Blast Mitigation Seat Analysis: Evaluation of Lumbar Compression Data Trends in 5th Percentile Female Anthropomorphic Test Device Performance Compared to 50th Percentile Male Anthropomorphic Test Device in Drop Tower Testing

2016 ◽  
Author(s):  
Kelly Bosch
Keyword(s):  
Lumbar Spine ◽  
Vertical Direction ◽  
Drop Tower ◽  
Blast Mitigation ◽  
Test Device ◽  
Military Population ◽  
Data Set ◽  
System Survivability ◽  
Blast Energy ◽  
Hybrid Iii

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.

Blast Mitigation Seat Analysis: Assessment of the Effect of Personal Protective Equipment on the 5th Percentile Female Anthropomorphic Test Device Performance in Drop Tower Evaluations

2015 ◽  
Author(s):  
Kelly Bosch ◽  
Katrina Harris ◽  
David Clark ◽  
Risa Scherer ◽  
Joseph Melotik
Keyword(s):  
Personal Protective Equipment ◽  
Drop Tower ◽  
Protective Equipment ◽  
Blast Mitigation ◽  
Military Population ◽  
Small Female ◽  
Data Set ◽  
Technical Publication ◽  
Blast Energy ◽  
Hybrid Iii

To address the lack of knowledge on the quantitative effects of Personal Protective Equipment (PPE) on the small occupant, 55 drop tower tests were conducted and the resulting responses were evaluated. A previous technical publication evaluated the results of drop tower testing of twelve models of blast energy-attenuating seats1. That study assessed the data recorded from three sizes of anthropomorphic test devices, or ATDs, including the Hybrid III 5th percentile female, the Hybrid III 50th percentile male, and the Hybrid III 95th percentile male. The forces, moments, and accelerations from the ATDs were compared to Injury Assessment Reference Values (IARVs) to validate the drop tower methodology and to evaluate the appropriateness of the IARVs developed for the three occupant sizes. The data review revealed that the maximum lumbar compression loads recorded by the ATDs was an effective “go/no-go” criteria for judging seat performance, and that the 5th percentile female ATD, or small occupant, was the most difficult to pass the corresponding lumbar compression IARV. Additionally, the 5th percentile female ATD exceeded its corresponding IARV for upper neck compression, leading to the motivation for this study; the data set from the previous technical publication was used in this study. Historically, blast mitigation seats are designed to accommodate the average sized occupant, or 50th percentile male. Moving forward, there is a new emphasis on extending the protection afforded to the full military population, including the small female. The data presented in this paper seeks to determine the effect of PPE on the lumbar compression and upper neck loads for the small occupant.

Effects of Lumbar Spine Assemblies and Body-Borne Equipment Mass on Anthropomorphic Test Device Responses During Drop Tests

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Daniel Aggromito ◽  
Mark Jaffrey ◽  
Allen Chhor ◽  
Bernard Chen ◽  
Wenyi Yan
Keyword(s):  
Lumbar Spine ◽  
Federal Aviation Administration ◽  
Relative Displacement ◽  
Drop Tower ◽  
Test Device ◽  
Hybrid Iii ◽  
Drop Tests ◽  
Occupant Injury ◽  
Maximum Relative Displacement ◽  
The Impact

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.

Time and temperature sensitivity of the hybrid III lumbar spine

2021 ◽  
pp. 1-6
Author(s):  
Allison L. Schmidt ◽  
Maria A. Ortiz-Paparoni ◽  
Jay K. Shridharani ◽  
Roger W. Nightingale ◽  
Frank A. Pintar ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Temperature Sensitivity ◽  
Hybrid Iii

Multidirection Validation of a Finite Element 50th Percentile Male Hybrid III Anthropomorphic Test Device for Spaceflight Applications

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Derek A. Jones ◽  
James P. Gaewsky ◽  
Mona Saffarzadeh ◽  
Jacob B. Putnam ◽  
Ashley A. Weaver ◽  
...  
Keyword(s):  
Finite Element ◽  
Injury Risk ◽  
Fe Model ◽  
Fe Modeling ◽  
Test Device ◽  
Qualitative And Quantitative ◽  
Hybrid Iii ◽  
Physical Tests ◽  
Quantitative Results ◽  
Male Hybrid

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.

