Optimisation of Ceramic/Steel Composite Armour of a Constant Thickness

Volume 1 ◽  
2004 ◽  
Author(s):  
Tanju Cakir ◽  
R. Orhan Yildirim ◽  
Bilgehan Ogel
Keyword(s):  
Ceramic Tile ◽  
Steel Plate ◽  
Plate Thickness ◽  
Impact Resistance ◽  
Thickness Ratio ◽  
Constant Thickness ◽  
Impact Behaviour ◽  
Back Plate ◽  
Steel Composite ◽  
The Impact

Impact resistance of ceramic/steel composite armour against 7.62 mm AP (armour piercing) projectile is examined analytically, numerically and experimentally. Total armour thickness is taken to be constant. Ceramic tile thickness and steel plate thickness are changed to observe the effect of the variation of the thickness ratio on the impact behaviour of ceramic/steel armour. Results show that the impact behaviour of ceramics is related to the ceramic tile thickness and back plate thickness. It is found that there is an optimum ceramic/steel thickness ratio which provides the best protection against a specified threat for a constant total armour thickness.

scholarly journals Column Stiffness Requirements for Diagonally Stiffened Steel Plate Shear Walls

2020 ◽  
Vol 9 (5) ◽  
pp. 101-109
Keyword(s):  
Aspect Ratio ◽  
Steel Plate ◽  
Numerical Models ◽  
Shear Walls ◽  
Shear Capacity ◽  
Thickness Ratio ◽  
Steel Plate Shear Wall ◽  
Out Of Plane ◽  
The Impact ◽  
Stiffened Steel

Various numerical models of diagonally stiffened steel plate shear wall were tested under push-over loads to study the required stiffness of columns of diagonally stiffened SPSWs. This research presents a parametric study to explore the influence of varying the infill panel’s thickness, width, and height and the number of floors on the stiffness of the edge columns, and to propose expressions to predict the column’s in-plane stiffness and area required for preliminary design. Different SPSWs were modeled with a range of several stories, an aspect ratio, and height to thickness ratio, respectively, of (n=3-7), (Lp /hp=1-2), and (λ=200-400). The results indicated that the number of floors (n) has a great effect on the wall’s shear capacity. A greater number of floors lead to buckling in columns and early failure of the system, and subsequently, an increase in the column’s rigidity is required. Moreover, an equation is proposed to calculate the value of ωh required for sufficient inertia of the column. Higher the drift is, lower the shear capacity of the wall is, particularly for walls with a larger aspect ratio (Lp /hp > 1.5), and smaller height to thickness ratio (λ < 400). It is proposed that the columns’ out-of-plane stiffness divided by its in-plane stiffness to be equal or greater than 0.4. An equation is also proposed to predict the required columns’ rx substantial to assure that the columns can resist the impact of the tension field and the plate achieves full yield strength.

Influence of impactor nature, mass, size and shape on ballistic resistance of mild steel and Armox 500 T steel

2018 ◽  
Vol 10 (2) ◽  
pp. 174-197 ◽  
Author(s):  
Senthil Kasilingam ◽  
Mohd Ashraf Iqbal ◽  
Rupali Senthil
Keyword(s):  
Mild Steel ◽  
Steel Plate ◽  
Impact Resistance ◽  
Hardened Steel ◽  
Steel Plates ◽  
Material Parameters ◽  
Ballistic Resistance ◽  
Steel Target ◽  
Mass Size ◽  
The Impact

This study is based on the finite element investigation of the response of mild steel and Armox 500 T steel targets subjected to macro- and micro-size impactor. The simulations were carried out on target against penetrator with varying masses, sizes, shapes and different nature (rigid and deformable projectiles) using ABAQUS/Explicit. The material parameters of Johnson–Cook elasto-viscoplastic model were employed for predicting the behaviour of the target. The impact resistance of mild steel and Armox 500 T steel plates has been studied against flat nose having masses of 4, 8, 13.5, 27, 32 and 64 kg. The influence of temperature has also been studied numerically for particular penetrator. To study the influence of nature of projectile, the simulations were performed on mild steel and Armox 500 T steel targets against deformable 2024 aluminium flat, hardened steel flat and hardened steel conical impactors at 950 and 150 m/s incidence velocities. Also, the simulations were carried out on given target against 7.62 and 12.7 mm armour piercing incendiary ogival nose projectiles. The performance of (4.7 + 4.7 mm) 9.4-mm-thick equivalent mild steel and Armox 500 T steel plate in combination has also been studied against 7.62 armour piercing incendiary ogival nose projectiles at 950 and 150 m/s incidence velocities. The study thus presents a detailed investigation in terms of penetration, perforation and failure mechanism of mild steel and Armox 500 T steel target and leads to some important conclusions pertaining to the force and resistance offered by the target.

scholarly journals Simulation Analysis of Void Defect Detection in Sandwich-Structured Immersed Tunnel Using Elastic Wave

