Nanoindentation on a Ni Nanodot-Patterned Surface

2008 ◽  
Author(s):  
Hengyu Wang ◽  
Min Zou ◽  
Robert L. Jackson ◽  
Preston R. Larson ◽  
Matthew B. Johnson
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Experimental Results ◽  
Spherical Contact ◽  
Patterned Surface ◽  
Size And Shape ◽  
Ordered Arrays ◽  
Simulation Results ◽  
Good Agreement

Nanoindentation on a Ni nanodot-patterned surface (NDPS) was investigated experimentally and numerically. The Ni NDPS consists of well-ordered arrays of Ni nanodots with approximately the same size and shape. The nanoindentation experiments were performed on the Ni NDPS using diamond tips of 1 and 5 μm radii of curvature. To efficiently simulate large number of nanodots in contact, numerical simulations were carried out using formulae empirically fitted from a finite element (FE) study of a single spherical contact. The simulation results were found to be in good agreement with the experimental results.

scholarly journals Numerical Simulations of V-Shaped Plates Subjected to Blast Loadings: A Validation Study

2016 ◽  
Vol 10 (11) ◽  
pp. 203
Author(s):  
Mohd Zaid Othman ◽  
Qasim H. Shah ◽  
Muhammad Akram Muhammad Khan ◽  
Tan Kean Sheng ◽  
M. A. Yahaya ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Variable Mass ◽  
Blast Loading ◽  
Experimental Results ◽  
Average Difference ◽  
Simulation Results ◽  
Blast Loadings ◽  
Carrier Vehicle ◽  
Good Agreement

A series of numerical simulations utilizing LS-DYNA was performed to determine the mid-point deformations of V-shaped plates due to blast loading. The numerical simulation results were then compared with experimental results from published literature. The V-shaped plate is made of DOMEX 700 and is used underneath an armour personal carrier vehicle as an anti-tank mine to mitigate the effects of explosion from landmines in a battlefield. The performed numerical simulations of blast loading of V-shaped plates consisted of various angles i.e. 60°, 90°, 120°, 150° and 180°; variable mass of explosives located at the central mid-point of the V-shaped vertex with various stand-off distances. It could be seen that the numerical simulations produced good agreement with the experimental results where the average difference was about 26.6%.

Effects of Materials on Formation of Double-Layered Liners Shaped Charges

2009 ◽  
Vol 79-82 ◽  
pp. 1277-1280
Author(s):  
Yu Zheng ◽  
Xiao Ming Wang ◽  
Wen Bin Li ◽  
Wen Jin Yao
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Numerical Simulations ◽  
Double Layer ◽  
Two Dimensional ◽  
Materials Properties ◽  
X Ray ◽  
Dimensional Finite Element ◽  
Simulation Results ◽  
Good Agreement

In order to study the effects of liner materials on the formation of Shaped Charges with Double Layer Liners (SCDLL) into tandem Explosively Formed Projectile (EFP), the formation mechanism of DLSCL was studied. Utilizing two-dimensional finite element dynamic code AUTODYN, the numerical simulations on the mechanical phenomenon of SCDLL forming into tandem EFP were carried out. X-ray pictures were obtained after Experiments on SCDLL. Comparisons between experimental results and numerical simulation results have good agreement. It can be concluded from the results that the materials properties and configurations of both liners are crucial to the formation of tandem EFP.

Integrated Flow Analysis During Filling and Post-Filling Stage of Semiconductor Encapsulation

1999 ◽  
Vol 122 (1) ◽  
pp. 20-27 ◽  
Author(s):  
Sejin Han ◽  
K. K. Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Flow Analysis ◽  
Rectangular Cavity ◽  
Experimental Results ◽  
Molding Compound ◽  
Filling Stage ◽  
Semiconductor Chip ◽  
Simulation Results ◽  
Good Agreement

In this paper, flow during the filling and post-filling stages in semiconductor chip encapsulation has been analyzed. A finite-element method based on the Hele-Shaw approximation is used for the flow analysis in the chip cavity. The compressibility of the epoxy-molding compound has been considered to analyze the post-filling stage. The model has been verified by comparing resulting predictions with experimental results. Specifically, pressure has been measured in a rectangular cavity and compared with simulation results. The calculated and experimental results show good agreement. [S1043-7398(00)00101-8]

