High Velocity Impact Properties Characterization of Nano-Phased Bi-Layered Body Armor

2011 ◽  
Author(s):  
Sirajus Salekeen ◽  
Mohammad G. Kibria Khan ◽  
Shaik Jeelani
Keyword(s):  
High Velocity ◽  
Body Armor ◽  
Ceramic Layer ◽  
Mechanical And Thermal Properties ◽  
Element Analysis ◽  
Alumina Layer ◽  
Gas Gun ◽  
Layer Composite ◽  
Ballistic Properties ◽  
Composite Armor

It has been already established by different investigators that addition of nano-reinforcements to plastics and fibers further enhances the mechanical and thermal properties of these materials. In this investigation, we have tested a bi-layer composite armor made of a ceramic layer and a nano-reinforcement infused epoxy layer. Our objective is to determine whether the infusion of nano-reinforcements in an epoxy layer enhances the ballistic properties of this bi-layer armor system. This bi-layered armor which was made of an alumina layer and a nano-infused epoxy layer was tested by a Fragment Simulating Projectile (FSP) method. Silica nanoparticles and multi walled carbon nanotubes (MWCNT) with a loading range of 0–1wt% were used for this purpose. Armors having the same thickness but made of only a single pure ceramic layer and a bi-layer composite made of a ceramic layer and a neat epoxy layer were also tested for comparison purposes. A gas gun with high velocity projectile was used to perform the experiment. A striking velocity of about 400m/s was used to hit the target armor plate. The striking velocity of the projectile was obtained by maintaining a breach end pressure of helium gas in the gas gun at about 500 psi. The striking velocity was chosen at a level which was well above the ballistic limits of the armor materials. A finite element analysis was also performed to evaluate the ballistic properties of the composite armor and to compare those with the experimental data. Numerical and experimental results for the residual velocity of the piercing bullets were found to be in good agreement. Details of the experimental and numerical data are presented in this paper.

Investigations on Dynamic Puncture Behaviors of Integrated Composite Reinforced with Varying Fabrics

2013 ◽  
Vol 365-366 ◽  
pp. 1070-1073 ◽  
Author(s):  
Chia Chang Lin ◽  
Ting Ting Li ◽  
Ching Wen Lou ◽  
Jan Yi Lin ◽  
Jia Horng Lin
Keyword(s):  
Performance Improvement ◽  
Cost Reduction ◽  
Body Armor ◽  
Packaging Materials ◽  
Puncture Resistance ◽  
Fabric Reinforcement ◽  
Number Of Layers ◽  
Layer Composite ◽  
Puncture Force ◽  
And Performance

The dynamic puncture resistance of multi-layer integrated composite which was comprised of glass fabric reinforcement or Kevlar fabric reinforcement and nonwovens were discussed as related to recycled Kevlar fibers amount, number of layer and K-ply position for purpose of cost reduction and performance improvement. The result shows that, 20 wt% Kevlar fibers contained in nonwovens have the optimum puncture resistance. And the dynamic puncture force increases linearly with number of layers, and also improves proportionally as increasing number of K-ply. The resultant multi-layer composite is expected to be used as body armor interlayer and packaging materials.

scholarly journals Numerical Evaluation of a Light-Gas Gun Facility for Impact Test

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
C. Rahner ◽  
H. A. Al-Qureshi ◽  
D. Stainer ◽  
D. Hotza ◽  
M. C. Fredel
Keyword(s):  
High Velocity ◽  
Numerical Evaluation ◽  
Impact Test ◽  
Experimental Tests ◽  
Reservoir Pressure ◽  
One Stage ◽  
Gas Gun ◽  
Numerical Predictions ◽  
High Velocity Impacts ◽  
Different Types

Experimental tests which match the application conditions might be used to properly evaluate materials for specific applications. High velocity impacts can be simulated using light-gas gun facilities, which come in different types and complexities. In this work different setups for a one-stage light-gas gun facility have been numerically analyzed in order to evaluate their suitability for testing materials and composites used as armor protection. A maximal barrel length of 6 m and a maximal reservoir pressure of a standard industrial gas bottle (20 MPa) were chosen as limitations. The numerical predictions show that it is not possible to accelerate the projectile directly to the desired velocity with nitrogen, helium, or hydrogen as propellant gas. When using a sabot corresponding to a higher bore diameter, the necessary velocity is achievable with helium and hydrogen gases.

Effect of Temperature, Reeling Speed and Pipe Tension on the Performance of Field Joint Coating During Reeling of Offshore Pipelines

2021 ◽  
Author(s):  
Rajaram Dhole ◽  
Ismael Ripoll ◽  
Sabesan Rajaratnam ◽  
Celine Jablonski
Keyword(s):  
Influential Factors ◽  
Influential Factor ◽  
Effect Of Temperature ◽  
Mechanical And Thermal Properties ◽  
Peak Strain ◽  
Element Analysis ◽  
Novel Approach ◽  
Laboratory Test Results ◽  
Coating Design ◽  
Highly Strained

