scholarly journals The Influence of Temperature in the Al 2024-T3 Aluminum Plates Subjected to Impact: Experimental and Numerical Approaches

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4268
Author(s):  
Maciej Klosak ◽  
Rafael Santiago ◽  
Tomasz Jankowiak ◽  
Amine Bendarma ◽  
Alexis Rusinek ◽  
...  
Keyword(s):  
Element Model ◽  
Material Failure ◽  
Ballistic Limit ◽  
Influence Of Temperature ◽  
Gas Gun ◽  
Test Conditions ◽  
Reliable Model ◽  
Aluminum Plates ◽  
Al 2024 ◽  
Numerical Approaches

In this paper, perforation experiments were carried out and numerically modelled in order to analyze the response of 2024-T3 aluminum alloy plates under different initial temperatures T0. This alloy has a particular relevance since it is widely used as a structural component in aircrafts, but it is also interesting for other sectors of industry. A gas gun projectile launcher was used to perform impacts within initial velocities V0 from 40 m/s to 120 m/s and at temperatures varying from 293 K to 573 K. A temperature softening of the material was observed which was manifested in the reduction in the ballistic limit by 10% within the temperature range studied. Changes in the material failure mode were also observed at different test conditions. Additionally, a finite element model was developed to predict the material response at high velocities and to confirm the temperature softening that was observed experimentally. An optimization of the failure criterion resulted in a reliable model for such mild aluminum alloys. The results reported here may be used for different applications in the automotive and military sectors.

scholarly journals Stiffness Estimation and Equivalence of Boundary Conditions in FEM Models

2021 ◽  
Vol 11 (4) ◽  
pp. 1482
Author(s):  
Róbert Huňady ◽  
Pavol Lengvarský ◽  
Peter Pavelka ◽  
Adam Kaľavský ◽  
Jakub Mlotek
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Boundary Conditions ◽  
Model Updating ◽  
Element Model ◽  
Computational Time ◽  
Stiffness Coefficients ◽  
First Case ◽  
Numerical Approaches

The paper deals with methods of equivalence of boundary conditions in finite element models that are based on finite element model updating technique. The proposed methods are based on the determination of the stiffness parameters in the section plate or region, where the boundary condition or the removed part of the model is replaced by the bushing connector. Two methods for determining its elastic properties are described. In the first case, the stiffness coefficients are determined by a series of static finite element analyses that are used to obtain the response of the removed part to the six basic types of loads. The second method is a combination of experimental and numerical approaches. The natural frequencies obtained by the measurement are used in finite element (FE) optimization, in which the response of the model is tuned by changing the stiffness coefficients of the bushing. Both methods provide a good estimate of the stiffness at the region where the model is replaced by an equivalent boundary condition. This increases the accuracy of the numerical model and also saves computational time and capacity due to element reduction.

scholarly journals Fatigue Life Appraisal and Its Corrected Stress Intensity Factor for Repaired Off-CentrallyCracked Aluminum Plates

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4014
Author(s):  
Xiang You ◽  
Zhiyu Wang ◽  
Xiafang Zhou ◽  
Zifeng Liu ◽  
Ruijuan Jiang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Element Model ◽  
Crack Size ◽  
Plate Edge ◽  
Life Estimation ◽  
Fatigue Life Estimation ◽  
Life Improvement ◽  
Edge Cracks ◽  
Aluminum Plates ◽  
Sensitive Parameters

This paper presents an experimental study on the fatigue life estimation of off-centrally cracked aluminum plates. Typical theoretical equations for off-central, central and edge cracks were reviewed and compared in terms of their sensitive parameters and applicability. A finite element model has been validated in its capacity in modelling the influences of eccentricity and crack size on the boundary correction coefficients. The Forman equation has been employed along with numerical results for the prediction of fatigue lives. Based on the test data, the fatigue life results of aluminum plates with and without patched laminate repair have been compared with codified fatigue classes. It is demonstrated that the repair at the crack tip close to the plate edge is effective in the fatigue life improvement for off-centrally crackedaluminum plates.

scholarly journals Friction-induced vibrations in the framework of dynamic substructuring

2020 ◽  
Author(s):  
Jacopo Brunetti ◽  
Walter D’Ambrogio ◽  
Annalisa Fregolent
Keyword(s):  
A Priori ◽  
Element Model ◽  
Friction Forces ◽  
Coupling Conditions ◽  
Contact Points ◽  
Dynamic Substructuring ◽  
Reliable Model ◽  
Time Invariant ◽  
Substructuring Techniques ◽  
Vibrating Systems

AbstractIn complex vibrating systems, contact and friction forces can produce a dynamic response of the system (friction-induced vibrations). They can arise when different parts of the system move one with respect to the other generating friction force at the contact interface. Component mode synthesis and more in general substructuring techniques represent a useful and widespread tool to investigate the dynamic behavior of complex systems, but classical techniques require that the component subsystems and the coupling conditions (compatibility of displacements and equilibrium of forces) are time invariant. In this paper, a substructuring method is proposed that, besides accounting for the macroscopic sliding between substructures, is able to consider also the local vibrations of the contact points and the geometric nonlinearity due to the elastic deformation, by updating the coupling conditions accordingly. This allows to obtain a more reliable model of the contact interaction and to analyze friction-induced vibrations. Therefore, the models of the component substructures are time invariant, while the coupling conditions become time dependent and a priori unknown. The method is applied to the study of a finite element model of two bodies in frictional contact, and the analysis is aimed to the validation of the proposed method for the study of dynamic instabilities due to mode coupling.

