Numerical study of theanti-penetration performance of sandwich composite armor containing ceramic honeycomb structures filled with aluminum alloy

2021 ◽  
pp. 154851292199592
Author(s):  
Hongwei Zhu ◽  
Changfang Zhao
Keyword(s):  
Numerical Simulation ◽  
Aluminum Alloy ◽  
High Speed ◽  
Penetration Resistance ◽  
Sandwich Composite ◽  
Honeycomb Structures ◽  
Rigid Projectile ◽  
Composite Armor ◽  
Ceramic Honeycomb ◽  
The Impact

The aim of this work was to study the anti-penetration effect of sandwich composite armor with ceramic honeycomb structures filled with aluminum alloy under the impact of high-speed projectiles. The finite element software ABAQUS was used to conduct numerical simulation research on the process of a standard 12.7-mm projectile penetrating sandwich composite armor. The armor-piercing projectile model was simplified as a rigid body. The numerical simulation models were applied to three different sandwich composite armor structures (A, B, and C), each with a total armor thickness of 25 mm. The penetration resistance of the three kinds of composite armor was studied. We obtained velocity curves for the rigid projectile penetrating the different structures. The failure forms and penetration resistance characteristics of the three composite armor structures adopted in this paper were analyzed. In addition, the velocity reduction ratio is proposed as an index to evaluate the penetration resistance performance of the armor. The simulation results revealed decreasing rates of projectile speed in the structures A, B, and C of 69.6%, 91.1%, and 100%, respectively. The third composite armor (structure C) designed here has excellent penetration resistance and can block the penetration of a high-speed (818m/s) rigid projectile. This study can provide some reference for the application of laminated armor material in anti-penetration protection structures.

scholarly journals Numerical simulation and experimental research of cavitation nozzle based on equation curve

2021 ◽  
Author(s):  
Lifu Wang ◽  
Dongyan Shi ◽  
Zhixun Yang ◽  
Guangliang Li ◽  
Chunlong Ma ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Flow Field ◽  
High Speed ◽  
Quadratic Equation ◽  
Outer Contour ◽  
Study Results ◽  
Fluent Software ◽  
The Impact ◽  
Better Than

Abstract To further investigate and improve the cleaning ability of the cavitation nozzle, this paper proposes a new model that is based on the Helmholtz nozzle and with the quadratic equation curve as the outer contour of the cavitation chamber. First, the numerical simulation of the flow field in the nozzle chamber was conducted using FLUENT software to analyze and compare the impact of the curve parameters and Reynolds number on the cleaning effect. Next, the flow field was captured by a high-speed camera in order to study the cavitation cycle and evolution process. Then, experiments were performed to compare the cleaning effect of the new nozzle with that of the Helmholtz nozzle. The study results demonstrate that effective cavitation does not occur when the diameter of the cavitation chamber is too large. For the new nozzle, with the increase of the Reynolds number, the degree of cavitation in the chamber first increases and then decreases; the cleaning effect is much better than that of a traditional Helmholtz nozzle under the same conditions; the nozzle has the best cleaning effect for the stand-off distance of 300 mm.

Investigation and Modeling of Flag Generation in Honeycomb Sandwich Panel Machining

2018 ◽  
Author(s):  
Derek M. Yip-Hoi ◽  
David D. Gill
Keyword(s):  
Geometric Modeling ◽  
High Speed ◽  
Tool Path ◽  
Sandwich Panels ◽  
Cutting Parameters ◽  
Honeycomb Structures ◽  
Anisotropic Mechanical Properties ◽  
Honeycomb Sandwich ◽  
Low Stiffness ◽  
The Impact

Light weight honeycomb structures lend themselves to important applications in aerospace. These range from aerodynamic and structural components such as wing edges, flaps, rotor blades and engine cowlings, to aircraft interior structures such as overhead luggage bins, compartment liners, bulkheads and the monument structures found in galleys and lavatory areas. Often the honeycomb is formed into a composite ply sandwich with fiberglass face sheets bonded to the honeycomb core. These panels are cut to shape using CNC routers and specially designed cutting tools. However, the quality of the cuts generated even with these special tools leaves much to be desired. The low stiffness of the structure leads to imperfections such as fraying of the cut face sheet edges and the generation of flags along the cut honeycomb edge. These impact the ease of assembly and often require manually intensive reworking to mitigate. The cutting of honeycomb structures and sandwich panels is challenging due to low stiffness, anisotropic mechanical properties and a high proportion of interrupted cutting due to the air voids that are present. The cutting mechanics are not well understood at this time. This paper presents findings from the study of cutting of honeycomb sandwich panels using high speed videography and correlates these with results of geometric modeling of the engagement between the cutter and workpiece. The study includes the impact of the trajectory of the tool path through the cell structures on the generation of flagging. It also reports on the effects of two different cutting tool geometries and the introduction of a lead angle on the size and structure of the flags generated. These findings present the case for a research regime similar to the one completed for solid metals, into modeling the mechanics behind machining honeycomb structures. This will help manufacturers using these materials to make better choices in the tools, cutting parameters and machining strategies that they employ in their process planning.

