Numerical Study on Damage Response of Ship Composite Armor Structures to Contact Underwater Explosion

2009 ◽  
Vol 79-82 ◽  
pp. 1329-1332
Author(s):  
Li Yang ◽  
Yu Wang ◽  
Qing Ming Zhang ◽  
Zhi Peng Du
Keyword(s):  
Numerical Study ◽  
Impact Resistance ◽  
Underwater Explosion ◽  
Whole Process ◽  
Damage Response ◽  
Detached Shock Wave ◽  
Composite Armor ◽  
Potential Applicability ◽  
New Type ◽  
The Impact

As a new type of protection design, composite armor structures have good performance in impact resistance, and have been widely used in ship structure protection. Due to its academic value and potential applicability, the dynamic characteristics of ship composite armor structures were studied in this paper. The whole process of the shaped charge’s explosion and penetration, and the ship composite armor structures’ damage response were described. According to the numerical simulation with Ansys-Autodyn, it was found that the ship composite armor structures were damaged not only by the explosively formed projectile but also by the detached shock wave in the conditions of contact underwater explosion and the thickness of composite armor structures was the main factor effecting the impact resistance properties.

scholarly journals Preparation and Impact Resistance Properties of Hybrid Silicone-Ceramics Composites

2020 ◽  
Vol 10 (24) ◽  
pp. 9098
Author(s):  
Katarzyna Kośla ◽  
Paweł Kubiak ◽  
Marzena Fejdyś ◽  
Karolina Olszewska ◽  
Marcin Łandwijt ◽  
...  
Keyword(s):  
Impact Resistance ◽  
Young Modulus ◽  
Drop Tower ◽  
Body Armor ◽  
Soft Body ◽  
Ballistic Performance ◽  
Composite Armor ◽  
New Type ◽  
The Impact ◽  
Soft Body Armor

This article presents the method of preparation a new type of ballistic armor based on hybrid silicone-ceramic (HSC) composites with considerable flexibility. An experimental study on the ballistic behavior of HSC composites connected with soft body armor is presented against FSP.22 fragments. The effect of Al2O3 ceramics on the ballistic performance of HSC composite was investigated, and the fragmentation resistance process of the composite armor combining the HSC composite and soft aramid insert is clarified. Furthermore, impact resistance tests made with a drop tower which allows for a gravity drop of a mass along vertical guides onto a sample placed with an energy of 5 J were performed. The results presented in this paper show that the HSC composites can be successfully used as a hard body armor. However, they do not exhibit the properties of absorbing the impact energy generated during the drop tower tests. The test results show that the ballistic performance of composite armors is influenced by the hardness and Young modulus of ceramics and soft body armor panel. Additionally, in the article, the results of mechanical properties of silicones used for preparation of composites were presented and compiled to determine their role in the performance of impact protection.

Experimental and Numerical Study of Basalt FRP Strip Strengthened RC Slabs under Impact Loads

2020 ◽  
Vol 20 (06) ◽  
pp. 2040001 ◽  
Author(s):  
Wensu Chen ◽  
Thong M. Pham ◽  
Mohamed Elchalakani ◽  
Huawei Li ◽  
Hong Hao ◽  
...  
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Numerical Study ◽  
Impact Resistance ◽  
Basalt Fiber ◽  
Impact Behavior ◽  
Impact Loads ◽  
Quantitative Measurements ◽  
Rc Slabs ◽  
The Impact

Basalt fiber-reinforced polymer (BFRP) has been applied for strengthening concrete structures. However, studies on reinforced concrete (RC) slabs strengthened by BFRP strips under impact loads are limited in open literature. This study investigates the efficiency of using BFRP strips with various strengthening layouts and anchoring schemes on the impact resistance of RC slabs. A total of 11 two-way square slabs were prepared and tested, including one reference specimen without strengthening and ten slabs strengthened with BFRP strips and/or anchors. The RC slabs were impacted by a drop weight with increasing height until slab failure. The observed failure modes include punching shear failure, BFRP sheet debonding and reinforcement fracture. The failure modes and the effects of using various strengthening schemes on the impact resistant capacity of RC slabs were examined. The quantitative measurements, such as impact velocity, indentation depth and diameter, were compared and discussed. In addition, numerical studies were carried out by using LS-DYNA to simulate the impact tests of RC slabs with and without BFRP strengthening. With the calibrated numerical model, the impact behavior of slabs with various dimensions and strengthening layouts under different impact intensities can be predicted with good accuracy.

