Simulation of an Armoured Vehicle for Blast Loading

2017 ◽  
Vol 67 (4) ◽  
pp. 449 ◽  
Author(s):  
Sanjit Mahajan ◽  
R. Muralidharan
Keyword(s):  
Finite Element ◽  
Numerical Methods ◽  
Time History ◽  
Material Model ◽  
Element Model ◽  
Local Deformation ◽  
Comparison Results ◽  
History Of ◽  
Areas Of Interest ◽  
Improvised Explosive

Occupant safety in an armoured vehicle is of paramount importance. Most serious threat to armoured vehicles comes in the form of explosion of buried charge or an improvised explosive device. The use of numerical methods in the validation process of light armoured vehicles reduces the number of prototypes required and decreases the design time. This paper elucidates the process by which one such validation using numerical methods was done. The process of finite element method used for simulation of blast is a prominent method of numerical method of simulation. The finite element model (FEM) process starts with discretisation. By discretisation or meshing, Shell (Quad/Tria) and solid (Tetra/Hexa) elements are generated. The FEM thus created is provided with relevant material model / properties and loading and boundary conditions. The loading conditions are adopted from STANAG 4569 Level II standards. Local deformation, global displacement, stresses and time history of displacement of particular areas of interest are obtained as results. Comparison results include the effect of with and without thermal softening under blast. Based on the results and comparison, suggestions regarding re-engineering the vehicle are presented.

scholarly journals Structural Response of Submerged Air-Backed Plates by Experimental and Numerical Analyses

2000 ◽  
Vol 7 (6) ◽  
pp. 333-341 ◽  
Author(s):  
Lloyd Hammond ◽  
Raphael Grzebieta
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Structural Response ◽  
Time History ◽  
Element Model ◽  
Steel Plates ◽  
Small Scale ◽  
History Of ◽  
Structural Responses ◽  
The Finite Element Model

This paper presents the results of a series of small-scale underwater shock experiments that measured the structural responses of submerged, fully clamped, air-backed, steel plates to a range of high explosive charge sizes. The experimental results were subsequently used to validate a series of simulations using the coupled LS-DYNA/USA finite element/boundary element codes. The modelling exercise was complicated by a significant amount of local cavitation occurring in the fluid adjacent to the plate and difficulties in modelling the boundary conditions of the test plates. The finite element model results satisfactorily predicted the displacement-time history of the plate over a range of shock loadings although a less satisfactory correlation was achieved for the peak velocities. It is expected that the predictive capability of the finite element model will be significantly improved once hydrostatic initialisation can be fully utilised with the LS-DYNA/USA software.

Finite Element Analysis of Reinforced Masonry House in Towns and Villages in the Earthquake

2013 ◽  
Vol 645 ◽  
pp. 367-372
Author(s):  
Jing He
Keyword(s):  
Finite Element ◽  
Time History ◽  
Material Model ◽  
Element Model ◽  
Original Model ◽  
Amplification Coefficient ◽  
Element Analysis ◽  
Fracture Development ◽  
Earthquake Load ◽  
Reinforcement Model

Based on the finite element theory, adopting th e concrete material model which suffers a single vertical earthquake load. The article studies the mode, acceleration time-history curve and stress distribution. The comp arison of theoretical analysis and simulation result shows that the finite element model of the masonry buildings is reasonable and practical. And model is used to the comparison between the reinforcement model and original model in four aspects (model mode, fracture development situation, the acceleration amplification coefficient and the displacement of the wall between windows). Through the analysis, the test result has been supplemented, getting the seismic performance of original model and the increased degree of earthquake magnitude after reinforced.

Delamination in the scoring and folding of paperboard

TAPPI Journal ◽  
2012 ◽  
Vol 11 (1) ◽  
pp. 61-66 ◽  
Author(s):  
DOEUNG D. CHOI ◽  
SERGIY A. LAVRYKOV ◽  
BANDARU V. RAMARAO
Keyword(s):  
Finite Element ◽  
Plane Deformation ◽  
Strain Analysis ◽  
Local Strain ◽  
Uniaxial Stress ◽  
Material Model ◽  
Element Model ◽  
Plastic Behavior ◽  
Stress Strain ◽  
Strain Fields

Delamination between layers occurs during the creasing and subsequent folding of paperboard. Delamination is necessary to provide some stiffness properties, but excessive or uncontrolled delamination can weaken the fold, and therefore needs to be controlled. An understanding of the mechanics of delamination is predicated upon the availability of reliable and properly calibrated simulation tools to predict experimental observations. This paper describes a finite element simulation of paper mechanics applied to the scoring and folding of multi-ply carton board. Our goal was to provide an understanding of the mechanics of these operations and the proper models of elastic and plastic behavior of the material that enable us to simulate the deformation and delamination behavior. Our material model accounted for plasticity and sheet anisotropy in the in-plane and z-direction (ZD) dimensions. We used different ZD stress-strain curves during loading and unloading. Material parameters for in-plane deformation were obtained by fitting uniaxial stress-strain data to Ramberg-Osgood plasticity models and the ZD deformation was modeled using a modified power law. Two-dimensional strain fields resulting from loading board typical of a scoring operation were calculated. The strain field was symmetric in the initial stages, but increasing deformation led to asymmetry and heterogeneity. These regions were precursors to delamination and failure. Delamination of the layers occurred in regions of significant shear strain and resulted primarily from the development of large plastic strains. The model predictions were confirmed by experimental observation of the local strain fields using visual microscopy and linear image strain analysis. The finite element model predicted sheet delamination matching the patterns and effects that were observed in experiments.