On drop-tower test methodology for blast mitigation seat evaluation

2010 ◽  
Vol 37 (12) ◽  
pp. 1180-1187 ◽  
Author(s):  
Ming Cheng ◽  
Jean-Philippe Dionne ◽  
Aris Makris
Keyword(s):  
Drop Tower ◽  
Blast Mitigation ◽  
Test Methodology

Comparison of Human Surrogate Responses in Underbody Blast Loading Conditions

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
K. Ott ◽  
D. Drewry ◽  
M. Luongo ◽  
J. Andrist ◽  
R. Armiger ◽  
...  
Keyword(s):  
Vertical Direction ◽  
Whole Body ◽  
Matched Pair ◽  
Loading Conditions ◽  
Occupant Safety ◽  
Vertical Loading ◽  
Impact Biomechanics ◽  
Biomechanical Response ◽  
Hybrid Iii

Abstract Impact biomechanics research in occupant safety predominantly focuses on the effects of loads applied to human subjects during automotive collisions. Characterization of the biomechanical response under such loading conditions is an active and important area of investigation. However, critical knowledge gaps remain in our understanding of human biomechanical response and injury tolerance under vertically accelerated loading conditions experienced due to underbody blast (UBB) events. This knowledge gap is reflected in anthropomorphic test devices (ATDs) used to assess occupant safety. Experiments are needed to characterize biomechanical response under UBB relevant loading conditions. Matched pair experiments in which an existing ATD is evaluated in the same conditions as a post mortem human subject (PMHS) may be utilized to evaluate biofidelity and injury prediction capabilities, as well as ATD durability, under vertical loading. To characterize whole body response in the vertical direction, six whole body PMHS tests were completed under two vertical loading conditions. A series of 50th percentile hybrid III ATD tests were completed under the same conditions. Ability of the hybrid III to represent the PMHS response was evaluated using a standard evaluation metric. Tibial accelerations were comparable in both response shape and magnitude, while other sensor locations had large variations in response. Posttest inspection of the hybrid III revealed damage to the pelvis foam and skin, which resulted in large variations in pelvis response. This work provides an initial characterization of the response of the seated hybrid III ATD and PMHS under high rate vertical accelerative loading.

scholarly journals Predictors of extended length of stay, discharge to inpatient rehab, and hospital readmission following elective lumbar spine surgery: introduction of the Carolina-Semmes Grading Scale

2017 ◽  
Vol 27 (4) ◽  
pp. 382-390 ◽  
Author(s):  
Matthew J. McGirt ◽  
Scott L. Parker ◽  
Silky Chotai ◽  
Deborah Pfortmiller ◽  
Jeffrey M. Sorenson ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Length Of Stay ◽  
Spine Surgery ◽  
Hospital Readmission ◽  
Inpatient Rehabilitation ◽  
Lumbar Spine Surgery ◽  
Day Hospital ◽  
Data Set ◽  
Inpatient Facility ◽  
Grading Scale

OBJECTIVEExtended hospital length of stay (LOS), unplanned hospital readmission, and need for inpatient rehabilitation after elective spine surgery contribute significantly to the variation in surgical health care costs. As novel payment models shift the risk of cost overruns from payers to providers, understanding patient-level risk of LOS, readmission, and inpatient rehabilitation is critical. The authors set out to develop a grading scale that effectively stratifies risk of these costly events after elective surgery for degenerative lumbar pathologies.METHODSThe Quality and Outcomes Database (QOD) registry prospectively enrolls patients undergoing surgery for degenerative lumbar spine disease. This registry was queried for patients who had undergone elective 1- to 3-level lumbar surgery for degenerative spine pathology. The association between preoperative patient variables and extended postoperative hospital LOS (LOS ≥ 7 days), discharge status (inpatient facility vs home), and 90-day hospital readmission was assessed using stepwise multivariate logistic regression. The Carolina-Semmes grading scale was constructed using the independent predictors for LOS (0–12 points), discharge to inpatient facility (0–18 points), and 90-day readmission (0–6 points), and its performance was assessed using the QOD data set. The performance of the grading scale was then confirmed separately after using it in 2 separate neurosurgery practice sites (Carolina Neurosurgery & Spine Associates [CNSA] and Semmes Murphey Clinic).RESULTSA total of 6921 patients were analyzed. Overall, 290 (4.2%) patients required extended LOS, 654 (9.4%) required inpatient facility care/rehabilitation on hospital discharge, and 474 (6.8%) were readmitted to the hospital within 90 days postdischarge. Variables that remained as independently associated with these unplanned events in multivariate analysis included age ≥ 70 years, American Society of Anesthesiologists Physical Classification System class > III, Oswestry Disability Index score ≥ 70, diabetes, Medicare/Medicaid, nonindependent ambulation, and fusion. Increasing point totals in the Carolina-Semmes scale effectively stratified the incidence of extended LOS, discharge to facility, and readmission in a stepwise fashion in both the aggregate QOD data set and when subsequently applied to the CNSA/Semmes Murphey practice groups.CONCLUSIONSThe authors introduce the Carolina-Semmes grading scale that effectively stratifies the risk of prolonged hospital stay, need for postdischarge inpatient facility care, and 90-day hospital readmission for patients undergoing first-time elective 1- to 3-level degenerative lumbar spine surgery. This grading scale may be helpful in identifying patients who may require additional resource utilization within a global period after surgery.