Ballistic Performance of Sandwich Composite Armor System

2020 ◽  
Author(s):  
Shah Alam ◽  
Samhith Shakar
Keyword(s):  
Impact Resistance ◽  
Absorption Capacity ◽  
Sandwich Composite ◽  
Skin Thickness ◽  
Ballistic Performance ◽  
Backing Plate ◽  
Composite Armor ◽  
Corrugated Structure ◽  
The Impact ◽  
Armor System

Abstract This study focused on the design, modelling and the analysis of the dynamic response of composite armor system, constructed with Kevlar 29 as front skin, Alumina-ceramic filled in x shaped corrugated structure as core and bottom skin Kevlar 29 and T800S, in terms of residual velocity, energy absorption capacity and limiting velocity. The core cell size, height, thickness, skin thickness, etc., will be varied to get their influence on the impact resistance. The design parameter will be investigated for the sandwich composite armor with various configurations and stacking sequence of Alumina Ceramics, Kevlar 29 and T800S. The sandwich typically consists of front plate, core and backing plate, which will be impacted at different velocities starting at 100m/s till significant armor penetration. The ballistic limit velocity (V50) will be determined from the analysis. The non-linear explicit dynamic analysis and simulation results computed using the software ABAQUS will be validated by experiment. From the data obtained it can be suggested which composite armor has improved impact resistance and performance.

Influence of Interphase Properties on the Macroscopic Response of Single- and Double-Walled CNT/Epoxy Nanocomposites: A Numerical Study

2012 ◽  
Vol 714 ◽  
pp. 3-11 ◽  
Author(s):  
David Weidt ◽  
Łukasz Figiel ◽  
Martin Buggy
Keyword(s):  
Shear Stress ◽  
Carbon Nanotube ◽  
Mechanical Performance ◽  
Numerical Study ◽  
Impact Resistance ◽  
Shear Stiffness ◽  
Epoxy Nanocomposites ◽  
Cfrp Laminates ◽  
The Impact ◽  
Walled Cnts

A concept for improving the impact resistance of carbon fibre reinforced plastic (CFRP) laminates by using a carbon nanotube (CNT)/epoxy surface coating is presented. An initial parametric numerical study shows the effects of interphase properties on the macroscopic stress-strain behaviour of carbon nanotube/epoxy nanocomposites. Finite element (FE) simulations carried out for fully aligned single-walled CNTs (SWCNTs) and double-walled CNTs (DWCNTs) investigated the influence of properties of the polymer/CNT interphase and the interwall phase of DWCNTs. They reveal that a high shear stiffness of the CNT/polymer interphase is essential to take the full advantage of the load-bearing ability of the inner wall of the DWCNT, and thus enhance the mechanical performance of the nanocomposite. Furthermore the interphase shear stress distributions in interwall and CNT/polymer interphase of a DWCNT point out the relationship between CNT/epoxy interphase damage propagation and shear stress in the interwall phase.

scholarly journals Experimental and numerical study of axially-loaded RC columns and frame columns under lateral impact loading

2021 ◽  
Author(s):  
Zheng Luo ◽  
Wang Yinhui
Keyword(s):  
Impact Load ◽  
Numerical Study ◽  
Impact Resistance ◽  
Impact Excitation ◽  
Lateral Impact ◽  
Axial Loads ◽  
Free Standing ◽  
Positive Role ◽  
The Moment ◽  
The Impact

