scholarly journals Injury analysis using Anthropomorphic Test Device under vertical shock loads

2017 ◽  
Vol 2 (4) ◽  
pp. 385
Author(s):  
A. Prasanna ◽  
G. K. Kannan ◽  
N. Mohan ◽  
Shivaraj Yaranal ◽  
Kartik S. Patil ◽  
...  

<p class="p1">Natural and manmade injuries due to terrorism, military weapon and accidents lead to cutting edge research for engineers and clinicians alike. The study of injury and its mechanism can help in predicting the severity of an injury which in turn shall guide the engineers to design safer structures and medical specialists in treating casualties. This article summarizes the various advancements and technologies available in the field of Injury Analysis. The objective of the study is to quantify the levels of an injury which occurs when an Anthropomorphic Test Device is subjected to a given vertical impact load. As a baseline a half sine shock test simulating the vertical impact was carried out on Hybrid III 50th percentile male dummy and injury analysis was done based on the standards prescribed by NATO TR-HFM-090. In the present test the injury analysis predicts that the injury during the loading is well within 10% probability of an AIS 2 or greater (AIS 2+).</p>

Author(s):  
Shaun Eshraghi ◽  
Kristine Severson ◽  
David Hynd ◽  
A. Benjamin Perlman

The Hybrid-III Rail Safety (H3-RS) anthropomorphic test device (ATD), also known as a crash test dummy, was developed by the Rail Safety and Standards Board (RSSB), DeltaRail (now Resonate Group Ltd.), and the Transport Research Laboratory (TRL) in the United Kingdom between 2002 and 2005 for passenger rail safety applications [1]. The H3-RS is a modification of the standard Hybrid-III 50th percentile male (H3-50M) ATD with additional features in the chest and abdomen to increase its biofidelity and eight sensors to measure deflection. The H3-RS features bilateral (left and right) deflection sensors in the upper and lower chest and in the upper and lower abdomen; whereas, the standard H3-50M only features a single unilateral (center) deflection sensor in the chest with no deflection sensors located in the abdomen. Additional H3-RS research was performed by the Volpe National Transportation Systems Center (Volpe Center) under the direction of the U.S. Department of Transportation, Federal Railroad Administration (FRA) Office of Research, Development, and Technology. The Volpe Center contracted with TRL to conduct a series of dynamic pendulum impact tests [2]. The goal of testing the abdomen response of the H3-RS ATD was to develop data to refine an abdomen design that produces biofidelic and repeatable results under various impact conditions with respect to impactor geometry, vertical impact height, and velocity. In this study, the abdominal response of the H3-RS finite element (FE) model that TRL developed is validated using the results from pendulum impact tests [2]. Results from the pendulum impact tests and corresponding H3-RS FE simulations are compared using the longitudinal relative deflection measurements from the internal sensors in the chest and abdomen as well as the longitudinal accelerometer readings from the impactor. The abdominal response of the H3-RS FE model correlated well with the physical ATD as the impactor geometry, vertical impact height, and velocity were changed. There were limitations with lumbar positioning of the H3-RS FE model as well as the material definition for the relaxation rate of the foam in the abdomen that can be improved in future work. The main goal of validating the abdominal response of the dummy model is to enable its use in assessing injury potential in dynamic sled testing of crashworthy workstation tables, the results of which are presented in a companion paper [3]. The authors used the model of the H3-RS ATD to study the 8G sled test specified in the American Public Transportation Association (APTA) workstation table safety standard [4]. The 8G sled test is intended to simulate the longitudinal crash accleration in a severe train-to-train collision involving U.S. passenger equipment. Analyses of the dynamic sled test are useful for studying the sensitivity of the sled test to factors such as table height, table force-crush behavior, seat pitch, etc., which help to inform discussions on revisions to the test requirements eventually leading to safer seating environments for passengers.


2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Derek A. Jones ◽  
James P. Gaewsky ◽  
Mona Saffarzadeh ◽  
Jacob B. Putnam ◽  
Ashley A. Weaver ◽  
...  

