A Numerical Study on Ductile Material Failure

2006 ◽  
Vol 324-325 ◽  
pp. 483-486
Author(s):  
K. Qin ◽  
Li Ming Yang
Keyword(s):  
Numerical Simulations ◽  
Numerical Study ◽  
Hydrostatic Stress ◽  
Element Model ◽  
Ductile Material ◽  
Dominant Factor ◽  
Strain Rates ◽  
Ductile Materials ◽  
Relative Spacing ◽  
The Relationship

Experiments show that the failure of ductile materials can be characterized by a rate-independent parameter, relative spacing d defined as the ratio of the distance between two voids and the radius of voids. In this study, this experimental phenomenon is analyzed via numerical simulations using 3-D finite element model. Considering that hydrostatic stress is a dominant factor in the evolution of microvoid nucleation, growth and coalescence in ductile materials, numerical simulations are performed to obtain the relationship between relative spacing d and hydrostatic stress in the ligament between voids. Numerical results show that hydrostatic stress along matrix ligament is sensitive to the change of the relative spacing. Further analysis shows that the failure of ductile materials can modeled by using a criterion of the threshold of local hydrostatic stress in the ligament. Based on such a criterion, a curve displaying the relationship between the strength of ductile material and strain rate is obtained numerically. It is concluded that the failure criterion of ductile materials can be described by using local hydrostatic stress and relative spacing between two voids, which is not sensitive to strain rates.

Crushing Behavior of SKYDEX® Material

2013 ◽  
Vol 535-536 ◽  
pp. 121-124
Author(s):  
Feng Zhu ◽  
Bin Hui Jiang ◽  
King H. Yang ◽  
Dong Ruan ◽  
Mike S. Boczek ◽  
...  
Keyword(s):  
Numerical Study ◽  
Thermoplastic Polyurethane ◽  
Deformation Mode ◽  
Element Model ◽  
Fe Model ◽  
Strain Rates ◽  
Cellular Solids ◽  
Compression Tests ◽  
Crushing Behavior ◽  
The Relationship

SKYDEX material is an advanced lightweight porous medium consisting of layers of periodic twin-hemispherical microstructures made of thermoplastic polyurethane. This material is used widely in personnel and structural protection. This paper reports a combined experimental and numerical study on crushing behavior of such material. Compression tests were conducted on the SKYDEX panels at the strain rates of 0.01~10 s-1. A 3D finite element model was developed and validated against experimental data. Based on the FE model, the deformation mode of the microstructures, strength, energy absorption, as well as strain rate effect were predicted and analyzed. Additional simulations were conducted to establish the relationship between the peak strength coefficient and relative density. SKYDEX® material has been found to be a competitive energy absorber among cellular solids.

Numerical Study on the Deformation of a Net Panel in Steady and Oscillatory Flow

2015 ◽  
Author(s):  
Jing Shen ◽  
Hongde Qin ◽  
Leixin Ma ◽  
Shixiao Fu
Keyword(s):  
Oscillatory Flow ◽  
Numerical Study ◽  
Element Model ◽  
Reduction Ratio ◽  
Test Case ◽  
Hydrodynamic Coefficients ◽  
Projected Area ◽  
Area Reduction ◽  
Number Frequency ◽  
The Relationship

Based on the hydrodynamic coefficients obtained in a series of experiment on a full-scale net panel, numerical simulation is conducted to study the interaction between flow and the flexible net in waves and current. Finite element model was constructed and modified Morison Equation was adopted to estimate the deformation of the net sheet. The deformation of the net sheet was investigated quantitatively by estimating the minimum projected area and comparing the area reduction ratio under each test case. Furthermore, the relationship between the net’s area reduction ratio and the nondimensionalized parameters in the model testing, including the structure’s Reynolds number, KC number, frequency parameter and reduced velocity was discussed.

LOYALITAS PELANGGAN: PERAN CITRA MEREK DAN KUALITAS PRODUK

2019 ◽  
Vol 4 (3) ◽  
pp. 391-400
Author(s):  
Machmed Tun Ganyang
Keyword(s):  
Regression Analysis ◽  
Product Quality ◽  
Customer Loyalty ◽  
Brand Image ◽  
Dominant Factor ◽  
Consumer Loyalty ◽  
The Relationship

This study aims to examine the relationship between brand image and product quality on customer loyalty in sports products. Data were collected through a questionnaire of 68 respondents. Through regression analysis, the results show that brand image and quality can explain variations in consumer loyalty with the brand image as a dominant factor. This finding implies that producers can increase consumer loyalty by enhancing brand image. Companies need to think about how to develop key messages so that consumers can clearly understand the position of the product. The unique aspects of the product need to be improved to create a special impression on the customer. Keywords: brand image, produk quality, customer loyalty

Using Ansys for Design and Numerical Study of a Specific Fixed Wing UAV

2018 ◽  
Vol 55 (4) ◽  
pp. 652-657 ◽  
Author(s):  
Gabriel Murariu ◽  
Razvan Adrian Mahu ◽  
Adrian Gabriel Murariu ◽  
Mihai Daniel Dragu ◽  
Lucian P. Georgescu ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Unmanned Aerial Vehicle ◽  
Numerical Study ◽  
Flight Time ◽  
Cluster System ◽  
Numerical Results ◽  
Operational Performance ◽  
Gliding Flight ◽  
Aerial Vehicle ◽  
Constant Altitude