Design of Gas gun barrel support structure by finite element model updating using optimization techniques

2020 ◽  
Vol 22 ◽  
pp. 3027-3036
Author(s):  
Thoutam Aravind Kumar ◽  
Nuli S.G.R.S Sidhardha ◽  
Arun Tom Mathew ◽  
Devendiran S ◽  
Venkatesan Kannan ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Element Model ◽  
Optimization Techniques ◽  
Finite Element Model Updating ◽  
Support Structure ◽  
Gas Gun ◽  
Gun Barrel

Effect of Temperature on Crater Formation and Ejecta Composition in Aluminum Alloy Targets

2012 ◽  
Vol 706-709 ◽  
pp. 768-773
Author(s):  
Masahiro Nishida ◽  
Koichi Hayashi ◽  
Junichi Nakagawa ◽  
Yoshitaka Ito
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Low Temperature ◽  
Room Temperature ◽  
Effect Of Temperature ◽  
Crater Formation ◽  
Influence Of Temperature ◽  
Gas Gun ◽  
Influence Of Temperature On ◽  
Increasing Temperature

The influence of temperature on crater formation and ejecta composition in thick aluminum alloy targets were investigated for impact velocities ranging from approximately 1.5 to 3.5 km/s using a two-stage light-gas gun. The diameter and depth of the crater increased with increasing temperature. The ejecta size at low temperature was slightly smaller than that at high temperature and room temperature. Temperature did not affect the size ratio of ejecta. The scatter diameter of the ejecta at high temperature was slightly smaller than those at low and room temperatures.

Estimation of Ballistic Limit Velocities for Woven Composite Beams

2009 ◽  
Author(s):  
E. Sevkat ◽  
B. M. Liaw ◽  
F. Delale ◽  
B. B. Raju
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Damage Model ◽  
Experimental Tests ◽  
Composite Beams ◽  
Ballistic Limit ◽  
Gas Gun ◽  
Graphite Fibers ◽  
Ballistic Limit Velocity ◽  
Good Agreement

This paper presents an experimental and numerical study to estimate ballistic limit velocity, V50, of plain-weave hybrid S2 glass-IM7 graphite fibers/toughened SC-79 resin (cured at 177°C) composite beams. The tests were conducted on hybrid S2 glass-IM7 graphite fibers/toughened SC-79 resin and nonhybrid S2 glass-fiber/toughened SC-79 resin composites beams using high-speed gas-gun. The ballistic impact tests were then modeled using 3-D dynamic nonlinear finite element (FE) code, LS-DYNA, modified with a proposed user-defined nonlinear-orthotropic damage model. The ballistic limit velocities, V50, for both composite beams were then estimated using (a) only experimental tests, (b) combined experimental and numerical tests, (c) FE calculated residual velocities, and (d) FE calculated residual and transferred energies. For each type of composite beams, the parameters for the well-known Lambert-Jones equation were also computed. Good agreement between experimental and numerical results was observed.

The Numerical Method as Applied to Impact Resistance Analysis of Ogival Nose Projectiles on 6061-T651 Aluminum Plates

2012 ◽  
Vol 28 (4) ◽  
pp. 715-726 ◽  
Author(s):  
Y.-L. Chen ◽  
H.-C. Chen
Keyword(s):  
Numerical Method ◽  
Predictive Model ◽  
Penetration Depth ◽  
High Speed ◽  
Ballistic Limit ◽  
Residual Velocity ◽  
Finite Element Software ◽  
Limit Velocity ◽  
Aluminum Plates ◽  
Ballistic Limit Velocity

ABSTRACTThis research takes the resistance formula of spherical cavity expansion theory as its foundation. It establishes a predictive model of the residual velocity, ballistic limit velocity, and penetration depth of ogival nose projectiles striking metal target plates at high speed. They are aimed at 6061-T651 aluminum plates of different thicknesses using the iterative algorithm of the numerical method, thereby investigating the theoretical calculation of the residual velocity, penetration depth, ballistic limit velocity, and changes in resistance of ogival nose projectiles when making a normal impact target. In addition to analyzing the resistance undergone by the projectile nose section, this predictive model also considers the effects of friction resistance of the projectile shank section. In this research, we also used the finite element software LS-DYNA to perform a simulated analysis on the penetration depth of the aluminum plate after normal perforation by ogival nose projectiles. Ballistic test experiments were then performed using 0.30” AP (armor piercing) bullets. Finally, a comparative analysis was performed based on the theoretical model, experiments, and numerical simulation results.

Modelling High Velocity Impact on Aluminium Alloy 7075-T6 under Axial Pretension

2014 ◽  
Vol 629 ◽  
pp. 498-502 ◽  
Author(s):  
K.A. Kamarudin ◽  
Al Emran Ismail
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Aluminium Alloy ◽  
High Velocity ◽  
Numerical Study ◽  
Element Model ◽  
Ballistic Limit ◽  
High Velocity Impact ◽  
Velocity Impact

This paper explains the utilisation of finite element model to analyse the ballistic limit of aluminium alloy 7075-T6 impacted by 8.33 g with 12.5 mm radius rigid spherical projectiles. This numerical study was compared with the results obtained experimentally. During impact, the targets were subjected to either non- or uniaxial- pretension and the projectile travelled horizontally to the target. It was observed that pretensioned targets were more vulnerable, which reduced the ballistic limit. The existence of harmful failures owing to pretension impact was ascertained and compared with the non-pretension targets.

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