The use of anthropomorphic test devices (ATDs) for calculating injury risk of occupants in spaceflight scenarios is crucial for ensuring the safety of crewmembers. Finite element (FE) modeling of ATDs reduces cost and time in the design process. The objective of this study was to validate a Hybrid III ATD FE model using a multidirection test matrix for future spaceflight configurations. Twenty-five Hybrid III physical tests were simulated using a 50th percentile male Hybrid III FE model. The sled acceleration pulses were approximately half-sine shaped, and can be described as a combination of peak acceleration and time to reach peak (rise time). The range of peak accelerations was 10–20 G, and the rise times were 30–110 ms. Test directions were frontal (−GX), rear (GX), vertical (GZ), and lateral (GY). Simulation responses were compared to physical tests using the correlation and analysis (CORA) method. Correlations were very good to excellent and the order of best average response by direction was −GX (0.916±0.054), GZ (0.841±0.117), GX (0.792±0.145), and finally GY (0.775±0.078). Qualitative and quantitative results demonstrated the model replicated the physical ATD well and can be used for future spaceflight configuration modeling and simulation.


Author(s):  
Kelly Bosch

Although blast mitigation seats are historically designed to protect the 50th percentile male occupant based on mass, the scope of the occupant centric platform (OCP) Technology Enabled Capability Demonstration (TEC-D) within the U.S. Army Tank Automotive Research Development Engineering Center (TARDEC) Ground System Survivability has been expanded to encompass lighter and heavier occupants which represents the central 90th percentile of the military population. A series of drop tower tests were conducted on twelve models of blast energy-attenuating (EA) seats to determine the effects of vertical accelerative loading on ground vehicle occupants. Two previous technical publications evaluated specific aspects of the results of these drop tower tests on EA seats containing the three sizes of anthropomorphic test devices (ATDs) including the Hybrid III 5th percentile female, the Hybrid III 50th percentile male, and the Hybrid III 95th percentile male. The first publication addressed the overall trends of the forces, moments, and accelerations recorded by the ATDs when compared to Injury Assessment Reference Values (IARVs), as well as validating the methodology used in the drop tower evaluations1. Review of ATD data determined that the lumbar spine compression in the vertical direction could be used as the “go/no-go” indicator of seat performance. The second publication assessed the quantitative effects of Personal Protective Equipment (PPE) on the small occupant, as the addition of a helmet and Improved Outer Tactical Vest (IOTV) with additional gear increased the weight of the 5th percentile female ATD more than 50%2. Comparison of the loading data with and without PPE determined that the additional weight of PPE increased the overall risk of compressive injury to the lumbar and upper neck of the small occupant during an underbody blast event. Using the same data set, this technical paper aimed to evaluate overall accelerative loading trends of the 5th percentile female ATD when compared to those of the 50th percentile male ATD in the same seat and PPE configuration. This data trend comparison was conducted to gain an understanding of how seat loading may differ with a smaller occupant. The focus of the data analysis centered around the lumbar spine compression, as this channel was the most likely to exceed the IARV limit for the 5th percentile female ATD. Based on the previous analysis of this data set, the lightest occupant trends showed difficulty in protecting against lumbar compression injuries with respect to the 5th percentile female’s IARV, whereas the larger occupants experienced fewer issues in complying with their respective IARVs for lumbar compression. A review of pelvis acceleration was also conducted for additional kinetic insight into the motion of the ATDs as the seat strokes. This analysis included a review of how the weight and size of the occupant may affect the transmission of forces through a stroking seat during the vertical accelerative loading impulse.


2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Daniel Aggromito ◽  
Mark Jaffrey ◽  
Allen Chhor ◽  
Bernard Chen ◽  
Wenyi Yan

When simulating or conducting land mine blast tests on armored vehicles to assess potential occupant injury, the preference is to use the Hybrid III anthropomorphic test device (ATD). In land blast events, neither the effect of body-borne equipment (BBE) on the ATD response nor the dynamic response index (DRI) is well understood. An experimental study was carried out using a drop tower test rig, with a rigid seat mounted on a carriage table undergoing average accelerations of 161 g and 232 g over 3 ms. A key aspect of the work looked at the various lumbar spine assemblies available for a Hybrid III ATD. These can result in different load cell orientations for the ATD which in turn can affect the load measurement in the vertical and horizontal planes. Thirty-two tests were carried out using two BBE mass conditions and three variations of ATDs. The latter were the Hybrid III with the curved (conventional) spine, the Hybrid III with the pedestrian (straight) spine, and the Federal Aviation Administration (FAA) Hybrid III which also has a straight spine. The results showed that the straight lumbar spine assemblies produced similar ATD responses in drop tower tests using a rigid seat. In contrast, the curved lumbar spine assembly generated a lower pelvis acceleration and a higher lumbar load than the straight lumbar spine assemblies. The maximum relative displacement of the lumbar spine occurred after the peak loading event, suggesting that the DRI is not suitable for assessing injury when the impact duration is short and an ATD is seated on a rigid seat on a drop tower. The peak vertical lumbar loads did not change with increasing BBE mass because the equipment mass effects did not become a factor during the peak loading event.


