An Objective Evaluation of Mass Scaling Techniques Utilizing Computational Human Body Finite Element Models

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Matthew L. Davis ◽  
F. Scott Gayzik
Keyword(s):  
Human Body ◽  
Method Development ◽  
Human Subjects ◽  
Objective Evaluation ◽  
Similarity Score ◽  
Mass Scaling ◽  
Response Data ◽  
Human Body Models ◽  
Single Technique ◽  
Equal Density

Biofidelity response corridors developed from post-mortem human subjects are commonly used in the design and validation of anthropomorphic test devices and computational human body models (HBMs). Typically, corridors are derived from a diverse pool of biomechanical data and later normalized to a target body habitus. The objective of this study was to use morphed computational HBMs to compare the ability of various scaling techniques to scale response data from a reference to a target anthropometry. HBMs are ideally suited for this type of study since they uphold the assumptions of equal density and modulus that are implicit in scaling method development. In total, six scaling procedures were evaluated, four from the literature (equal-stress equal-velocity, ESEV, and three variations of impulse momentum) and two which are introduced in the paper (ESEV using a ratio of effective masses, ESEV-EffMass, and a kinetic energy approach). In total, 24 simulations were performed, representing both pendulum and full body impacts for three representative HBMs. These simulations were quantitatively compared using the International Organization for Standardization (ISO) ISO-TS18571 standard. Based on these results, ESEV-EffMass achieved the highest overall similarity score (indicating that it is most proficient at scaling a reference response to a target). Additionally, ESEV was found to perform poorly for two degree-of-freedom (DOF) systems. However, the results also indicated that no single technique was clearly the most appropriate for all scenarios.

Optimization of Underbody Blast Energy-Attenuating Seat Mechanisms Using Modified MADYMO Human Body Models

2021 ◽  
Author(s):  
Kelly Bosch ◽  
Ann Bailey ◽  
E. Meade Spratley ◽  
Robert S. Salzar ◽  
Paul Begeman ◽  
...  
Keyword(s):  
Human Body ◽  
Dynamic Models ◽  
High Rate ◽  
Human Body Model ◽  
Response Data ◽  
Blast Energy ◽  
Injury Criteria ◽  
Optimal Force ◽  
Spine Injuries ◽  
Human Body Models

Abstract Though energy attenuating (EA) seats for air and spacecraft applications have existed for decades, they have not yet been fully characterized for their energy attenuation capability or resulting effect on occupant protection in vertical underbody blast. EA seats utilize stroking mechanisms to absorb energy and reduce the vertical forces imparted on the occupant's pelvis and lower spine. Using dynamic rigid-body modeling, a tool to determine optimal force and deflection limits was developed to reduce pelvis and lower spine injuries in underbody blast events using a generic seat model. MAthematical DYnamic MOdels (MADYMO) and modeFRONTIER software were leveraged for this study. This optimizing tool may be shared with EA seat manufacturers and applied to military seat development efforts for EA mechanisms for a given occupant and designated blast severity. To optimally tune the EA seat response, the MADYMO Human Body Model (HBM) was first updated to improve its fidelity in kinematic response data for high rate vertical accelerative loading relative to experimental data from laboratory simulated underbody blast tests using post-mortem human surrogates (PMHS). Subsequently, using available injury criteria for underbody blast, the optimization tool demonstrated the ability to identify successful EA mechanism configurations to reduce forces and accelerations in the pelvis and lower spine HBM to presumed non-injurious levels. This tool could be tailored by varying input pulses, force and deflection limits, and occupant size to evaluate EA mechanism designs.

Tissue necrosis and passage of fluid due to cold stress from the thermally damaged human body peripherals: A mathematical model

2015 ◽  
Vol 04 (02) ◽  
pp. 1550012
Author(s):  
M. A. Khanday ◽  
Fida Hussain ◽  
Khalid Nazir
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Heat Equation ◽  
Cold Stress ◽  
Human Body ◽  
Human Subjects ◽  
Diffusion Equations ◽  
Tissue Necrosis ◽  
Cold Temperatures ◽  
Element Technique

The development of cold injury takes place in the human subjects by means of crystallization of tissues in the exposed regions at severe cold temperatures. The process together with the evaluation of the passage of fluid discharge from the necrotic regions with respect to various degrees of frostbites has been carried out by using variational finite element technique. The model is based on the Pennes' bio-heat equation and mass diffusion equations together with suitable initial and boundary conditions. The results are analyzed in relation with atmospheric temperatures and other parameters of the tissue medium.