This article presents the design of a specific unmanned aerial vehicle UAV prototype own building. Our UAV is a flying wing type and is able to take off with a little boost. This system happily combines some major advantages taken from planes namely the ability to fly horizontal, at a constant altitude and of course, the great advantage of a long flight-time. The aerodynamic models presented in this paper are optimized to improve the operational performance of this aerial vehicle, especially in terms of stability and the possibility of a long gliding flight-time. Both aspects are very important for the increasing of the goals� efficiency and for the getting work jobs. The presented simulations were obtained using ANSYS 13 installed on our university� cluster system. In a next step the numerical results will be compared with those during experimental flights. This paper presents the main results obtained from numerical simulations and the obtained magnitudes of the main flight coefficients.

scholarly journals Dynamics of Single Droplet Splashing on Liquid Film by Coupling FVM with VOF

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 841
Author(s):  
Yuzhen Jin ◽  
Huang Zhou ◽  
Linhang Zhu ◽  
Zeqing Li
Keyword(s):  
Liquid Film ◽  
Weber Number ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Single Droplet ◽  
Navier Stokes Equations ◽  
Volume Method ◽  
The Relationship

A three-dimensional numerical study of a single droplet splashing vertically on a liquid film is presented. The numerical method is based on the finite volume method (FVM) of Navier–Stokes equations coupled with the volume of fluid (VOF) method, and the adaptive local mesh refinement technology is adopted. It enables the liquid–gas interface to be tracked more accurately, and to be less computationally expensive. The relationship between the diameter of the free rim, the height of the crown with different numbers of collision Weber, and the thickness of the liquid film is explored. The results indicate that the crown height increases as the Weber number increases, and the diameter of the crown rim is inversely proportional to the collision Weber number. It can also be concluded that the dimensionless height of the crown decreases with the increase in the thickness of the dimensionless liquid film, which has little effect on the diameter of the crown rim during its growth.

scholarly journals Experimental testing and 3D meso-scale numerical simulations of SCC subjected to high compression strain rates

2021 ◽  
Vol 302 ◽  
pp. 124379
Author(s):  
Małgorzata Pająk ◽  
Paweł Baranowski ◽  
Jacek Janiszewski ◽  
Michał Kucewicz ◽  
Łukasz Mazurkiewicz ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Experimental Testing ◽  
Strain Rates ◽  
Compression Strain ◽  
High Compression ◽  
Meso Scale

scholarly journals Development of a Novel Damage Detection Framework for Truss Railway Bridges Using Operational Acceleration and Strain Response

Vibration ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 422-445
Author(s):  
Md Riasat Azim ◽  
Mustafa Gül
Keyword(s):  
Damage Detection ◽  
Damage Identification ◽  
Numerical Study ◽  
Damage Index ◽  
Strain Analysis ◽  
Time History ◽  
Principal Component ◽  
Element Model ◽  
Railway Bridges ◽  
Truss Bridge

Railway bridges are an integral part of any railway communication network. As more and more railway bridges are showing signs of deterioration due to various natural and artificial causes, it is becoming increasingly imperative to develop effective health monitoring strategies specifically tailored to railway bridges. This paper presents a new damage detection framework for element level damage identification, for railway truss bridges, that combines the analysis of acceleration and strain responses. For this research, operational acceleration and strain time-history responses are obtained in response to the passage of trains. The acceleration response is analyzed through a sensor-clustering-based time-series analysis method and damage features are investigated in terms of structural nodes from the truss bridge. The strain data is analyzed through principal component analysis and provides information on damage from instrumented truss elements. A new damage index is developed by formulating a strategy to combine the damage features obtained individually from both acceleration and strain analysis. The proposed method is validated through a numerical study by utilizing a finite element model of a railway truss bridge. It is shown that while both methods individually can provide information on damage location, and severity, the new framework helps to provide substantially improved damage localization and can overcome the limitations of individual analysis.

Scale-dependent merging of baroclinic vortices

1994 ◽  
Vol 264 ◽  
pp. 81-106 ◽  
Author(s):  
J. Verron ◽  
S. Valcke
Keyword(s):  
Numerical Simulations ◽  
Critical Point ◽  
Lower Layer ◽  
Interaction Mechanism ◽  
Competitive Effects ◽  
Different Types ◽  
Shape Effects ◽  
Baroclinic Vortices ◽  
The Relationship ◽  
Stratified Model

The influence of stratification on the merging of like-sign vortices of equal intensity and shape is investigated by numerical simulations in a quasi-geostrophic, two-layer stratified model. Two different types of vortices are considered: vortices defined as circular patches of uniform potential vorticity in the upper layer but no PV anomaly in the lower layer (referred to as PVI vortices), and vortices defined as circular patches of uniform relative vorticity in the upper layer but no motion in the lower layer (referred to as RVI vortices). In particular, it is found that, in the RVI case, the merging behaviour depends strongly on the magnitude of the stratification (i.e. the ratio of internal Rossby radius and vortex radius). The critical point here appears to be whether or not the initial eddies have a deep flow signature in terms of PV.The specific phenomenon of scale-dependent merging observed is interpreted in terms of the competitive effects of hetonic interaction and vortex shape. In the case of weaker stratification, the baroclinic structure of the eddies can be seen as dominated by a mechanism of hetonic interaction in which bottom flow appears to counteract the tendency of surface eddies to merge. In the case of larger stratification, the eddy interaction mechanism is shown to be barotropically dominated, although interface deformation still determines the actual eddy vorticity profile during the initialization stage. Repulsion (hetonic) effect therefore oppose attraction (barotropic shape) effects in a competitive process dependent on the relationship between the original eddy lengthscale and the first internal Rossby radius.A concluding discussion considers the implications of such analysis for real situations, in the ocean or in the laboratory.

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