Author(s):  
Gianmarco Galmarini ◽  
Massimiliano Gobbi ◽  
Gianpiero Mastinu ◽  
Giorgio Previati

In this paper a method for the evaluation of the dynamic performance of neck protection devices for motorcyclists is presented. The research project involves both experimental and numerical activities. An impulsive load is applied to the head of a 50th percentile male Hybrid III dummy while wearing a helmet by means of a pendulum of calibrated mass starting from a well-defined initial condition. The impact load and the load at the neck of the dummy are measured by means of two six axes load cells. Additionally, head linear and rotational accelerations are measured. The test procedure shows a very good repeatability and allows for the comparison of the force passing through the neck with and without neck protection devices. Since neck protection devices should work in situations in which no relevant head injuries are present, the experimental parameters (pendulum mass and speed) are chosen to cause a high probability of injuries to the neck together with a low probability of damages to the head while wearing a standard helmet. Injury indices, found in the literature, have been used to determine the neck injury level. A multibody model of the human neck, developed in Matlab™ SimMechanics™, is validated by using the data acquired during the tests. A study of real-world crashes has allowed the identification of reference impact scenarios which have been simulated by using the multibody model. The validated model is suitable to determine the chance that a motorcyclist would have significant neck injury with or without a neck protecting device.


Author(s):  
Nicholas H. Yang ◽  
Kathleen Allen Rodowicz ◽  
David Dainty

Traumatic brain injury may occur in baseball due to a head impact with a thrown, pitched, or batted ball. It has been shown that the average pitching speed of youth pitchers and high school pitchers is approximately 63 mph (28 m/s) and 74 mph (33 m/s), respectively. At pitching speeds of approximately 52 mph (23 m/s), the bat exit velocity (BEV) for metal bats has been shown to be approximately 100 mph (45 m/s). Head kinematics, such as linear and angular head accelerations, are often used to establish head injury risk for head impacts. With a possible ball impact velocity reaching speeds in excess of those typically tested for baseball headgear, it is necessary to understand how the head will respond to high velocity impacts in both helmeted and non-helmeted situations. In this study, head impacts were delivered to the front and side of a Hybrid III 50th percentile male anthropomorphic test device (ATD) by a baseball traveling at speeds of 60 mph (27 m/s), 75 mph (34 m/s), and 100 mph (45 m/s). Head impacts were performed on the non-helmeted ATD head and with the ATD wearing a standard batting helmet certified in accordance with the NOCSAE standard. The Hybrid III headform was instrumented with a nine accelerometer array to measure linear accelerations of the head and determine angular accelerations. Peak resultant linear head accelerations for the non-helmeted ATD were approximately 200–400 g for frontal impacts and approximately 220–480 g for lateral impacts. Peak resultant angular head accelerations for the non-helmeted condition were approximately 17,000–32,000 rad/s2 for frontal impacts and approximately 30,000–60,000 rad/s2 for lateral impacts. For the helmeted ATD, peak resultant linear accelerations of the head were approximately 70–300 g for frontal impacts and approximately 80–360 g for lateral impacts. Peak resultant angular head accelerations for the helmeted ATD were approximately 5,000–14,000 rad/s2 for frontal impacts and approximately 7,500–30,000 rad/s2 for lateral impacts. HIC values for the non-helmeted ATD were approximately 193–1,025 for frontal impacts and approximately 241–1,588 for lateral impacts. SI values for the non-helmeted ATD were approximately 235–1,267 for frontal impacts and approximately 285–1,844 for lateral impacts. HIC values for the helmeted ATD were approximately 16–415 for frontal impacts and approximately 23–585 for lateral impacts. SI values for the helmeted ATD were approximately 25–521 for frontal impacts and approximately 32–708 for lateral impacts. In comparison to the non-helmeted condition, the results demonstrate the effectiveness of a batting helmet in mitigating head accelerations for the frontal and lateral impact conditions tested.


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