A Modified Finite Element Model for Electromagnetic Tube Compression Process

2012 ◽  
Vol 468-471 ◽  
pp. 456-460
Author(s):  
M. Sedighi ◽  
M. Khandaei ◽  
M.A> Liaghat
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Fem Simulation ◽  
Element Model ◽  
Experimental Results ◽  
Current Load ◽  
Compression Process ◽  
Simulation Results ◽  
Magnetic Potentials ◽  
Good Agreement

This paper presents an approach for modification a FEM simulation of electromagnetic tube compression process which has been presented by Mamalis. Electromagnetic free compression of a tube inside a coil has been simulated by using elements with coupled DOFs of electrical and magnetic potentials and displacement components. Mamalis's simulation results show a degree of disagreement with experimental results. In the present work, the coil has been modeled as separate parallel rings and a new correction factor has been determined for the current load applied on the coil. Comparison between simulation and experimental results shows a good agreement at the middle of workpiece with a reasonable error at workpiece ends.

The penetration and ricochet of ogive-nosed rigid projectiles obliquely impacting metallic targets

2021 ◽  
pp. 204141962110377
Author(s):  
Yaniv Vayig ◽  
Zvi Rosenberg
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Dynamic Pressure ◽  
Oblique Impacts ◽  
Simulation Results ◽  
The Impact ◽  
Penetration Depths ◽  
Resistance To Penetration ◽  
Good Agreement

A large number of 3D numerical simulations were performed in order to follow the trajectory changes of rigid CRH3 ogive-nosed projectiles, impacting semi-infinite metallic targets at various obliquities. These trajectory changes are shown to be related to the threshold ricochet angles of the projectile/target pairs. These threshold angles are the impact obliquities where the projectiles end up moving in a path parallel to the target’s face. They were found to depend on a non-dimensional entity which is equal to the ratio between the target’s resistance to penetration and the dynamic pressure exerted by the projectile upon impact. Good agreement was obtained by comparing simulation results for these trajectory changes with experimental data from several published works. In addition, numerically-based relations were derived for the penetration depths of these ogive-nosed projectiles at oblique impacts, which are shown to agree with the simulation results.

Effect of Ramp Angle on the Anti-Loosening Ability of Wedge Self-Locking Nuts Under Vibration

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Jianhua Liu ◽  
Hao Gong ◽  
Xiaoyu Ding
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Production Technology ◽  
Material Properties ◽  
Threshold Value ◽  
Commercial Production ◽  
Experimental Results ◽  
Fe Method ◽  
Transversal Vibration

Recently, the wedge self-locking nut, a special anti-loosening product, is receiving more attention because of its excellent reliability in preventing loosening failure under vibration conditions. The key characteristic of a wedge self-locking nut is the special wedge ramp at the root of the thread. In this work, the effect of ramp angle on the anti-loosening ability of wedge self-locking nuts was studied systematically based on numerical simulations and experiments. Wedge self-locking nuts with nine ramp angles (10 deg, 15 deg, 20 deg, 25 deg, 30 deg, 35 deg, 40 deg, 45 deg, and 50 deg) were modeled using a finite element (FE) method, and manufactured using commercial production technology. Their anti-loosening abilities under transversal vibration conditions were analyzed based on numerical and experimental results. It was found that there is a threshold value of the initial preload below which the wedge self-locking nuts would lose their anti-loosening ability. This threshold value of initial preload was then proposed for use as a criterion to evaluate the anti-loosening ability of wedge self-locking nuts quantitatively and to determine the optimal ramp angle. Based on this criterion, it was demonstrated, numerically and experimentally, that a 30 deg wedge ramp resulted in the best anti-loosening ability among nine ramp angles studied. The significance of this study is that it provides an effective method to evaluate the anti-loosening ability of wedge self-locking nuts quantitatively, and determined the optimal ramp angle in terms of anti-loosening ability. The proposed method can also be used to optimize other parameters, such as the material properties and other dimensions, to guarantee the best anti-loosening ability of wedge self-locking nuts.

