Anthropomorphic Test Device Research Articles

An Experimental Platform Generating Simulated Blunt Impacts to the Head Due to Rearward Falls.

Impacts to the back of the head due to rearward falls, also referred to as "backfall" events, represent a common source of TBI for athletes and soldiers. A new experimental apparatus is described for replicating the linear and rotational kinematics of the head during backfall events. An anthropomorphic test device (ATD) with a head-borne sensor suite was configured to fall backwards from a standing height, inducing contact between the rear of the head and a ground surface simulant. A pivoting swing arm and release strap were used to generate consistent and realistic head kinematics. Backfall experiments were performed with the ATD fitted with an American football helmet and the resulting linear and rotational head kinematics, as well as calculated injury metrics, compared favorably with those of football players undergoing similar impacts during games or play reconstructions. This test method complements existing blunt impact helmet performance experiments, such as drop tower and pneumatic ram test methods, which may not be able to fully reproduce head-neck-torso kinematics during a backfall event.

Time and temperature sensitivity of the hybrid III lumbar spine

Objective Researchers have found a variety of uses for the Hybrid III (HIII) dummy that fall beyond the scope of its original purpose as an automotive crash test dummy. Some of these expanded roles for the HIII introduce situations that were not envisioned in the dummy’s original design parameters, such as a relatively rapid succession of tests or outdoor testing scenarios where temperature is not easily controlled. This study investigates how the axial compressive stiffness of the HIII lumbar spine component is affected by the duration of the time interval between tests. Further, it measures the effect of temperature on the compressive stiffness of the lumbar spine through a range of temperatures relevant to indoor and outdoor testing. Methods High-rate axial compression tests were run on a 50th percentile male HIII lumbar component in a materials testing machine. To characterize the effects of tests recovery intervals, between-test recovery was varied from 2 hours to 1 minute. To quantify temperature effects, environmental temperature conditions of 12.5°, 25°, and 37.5 °C were tested. Results During repeated compressive loading, the force levels decreased consistently across long and short rest intervals. Even after 2 hours of rest between tests, full viscoelastic recovery was not observed. Temperature effects were pronounced, resulting in compressive force differences of 261% over the range of 12.5° to 37.5 °C. Compared to the stiffness of the lumbar at 25 °C, the stiffness at 37.5 °C fell by 40%; at 12.5 °C, the stiffness more than doubled, increasing by 115%. Conclusions A modest decrease in temperature can be sufficient to dramatically change the response and repeatability of the lumbar HIII component in compressive loading. The large magnitude of the temperature effect has severe implications in its ability to overwhelm the contributions of targeted test variables. These findings highlight the importance of controlling, monitoring and reporting temperature conditions during HIII testing, even in indoor laboratory environments.

Dynamic metrics to differentiate booster performance

Objective The purpose of this research was to explore candidate booster performance metrics that may have the potential to identify less effective booster systems, because current FMVSS No. 213 booster performance requirements can be met without a booster. Methods To provide a more realistic test environment, dynamic testing was performed using a surrogate seat belt retractor on the most recent preliminary design update proposed for the FMVSS No. 213 seat assembly. Given that field data show that belt-positioning boosters are effective at reducing injury risk, potential testing measures were assessed relative to data collected for the no-booster condition. Eleven booster products were evaluated, as well as the no-booster condition, with 6 tests performed using the Hybrid III 10-year-old and 33 tests run with the Hybrid III 6-year-old. Results Possible metrics associated with good anthropomorphic test device (ATD) kinematics (no submarining or rollout) were the difference between knee and head excursion, maximum torso angle, lumbar spine Moment Z, and lumbar spine Force Y. Conclusions When testing boosters under more realistic dynamic conditions, the proposed metrics would allow better discernment of less effective boosters, because they differentiate performance relative to the no-booster condition.

Whole Body PMHS Response in Injurious Experimental Accelerative Loading Events.