Unsupervised construction of human body models

2018 ◽  
Vol 47 ◽  
pp. 68-84
Author(s):  
Thomas Walther ◽  
Rolf P. Würtz
Keyword(s):  
Human Body ◽  
Human Body Models

scholarly journals Design of a field trial to develop a tabletop platform for rapid detection of XDR-TB in clinical samples (Preprint)

2020 ◽  
Author(s):  
Naomi Hillery ◽  
Marva Seifert ◽  
Donald G Catanzaro ◽  
Symone McKinnon ◽  
Rebecca E Colman ◽  
...  
Keyword(s):  
Clinical Study ◽  
Data Collection ◽  
Study Design ◽  
Human Subjects ◽  
Bacterial Load ◽  
Objective Evaluation ◽  
Clinical Samples ◽  
Prospective Clinical Study ◽  
Global Public Health ◽  
Drug Concentrations

BACKGROUND Extensively drug-resistant tuberculosis (XDR-TB) continues to be a serious threat to global public health, due in part to the lack of accurate and efficient diagnostic devices for XDR-TB. A prospective clinical study in an intended-use cohort was designed to evaluate the Akonni Biosystems XDR-TB TruArray® and Lateral Flow Cell (XDR-LFC), which has the potential to address this gap in TB diagnostics. OBJECTIVE The objective of this publication is to share documentation of the study conceptualization and design that is replicable and of use to the scientific community. METHODS This clinical study was conducted in three phases, the first to observe changes in bacterial load and culture positivity in patient sputa over time and better understand the diversity of prospective clinical samples, the second to prospectively collect clinical samples for sensitivity and specificity testing of the Akonni Biosystems XDR-LFC device, and the third to explore anti-TB drug concentrations in serum over the course of DR-TB treatment. RESULTS The methodology described includes the study design, laboratory sample handling, data collection, and human subjects protection elements of the clinical study to evaluate a potential new XDR-TB diagnostic device. The complex systems implemented facilitated thorough clinical data collection for objective evaluation of the device. This trial is closed to recruitment. Follow-up data collection and analysis are in progress. CONCLUSIONS This publication outlined the methods used in a prospective cohort study to evaluate a device to rapidly detect XDR-TB. The documentation of this clinical study design may be of use to other researchers with similar goals.

Morphological Evolution of French Military Personnels

2000 ◽  
Vol 44 (38) ◽  
pp. 744-747
Author(s):  
Régis Mollard ◽  
Pierre Yves Hennion ◽  
Alex Coblentz
Keyword(s):  
Human Body ◽  
Morphological Evolution ◽  
The Body ◽  
Lower Limbs ◽  
Morphological Transformation ◽  
Military Population ◽  
Morphological Modification ◽  
Human Body Models ◽  
The Individual ◽  
The Military

The survey realized in 1992 on a military population allowed to collect anthropometric data on 688 males and 328 females. Among 73 measurements and 3 index, 26 of them have been retained for the comparison with previous surveys. Generally used for dimensioning human body models these data represent somatic measurements of reference, as weight and stature and segmentary measurements of trunk and limbs. A comparison with previous data, collected on a equivalent military population in 1973, confirms the modifications along the time are so significant that they can be considered as a phenomenon of morphological evolution. Likewise, the modification of the academic levels, average age and socio-cultural structures in the populations are combined to increase the anthropometric variability. It appears the military population presents a morphological modification with an overall increase in weight, stature and correlated dimensions. Otherwise, a light decrease of the cormic index indicates that the morphological transformation influences on the body proportions, with an increase more notable for the lower limbs compared to the trunk. The collected anthropometric information allow to update the Individual Database of ERGODATA from which ergonomie recommendations and statistical and morphological models of the human body can be proposed.

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