Abstract Pipelines are coated with insulating material that minimizes heat losses to the environment. Reeled pipe can experience nominal bending strain in the order of 1% to 2%. Thick coating on the pipe is inherently more highly strained, because of concentrations that occur at the interface between parent coating and field joint coating. Occasionally, contractors who specialize in pipe-lay using the reeling method have experienced difficulties relating to unexpected disbondment and cracks in coating at these interfaces. Any disbonded coating is routinely identified and repaired, but it is important to understand the influential factors that could lead to this type of coating disbondment. It is known in the industry that parameters such as temperature, reeling speed and pipe tension are influential but the relative influence of the factors is not well understood. In addition, there is currently no industry code or recommended practice that proposes the strain levels that the coating could safely withstand prior to cracking. This paper addresses thermo-mechanical aspects of coating design and presents a novel approach to quantify which parameters have the largest influence. In the presented assessments, coating strain was assessed using finite element analysis. Material input was selected from a combination of typical values and specific laboratory test results for polypropylene (PP) and injection molded polypropylene (IMPP). An essential aspect was that the mechanical and thermal properties of the PP were related to temperature and strain rate. Strain rates in the coating during reeling operations were obtained from global FE models. Detailed local FE models incorporated all the material and load inputs and temperature conditions that are necessary to determine peak strain values in the coating; the peak strain values would indicate the locations of potential coating disbondment. The study is purely a strain assessment and excludes any potential for defects or delamination in the coating that could result from its manufacturing process. This strain-based study revealed that coating temperature during reeling is the most influential factor on strain level in the coating. Reeling speed and pipe tension are parameters providing secondary influences.

Probabilistic Finite-Element Analysis of S2-Glass Epoxy Composite Beams for Damage Initiation Due to High-Velocity Impact

2016 ◽  
Vol 2 (4) ◽  
Author(s):  
Shivdayal Patel ◽  
Suhail Ahmad ◽  
Puneet Mahajan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Velocity ◽  
Laminated Composite ◽  
Composite Plates ◽  
High Velocity Impact ◽  
Element Analysis ◽  
Fiber Failure ◽  
Velocity Impact ◽  
Damage Initiation

The safety predictions of composite armors require a probabilistic analysis to take into consideration scatters in the material properties and initial velocity. Damage initiation laws are used to account for matrix and fiber failure during high-velocity impact. A three-dimensional (3D) stochastic finite-element analysis of laminated composite plates under impact is performed to determine the probability of failure (Pf). The objective is to achieve the safest design of lightweight composite through the most efficient ply arrangement of S2 glass epoxy. Realistic damage initiation models are implemented. The Pf is obtained through the Gaussian process response surface method (GPRSM). The antisymmetric cross-ply arrangement is found to be the safest based on maximum stress and Yen and Hashin criteria simultaneously. Sensitivity analysis is performed to achieve the target reliability.

scholarly journals A Review on Numerical Analysis of RC Flat Slabs Exposed to Fire

2020 ◽  
Vol 27 (1) ◽  
pp. 1-5
Author(s):  
Hanadi Naji ◽  
Nibras Khalid ◽  
Mutaz Medhlom
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Analysis ◽  
Bending Moment ◽  
Mechanical And Thermal Properties ◽  
Vertical Deflection ◽  
Element Analysis ◽  
Flat Slabs ◽  
Numerical Studies ◽  
The Finite Element Analysis

This paper aims at presenting and discussing the numerical studies performed to estimate the mechanical and thermal behavior of RC flat slabs at elevated temperature and fire. The numerical analysis is carried out using finite element programs by developing models to simulate the performance of the buildings subjected to fire. The mechanical and thermal properties of the materials obtained from the experimental work are involved in the modeling that the outcomes will be more realistic. Many parameters related to fire resistance of the flat slabs have been studied and the finite element analysis results reveal that the width and thickness of the slab, the temperature gradient, the fire direction, the exposure duration and the thermal restraint are important factors that influence the vertical deflection, bending moment and force membrane of the flat slabs exposed to fire. However, the validation of the models is verified by comparing their results to the available experimental date. The finite element modeling contributes in saving cost and time consumed by experiments.

Preliminary Study on the High-Pressure Equation of State of Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 161-165
Author(s):  
Chu Jie Jiao ◽  
Guo Ping Jiang ◽  
Le Gao
Keyword(s):  
High Pressure ◽  
Equation Of State ◽  
High Velocity ◽  
Wave Speed ◽  
Volume Strain ◽  
Pressure Equation ◽  
Gas Gun ◽  
Shock Hugoniot ◽  
Preliminary Study ◽  
Relationship Of

The shock Hugoniot relationship of concrete was studied based on concrete test subjected to the high-velocity impacting loading by one stage gas gun. The P-U(pressure-partical speed) shock Hugoniot relationship curve of concrete was gained from the D-U(shocking wave speed-partical speed) curve of concrete, and the equation of volume pressure P and volume strain v was put forward according to the example analysis. Moreover, based on the polynomial Grьneisen equation, the parameters of high-pressure equation of state of concrete were got by fitting the test date, and the theoretical values from the equation matched well with the experimental ones.

Study on Design of Metallic Sandwish Structure and its Mechanical and Thermal Properties

2013 ◽  
Vol 461 ◽  
pp. 85-94
Author(s):  
Rui Qiao ◽  
Ce Guo ◽  
Chun Sheng Zhu ◽  
Zhen Dong Dai ◽  
Xiao Ting Jiang
Keyword(s):  
Finite Element ◽  
Compressive Force ◽  
Fem Analysis ◽  
Displacement Curve ◽  
Mechanical And Thermal Properties ◽  
Stainless Steel Sheet ◽  
Metallic Structure ◽  
Element Analysis ◽  
Static Experiment ◽  
Force Displacement

Based on the microstructure of the beetles elytras cross-section, a bio-inspired metallic structure was designed. The mechanical property and the thermal property of the structure were analyzed with finite element method, and the compressive force-displacement curve and temperature distribution the structure were obtained, respectively. At the same time, the bio-inspired metallic structure sample was made with the material of the stainless steel sheet, and the quasi-static experiment and the thermal experiment of the structure were carried out. Comparing the experimental results with the FEM analysis, the results proved both the accuracy and reliability of FEM. Key words:beetle elytra;microstructure;bio-inspired structure; finite element analysis

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