently to prevent injury. This study indicates that strong, non-deforming roofs along with belt pretension diminishes neck injury.

scholarly journals An Experimentally Validated Finite Element Model of the Lower Limb to Investigate the Efficacy of Blast Mitigation Systems

2021 ◽  
Vol 9 ◽  
Author(s):  
Eduardo A. Rebelo ◽  
Grigoris Grigoriadis ◽  
Diagarajen Carpanen ◽  
Anthony M. J. Bull ◽  
Spyros D. Masouros
Keyword(s):  
Finite Element ◽  
Injury Risk ◽  
Injury Severity ◽  
Proximal Tibia ◽  
Assessment Tool ◽  
Traumatic Injury ◽  
Element Model ◽  
Fe Model ◽  
Loading Conditions ◽  
Injury Burden

Improvised explosive devices (IEDs) used in the battlefield cause damage to vehicles and their occupants. The injury burden to the casualties is significant. The biofidelity and practicality of current methods for assessing current protection to reduce the injury severity is limited. In this study, a finite-element (FE) model of the leg was developed and validated in relevant blast-loading conditions, and then used to quantify the level of protection offered by a combat boot. An FE model of the leg of a 35 years old male cadaver was developed. The cadaveric leg was tested physically in a seated posture using a traumatic injury simulator and the results used to calibrate the FE model. The calibrated model predicted hindfoot forces that were in good correlation (using the CORrelation and Analysis or CORA tool) with data from force sensors; the average correlation and analysis rating (according to ISO18571) was 0.842. The boundary conditions of the FE model were then changed to replicate pendulum tests conducted in previous studies which impacted the leg at velocities between 4 and 6.7 m/s. The FE model results of foot compression and peak force at the proximal tibia were within the experimental corridors reported in the studies. A combat boot was then incorporated into the validated computational model. Simulations were run across a range of blast-related loading conditions. The predicted proximal tibia forces and associated risk of injury indicated that the combat boot reduced the injury severity for low severity loading cases with higher times to peak velocity. The reduction in injury risk varied between 6 and 37% for calcaneal minor injuries, and 1 and 54% for calcaneal major injuries. No injury-risk reduction was found for high severity loading cases. The validated FE model of the leg developed here was able to quantify the protection offered by a combat boot to vehicle occupants across a range of blast-related loading conditions. It can now be used as a design and as an assessment tool to quantify the level of blast protection offered by other mitigation technologies.

A Commented Synopsis of the Report of the Committee for the National Tire Efficiency Study4

2007 ◽  
Vol 35 (2) ◽  
pp. 70-93
Author(s):  
Marion G. Pottinger ◽  
Joseph D. Walter ◽  
John D. Eagleburger
Keyword(s):  
Traffic Safety ◽  
Rolling Resistance ◽  
The United States ◽  
Final Report ◽  
Highway Traffic ◽  
National Academy Of Sciences ◽  
Scrap Tire ◽  
National Highway Traffic Safety ◽  
Fuel Savings ◽  
Time Required

Abstract The Congress of the United States petitioned the Transportation Research Board of the National Academy of Sciences to study replacement passenger car tire rolling resistance in 2005 with funding from the National Highway Traffic Safety Administration. The study was initiated to assess the potential for reduction in replacement tire rolling resistance to yield fuel savings. The time required to realize these savings is less than the time required for automotive and light truck fleet replacement. Congress recognized that other factors besides fuel savings had to be considered if the committee’s advice was to be a reasonable guide for public policy. Therefore, the study simultaneously considered the effect of potential rolling resistance reductions in replacement tires on fuel consumption, wear life, scrap tire generation, traffic safety, and consumer spending for tires and fuel. This paper summarizes the committee’s report issued in 2006. The authors, who were members of the multidisciplinary committee, also provide comments regarding technical difficulties encountered in the committee’s work and ideas for alleviating these difficulties in further studies of this kind. The authors’ comments are clearly differentiated so that these comments will not be confused with findings, conclusions, and recommendations developed by the committee and contained in its final report.

Distribution of Speed and Acceleration on a Tread Wear Course

1981 ◽  
Vol 9 (1) ◽  
pp. 19-25 ◽  
Author(s):  
G. S. Ludwig ◽  
F. C. Brenner
Keyword(s):  
Traffic Safety ◽  
Highway Traffic ◽  
National Highway Traffic Safety ◽  
Level Crossings ◽  
Acceleration Level ◽  
Longitudinal Acceleration ◽  
Acceleration Data ◽  
National Highway

Abstract Belted bias and radial Course Monitoring Tires were run over the National Highway Traffic Safety Administration tread wear course at San Angelo on a vehicle instrumented to measure lateral and longitudinal accelerations, speed, and number of wheel rotations. The data were recorded as histograms. The distribution of speed, the distributions of lateral and longitudinal acceleration, and the number of acceleration level crossings are given. Acceleration data for segments of the course are also given.

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