Restraint Systems in Tactical Vehicles: Uncertainty Study Involving Airbags, Seatbelts, and Military Gear

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Dorin Drignei ◽  
Zissimos P. Mourelatos ◽  
Ervisa Zhamo ◽  
Jingwen Hu ◽  
Cong Chen ◽  
...  
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Body Size ◽  
Injury Risk ◽  
Risk Distribution ◽  
Frontal Crashes ◽  
Safety Features ◽  
The Impact

Adding advanced safety features (e.g., airbags) to restraint systems in tactical vehicles could decrease the injury risk of their occupants. The impact of frontal crashes on the occupants has been assessed recently through experimental data and finite element (FE) models. However, the number of such experiments is relatively small due to high cost. In this paper, we conduct an uncertainty study to infer the advantage of including advanced safety features, if a larger number of experiments were possible. We introduce the concept of group injury risk distribution that allows us to quantify under uncertainty the injury risk associated with advanced safety features, while averaging out the effect of uncontrollable factors such as body size. Statistically, the group injury risk distribution is a mixture of individual injury risk distributions of design conditions in the group. We infer that advanced safety features have the potential to reduce substantially injury risk in frontal crashes.

Restraint Systems in Tactical Vehicles: Uncertainty Study Involving Airbags, Seatbelts and Military Gear

2017 ◽  
Author(s):  
Dorin Drignei ◽  
Zissimos P. Mourelatos ◽  
Ervisa Zhamo ◽  
Jingwen Hu ◽  
Cong Chen ◽  
...  
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Body Size ◽  
Injury Risk ◽  
Finite Element Models ◽  
Risk Distribution ◽  
Frontal Crashes ◽  
Safety Features ◽  
The Impact

Adding advanced safety features (e.g. airbags) to restraint systems in tactical vehicles could decrease the injury risk of their occupants. The impact of frontal crashes on the occupants has been assessed recently through experimental data and finite element models. However, the number of such experiments is relatively small due to high cost. In this paper, we conduct an uncertainty study to infer the advantage of including advanced safety features, if a larger number of experiments were possible. We introduce the concept of group injury risk distribution that allows us to quantify under uncertainty the injury risk associated with advanced safety features, while averaging out the effect of uncontrollable factors such as body size. Statistically, the group injury risk distribution is a mixture of individual injury risk distributions of design conditions in the group. We infer that advanced safety features reduce the injury risk by at least two thirds in frontal crashes.

Techniques in Finite Element Modeling of Helmeted-Head Biomechanics

2009 ◽  
Author(s):  
Andrzej Przekwas ◽  
X. G. Tan ◽  
Z. J. Chen ◽  
Xianlian Zhou ◽  
Debbie Reeves ◽  
...  
Keyword(s):  
Finite Element ◽  
Brain Injury ◽  
Injury Risk ◽  
High Energy ◽  
Dense Layer ◽  
Hard Material ◽  
Absorption Mechanism ◽  
Military Applications ◽  
Main Components ◽  
The Impact

Generally a helmet comprises two main components: the shell and the fitting system. Despite the variations in designs due to the different usage requirements, typically helmets are intended to protect the user’s head through an energy absorption mechanism. The weight and volume are important factors in helmet design since both may alter the injury risk to the head and neck. The helmet outer shell is usually made of hard material that will deform when it is hit by hard objects. This action disperses energy from the impact to lessen the force before it reaches the head. The fitting system frequently includes a dense layer that cushions and absorbs the energy as a result of relative motion between the helmet and the head. A balance needs to be achieved on how strong and how stiff a helmet should be to provide the best possible protection. If a helmet is too stiff it can be less able to prevent brain injury in the kinds of impacts that may occur. If it is too flexible or soft, it might not protect the user in a violent, high-energy crash. For military applications, the requirements for helmet performance may be even more demanding. Not only do helmets have to protect a Soldier’s head from blunt impacts, but helmets also are expected to provide mounting platforms for ancillary devices and to function in ballistic and blast events as well.

scholarly journals Finite Element Simulations of the ID Venous System to Treat Venous Compression Disorders: From Model Validation to Realistic Implant Prediction

2021 ◽  
Author(s):  
Alissa Zaccaria ◽  
Francesco Migliavacca ◽  
David Contassot ◽  
Frederic Heim ◽  
Nabil Chakfe ◽  
...  
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Element Model ◽  
Venous System ◽  
Venous Compression ◽  
Risk Of Rupture ◽  
Model Reliability ◽  
The Impact ◽  
Force Displacement ◽  
Realistic Geometry

AbstractThe ID Venous System is an innovative device proposed by ID NEST MEDICAL to treat venous compression disorders that involve bifurcations, such as the May-Thurner syndrome. The system consists of two components, ID Cav and ID Branch, combined through a specific connection that prevents the migration acting locally on the pathological region, thereby preserving the surrounding healthy tissues. Preliminary trials are required to ensure the safety and efficacy of the device, including numerical simulations. In-silico models are intended to corroborate experimental data, providing additional local information not acquirable by other means. The present work outlines the finite element model implementation and illustrates a sequential validation process, involving seven tests of increasing complexity to assess the impact of each numerical uncertainty separately. Following the standard ASME V&V40, the computational results were compared with experimental data in terms of force-displacement curves and deformed configurations, testing the model reliability for the intended context of use (differences < 10%). The deployment in a realistic geometry confirmed the feasibility of the implant procedure, without risk of rupture or plasticity of the components, highlighting the potential of the present technology.

