Experimentally validated predictive finite element modeling of the V0-V100 probabilistic penetration response of a Kevlar fabric against a spherical projectile

2018 ◽  
Vol 9 (4) ◽  
pp. 504-524 ◽  
Author(s):  
Gaurav Nilakantan
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Modeling ◽  
Element Model ◽  
Ballistic Impact ◽  
Impact Testing ◽  
Woven Fabric ◽  
Projectile Impact ◽  
Element Modeling ◽  
The Impact

This work presents the first fully validated and predictive finite element modeling framework to generate the probabilistic penetration response of an aramid woven fabric subjected to ballistic impact. This response is defined by a V0-V100 curve that describes the probability of complete fabric penetration as a function of projectile impact velocity. The exemplar case considered in this article comprises a single-layer, fully clamped, plain-weave Kevlar fabric impacted at the center by a 0.22 cal spherical steel projectile. The fabric finite element model comprises individually modeled three-dimensional warp and fill yarns and is validated against the experimental material microstructure. Sources of statistical variability including yarn strength and modulus, inter-yarn friction, and precise projectile impact location are mapped into the finite element model. A series of impact simulations at varying projectile impact velocities is executed using LS-DYNA on the fabric models, each comprising unique mappings. The impact velocities and outcomes (penetration, non-penetration) are used to generate the numerical V0-V100 curve which is then validated against the experimental V0-V100 curve obtained from ballistic impact testing and shown to be in excellent agreement. The experimental data and its statistical analysis used for model input and validation, namely, the Kevlar yarn tensile strengths and moduli, inter-yarn friction, and fabric ballistic impact testing, are also reported.

scholarly journals Characterization of Maple and Ash Material Properties for the Finite Element Modeling of Wood Baseball Bats

2018 ◽  
Vol 8 (11) ◽  
pp. 2256 ◽  
Author(s):  
Joshua Fortin-Smith ◽  
James Sherwood ◽  
Patrick Drane ◽  
David Kretschmann
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Material Properties ◽  
Charpy Impact ◽  
Impact Testing ◽  
Charpy Test ◽  
Ball Impact ◽  
Element Modeling ◽  
The Impact ◽  
Baseball Bats

To assist in developing a database of wood material properties for the finite element modeling of wood baseball bats, Charpy impact testing at strain rates comparable to those that a wood bat experiences during a bat/ball collision is completed to characterize the failure energy and strain-to-failure as a function of density and slope-of-grain (SoG) for northern white ash (Fraxinus americana) and sugar maple (Acer saccharum). Un-notched Charpy test specimens made from billets of ash and maple that span the range of densities and SoGs that are approved for making professional baseball bats are impacted on either the edge grain or face grain. High-speed video is used to capture each test event and image analysis techniques are used to determine the strain-to-failure for each test. Strain-to-failure as a function of density relations are derived and these relations are used to calculate inputs to the *MAT_WOOD (Material Model 143) and *MAT_EROSION material options in LS-DYNA for the subsequent finite element modeling of the ash and maple Charpy Impact tests and for a maple bat/ball impact. The Charpy test data show that the strain-to-failure increases with increasing density for maple but the strain-to-failure remains essentially constant over the range of densities considered in this study for ash. The flat response of the ash data suggests that ash-bat durability is less sensitive to wood density than maple-bat durability. The available SoG results suggest that density has a greater effect on the impact failure properties of the wood than SoG. However, once the wood begins to fracture, SoG plays a large role in the direction of crack propagation of the wood, thereby determining if the shape of the pieces breaking away from the bat are fairly blunt or spear-like. The finite element modeling results for the Charpy and bat/ball impacts show good correlation with the experimental data.