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 ◽  
...  
Keyword(s):  
Impact Load ◽  
Cutting Edge ◽  
Test Device ◽  
Shock Loads ◽  
Shock Test ◽  
Medical Specialists ◽  
Present Test ◽  
Hybrid Iii ◽  
Vertical Impact ◽  
Injury Analysis

<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>

Capturing Three-Dimensional In Vivo Lumbar Intervertebral Joint Kinematics Using Dynamic Stereo-X-Ray Imaging

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Ameet K. Aiyangar ◽  
Liying Zheng ◽  
Scott Tashman ◽  
William J. Anderst ◽  
Xudong Zhang
Keyword(s):  
Lumbar Spine ◽  
Three Dimensional ◽  
Lumbar Vertebrae ◽  
Lumbar Vertebra ◽  
Weight Lifting ◽  
Data Set ◽  
X Ray ◽  
Biomechanical Models ◽  
Lifting Task

Availability of accurate three-dimensional (3D) kinematics of lumbar vertebrae is necessary to understand normal and pathological biomechanics of the lumbar spine. Due to the technical challenges of imaging the lumbar spine motion in vivo, it has been difficult to obtain comprehensive, 3D lumbar kinematics during dynamic functional tasks. The present study demonstrates a recently developed technique to acquire true 3D lumbar vertebral kinematics, in vivo, during a functional load-lifting task. The technique uses a high-speed dynamic stereo-radiography (DSX) system coupled with a volumetric model-based bone tracking procedure. Eight asymptomatic male participants performed weight-lifting tasks, while dynamic X-ray images of their lumbar spines were acquired at 30 fps. A custom-designed radiation attenuator reduced the radiation white-out effect and enhanced the image quality. High resolution CT scans of participants' lumbar spines were obtained to create 3D bone models, which were used to track the X-ray images via a volumetric bone tracking procedure. Continuous 3D intervertebral kinematics from the second lumbar vertebra (L2) to the sacrum (S1) were derived. Results revealed motions occurring simultaneously in all the segments. Differences in contributions to overall lumbar motion from individual segments, particularly L2–L3, L3–L4, and L4–L5, were not statistically significant. However, a reduced contribution from the L5–S1 segment was observed. Segmental extension was nominally linear in the middle range (20%–80%) of motion during the lifting task, but exhibited nonlinear behavior at the beginning and end of the motion. L5–S1 extension exhibited the greatest nonlinearity and variability across participants. Substantial AP translations occurred in all segments (5.0 ± 0.3 mm) and exhibited more scatter and deviation from a nominally linear path compared to segmental extension. Maximum out-of-plane rotations (<1.91 deg) and translations (<0.94 mm) were small compared to the dominant motion in the sagittal plane. The demonstrated success in capturing continuous 3D in vivo lumbar intervertebral kinematics during functional tasks affords the possibility to create a baseline data set for evaluating the lumbar spinal function. The technique can be used to address the gaps in knowledge of lumbar kinematics, to improve the accuracy of the kinematic input into biomechanical models, and to support development of new disk replacement designs more closely replicating the natural lumbar biomechanics.

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