THOR dummy chest deflection response in oblique and lateral far-side sled tests

Abstract

Objective: The focus of this study is side impact. Though occupant injury assessment and protection in nearside impacts has received considerable attention and safety standards have been promulgated, field studies show that a majority of far-side occupant injuries are focused on the head and thorax. The 50th percentile male Test Device for Human Occupant Restraint (THOR) has been used in oblique and lateral far-side impact sled tests, and regional body accelerations and forces and moments recorded by load cells have been previously reported. The aim of this study is to evaluate the chestband-based deflection responses from these tests.

Methods: The 3-point belt–restrained 50th percentile male THOR dummy was seated upright in a buck consisting of a rigid flat seat, simulated center console, dashboard, far-side side door structure, and armrest. It was designed to conduct pure lateral and oblique impacts. The center console, dashboard, simulated door structure, and armrest were covered with energy-absorbing materials. A center-mounted airbag was mounted to the right side of the seat. Two 59-gage chestbands were routed on the circumference of the thorax, with the upper and lower chestbands at the level of the third and sixth ribs, respectively, following the rib geometry. Oblique and pure lateral far-side impact tests with and without airbags were conducted at 8.3 m/s. Maximum chest deflections were computed by processing temporal contours using custom software and 3 methods: Procedures paralleling human cadaver studies, using the actual anchor point location and actual alignment of the InfraRed Telescoping Rods for the Assessment of Chest Compression (IR-TRACC) in the dummy on each aspect—that is, right or left,—and using the same anchor location of the internal sensor but determining the location of the peak chest deflection on the contour confined to the aspect of the sensor; these were termed the SD, ID, and TD metrics, respectively.

Results: All deformation contours at the upper and lower thorax levels and associated peak deflections are given for all tests. Briefly, the ID metrics were the lowest in magnitude for both pure lateral and oblique modes, regardless of the presence or absence of an airbag. This was followed by the TD metric, and the SD metric produced the greatest deflections.

Conclusion: The chestbands provide a unique opportunity to compute peak deflections that parallel current IR-TRACC-type deflections and allow computation of peak deflections independent of the initial point of attachment to the rib. The differing locations of the peak deflection vectors along the rib contours for different test conditions suggest that a priori attachment is less effective. Further, varying magnitudes of the differences between ID and TD metrics underscore the difficulty in extrapolating ID outputs under different conditions: Pure lateral versus oblique, airbag presence, and thoracic levels. Deflection measurements should, therefore, not be limited to an instrument that can only track from a fixed point. For improved predictions, these results suggest the need to investigate alternative techniques, such as optical methods to improve chest deflection measurements for far-side occupant injury assessment and mitigation.     

Injuries in Full-Scale Vehicle Side Impact Moving Deformable Barrier and Pole Tests Using Postmortem Human Subjects

Objective: To conduct near-side moving deformable barrier (MDB) and pole tests with postmortem human subjects (PMHS) in full-scale modern vehicles, document and score injuries, and examine the potential for angled chest loading in these tests to serve as a data set for dummy biofidelity evaluations and computational modeling.

Methods: Two PMHS (outboard left front and rear seat occupants) for MDB and one PMHS (outboard left front seat occupant) for pole tests were used. Both tests used sedan-type vehicles from same manufacturer with side airbags. Pretest x-ray and computed tomography (CT) images were obtained. Three-point belt-restrained surrogates were positioned in respective outboard seats. Accelerometers were secured to T1, T6, and T12 spines; sternum and pelvis; seat tracks; floor; center of gravity; and MDB. Load cells were used on the pole. Biomechanical data were gathered at 20 kHz. Outboard and inboard high-speed cameras were used for kinematics. X-rays and CT images were taken and autopsy was done following the test. The Abbreviated Injury Scale (AIS) 2005 scoring scheme was used to score injuries.

Results: MDB test: male (front seat) and female (rear seat) PMHS occupant demographics: 52 and 57 years, 177 and 166 cm stature, 78 and 65 kg total body mass. Demographics of the PMHS occupant in the pole test: male, 26 years, 179 cm stature, and 84 kg total body mass. Front seat PMHS in MDB test: 6 near-side rib fractures (AIS = 3): 160–265 mm vertically from suprasternal notch and 40–80 mm circumferentially from center of sternum. Left rear seat PMHS responded with multiple bilateral rib fractures: 9 on the near side and 5 on the contralateral side (AIS = 3). One rib fractured twice. On the near and contralateral sides, fractures were 30–210 and 20–105 mm vertically from the suprasternal notch and 90–200 and 55–135 mm circumferentially from the center of sternum. A fracture of the left intertrochanteric crest occurred (AIS = 3). Pole test PMHS had one near-side third rib fracture. Thoracic accelerations of the 2 occupants were different in the MDB test. Though both occupants sustained positive and negative x-accelerations to the sternum, peak magnitudes and relative changes were greater for the rear than the front seat occupant. Magnitudes of the thoracic and sternum accelerations were lower in the pole test.