HYPER-ELASTIC PARAMETER ESTIMATION OF HUMAN HEEL-PAD: A FINITE ELEMENT AND EVOLUTIONARY BASED ALGORITHM

2012 ◽  
Vol 12 (03) ◽  
pp. 1250034 ◽  
Author(s):  
M. M. KHANI ◽  
H. KATOOZIAN ◽  
K. AZMA ◽  
I. NASEH ◽  
A. H. SALIMI
Keyword(s):  
Experimental Data ◽  
Genetic Algorithm ◽  
Finite Element ◽  
Nonlinear Material ◽  
Elastic Behavior ◽  
Diabetic Patients ◽  
Initial Contact ◽  
Heel Pad ◽  
Hyper Elastic ◽  
The Impact

The heel-pad as a biological shock absorber has an important role in the initial contact phase of gait cycle dissipating the impact forces resulted in locomotion. An axisymmetric finite element model of human heel-pad has been generated and the heel-pad experimental data deduced from a published force-deflection graph of the same specimen (Iain R. Spears, Janice E. Miller-Young), Iterative identification task has been used to extract nonlinear material properties describing hyper-elastic behavior of heel-pad. The genetic algorithm was incorporated into estimation process using an interface program. Two parameters of hyper-elastic materials potential energy function represented by Mooney–Rivlin were determined by using the genetic algorithm technique to minimize the displacement error between the experimental data and the corresponding finite element results after a considerable number of iterations. The result can be used for design and construction of synthetic heel-pad and therapeutic foot wear as well as insoles, especially for diabetic patients.

An Integrated Modeling Method to Evaluate Fleet Safety Performance of New Vehicle Designs

2013 ◽  
Author(s):  
Randa Radwan Samaha ◽  
Priyaranjan Prasad ◽  
Dhafer Marzougui ◽  
Chongzhen Cui ◽  
Cing-Dao (Steve) Kan ◽  
...  
Keyword(s):  
Finite Element ◽  
Real World ◽  
Injury Risk ◽  
Three Dimensional ◽  
Structural Models ◽  
Passenger Compartment ◽  
Different Types ◽  
Structural Deformations ◽  
Scale Test ◽  
Frontal Crashes

A methodology for Evaluating Fleet, i.e., self and partner, Protection (EFP) of new vehicle designs is developed through a systems modeling approach driven by structural and occupant modeling and real world crash and full scale test data. The EFP methodology consists of a virtual model simulating the real world crash environment (i.e., different types of vehicles, impact velocities, impact directions, impact types, etc.). A concept or new vehicle design could be introduced into this model to evaluate the safety of its occupants and those of other vehicles with which it is involved in crashes. The initial implementation of EFP methodology is to frontal crashes where the modeled crash configurations are derived from a new crash taxonomy based on real world structural engagement. Simulation data to drive the methodology is obtained from finite element structural models of the vehicles. Occupant responses are based on three dimensional articulated rigid body models of the occupant and the passenger compartment. The occupant is restrained by seat belts and airbags and the structural deformations and kinematics of the passenger compartment needed to drive the occupant models are predicted by the finite element structural models. Both the structural and the occupant models are subjected to validation and robustness checks for the modeled crash configurations. The aggregate of injury risk across vehicle classes, impact speeds, occupant sizes, and crash configurations, weighted by relative frequency of the specific event in real world crashes, is used as a measure of overall societal safety. Results from a proof-of-concept application are presented.

scholarly journals A Hyper-Viscoelastic Continuum-Level Finite Element Model of the Spinal Cord Assessed for Transverse Indentation and Impact Loading

2021 ◽  
Vol 9 ◽  
Author(s):  
Aleksander Rycman ◽  
Stewart McLachlin ◽  
Duane S. Cronin
Keyword(s):  
Experimental Data ◽  
Spinal Cord ◽  
Finite Element ◽  
Impact Loading ◽  
Material Properties ◽  
Injury Risk ◽  
Model Parameters ◽  
Pia Mater ◽  
Level Model ◽  
Linear Material