Previous studies involving whole-body post-mortem human surrogates (PHMS) have generated biomechanical response specifications for physically simulated accelerative loading intended to reproduce seat and floor velocity histories occurring in under-body blast (UBB) events (e.g.,. References 10, 11, 21 These previous studies employed loading conditions that only rarely produced injuries to the foot/ankle and pelvis, which are body regions of interest for injury assessment in staged UBB testing using anthropomorphic test devices. To investigate more injurious whole-body conditions, three series of tests were conducted with PMHS that were equipped with military personal protective equipment and seated in an upright posture. These tests used higher velocity and shorter duration floor and seat inputs than were previously used with the goal of producing pelvis and foot/ankle fractures. A total of nine PMHS that were approximately midsize in stature and mass were equally allocated across three loading conditions, including a 15.5m/s, 2.5ms time-to-peak (TTP) floor velocity pulse with a 10m/s, 7.5ms TTP seat pulse; a 13m/s, 2.5ms TTP floor pulse with a 9.0m/s, 5ms TTP seat pulse; and a 10m/s, 2.5ms TTP floor pulse with a 6.5m/s, 7.5ms TTP seat pulse. In the first two conditions, the seat was padded with a ~ 120-mm-thick foam cushion to elongate the pulse experienced by the PMHS. Of the nine PMHS tests, five resulted in pelvic ring fractures, five resulted in a total of eight foot/ankle fractures (i.e.,two unilateral and three bilateral fractures), and one produced a femur fracture. Test results were used to develop corridors describing the variability in kinematics and in forces applied to the feet, forces applied to the pelvis and buttocks in rigid seat tests, and in forces applied to the seat foam in padded seat tests. These corridors and the body-region specific injury/no-injury response data can be used to assess the performance and predictive capability of anthropomorphic test devices and computational models used as human surrogates in simulated UBB testing.

Estimation of a statistical geometric model for the cervical vertebrae of children aged 10–18 years

Child neck injuries in motor vehicle crashes (MVCs) result in high morbidity and mortality rates. Estimating a statistical cervical vertebrae geometric model and quantifying the variations of the size and shape with age are very important for investigating the dynamic response and injury risk to a child's cervical spine, as well as for providing a geometric basis for developing child anthropomorphic test devices (ATDs) and finite element models (FEMs) of different ages. In this study, spatial geometric points were automatically extracted from the cervical vertebrae computed tomography (CT) scans of 30 children aged 10 to 18 years old (YO), and a statistical geometric model was estimated for the cervical vertebrae as a function of age and neck circumference/neck length according to the method of principal component analysis and regression (PCA&R). Based on this statistical model, geometric point sets representing cervical vertebrae geometries at different ages and percentiles were generated and formed to envelope surfaces. Meanwhile, the size changes of the cervical vertebrae with child growth from 10 to 18 YO were quantified. In general, the anteroposterior length (APL), transverse process width (TPW), vertebral body height (VBH), and vertebral body depth (VBD) of the cervical vertebrae increase with age; the VBH and VBD increase faster than the APL and TPW. Compared with other vertebrae, the APL of C7 is larger, and the rate of increase of C1 with age is evidently slower. The TPWs of C1 and C7 are greater than those of C2 to C6. C7 has higher average values for the VBH and VBD than C3 to C6.

Evaluation of the Effect of a Rear Operator Guard on the Overall Safety for Operators of Standup Lift Trucks

Abstract Standup high lift trucks have an open operator compartment designed to allow for easy egress from the truck in the event of an off-dock, off-trailer, or tip-over accident. The open compartment design also protects the operator during nontip-over collision accidents, provided the operator maintains him or herself within the compartment before impact. However, it has been suggested that an additional rear operator guard would better protect operators during nontip-over collision accidents. This study aimed to investigate operator injury potential and kinematics during off-dock and off-trailer accidents where the presence of a rear operator guard prevents the operator from exiting the truck and to evaluate the potential for an operator to restrain him or herself within the operator compartment of a standup lift truck during an off-dock or off-trailer accident. An instrumented anthropomorphic test device (ATD) was subjected to a series of off-dock accidents and a single off-trailer accident utilizing three different standup lift trucks. The kinematics and loads experienced by the ATD were quantified and correlated to human injury potential. Additionally, this study examined the potential for a rear operator guard to impede operator egress during an off-dock or off-trailer accident. Testing demonstrated the potential for serious or greater injury to an operator subjected to an off-dock or off-trailer accident. The authors conclude that a rear guard would negatively impact the overall safety of a standup lift truck in most working environments.