Conclusions: This is the first study to use PMHS occupants in MDB and pole tests in the same recent model year vehicles with side airbag and head curtain restraints. Injuries to the unilateral thorax for the front seat PMHS in contrast to the bilateral thorax and hip for the rear seat occupant in the MDB test indicate the effects of impact on the seating location and restraint system. Posterolateral locations of fractures to the front seat PMHS are attributed to constrained kinematics of occupant interaction with torso side airbag restraint system. Angled loading to the rear seat occupant from coupled sagittal and coronal accelerations of the sternum representing anterior thorax loading contributed to bilateral fractures. Inward bending initiated by the distal femur complex resulting in adduction of ipsilateral lower extremity resulted in intertrochanteric fracture to the rear seat occupant. These results serve as a data set for evaluating the biofidelity of the WorldSID and federalized side impact dummies and assist in validating human body computational models, which are increasingly used in crashworthiness studies.     

Lower Leg Injury Reference Values and Risk Curves from Survival Analysis for Male and Female Dummies: Meta-analysis of Postmortem Human Subject Tests

Objective: Derive lower leg injury risk functions using survival analysis and determine injury reference values (IRV) applicable to human mid-size male and small-size female anthropometries by conducting a meta-analysis of experimental data from different studies under axial impact loading to the foot–ankle–leg complex.

Methods: Specimen-specific dynamic peak force, age, total body mass, and injury data were obtained from tests conducted by applying the external load to the dorsal surface of the foot of postmortem human subject (PMHS) foot–ankle–leg preparations. Calcaneus and/or tibia injuries, alone or in combination and with/without involvement of adjacent articular complexes, were included in the injury group. Injury and noninjury tests were included. Maximum axial loads recorded by a load cell attached to the proximal end of the preparation were used. Data were analyzed by treating force as the primary variable. Age was considered as the covariate. Data were censored based on the number of tests conducted on each specimen and whether it remained intact or sustained injury; that is, right, left, and interval censoring. The best fits from different distributions were based on the Akaike information criterion; mean and plus and minus 95% confidence intervals were obtained; and normalized confidence interval sizes (quality indices) were determined at 5, 10, 25, and 50% risk levels. The normalization was based on the mean curve. Using human-equivalent age as 45 years, data were normalized and risk curves were developed for the 50th and 5th percentile human size of the dummies.

Results: Out of the available 114 tests (76 fracture and 38 no injury) from 5 groups of experiments, survival analysis was carried out using 3 groups consisting of 62 tests (35 fracture and 27 no injury). Peak forces associated with 4 specific risk levels at 25, 45, and 65 years of age are given along with probability curves (mean and plus and minus 95% confidence intervals) for PMHS and normalized data applicable to male and female dummies. Quality indices increased (less tightness-of-fit) with decreasing age and risk level for all age groups and these data are given for all chosen risk levels.

Conclusions: These PMHS-based probability distributions at different ages using information from different groups of researchers constituting the largest body of data can be used as human tolerances to lower leg injury from axial loading. Decreasing quality indices (increasing index value) at lower probabilities suggest the need for additional tests. The anthropometry-specific mid-size male and small-size female mean human risk curves along with plus and minus 95% confidence intervals from survival analysis and associated IRV data can be used as a first step in studies aimed at advancing occupant safety in automotive and other environments.     

Survey of polyfluorinated chemicals (PFCs) in the atmosphere over the northeast Atlantic Ocean

High volume air sampling in Bermuda, Sable Island (Nova Scotia) and along a cruise track from the Gulf of Mexico to northeast coast of the USA, was carried out to assess air concentrations, particle-gas partitioning and transport of polyfluorinated chemicals (PFCs) in this region. Samples were collected in the summer of 2007. Targeted compounds included the neutral PFCs: fluorotelomer alcohols (FTOHs), perfluoroalkyl sulfonamides (FOSAs) and perfluoroalkyl sulfonamido ethanols (FOSEs).Among the FTOHs, 8:2 FTOH was dominant in all samples. Sum of the concentration of FTOHs (gas+particle phase) were higher in Bermuda (mean, 34 pg m^?3) compared to Sable Island (mean, 16 pg m^?3). In cruise samples, sum of FTOHs were highly variable (mean, 81 pg m^?3) reflecting contributions from land-based sources in the northeast USA with concentrations reaching as high as 156 pg m^?3.Among the FOSAs and FOSEs, MeFOSE was dominant in all samples. In Bermuda, levels of MeFOSE were exceptionally high (mean, 62 pg m^?3), exceeding the FTOHs. Sable Island samples also exhibited the dominance of MeFOSE but at a lower concentration (mean, 15 pg m^?3). MeFOSE air concentrations (pg m^?3) in cruise samples ranged from 1.6 to 73 and were not linked to land-based sources. In fact high concentrations of MeFOSE observed in Bermuda were associated with air masses that originated over the Atlantic Ocean.The partitioning to particles for 8:2 FTOH, 10:2 FTOH, MeFOSE and EtFOSE ranged from as high as 15 to 42% for cruise samples to 0.9 to 14% in Bermuda. This study provides key information for validating and developing partitioning and transport models for the PFCs.     