BOUNDARY CONDITIONS IN FINITE ELEMENT MODELING OF STRATIFIED COASTAL CIRCULATION

1988 ◽  
Vol 1 (21) ◽  
pp. 190
Author(s):  
George C. Christodoulou ◽  
George D. Economou
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Finite Element Model ◽  
Finite Element Modeling ◽  
Coastal Waters ◽  
Stratified Flow ◽  
Element Model ◽  
Numerical Computations ◽  
Element Modeling ◽  
Sponge Layer

The effect of boundary conditions on numerical computations of stratified flow in coastal waters is examined. Clamped, free radiation and sponge layer conditions are implemented in a two-layer finite element model and the results of simple tests in a two-layer stratified basin are presented.

scholarly journals Three-dimensional finite element modeling for evaluation of laryngomalacia severity in infants and children

2020 ◽  
Vol 48 (6) ◽  
pp. 030006052092640
Author(s):  
Hongming Xu ◽  
Jiali Chen ◽  
Shilei Pu ◽  
Xiaoyan Li
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Finite Element Model ◽  
Finite Element Modeling ◽  
Three Dimensional ◽  
Element Model ◽  
3D Finite Element ◽  
Element Modeling ◽  
Laryngeal Cartilage ◽  
Computed Tomography Images

This study was performed to investigate the feasibility of using a three-dimensional (3D) finite element model for laryngomalacia severity assessment. We analyzed laryngeal computed tomography images of seven children with laryngomalacia using Mimics software. The gray threshold of different tissues was distinguishable, and a 3D visualization model and finite element model were constructed. The laryngeal structure parameters were defined. The peak von Mises stress (PVMS) value was obtained through laryngeal mechanical analysis. The PVMS values of the laryngeal soft tissue and cartilage scaffolds were independently correlated with disease severity. After stress loading the model, the relationship between laryngomalacia severity and the PVMS value was apparent. However, the PVMS value of laryngeal soft tissue was not correlated with laryngomalacia severity. This study established the efficacy of a finite element model to illustrate the morphological features of the laryngeal cavity in infants with laryngomalacia. However, further study is required before widespread application of 3D finite element modeling of laryngomalacia. PVMS values of the laryngeal cartilage scaffold might be useful for assessment of laryngomalacia severity. These findings support the notion that structural abnormalities of the laryngeal cartilage may manifest as quantifiable changes in stress variants of the supraglottic larynx.

Patient Specific Finite Element Modeling of a Human Skull

2006 ◽  
Vol 49 ◽  
pp. 227-234 ◽  
Author(s):  
Norio Inou ◽  
Michihiko Koseki ◽  
Koutarou Maki
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Modeling ◽  
Image Data ◽  
Element Model ◽  
Biomechanical Study ◽  
Modeling Method ◽  
Patient Specific ◽  
Human Skull ◽  
Element Modeling

This paper presents automated finite element modeling method and application to a biomechanical study. The modeling method produces a finite element model based on the multi-sliced image data adaptively controlling the element size according to complexity of local bony shape. The method realizes a compact and precise finite element model with a desired total number of nodal points. This paper challenges to apply this method to a human skull because of its intricate structure. To accomplish the application of the human skull, we analyze characteristics of bony shape for a mandible and a skull. Using the analytical results, we demonstrate that the proposed modeling method successfully generates a precise finite element model of the skull with fine structures.

Finite Element Modeling for Tap Design Improvement in Form Tapping

2005 ◽  
Vol 128 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Curtis Warrington ◽  
Shiv Kapoor ◽  
Richard DeVor
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Modeling ◽  
Element Model ◽  
Design Parameters ◽  
Process Conditions ◽  
Design Improvement ◽  
Element Modeling ◽  
Form Tapping

The form tapping process typically yields unfinished threads known as split crests. Thread quality can be greatly improved by reducing the size and severity of split crest formation. This paper develops a finite element model to simulate form tapping with an eye towards the reduction of split crests. The model is validated against linear scratch experiments, and simulations are compared to actual tapping. The effects of various tap design parameters and tapping process conditions on the formation of split crests are investigated to strive toward an optimal tap design.