Dynamic Loading on Turbofan Blades Due to Bird-Strike

2011 ◽  
Vol 133 (12) ◽  
Author(s):  
Sunil K. Sinha ◽  
Kevin E. Turner ◽  
Nitesh Jain
Keyword(s):  
Dynamic Loading ◽  
Time History ◽  
Material Model ◽  
Bird Strike ◽  
Dynamical Equations ◽  
Nonlinear Dynamical ◽  
History Of ◽  
Measured Strain ◽  
Dynamic Loading Condition ◽  
Fan Blade

In the present paper, a hydrodynamic bird material model made up of water and air mixture is developed, which produces good correlation with the measured strain-gauge test data in a panel test. This parametric bird projectile model is used to generate the time-history of the transient dynamic loads on the turbofan engine blades for different size birds impacting at varying span locations of the fan blade. The problem is formulated in 3D vector dynamics equations using a nonlinear trajectory analysis approach. The analytical derivation captures the physics of the slicing process by considering the incoming bird in the shape of a cylindrical impactor as it comes into contact with the rotating fan blades modeled as a pretwisted plate with a camber. The contact-impact dynamic loading on the airfoil produced during the bird-strike is determined by solving the coupled nonlinear dynamical equations governing the movement of the bird-slice in time-domain using a sixth-order Runge-Kutta technique. The analytically predicted family of load time-history curves enables the blade designer to readily identify the critical impact location for peak dynamic loading condition during the bird-ingestion tests mandated for certification by the regulatory agencies.

scholarly journals Numerical simulation of blanking process

2018 ◽  
Vol 157 ◽  
pp. 02038
Author(s):  
Peter Pecháč ◽  
Milan Sága
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Steel Sheet ◽  
Plastic Material ◽  
Material Model ◽  
Rolled Steel ◽  
Finite Element Software ◽  
History Of ◽  
Cold Rolled ◽  
Blanking Process

This paper presents numerical simulation of blanking process for cold-rolled steel sheet metal. The problem was modeled using axial symmetry in commercial finite element software ADINA. Data obtained by experimental measurement were used to create multi-linear plastic material model for simulation. History of blanking force vs. tool displacement was obtained.

Experimental Study and Numerical Analysis of Sihui Metro Depot and the Superstructure

2012 ◽  
Vol 226-228 ◽  
pp. 176-180
Author(s):  
Jing Zhang ◽  
Bin Zhang ◽  
Ying Hua Liu ◽  
Long Qi Wang ◽  
Yu Bin Wu
Keyword(s):  
Time History ◽  
Field Tests ◽  
Element Model ◽  
Test Analysis ◽  
3 Dimensional ◽  
Dimensional Finite Element ◽  
Calculation Results ◽  
History Of ◽  
The Given ◽  
The Waves

Field tests were carried out on Sihui metro depot of Beijing metro line 1 and its superstructure. The acceleration time history of sleepers and floors of the building was obtained, and the waves-propagation laws of building were studied through the tests. Test analysis shows that the structure vibrations show zigzag tendencies ascends with the height of the building. Based on current situation of Sihui metro depot, a metro-soil-building 3-dimensional finite element model is established on ANSYS. By using actual acceleration of sleepers as inputs, the dynamic responds rule of the superstructure is obtained. Compared calculation results with the experimental results, the given numerical model can predict the vibrations of the building induced by moving trains quite well. This method can provide guidance and technical support for future development of superstructure.

scholarly journals Seismic Failure Pattern Prediction in a Historical Masonry Minaret under Different Earthquakes

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Halil Nohutcu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Nonlinear Analysis ◽  
Dynamic Characteristics ◽  
Time History ◽  
Element Model ◽  
Ambient Vibration ◽  
Tension Stress ◽  
Historical Structures ◽  
Ambient Vibration Tests