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Ruiqiang Liu ◽  
Songhui Li ◽  
Guoxin Zhang ◽  
Shenyou Song ◽  
Jianda Xin
Keyword(s):  
Influencing Factors ◽  
Steel Plate ◽  
Plate Thickness ◽  
Image Method ◽  
Detection Accuracy ◽  
Imaging Method ◽  
Waveform Data ◽  
Immersed Tunnel ◽  
Void Defects ◽  
The Impact

Void defects can be easily generated between a steel plate and concrete joint due to the complicated internal structure of a sandwich-structured immersed tunnel (SSIT), which affect the overall bearing capacity of the main structure of the immersed tube tunnel. A prototype experiment was conducted to study the application of impact imaging method in the nondestructive detection of void defects in SSITs. The detection criterion for the impact imaging method was established based on the features of the waveform data. Nevertheless, the influence of steel plate thickness, material properties, void location, and structure on the detection accuracy of the impact imaging method is unclear. Therefore, numerical simulation was applied to study the influencing factors by establishing a different condition model. Good agreement between the experimental and numerical results was observed for the response waveform collected from the inspection area. Using the calculation model and identified material parameters validated in the active prototype experiment, numerical simulations of several sets, which considered all influencing factors, were performed. The application scope and sensitivity of the impact image method were recommended to reduce misjudgement in practical applications and improve detection accuracy.

The assessment of impact damage caused by dropped objects on floating offshore structures

2020 ◽  
pp. 147509022097258
Author(s):  
Ozgur Ozguc
Keyword(s):  
Impact Damage ◽  
Plate Thickness ◽  
Impact Resistance ◽  
Offshore Structures ◽  
Structural Evaluation ◽  
Hull Structure ◽  
Reaction Forces ◽  
Buckling Failure ◽  
Environmental Events ◽  
The Impact

Offshore facilities are exposed to the risk of accidental damages caused by fire, explosion, dropped objects, extreme environmental events and vessel collision poses a big threat to the safety and operation. During any lifting work, either from a supply vessel to the installation or from within the installation or plant itself, there is a potential danger when objects are being lifted for a dropped object accident to take place. This paper introduces extensive dropped object analyses applied in the design of Floating Production Storage Offloading (FPSO) offshore units, where non-linear finite element analyses are performed using an explicit LS-DYNA tool. In the structural evaluation, the hull parts such as infill deck, galley, and main lay-down located on poop deck, and cargo deck are taken into account. The dropped objects study is to find out what happens to the FPSO hull structure if the heavy items are dropped. The drop object impact analyses show that even though some structural members were permanently deformed by drop loads, however, there was no failure taken place in accordance with the plastic strain criteria as per NORSOK Code. It is discovered that the pillars supporting the main lay-down area have not been suffered from buckling failure through examined reaction forces. Further, the impact resistance of a deck depends on the plate thickness and the size and spacing of the supporting stringers.

scholarly journals Sensitivity Analysis of Steel-Plate Concrete Containment against a Large Commercial Aircraft

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2829
Author(s):  
Xiuyun Zhu ◽  
Jianbo Li ◽  
Gao Lin ◽  
Rong Pan ◽  
Liang Li
Keyword(s):  
Sensitivity Analysis ◽  
Plastic Strain ◽  
Steel Plate ◽  
Concrete Strength ◽  
Plate Thickness ◽  
Time History ◽  
Commercial Aircraft ◽  
Strength Grade ◽  
Displacement Response ◽  
The Impact

Due to the excellent impact resistant performance of steel-plate concrete (SC) structure compared with the conventional reinforced concrete (RC) structure, SC structure is preferred to be used in the design of external walls of nuclear island buildings for new nuclear power plants (NPPs). This study aims at evaluating the effect of material and geometric parameters of SC containment on its impact resistant performance, thus the numerical simulation and sensitivity analysis of SC containment subjected to malicious large commercial aircraft attack are conducted based on the force time-history analysis method. The results show that: (1) the impact resistant performance of full SC containment is better than that of half SC containment; (2) for relatively thin full SC containment, the impact response and concrete damage can be significantly reduced by the enhancing of concrete strength grade or the increasing of steel plate thickness; (3) for the thicker full SC containment, concrete strength grade has only a slight influence on the impact displacement response, and the increasing of steel plate thickness has no significant effect on mitigating the impact displacement response. However, the increasing of steel plate thickness can effectively reduce its plastic strain, and the decreasing of strength grade of steel plate may obviously increase its plastic strain; and (4) concrete thickness plays a decisive role on the improvement of impact resistance, which is more effective than the enhancing of concrete strength grade. Resultantly, this paper provides a reference and guidance for the design of SC structure external walls of nuclear island buildings against a large commercial aircraft.

Parametric Study of Hysteretic Behaviour of Combined Welded Heavy Steel Plates with Accumulative Damage

2011 ◽  
Vol 194-196 ◽  
pp. 1887-1891
Author(s):  
Na Yang ◽  
Jing Jing Zhang ◽  
Ting Guo
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Plastic Strain ◽  
Steel Plate ◽  
Plate Thickness ◽  
Damage Model ◽  
Thickness Ratio ◽  
Steel Plates ◽  
Hysteretic Behavior ◽  
Previous Researcher

The accumulative damage model in which the material’s plastic strain is defined as variable and the energy dissipation is also considered is applied to the combined welded heavy steel plates. And the reliability of the model is confirmed by comparing the computed results in finite element project ABAQUS to tested results from previous researcher. On that basis, a series of steel plate components are computed to analyze their hysteretic curves and ductility factors. The influences of steel plate thickness, web’s height-thickness ratio and flange’s width-thickness ratio on hysteretic behavior are studied.

