Pelvic Response of a Total Human Body Finite Element Model During Simulated Injurious Under Body Blast Impacts

2020 ◽  
Author(s):  
Caitlin Weaver ◽  
Berkan Guleyupoglu ◽  
Anna Miller ◽  
Michael Kleinberger ◽  
Joel D Stitzel
Keyword(s):  
Human Body ◽  
Military Personnel ◽  
Injury Risk ◽  
Element Model ◽  
Peak Force ◽  
Load Path ◽  
Specific Test ◽  
Pubic Ramus ◽  
Cross Sectional ◽  
Superior Pubic Ramus

Abstract Military operations in Iraq and Afghanistan have resulted in the increased exposure of military personnel to explosive threats. Combat-related pelvic fractures are a relatively new battlefield injury that pose a serious threat to military personnel. Injury prediction for these events continues to be a challenge due to the limited availability of blast-specific test studies and the use of established automotive-based injury criteria that do not directly translate to combat-related exposures. The objective of this study is to evaluate the pelvic response of the Global Human Body Models Consortium (GHBMC) 50th percentile detailed male model (v4.3) in under body blast (UBB) loading scenarios. Nine simulations were conducted with mild or enhanced threat levels, and nominal or obtuse occupant positions. Cross-sectional force outputs from the superior pubic ramus (SPR), ilium, and sacroiliac (SI) regions were evaluated using previously developed injury risk curves. Additionally, maximum principal strain (MPS) data was extracted from the pelvic cortical bone elements. Results showed that shear force was the best predictor of fracture for the ischial and SI regions, while axial force was the best predictor for the SPR region. These outcomes were consistent with the load path of the simulated UBB events. The obtuse posture had higher peak force values for injurious and non-injurious outcomes for the SPR and SI region. The nominal posture had higher peak force values for non-injurious outcomes in the ischial region. These outcomes were supported by the MPS response present in these postures.

Finite Element-Based Pelvic Injury Metric Creation and Validation in Lateral Impact for a Human Body Model

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Caitlin M. Weaver ◽  
Alexander M. Baker ◽  
Matthew L. Davis ◽  
Anna N. Miller ◽  
Joel D. Stitzel
Keyword(s):  
Finite Element ◽  
Human Body ◽  
Roc Curve ◽  
Injury Risk ◽  
Curve Analysis ◽  
Pelvic Injury ◽  
Fe Model ◽  
Lateral Impact ◽  
Roc Curve Analysis ◽  
Cross Sectional

Pelvic fractures are serious injuries resulting in high mortality and morbidity. The objective of this study is to develop and validate local pelvic anatomical, cross section-based injury risk metrics for a finite element (FE) model of the human body. Cross-sectional instrumentation was implemented in the pelvic region of the Global Human Body Models Consortium (GHBMC M50-O) 50th percentile detailed male FE model (v4.3). In total, 25 lateral impact FE simulations were performed using input data from cadaveric lateral impact tests performed by Bouquet et al. The experimental force-time data were scaled using five normalization techniques, which were evaluated using log rank, Wilcoxon rank sum, and correlation and analysis (CORA) testing. Survival analyses with Weibull distribution were performed on the experimental peak force (scaled and unscaled) and the simulation test data to generate injury risk curves (IRCs) for total pelvic injury. Additionally, IRCs were developed for regional injury using cross-sectional forces from the simulation results and injuries documented in the experimental autopsies. These regional IRCs were also evaluated using the receiver operator characteristic (ROC) curve analysis. Based on the results of all the evaluation methods, the equal stress equal velocity (ESEV) and ESEV using effective mass (ESEV-EM) scaling techniques performed best. The simulation IRC shows slight under prediction of injury in comparison to these scaled experimental data curves. However, this difference was determined not to be statistically significant. Additionally, the ROC curve analysis showed moderate predictive power for all regional IRCs.

DEVELOPMENT OF A BELTED OCCUPANT FE MODEL FOR PREDICTION OF CHEST INJURY RISK BASED ON STRESS AND STRAIN ANALYSIS

2017 ◽  
Vol 17 (03) ◽  
pp. 1750060
Author(s):  
SEN XIAO ◽  
JIKUANG YANG ◽  
JING HUANG ◽  
JEFF R. CRANDALL
Keyword(s):  
Human Body ◽  
Injury Risk ◽  
Human Subjects ◽  
Strain Analysis ◽  
Element Model ◽  
Chest Injury ◽  
Stress And Strain ◽  
Fe Model ◽  
Human Body Model ◽  
Virtual Design

This study aims to investigate the chest injury in terms of chest deflections and rib fracture risks based on the stress/strain analysis via a belted occupant finite element model (BOM). The BOM was established using a human body model from the Global Human Body Models Consortium (GHBMC) and the model was validated against a frontal sled test with a Post-Mortem Human Subjects (PMHS). The bio-fidelity of the belted occupant model was then evaluated according to measured data from experimental test regarding detailed torso kinematics and seatbelt forces. The BOM was then used for prediction of the chest injury via calculated injury related parameters from simulations, including stress and strain distributions on the whole ribcage, which could not be fully measured in PMHS test. A study of chest injury risk was conducted with the validated model. Special concern is given to the injuries on rib fractures and chest deflections which have been correlated to the calculated stresses and strains. The results demonstrate that the validation can sufficiently meet the reconstruction of the test and the chest injury outcomes obtained from the simulation can fit the experiment, particularly the fracture risk of the rib 6 to the rib 11 on the chest along the seatbelt path. The current study provides a reference for virtual design and improvement of the chest injury investigation to better prevent chest injuries.