Response Corridors for Blunt Impacts to the Back

Corridors for the biofidelity of blunt impact to the back are important for sled and crash testing with Anthropomorphic Test Devices (ATDs). The Hybrid III is used in rear sled tests as part of Federal Motor Vehicle Safety Standards (FMVSS) 202a. The only corridor for biofidelity is the neck extension. Eight Post Mortem Human Subjects (PMHS) were subjected to 20 blunt impacts with a 15.2 cm (6 in.) diameter pendulum weighing 23.4 kg. The impact was below T1 at 4.5 m/s and 6.7 m/s and below T6 at 4.5 m/s centered on the back. Head, neck, and chest responses were reported in 2001 [8]. In this study, the responses were scaled to the 50th male Hybrid III, and corridors were determined defining biofidelity for blunt impacts to the back. The scaled data gives an average peak force of 3.44 kN ± 0.74 kN at T1 and 4.5 m/s, 5.08 kN ± 1.35 kN at T1 and 6.7 ms, and 3.4 kN ± 1.2 kN at T6 and 4.5 m/s. The corresponding scaled deflection was 44.0 ± 19.7 mm, 60.2 ± 21.2 mm, and 53.1 ± 16.5 mm. The average stiffness of the back was 1.21 kN/cm at T1 and 4.5 m/s, 1.17 kN/cm at T1 and 6.7 m/s, and 1.14 kN/cm at T6 and 4.5 m/s. The corridors help to define biofidelity and can be used to assess the performance of the Hybrid III, Biofidelic Rear Impact Dummy (BioRID) II, and other ATDs.

Methodology for Evaluation of WIAMan Injury Assessment Reference Curves Using Whole Body Match-Paired Data.

Development of the Warrior Injury Assessment Manikin (WIAMan) capability has included the creation of injury assessment reference curves (IARCs) specific to under-body blast (UBB) loading mechanisms and injuries. The WIAMan IARCs were created from high-rate vertical loading tests of component post-mortem human surrogates (PMHS) and analogous components of the WIAMan anthropomorphic test device (ATD). Validation of the WIAMan IARCs is required prior to the WIAMan ATD being utilized for injury assessment in live-fire vehicle test events. A portion of the validation process involves evaluating the ability of the IARCs to predict injury at the system level (whole body). This study evaluates a methodology to assess the performance of the WIAMan IARCs using match-paired tests of whole body PMHS and the WIAMan ATD. The methodology includes a qualitative analysis designed to identify false-positive and false-negative ATD predictions, as well as a quantitative analysis that utilizes area under the receiver-operating characteristic curve (AROC) and Brier score indices to grade IARC performance. Three WIAMan IARCs were used to exemplify the proposed methodology and results are provided. Attributes of the false-prediction, AROC, and Brier score portions of the methodology are presented, with results indicating the new methodology is thorough and robust in evaluation of IARCs.

Analysis of Biomechanical Neck-Loading Metrics as a Function of Impact Severity in Low-to-Moderate Speed Rear Impacts: Results from Hybrid III 50th Percentile Anthropomorphic Test Devices

Analysis of Biomechanical Neck-Loading Metrics as a Function of Impact Severity in Low-to-Moderate Speed Rear Impacts: Results from Hybrid III 50th Percentile Anthropomorphic Test Devices