scholarly journals Analytical and Finite Element Modeling of the Dynamic Characteristics of a Linear Feeding Stage with Different Arrangements of Rolling Guides

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Jyh-Cheng Chang ◽  
Jui-Pin Hung
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Modeling ◽  
Dynamic Characteristics ◽  
Element Model ◽  
Linear Guide ◽  
Element Modeling ◽  
Positioning Stage ◽  
The Finite Element Model

This study was aimed at investigating the dynamic behaviors of the linear driven feeding stage by means of the analytical and finite element modeling approaches. To assess the dynamic characteristics of the stages with different linear guide arrangements, the finite element model of the stages was created, in which the linear components with rolling interface were accurately modeled based on the Hertzian theory. On the other hand, the analytically mathematical model was derived to determine how the linear guide arrangement affects the dynamic characteristics of the stage. Results of the modal analysis show that the vibration behaviors of the positioning stage are dominated by the rigidity of the linear components and the platform. In addition, comparisons of the results from the two approaches further indicate that the platform rigidity is an important factor determining the accuracy of the prediction of the vibration frequencies by the analytically mathematical model. As a conclusion of the study, the analytically mathematical model can approximate well to the finite element model when the linear stage is designed with appropriate structure rigidity.

Finite Element Modeling Method of 3D Braided Composites Based on ICT Technique

2012 ◽  
Vol 236-237 ◽  
pp. 16-20
Author(s):  
Shu Yong Wang ◽  
Jian Fu ◽  
Qian Li Wang
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Composite Materials ◽  
Finite Element Model ◽  
Finite Element Modeling ◽  
Element Model ◽  
Braided Composites ◽  
Element Modeling ◽  
3D Braided Composites ◽  
The Finite Element Model

A finite element modeling method based on industrial computed tomography (ICT) technique is proposed to address the insufficient accuracy of traditional grinding method for the meso-structure analysis of composite materials. In this method, the slice images of 3D composites are first acquired by ICT technique. And then, the internal meso-structure images of composite materials are obtained through the digital image processing to the slice images. Finally the meso-structure images are converted to vector format and inputted ANSYS to build the finite element model for the analysis of the mechanical properties. The experimental results show that this method can establish the finite element model and reveal the internal structure and the inherent mechanical properties of composite materials. These researches provide a reference for the manufacture processing of 3D braided composites, and the theoretical basis for the optimal design and performance evaluation. It would be of significance for the improvement of the composites mechanical properties.

The Finite Element Modeling and Structure Analysis of Dust Removal Fan

2014 ◽  
Vol 1061-1062 ◽  
pp. 833-836
Author(s):  
Qian Peng Han ◽  
Bo Peng
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Modeling ◽  
Structure Analysis ◽  
Element Model ◽  
Dust Removal ◽  
Element Modeling ◽  
Nature Frequency

This paper mainly discussed the process to create finite element model of Y4-68 fan,and also analysis the nature frequency and liner static stress.According to the analysis result to determine the optimized parameters,to prepare for the stage of optimization.

Finite Element Modeling of the Response of Long Floating Structures Under Harmonic Excitation

1985 ◽  
Vol 107 (1) ◽  
pp. 48-53 ◽  
Author(s):  
C. Georgiadis
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Modeling ◽  
Wave Field ◽  
Element Model ◽  
Harmonic Excitation ◽  
Element Analysis ◽  
Floating Structures ◽  
Element Modeling

The response of long floating structures to a harmonic excitation is the basis for the response calculation in a short-crested wave field. This paper will present consistent formulas for obtaining the nodal loads in a finite element analysis. The accuracy of the method used is compared with the results obtained using a Rayleigh-Ritz approximation of the response with continuous eigenfunctions. The error of using an irrational finite element model is demonstrated for comparison, and to indicate to designers of similar structures the large effects which they may be overlooking.

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