Bullet Impact on Steel and Kevlar®/Steel Armor: Computer Modeling and Experimental Data

2004 ◽  
Author(s):  
Dale S. Preece ◽  
Vanessa S. Berg
Keyword(s):  
Impact Crater ◽  
Steel Plate ◽  
Plate Thickness ◽  
Material Model ◽  
Impact Craters ◽  
Full Penetration ◽  
The World ◽  
Good Comparison ◽  
The Impact ◽  
Witness Plate

Computer hydrocode analyses and ballistic testing have been used to investigate the effectiveness of steel plate armor against lead/copper bullets commonly available in the U.S. and across the world. Hydrocode simulations accurately predict the steel plate thickness that will prevent full penetration as well as the impact crater geometry (depth and diameter) in that thickness of steel armor for a 338 caliber bullet. Using the hydrocode model developed for steel armor, studies were also done for an armor consisting of a combination of Kevlar® and steel. These analyses were used to design the experiments carried out in the ballistics lab at Sandia National Laboratories. Ballistics lab testing resulted in a very good comparison between the hydrocode computer predictions for bullet impact craters in the steel plate armor and those measured during testing. During the experiments with the combination armor (Kevlar®/steel), the steel became a witness plate for bullet impact craters following penetration of the Kevlar®. Using the bullet impact craters in the steel witness plate it was determined that hydrocode predictions for Kevlar® armor are less accurate than for metals. This discrepancy results from the inability of the hydrocode (Eulerian) material model to accurately represent the behavior of the fibrous Kevlar®. Thus, this paper will present the hydrocode predictions and ballistics lab data for the interaction between a lead/copper bullet and several armoring schemes: 1) steel, 2) Kevlar®, and 3) a Kevlar®/steel combination.

scholarly journals Analytical and FEM Analyses of High-Speed Impact Behaviour of Al 2024 Alloy

Aerospace ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 281
Author(s):  
Navya Gara ◽  
Velmurugan Ramachandran ◽  
Jayaganthan Rengaswamy
Keyword(s):  
High Speed ◽  
Impact Resistance ◽  
Fem Analysis ◽  
Target Thickness ◽  
Model Parameters ◽  
Al Alloy ◽  
Ballistic Limit ◽  
Impact Behaviour ◽  
The Impact ◽  
Al 2024

The present work investigates the impact behaviour of Al 2024-T3 alloy using FEM analysis performed through LS DYNA software. Johnson–Cookvisco-plastic model is used to study the ballistic impact resistance of target Al alloy impacted by a rigid steel cylindrical projectile. The tensile properties of Al 2024-T3 alloy reported in the literature are used to estimate the J.C. model parameters. Impact velocities within a range of 50 m/s–900 m/s of the projectile were triggered onto Al alloy target thicknesses in the range of 3.18 mm–6.35 mm. To understand the accuracy of the FEM model, an analytical model proposed by Chen et al. for blunt-nosed projectiles on the ductile targets was used to compare with the obtained residual velocities from FEM simulations. It was observed that the ballistic limit velocities have led to the highest energy absorption behaviour of the Al 2024-T3 alloy for an impact velocity of 183 m/s and a 6.35 mm target thickness. The ballistic limit velocities have increased from 97 m/s to 183 m/s for the considered thickness range of 3.18 mm–6.35 mm. The impact failure was observed to have a petalling formation with two petals for thinner targets, while a full-fledged plugging with no petal formation for the 4.00 mm and 6.35 mm target thicknesses was observed.

Bending impact behaviour of sandwich beams with expanded polystyrene foam core: Analysis

2017 ◽  
Vol 21 (1) ◽  
pp. 230-259 ◽  
Author(s):  
Umut Caliskan ◽  
M Kemal Apalak
Keyword(s):  
Plate Thickness ◽  
Expanded Polystyrene ◽  
Design Parameters ◽  
Zone Model ◽  
Sandwich Beams ◽  
Polystyrene Foam ◽  
Foam Material ◽  
Impact Behaviour ◽  
Expanded Polystyrene Foam ◽  
The Impact

This study addresses the bending impact behaviour of sandwich beams made of a low density core bonded to two metal face sheets under low-velocity impact. The geometrical and material non-linearities were considered in the explicit dynamic analysis. The face sheets and core were made of aluminum and expanded polystyrene foam. The effects of design parameters, such as foam density, foam thickness, plate thickness, on the impact energy absorption of the joint were investigated. The foam material was modelled as a crushable foam material, and the cohesive response of the adhesive interface was analysed using the cohesive zone model. Experimental low-speed impact tests were carried out to validate the finite element analysis, and the temporal variations of the contact force and the permanent central deflections at the top and bottom faces of the sandwich beams were in good agreement.

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