Assessment of the 50th Hybrid III Responses in Blunt Rear Impacts to the Torso

<div class="section abstract"><div class="htmlview paragraph">Blunt impacts to the back of the torso can occur in vehicle crashes due to interaction with unrestrained occupants, or cargo in frontal crashes, or intrusion in rear crashes, for example. Six pendulum tests were conducted on the back of an instrumented 50th percentile male Hybrid III ATD (Anthropomorphic Test Device) to determine kinematic and biomechanical responses. The impact locations were centered with the top of a 15-cm diameter impactor at the T1 or at T6 level of the thoracic spine. The impact speed varied from 16 to 24 km/h.</div><div class="htmlview paragraph">Two 24 km/h tests were conducted at the T1 level and showed repeatability of setup and ATD responses. The 16 and 24 km/h tests at T1 and T6 were compared. Results indicated greater head rotation, neck extension moments and neck shear forces at T1 level impacts. For example, lower neck extension was 2.6 times and 3.8 times greater at T1 versus T6 impacts at 16 and 24 km/h, respectively.</div><div class="htmlview paragraph">A 24 km/h test at T1 was also conducted with a seatback attached to the ATD torso to assess the effect of padding. ATD biomechanical responses were lower with the seatback, except for upper neck extension; head acceleration was 30 g with the seatback and 95 g without it. Head and T1 velocities were similar with or without the seatback.</div><div class="htmlview paragraph">The ATD responses were compared with published PMHS (Post Mortem Human Subjects) responses. ATD biomechanical responses were greater overall due to a stiffer, more durable spine. Pendulum forces were over 15 kN higher with a shorter duration than in PMHS tests. The head-to-torso rotation was similar at 24 km/h. This study demonstrates that the Hybrid III ATD is a useful tool for assessing high energy occupant loading by the seat.</div></div>

Evaluation of Rotation Reduction Features in Infant and Extended-Use Convertible Child Restraint Systems during Frontal and Rear Impacts.

A correctly used child restraint system (CRS) is associated with a substantial reduction of injury and mortality risks in motor vehicle crashes and epidemiologic data suggests that toddlers are provided greater protection when restrained in a rearward-facing CRS compared to a forward-facing CRS. Some 'extended-use' European CRS models can accommodate children up to six years rearward-facing and have a support (load) leg and/or a pair of lower (Swedish) tethers to reduce rotation during frontal and rear impacts, respectively. Laboratory studies have found that a support leg reduces head and neck injury metrics of anthropomorphic test devices (ATDs) younger than three years in rearward-facing CRS models during frontal impacts. The objectives of the current study were to perform sled tests to: (1) evaluate the effects of using a support leg in rearward-facing infant and extended-use convertible CRS models during frontal impacts, (2) evaluate the effects of using a pair of lower tethers in a rearward-facing extended-use convertible CRS model during rear impacts and (3) compare responses of ATDs in an extendeduse convertible CRS with a support leg and a pair of lower tethers in rearward- and forward-facing configurations during frontal and rear impacts. The presence of a support leg in rearward-facing infant and extended-use convertible CRS models in frontal impacts was associated with reductions in head injury metrics across a range of pediatric ATDs and neck injury metrics were below injury tolerance values. Other strategies in the design of rearward-facing CRS and front row vehicle seatbacks may be available to further reduce head injury metrics. Lower tethers reduced the rearward rotation of an extended-use convertible CRS toward the vehicle seatback in rear impacts and were typically associated with reductions in head and neck injury metrics for the Q6 ATD, but not the Q3 ATD. For frontal impacts, neck injury metrics were typically greater for ATDs in the forward-facing extended-use convertible CRS, whereas head injury metrics were typically greater for the rearward-facing condition (with a support leg and a pair of lower tethers). Interactions of the ATD head and/or the rearward-facing extended-use convertible CRS with the blocker plate in rearward-facing frontal impacts need to be further investigated.

Analysis of the Head of a Simulation Crash Test Dummy with Speed Motion

The article presents a model of an anthropometric dummy designed for low velocity crash tests, designed in ADAMS. The model consists of rigid bodies connected with special joints with appropriately selected stiffness and damping. The simulation dummy has the appropriate dimensions, shape, and mass of individual elements to suit a 50 percentile male. The purpose of this article is to draw attention to low speed crash tests. Current dummies such as THOR and Hybrid III are used for crash tests at speeds above 40 km/h. In contrast, the low-speed test dummy currently used is the BioRID-II dummy, which is mainly adapted to the whiplash test at speeds of up to 16km/h. Thus, it can be seen that there is a gap in the use of crash test dummies. There are no low-speed dummies for side and front crash tests, and there are no dummies for rear crash tests between 16 km/h and 25 km/h. Which corresponds to a collision of a passenger vehicle with a hard obstacle at a speed of 30 km/h. Therefore, in collisions with low speeds of 20 km/h, the splash airbag will probably not be activated. The article contains the results of a computer simulation at a speed of 20 km/h vehicle out in the ADAMS program. These results were compared with the experimental results of the laboratory crash test using volunteers and the Hybrid III dummy. The simulation results are the basis for building the physical model dummy. The simulation aims to reflect the greatest possible compliance of the movements of individual parts of the human body during a collision at low speed.