Historical structures are the values that are of great importance to that country, showing the roots of a country, and must be passed on from generation to generation. This study attempts to make a contribution to this goal. Seismic damage pattern estimation in a historical brick masonry minaret under different ground motion levels is investigated by using updated finite element models based on ambient vibration data in this study. Imaret Mosque which was built in 1481 AD is selected for an application. Surveying measurement and material tests were conducted to obtain a 3D solid model and mechanical properties of the components of the minaret. Firstly, the initial 3D finite element model of the minaret was analyzed and numerical dynamic characteristics of the minaret were obtained. Then, ambient vibration tests as well as operational modal analysis were implemented in order to obtain the experimental dynamic characteristics of the minaret. The initial finite element model of the minaret was updated by using the experimental dynamic results. Lastly, linear and nonlinear time-history analyses of the updated finite element model of the minaret were carried out using the acceleration records of two different level earthquakes that occurred in Turkey, in Afyon-Dinar (1995) and Çay-Sultandağı (2002). A concrete damage plasticity model is considered in the nonlinear analyses. The conducted analyses indicate that the compressive and tension stress results of the linear analyses are not as realistic as the nonlinear analysis results. According to the nonlinear analysis, the Çay-Sultandağı earthquake would inflict limited damage on the minaret, whereas the Dinar earthquake would damage some parts of the elements in the transition segment of the minaret.

Study on the Structural and Aseismatical Performance of Multi-Storey Ancient Chinese Timber Structure Shangyou Tower of Palace Style

2012 ◽  
Vol 535-537 ◽  
pp. 2012-2016
Author(s):  
Da Feng Gao ◽  
Peng Fei Li ◽  
Lei Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Ground Motion ◽  
Vibration Isolation ◽  
Time History ◽  
Element Model ◽  
Timber Structure ◽  
Wooden Frame ◽  
Spring Element ◽  
The Ancient Chinese

Based on the rich previous experimental data, the multi-storey ancient Chinese timber structure shangyou tower of palace style was studied. ANSYS10.0 software was used to establish the finite element models. One finite element model of large wooden frame was established by applying semi-rigid spring element to simulate the joint of mortise-tenon, tou-kung and the connection on column foot in the real wooden structure. The other finite element model of antique building corresponding to the finite element model above was established. The first 10 inherent frequencies and vibrations of the two models were obtained by the method of Block Lanczos with full transient analysis. The model displacement and acceleration time history curves were obtained by taking the two models subjected to El-Centro ground motion, Taft ground motion and Lanzhou artificial ground motion excitation. By the results analysis of the two models, it can be find that the vibration isolation performance of the ancient Chinese timber structure mainly manifests in the column foot, tenon and mortise connection and the tou-kung layer.

A Virtual Model for Aluminum Hot Forging Using an Artificial Neural Network Material Model Within Finite Element Analysis

2005 ◽  
Author(s):  
B. Scott Kessler ◽  
A. Sherif El-Gizawy
Keyword(s):  
Finite Element ◽  
Effective Means ◽  
Hot Forging ◽  
Material Model ◽  
Element Model ◽  
Operating Conditions ◽  
Element Analysis ◽  
Preliminary Model ◽  
Wide Range ◽  
Artificial Neural

The accuracy of a finite element model for design and analysis of a metal forging operation is limited by the incorporated material model’s ability to predict deformation behavior over a wide range of operating conditions. Current rheological models prove deficient in several respects due to the difficulty in establishing complicated relations between many parameters. More recently, artificial neural networks (ANN) have been suggested as an effective means to overcome these difficulties. In the present work, a previously developed ANN with the ability to determine flow stresses based on strain, strain rate, and temperature is incorporated with finite element code. Utilizing this linked approach, a preliminary model for forging an aluminum wheel is developed. This novel method, along with a conventional approach, is then measured against the forging process as it is currently performed in actual production.

FE Modeling of the Three-Layer Human Carotid Artery Under Impact Loadings

2007 ◽  
Author(s):  
Aihong Zhao ◽  
Ken Digges ◽  
Mark Field ◽  
David Richens
Keyword(s):  
Finite Element ◽  
Carotid Artery ◽  
Model Simulation ◽  
Material Model ◽  
Element Model ◽  
Traumatic Rupture ◽  
Aortic Tissue ◽  
Fe Model ◽  
Arbitrary Lagrangian Eulerian ◽  
The Impact

Blunt traumatic rupture of the carotid artery is a rare but life threatening injury. The histology of the artery is key to understanding the aetiology of this injury. The carotid artery is composed of three layers known as the tunica intima, media, and adventitia, with distinct biomechanical properties. In order to examine the behaviour of the carotid artery under external load we have developed a three layer finite element model of this vessel. A rubber-like material model from LS-DYNA was selected for the FE model. The Arbitrary-Lagrangian Eulerian (ALE) approach was adopted to simulate the interaction between the fluid (blood) and the structure (carotid). To verify the FE model, the impact bending tests are simulated using this FE model. Simulation results agree with tests results well. Furthermore, the mechanical behaviour of carotid artery tissues under impact loading were revealed by the simulations. The results provide a basis for a more in-depth investigation of the carotid artery in vehicle crashes. In addition, it provides a basis for further work on aortic tissue finite element modeling.

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