Transport and Chronic Injuries Caused by Improper Use of Cell Phones：Evidences from 41 Studies (Preprint)

2020 ◽  
Author(s):  
Xinxi Cao ◽  
Yangyang Cheng ◽  
Chenjie Xu ◽  
Yabing Hou ◽  
Hongxi Yang ◽  
...  
Keyword(s):  
Human Body ◽  
Cell Phone ◽  
Injury Risk ◽  
Negative Impact ◽  
Mental Disease ◽  
Cell Phones ◽  
Cell Phone Use ◽  
Improper Use ◽  
Chronic Injuries ◽  
The Impact

BACKGROUND Cell phone use brought convenience to people, but using phones for a long period of time or in the wrong way and with a wrong posture might cause damage to the human body. OBJECTIVE To assess the impact of improper cell phone use on transport and chronic injuries. METHODS Studies were systematically searched in PubMed, EMBASE, Cochrane, and Web of Science up to April 4, 2019 and relevant reviews were searched to identify additional studies. A random-effects model was used to estimate the overall pooled estimates. RESULTS Cell phone users were at a higher risk for transport injuries (RR: 1.37, 95%CI: 1.221.55), long-term use of cell phones increased the transport injury risk to non-use or short-term use (RR: 2.10, 95% CI: 1.632.70). Neoplasm risk caused by cell phone use was 1.07 times that of non-use (95% CI: 1.011.14); Compared with non-use, cell phone use had a higher risk of eye disease, with a risk of 2.03 (95% CI: 1.273.23), the risk of mental disease was 1.26 (95% CI: 1.171.35), the risk of neurological disorder was 1.16 (95% CI: 1.021.32), and a pooled risk of other chronic injuries was 1.20 (95% CI: 0.981.59). CONCLUSIONS Cell phone use at inappropriate situations has a negative impact on the human body. Therefore, it is necessary to use cell phones correctly and reasonably.

Investigation on the free vibration behavior of sandwich conical shells with reinforced cores

2021 ◽  
pp. 109963622110204
Author(s):  
Mehdi Zarei ◽  
Gholamhossien Rahimi ◽  
Davoud Shahgholian-Ghahfarokhi
Keyword(s):  
Free Vibration ◽  
Orientation Angle ◽  
Element Model ◽  
Filament Winding ◽  
Vertex Angle ◽  
Sandwich Shell ◽  
Cross Sectional ◽  
Conical Shells ◽  
Vibration Behavior ◽  
Axial Forces

The free vibration behavior of sandwich conical shells with reinforced cores is investigated in the present study using experimental, analytical, and numerical methods. A new effective smeared method is employed to superimpose the stiffness contribution of skins with those of the stiffener in order to achieve equivalent stiffness of the whole structure. The stiffeners are also considered as a beam to support shear forces and bending moments in addition to the axial forces. Using Donnell’s shell theory and Galerkin method, the natural frequencies of the sandwich shell are subsequently derived. To validate analytical results, experimental modal analysis (EMA) is further conducted on the conical sandwich shell. For this purpose, a method is designed for manufacturing specimens through the filament winding process. For more validation, a finite element model (FEM) is built. The results revealed that all the validations were in good agreement with each other. Based on these analyses, the influence of the cross-sectional area of the stiffeners, the semi-vertex angle of the cone, stiffener orientation angle, and the number of stiffeners are investigated as well. The results achieved are novel and can be thus employed as a benchmark for further studies.

Contribution of Lamb wave modes in the formation of higher order modes cluster (HOMC) guided waves

2021 ◽  
pp. 095440622110424
Author(s):  
Z Abbasi ◽  
F Honarvar
Keyword(s):  
Finite Element ◽  
Wave Packet ◽  
Lamb Wave ◽  
Guided Waves ◽  
Element Model ◽  
Higher Order ◽  
Guided Wave ◽  
Cross Sectional ◽  
Higher Order Modes ◽  
Wave Modes