Biomechanical Analysis of Serious Neck Injuries Resulting from Judo.

To establish a basis for initial diagnosis and for proposing preventive measures for the serious neck injuries occasionally experienced by judo practitioners, the biomechanical mechanisms of these injuries were analyzed. Two male judo experts repeatedly threw an anthropomorphic test device (POLAR dummy) using three throwing techniques (Seoi-nage, Osoto-gari, and Ouchi-gari). The dummy’s kinematic data were captured using a high-speed digital camera, and the load and moment of the neck were measured with load cells. The neck injury criterion (Nij) and beam criterion were also calculated. In Seoi-nage, the anterior and parietal regions of the dummy’s head contacted the tatami (judo mat). Subsequently, most of the body weight was applied, with the neck experiencing the highest compression. However, in Osoto-gari and Ouchi-gari, the occipital region of the dummy’s head contacted the tatami. Significantly higher values of both Nij (median 0.68) and beam criterion (median 0.90) corresponding to a 34.7% to 37.1% risk of neck injury with an abbreviated injury scale score ≥2 were shown in Seoi-nage than in either Ouchi-gari or Osoto-gari. In judo, when thrown by the Seoi-nage technique, serious neck injuries can occur as a result of neck compression that occurs when the head contacts the ground.

Lower Neck Injury Assessment Risk Curves Based on Matched-Pair Human Data for Anthropomorphic Test Devices.

Under G +x accelerative loading, the Hybrid III anthropomorphic test device (ATD) is used to advance human safety. Although injury assessment risk curves (IARCs) are available at the level of the occipital condyles (commonly termed as upper neck), they do not exist for the cervical-thoracic junction (lower neck). The objectives of this study are to develop IARCs under G +x impact accelerations for the Hybrid III ATD and test device for human occupant restraint (THOR) ATD at the cervical thoracic junction. A series of Hybrid III ATD tests were conducted using input conditions that matched previously published cadaver tests. A separate series of THOR-ATD tests were conducted using the same input conditions that matched the same previously published cadaver tests. This type of experimental design where the cadaver input condition is the same as the ATD tests are termed matched-pair tests (Cadaver-Hybrid III and Cadaver-THOR-ATD). Injury outcomes from human cadaver tests were used with loads at the cervical thoracic junction, measured in the ATD tests. Data were censored based on injury outcomes and the number of tests conducted on each specimen. Parametric survival analysis was used to derive IARCs for cervical thoracic junction force-, moment-, and interaction-based lower neck injury criterion (LNic). Injuries were scored according to the Abbreviated Injury Scale scheme. Abbreviated Injury Scale 1 or 2 was scored as injured. The 50% risk levels for the Hybrid III ATD were 315 N, 70 Nm, and 1.12 for the cervical thoracic A/P shear force-, sagittal plane extension moment-, and LNic-based injury criterion, respectively. Results for the THOR ATD were 261 N, 69 Nm, and 1.51. This is the first study to develop cervical thoracic junction IARCs for the ATDs based on force, moment, and LNic for posterior to anterior loading.

Lower Limb Design for a Child Test Dummy, based on Osteogenesis Imperfecta characteristics

Active and passive safety have played an essential role in solidifying ground transportation. However, safety-focused on children with some rare diseases is little attacked. This article shows the design of a diseased leg prototype into a crash test dummy Q3, the novelty of this work is based on the morphology and biocompatibility of the lower limbs, which principal characteristics of this prototype replicate the shape of a child with bone-degenerative diseases. In this work, it shows the essential features that a child dummy of this type must contain in order to generate a homologation and approval under the strictest passive safety standards used in the automotive industry. Results show the important kinematics parameters and CAD bones development necessary to conform a new numerical crash test dummy prototype.