Finite Element (FE) modelling of spinal cord response to impact can provide unique insights into the neural tissue response and injury risk potential. Yet, contemporary human body models (HBMs) used to examine injury risk and prevention across a wide range of impact scenarios often lack detailed integration of the spinal cord and surrounding tissues. The integration of a spinal cord in contemporary HBMs has been limited by the need for a continuum-level model owing to the relatively large element size required to be compatible with HBM, and the requirement for model development based on published material properties and validation using relevant non-linear material data. The goals of this study were to develop and assess non-linear material model parameters for the spinal cord parenchyma and pia mater, and incorporate these models into a continuum-level model of the spinal cord with a mesh size conducive to integration in HBM. First, hyper-viscoelastic material properties based on tissue-level mechanical test data for the spinal cord and hyperelastic material properties for the pia mater were determined. Secondly, the constitutive models were integrated in a spinal cord segment FE model validated against independent experimental data representing transverse compression of the spinal cord-pia mater complex (SCP) under quasi-static indentation and dynamic impact loading. The constitutive model parameters were fit to a quasi-linear viscoelastic model with an Ogden hyperelastic function, and then verified using single element test cases corresponding to the experimental strain rates for the spinal cord (0.32–77.22 s−1) and pia mater (0.05 s−1). Validation of the spinal cord model was then performed by re-creating, in an explicit FE code, two independent ex-vivo experimental setups: 1) transverse indentation of a porcine spinal cord-pia mater complex and 2) dynamic transverse impact of a bovine SCP. The indentation model accurately matched the experimental results up to 60% compression of the SCP, while the impact model predicted the loading phase and the maximum deformation (within 7%) of the SCP experimental data. This study quantified the important biomechanical contribution of the pia mater tissue during spinal cord deformation. The validated material models established in this study can be implemented in computational HBM.

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.

scholarly journals Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

2015 ◽  
Vol 12 (19) ◽  
pp. 5871-5883 ◽  
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield
Keyword(s):  
Climate Change ◽  
Finite Element ◽  
Structural Integrity ◽  
Geometric Model ◽  
Algal Growth ◽  
Coralline Algae ◽  
Rocky Shores ◽  
Element Analysis ◽  
Scan Data ◽  
The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

A Fracture Mechanics Based Parametric Study of the Copper-to-Copper Direct Thermo-Compression Bonded Interface Using Finite Element Method

2013 ◽  
Author(s):  
Ah-Young Park ◽  
Satish Chaparala ◽  
Seungbae Park
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Parametric Study ◽  
Initial Crack ◽  
Bonding Interface ◽  
Interface Condition ◽  
Large Temperature ◽  
Bonded Interface ◽  
The Impact ◽  
Element Method

Through-silicon via (TSV) technology is expected to overcome the limitations of I/O density and helps in enhancing system performance of conventional flip chip packages. One of the challenges for producing reliable TSV packages is the stacking and joining of thin wafers or dies. In the case of the conventional solder interconnections, many reliability issues arise at the interface between solder and copper bump. As an alternative solution, Cu-Cu direct thermo-compression bonding (CuDB) is a possible option to enable three-dimension (3D) package integration. CuDB has several advantages over the solder based micro bump joining, such as reduction in soldering process steps, enabling higher interconnect density, enhanced thermal conductivity and decreased concerns about intermetallic compounds (IMC) formation. Critical issue of CuDB is bonding interface condition. After the bonding process, Cu-Cu direct bonding interface is obtained. However, several researchers have reported small voids at the bonded interface. These defects can act as an initial crack which may lead to eventual fracture of the interface. The fracture could happen due to the thermal expansion coefficient (CTE) mismatch between the substrate and the chip during the postbonding process, board level reflow or thermal cycling with large temperature changes. In this study, a quantitative assessment of the energy release rate has been made at the CuDB interface during temperature change finite element method (FEM). A parametric study is conducted to analyze the impact of the initial crack location and the material properties of surrounding materials. Finally, design recommendations are provided to minimize the probability of interfacial delamination in CuDB.

scholarly journals Investigation of the Thickness Differential on the Formability of Aluminum Tailor Welded Blanks

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 875
Author(s):  
Jie Wu ◽  
Yuri Hovanski ◽  
Michael Miles
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Numerical Model ◽  
Plastic Strain ◽  
Finite Element Model ◽  
Equivalent Plastic Strain ◽  
Element Model ◽  
Dome Height ◽  
Tailor Welded Blanks ◽  
Simulation Results

A finite element model is proposed to investigate the effect of thickness differential on Limiting Dome Height (LDH) testing of aluminum tailor-welded blanks. The numerical model is validated via comparison of the equivalent plastic strain and displacement distribution between the simulation results and the experimental data. The normalized equivalent plastic strain and normalized LDH values are proposed as a means of quantifying the influence of thickness differential for a variety of different ratios. Increasing thickness differential was found to decrease the normalized equivalent plastic strain and normalized LDH values, this providing an evaluation of blank formability.

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