Assessment of the environmental profile of PLA,PET and PS clamshell containers using LCA methodology

Life cycle assessments of bio-based polymer resin and products historically have shown favorable results in terms of environmental impacts and energy use compared to petroleum-based products. However, calculation of these impacts always depends on the system and boundary conditions considered during the study. This paper reports a cradle-to-cradle Life Cycle Assessment (LCA) of poly(lactic acid) (PLA) in comparison with poly(ethylene terephthalate) (PET) and poly(styrene) (PS) thermoformed clamshell containers, used for packaging of strawberries with emphasis on different end-of-life scenarios. It considers all the inputs such as fertilizers, pesticides, herbicides and seed corn required for the growing and harvesting of corn used for manufacturing PLA. For PET and PS, the extraction of crude oil and the entire cracking processes from crude oil through styrene and ethylene glycol and terephathalic acid are considered. Global warming, aquatic acidification, aquatic eutrophication, aquatic ecotoxicity, ozone depletion, non-renewable energy and respiratory organics, land occupation and respiratory inorganics were the selected midpoint impact categories. The geographical scope of the study reflects data from Europe, North America and the Middle East. PET showed the highest overall values for all the impact categories, mainly due to the higher weight of the containers. The main impacts to the environment were the resin production and the transportation stage of the resins and containers. This implies that the transportation stage of the package is an important contributor to the environmental impact of the packaging systems, and that it cannot be diminished.     

Role of UPP pathway in amelioration of diabetes-associated complications

Environmental Science and Pollution Research - Type 2 diabetes (T2D) is one of the most widely spread metabolic disorder also called as “life style” disease. Due to the alarming number...     

Mercury emissions and partitioning from Indian coal-fired power plants

In India coal combustion is the single largest source of emission of mercury which is a wide-spread persistent global toxicant, travelling across international borders through air and water. As a party to the Minamata convention, India aims to monitor and reduce Hg emissions and stricter norms are introduced for mercury emissions from power plants (30 μg/Nm³for flue gas in stack).This paper presents the results obtained during the experimental studies performed on mercury emissions at four coal-fired and one lignite-fired power plants in India. The mercury concentration in the feed coal varied between 0.12–0.27 mg/Kg. In the mercury mass balance, significant proportion of feed coal mercury has been found to be associated with fly ash, whereas bottom ash contained very low mercury. 80%–90% of mercury was released to air through stack gas. However, for circulating fluidised bed boiler burning lignite, about 64.8% of feed mercury was found to get captured in the fly ash and only 32.4% was released to air. The mercury emission factor was found to lie in the range of 4.7–15.7 mg/GJ.     

Designing hydro-energy led economic growth for pollution abatement: evidence from BRICS

Environmental Science and Pollution Research - Overutilized hydro-energy production through non-sustainable mode is detrimental for both the economy and the environment. Intermittent consumption of...     

Biodynamics of steering wheel induced facial trauma

The present study was undertaken to determine the impact biomechanics of the facial skeleton secondary to steering wheel loading. Because of the particular relevance of the zygomatic bony complex in facial trauma during motor-vehicle accidents, tests were conducted by impacting the zygoma using a vertical drop impact test system. Zygoma was impacted once onto either soft or rigid wheel surfaces at velocities of up to 6.7 m/s. Peak impact forces at the cadaver zygoma were computed from the generalized force and deformation histories using matrix transformation principles. Structural abnormalities were assessed using pre- and post-test plain radiography, two-and three-dimensional computed tomography, and defleshing techniques. At impact velocities of 1.7 to 6.7 m/s, the human cadaver zygoma did not exhibit clinically significant fractures if the peak force was below 1335 N for the soft wheel interface and 1153 N for the rigid wheel interface. Consequently, to mitigate facial injuries due to unsupported rim impact, the data from the present study suggests that the peak dynamic force should be kept within these limits.     

Prenatal ultrasound diagnosis of Apert's syndrome

A mother affected with Apert's syndrome was diagnosed by ultrasound scan at 16–17 weeks to have a fetus similarly affected. The typical features of acrocephaly and symmetrical syndactyly were seen. This is probably the first time that this condition has been diagnosed at such a gestation by ultrasound scan. The patient decided to continue the pregnancy, and intrauterine death occurred at 34 weeks. The diagnosis was confirmed by pathological examination.