In recent years, Higher Order Modes Cluster (HOMC) guided waves have been considered for ultrasonic testing of plates and pipes. HOMC guided waves consist of higher order Lamb wave modes that travel together as a single nondispersive wave packet. The objective of this paper is to investigate the effect of frequency-thickness value on the contribution of Lamb wave modes in an HOMC guided wave. This is an important issue that has not been thoroughly investigated before. The contribution of each Lamb wave mode in an HOMC guided wave is studied by using a two-dimensional finite element model. The level of contribution of various Lamb wave modes to the wave cluster is verified by using a 2D FFT analysis. The results show that by increasing the frequency-thickness value, the order of contributing modes in the HOMC wave packet increases. The number of modes that comprise a cluster also increases up to a specific frequency-thickness value and then it starts to decrease. Plotting of the cross-sectional displacement patterns along the HOMC guided wave paths confirms the shifting of dominant modes from lower to higher order modes with increase of frequency-thickness value. Experimental measurements conducted on a mild steel plate are used to verify the finite element simulations. The experimental results are found to be in good agreement with simulations and confirm the changes observed in the level of contribution of Lamb wave modes in a wave cluster by changing the frequency-thickness value.

scholarly journals Peak force and maximal shortening velocity of soleus fibers after non-weight-bearing and resistance exercise

1997 ◽  
Vol 82 (1) ◽  
pp. 189-195 ◽  
Author(s):  
Jeffrey J. Widrick ◽  
Robert H. Fitts
Keyword(s):  
Resistance Exercise ◽  
Elevated Level ◽  
Fiber Diameter ◽  
Weight Bearing ◽  
Normal Weight ◽  
Peak Force ◽  
Type I ◽  
Shortening Velocity ◽  
Adult Rats ◽  
Cross Sectional

Widrick, Jeffrey J., and Robert H. Fitts. Peak force and maximal shortening velocity of soleus fibers after non-weight-bearing and resistance exercise. J. Appl. Physiol. 82(1): 189–195, 1997.—This study examined the effectiveness of resistance exercise as a countermeasure to non-weight-bearing-induced alterations in the absolute peak force, normalized peak force (force/fiber cross-sectional area), peak stiffness, and maximal shortening velocity ( V o) of single permeabilized type I soleus muscle fibers. Adult rats were subjected to one of the following treatments: normal weight bearing (WB), non-weight bearing (NWB), or NWB with exercise treatments (NWB+Ex). The hindlimbs of the NWB and NWB+Ex rats were suspended for 14 days via tail harnesses. Four times each day, the NWB+Ex rats were removed from suspension and performed 10 climbs (∼15 cm each) up a steep grid with a 500-g mass (∼1.5 times body mass) attached to their tail harness. NWB was associated with significant reductions in type I fiber diameter, absolute force, normalized force, and stiffness. Exercise treatments during NWB attenuated the decline in fiber diameter and absolute force by almost 60% while maintaining normalized force and stiffness at WB levels. Type I fiber V oincreased by 33% with NWB and remained at this elevated level despite the exercise treatments. We conclude that in comparison to intermittent weight bearing only (J. J. Widrick, J. J. Bangart, M. Karhanek, and R. H. Fitts. J. Appl. Physiol. 80: 981–987, 1996), resistance exercise was more effective in attenuating alterations in type I soleus fiber absolute force, normalized force, and stiffness but was less effective in restoring type I fiber V oto WB levels.

scholarly journals The Influence of Social Support on Dyadic Functioning and Mental Health Among Military Personnel During Postdeployment Reintegration

2016 ◽  
Vol 132 (1) ◽  
pp. 85-92 ◽  
Author(s):  
Julie A. Cederbaum ◽  
Sherrie L. Wilcox ◽  
Kathrine Sullivan ◽  
Carrie Lucas ◽  
Ashley Schuyler
Keyword(s):  
Mental Health ◽  
Social Support ◽  
Military Personnel ◽  
Military Service ◽  
Well Being ◽  
Service Members ◽  
Traumatic Experiences ◽  
Military Leaders ◽  
Cross Sectional ◽  
Symptoms Of Depression

Objectives: Although many service members successfully cope with exposure to stress and traumatic experiences, others have symptoms of depression, posttraumatic stress disorder (PTSD), and anxiety; contextual factors may account for the variability in outcomes from these experiences. This work sought to understand mechanisms through which social support influences the mental health of service members and whether dyadic functioning mediates this relationship. Methods: We collected cross-sectional data as part of a larger study conducted in 2013; 321 military personnel who had at least 1 deployment were included in these analyses. Surveys were completed online; we collected data on demographic characteristics, social support, mental health measures (depression, PTSD, and anxiety), and dyadic functioning. We performed process modeling through mediation analysis. Results: The direct effects of social support on the mental health of military personnel were limited; however, across all types of support networks, greater social support was significantly associated with better dyadic functioning. Dyadic functioning mediated the relationships between social support and depression/PTSD only when social support came from nonmilitary friends or family; dyadic functioning mediated social support and anxiety only when support came from family. We found no indirect effects of support from military peers or military leaders. Conclusion: Findings here highlight the need to continue to explore ways in which social support, particularly from family and nonmilitary-connected peers, can bolster healthy intimate partner relationships and, in turn, improve the well-being of military service members who are deployed.

Sign in / Sign up

Export Citation Format

Share Document