The pendulum impact tests were carried out on one RC frame column and four RC free-standing columns. The effect of axial compression ratio and reinforcement ratio on the impact resistance of columns were compared by means of dynamic time curves of framed and freestanding columns under impact. The test results show that with the same impact load, though the presence of axial loads can play a positive role (e.g., reducing the residual displacement), it may lead to more severe local damage. Also, compared with free-standing columns, the frame column can be considered as a protective structure for its greater lateral stiffness and stronger crashworthiness. The corresponding finite element models are developed，and the influence of the axial loads on cross section force responses under impact excitation is deeply explored. The axial loads can significantly affect the distribution of the moment, the shear force, and also the damage for the column.

Investigating the behavior of silicon-coated Kevlar fabric under low-velocity impact: An experimental and numerical study

2018 ◽  
Vol 32 (5) ◽  
pp. 635-656 ◽  
Author(s):  
A Abbaszadeh ◽  
M Yazdani ◽  
F Abbasi ◽  
A Rashed
Keyword(s):  
Numerical Study ◽  
Aqueous Suspension ◽  
Impact Resistance ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Time Duration ◽  
Velocity Impact ◽  
Coated Fabrics ◽  
Drop Weight Test ◽  
The Impact

This study reports experimental and numerical behaviors of both dry and silicon-coated twill-weave Kevlar fabrics under low-velocity impact. Initially, the fabrics are augmented in silicon aqueous suspension with various particle concentrations, and then, increase in the weight and friction coefficient are studied. The low-velocity impact test results show that the best particle concentration to meet the mentioned requirements is about 10 wt%. The experiments indicate high-impact resistance of the target by increase in the number of fabric plies. It is found that silicon-coated fabrics under drop-weight test show more time duration of impact and better performance than dry fabrics. Furthermore, the tests show that in the dry fabrics, broader region stretches due to impact, while in silicon-coated fabrics, the damage is limited to the impact point. The numerical simulation is performed for the coated fabric, and the effect of fabric augmentation with silicon is introduced as yarn friction. The numerical results are in good agreement with the experimental results.

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Indirect Tensile ◽  
The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    

scholarly journals Effect of SWCNT-Tuball Paper on the Lightning Strike Protection of CFRPs and Their Selected Mechanical Properties

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3140
Author(s):  
Kamil Dydek ◽  
Anna Boczkowska ◽  
Rafał Kozera ◽  
Paweł Durałek ◽  
Łukasz Sarniak ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Copper Foil ◽  
Impact Resistance ◽  
Mechanical Analysis ◽  
Lightning Strike ◽  
Single Wall Carbon Nanotubes ◽  
Carbon Fibre Reinforced Polymer ◽  
The Impact

The main aim of this work was the investigation of the possibility of replacing the heavy metallic meshes applied onto the composite structure in airplanes for lightning strike protection with a thin film of Tuball single-wall carbon nanotubes in the form of ultra-light, conductive paper. The Tuball paper studied contained 75 wt% or 90 wt% of carbon nanotubes and was applied on the top of carbon fibre reinforced polymer before fabrication of flat panels. First, the electrical conductivity, impact resistance and thermo-mechanical properties of modified laminates were measured and compared with the reference values. Then, flat panels with selected Tuball paper, expanded copper foil and reference panels were fabricated for lightning strike tests. The effectiveness of lightning strike protection was evaluated by using the ultrasonic phased-array technique. It was found that the introduction of Tuball paper on the laminates surface improved both the surface and the volume electrical conductivity by 8800% and 300%, respectively. The impact resistance was tested in two directions, perpendicular and parallel to the carbon fibres, and the values increased by 9.8% and 44%, respectively. The dynamic thermo-mechanical analysis showed higher stiffness and a slight increase in glass transition temperature of the modified laminates. Ultrasonic investigation after lightning strike tests showed that the effectiveness of Tuball paper is comparable to expanded copper foil.

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