scholarly journals Small Caliber Bulletproof Test of Warships’ Hulls

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3848
Author(s):  
Radosław Kiciński ◽  
Andrzej Kubit
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Conditions ◽  
Finite Element Method Simulation ◽  
Material Model ◽  
Experimental Results ◽  
Material Constants ◽  
Steel Core ◽  
Calculation Results ◽  
Simulation Results

The article presents the characteristics of 1.3964 steel and the results of firing a 7.62 mm projectile with a steel core. A simplified Johnson–Cook material model for steel and projectile was used. Then, a FEM (finite element method) simulation was prepared to calibrate the material constants and boundary conditions necessary to be used in simulations of the entire hull model. It was checked how projectile modeling affects the FEM calculation results. After obtaining the simulation results consistent with the experimental results, using the model of a modern minehunter, the resistance of the ship’s hull to penetration by a small-caliber projectile was tested.

scholarly journals Qualitative Research of AZ31 Magnesium Alloy Aircraft Brackets Produced by a New Forging Method

2016 ◽  
Vol 61 (2) ◽  
pp. 1003-1008 ◽  
Author(s):  
A. Dziubińska ◽  
A. Gontarz ◽  
K. Dziedzic
Keyword(s):  
Qualitative Research ◽  
Finite Element ◽  
Magnesium Alloy ◽  
Numerical Results ◽  
Experimental Results ◽  
Az31 Magnesium Alloy ◽  
Forming Process ◽  
Closed Die Forging ◽  
Selection Of ◽  
Good Agreement

AbstractThe paper reports a selection of numerical and experimental results of a new closed-die forging method for producing AZ31 magnesium alloy aircraft brackets with one rib. The numerical modelling of the new forming process was performed by the finite element method.The distributions of stresses, strains, temperature and forces were examined. The numerical results confirmed that the forgings produced by the new forming method are correct. For this reason, the new forming process was verified experimentally. The experimental results showed good agreement with the numerical results. The produced forgings of AZ31 magnesium alloy aircraft brackets with one rib were then subjected to qualitative tests.

scholarly journals Optical turbulence and spectral condensate in long fibre lasers

2012 ◽  
Vol 468 (2145) ◽  
pp. 2496-2508 ◽  
Author(s):  
E. G. Turitsyna ◽  
Gregory Falkovich ◽  
Atalla El-Taher ◽  
Xuewen Shu ◽  
Paul Harper ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Intermediate State ◽  
Experimental Results ◽  
Fibre Laser ◽  
Optical Turbulence ◽  
Fibre Lasers ◽  
Sharp Transition ◽  
Narrow Spectrum ◽  
Good Agreement

We study numerically optical turbulence using the particular example of a recently created, ultra-long fibre laser. For normal fibre dispersion, we observed an intermediate state with an extremely narrow spectrum (condensate), which experiences instability and a sharp transition to a fluctuating regime with a wider spectrum. We demonstrate that the number of modes has an impact on the condensate's lifetime. The smaller the number of modes, the more resistant is the condensate to perturbations. Experimental results show a good agreement with numerical simulations.

A study on finite element analysis for simplification of curvature extrusion method

2018 ◽  
Vol 32 (19) ◽  
pp. 1840043
Author(s):  
J. O. Yu ◽  
Y. H. Kim ◽  
Nagamachi Takuo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Friction Coefficient ◽  
Extrusion Process ◽  
Experimental Results ◽  
Element Analysis ◽  
Extrusion Method ◽  
Good Agreement

To eliminate the complexity of curvature extrusion process, a new extrusion method was proposed. In this study, a finite element analysis for curvature extrusion was studied to commercialize this extrusion method that creates curvature in a tilting method. When simulating an extrusion process, it is important to fix the appropriate friction coefficient and fillet value to avoid peel-out problems such that the finite element disappears. Therefore, the actual extrusion results and the simulated results were compared to find conditions that the element would not disappear. There was a good agreement between the simulation and experimental results when the coefficient friction was 0.4 and the fillet was 0.4 mm.

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