Malaysian Vehicle Seat Anthropometry Studies: A Mini-Review

This paper focuses on anthropometry studies in Malaysia within a 10 years’ span. In the beginning, Malaysian anthropometry study has only been the interest of researchers from the medical field. However, in the past 10 years, other fields like the engineering and social studies began to explore aspects of anthropometry. Driver’s seat has been the central of ergonomic evaluation and analysis for automotive engineering. The data established for Malaysian driver’s seat includes the seat fit parameters, seat postural angles and seat pressure distributions. There were also studies that revealed that the collected data showed significant mismatches between the subjects and the anthropomorphic test device or better known as crash test dummies. Even though currently there are satisfactory data for Malaysian population, these data have to be reviewed subsequently as shown in many nations because there is usually some progress in growth.

Accidental Injuries Caused by Automotive Frontal Collision

ABSTRACT This study aimed to use a simulated vehicle to asses quantitatively the head and neck injuries of the occupants, in a frontal car crash, when the driver has only one hand on the steering wheel, such as while using a cell phone when driving. First, we conducted a survey of NHTSA reports on real laboratory tests of frontal collisions involving sedans. The effects of these collisions on the neck of a Hybrid III 50th percentile male crash test dummy were measured in terms of average head acceleration and force along the X, Z, and Y-axes. These acceleration, force and torque values obtained from the NHTSA database were used to validate the simulated model. The results obtained were compared with case E, the standard dummy position used in frontal collision tests. The results obtained in the simulation of the four cases of driving with only one hand demonstrate a probability of more than 67% that the driver will sustain AIS+2 injuries during a frontal crash. In all the cases, the skull fracture percentage was the most representative, occurring between 89 and 94% of cases where the driver had only one hand on the steering wheel.

К ВОПРОСУ ИСПЫТАНИЙ АМОРТИЗАЦИОННЫХ КРЕСЕЛ ДЛЯ ЭКИПАЖЕЙ ВЕРТОЛЕТОВ

Recommendations on improving the dynamic performance of shock-absorbing seats for helicopter pilots resulted from analysis of the Russian pilots' anthropometric data and helicopter 3-d attitude and position during emergency landing. The idea is to complement the existing list of impact tests with two more tests in which the impact vector will be perpendicular to the test-platform horizontal. One of these tests should be performed with a light anthropomorphic test device (Hybrid-III) representing a 5-percentile female and the other, heavy Hybrid-III representing a 95-percentile male. For horizontal impact testing, the 50-percentile male Hybrid-III should be replaced by the 95-percentile Hybrid-III.

The Influence of Occupant Grip on Ceiling Handrail and Injury Assessment in Collision

With the rapid increase in the number of cars, to bring a variety of convenience to mankind, at the same time, a number of traffic safety problems also followed, which causing serious injuries and property losses, bring more pain and regret to the people. Therefore, to accurately assess the damage of the personnel in the collision safety accident is very useful to improve the safety performance and functionality of the vehicle. so, the crash dummy plays an important role in the research of crash safety. At present, in the study of human body injury in the collision with dummy, the influence of roof handrails grasping state was not considered. Therefore, the software of LS-PREPOST and Oasys PRIM-ER are used to build model of automobile cockpit and dummy with hand grip ability, the acceleration environment of frontal crash was simulated by adding B-pillar acceleration curve from real vehicle crash test. Comparing injuries of dummies in free sitting posture and holding the roof armrest in collision. he simulation results show that when the dummy was grasping the roof armrest, the peak value of head acceleration and HIC values were 6.1% and 30.2% lower than the dummy was sitting freely, the maximum value of shear force, tensile force and bending moment of the neck were reduced by 87.4%, 76.9% and 42.9% respectively, and the maximum value of chest compression was reduced by 16.9%. The results provide a reference for the research of passive safety in collision.

Designing and testing a stand used to simulate the dummy head impact with different surfaces using CAD software

The aim of the paper was to design, assemble and test a stand used to analyse various crash scenarios for a crash test dummy head. This stand can be used to test the head impact with different surfaces, with or without a helmet, on soft or hard surfaces at different impact angles. The idea was to design the stand in the CAD software SolidWorks because this particular software has the feature of dynamic simulation of assemblies known as Motion Analysis. The results show that designing the stand was a success and the simulations show a good behaviour of the assembly with direct results generated in term of acceleration and force values obtained from the drop test of the head on a surface. Also, the surface can be adjusted for different impact angles and with different contact surfaces properties to extend the usability of the assembly.