Evaluation of the Impact Formulae for Rigid Projectile Striking on Concrete Target

2011 ◽  
Vol 368-373 ◽  
pp. 894-900 ◽  
Author(s):  
Hao Wu ◽  
Qin Fang
Keyword(s):  
Penetration Depth ◽  
Empirical Formula ◽  
High Strength Concrete ◽  
High Speed ◽  
High Strength ◽  
Local Damage ◽  
High Speed Impact ◽  
Rigid Projectile ◽  
Semi Empirical ◽  
The Impact

Based on the large amounts of field impact tests with different projectile nosed shapes, the abilities of the existing classical empirical and semi-empirical impact formulae in predicting the local damage of normal and high strength concrete targets (NSCT & HSCT) under the strike of rigid projectile were evaluated. It finds that, firstly, for the penetration depth, the Forrestal and Chen & Li semi-empirical formulae, BRL and Whiffen empirical formulae are advised for the NSCT under the impact of ogive nosed projectile; and Chen & Li semi-empirical formula and ACE empirical formulae are advised for the NSCT under the impact of special nosed projectile; the dimensionless penetration depth of NSCT increases linearly with the non-dimensional impact factor. Secondly, for the penetration depth, Chen & Li semi-empirical formula is advised for the HSCT under the mid-to-high speed impact, and the existing formulae are not applicable while the speed of the projectile was relatively low. Thirdly, for the perforation mode of the target, the BRL and Chang empirical formulae are advised for the NSCT, and the Chen semi-empirical formula, ACE and BRL empirical formulae are advised for the HSCT.

Optimum Design of Composite Armor against Transverse Impact

2011 ◽  
Vol 335-336 ◽  
pp. 101-104
Author(s):  
Jian Guang Zhang ◽  
Zhen Qiang Zhu ◽  
De Quan Ma ◽  
Rong Guo Wang ◽  
Xiao Dong He
Keyword(s):  
Optimum Design ◽  
Element Model ◽  
Epoxy Composites ◽  
Optimum Thickness ◽  
Transverse Impact ◽  
Ballistic Resistance ◽  
Two Component ◽  
Rigid Projectile ◽  
Composite Armor ◽  
The Impact

This study presents an effective methodology for the optimum design of two-component armor. The armor consists of two plates: one is boron carbide ceramic and the other is kevlar/epoxy composites. The effect of the thickness of two plates on the ballistic limit velocities of the armor was investigated by Florence model. A finite element model was created using MSC.DYTRAN to simulate the impact of a rigid projectile on the composite armor. The optimum thickness of the ceramic and composite was obtained by evaluating the ballistic resistance efficiency.

Study on the AZ31B Magnesium Alloy in the Application on High-Speed Trains

2012 ◽  
Vol 535-537 ◽  
pp. 875-879 ◽  
Author(s):  
Jia Zhen Liu ◽  
Yan Hui Zhao ◽  
Lei Song ◽  
Zhong Xia Xiang
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Magnesium Alloy ◽  
High Speed ◽  
Equivalent Stress ◽  
Strength Analysis ◽  
Az31b Magnesium Alloy ◽  
High Speed Trains ◽  
6063 Aluminum Alloy ◽  
The Impact

6063 aluminum alloys are used as the luggage rack’s material on high-speed trains recently. The study on the AZ31B magnesium alloy is aimed to demonstrate the feasibility of the magnesium alloy’s application as the material of the luggage rack on high-speed trains. First, the mechanical properties of the AZ31B magnesium was obtained after a series of experimental tests on basic mechanical properties of the AZ31B magnesium alloy. The results show that the strength of the magnesium alloy is 1.25 times of the 6063 aluminum alloy and the impact toughness of the AZ31B magnesium alloy is twice as much as the 6063 aluminum alloy. Second, the stress distribution and the maximum value of the equivalent stress in given loading conditions was obtained by finite element strength analysis on the structure of the aluminum alloy luggage rack on high-speed trains. And the FE analysis results indicate that if the AZ31B magnesium alloy is used as the material of the luggage rack instead of the 6063 aluminum alloy, it will have a weight loss of the luggage rack for approximately 33%. In addition, the application of AZ31B magnesium alloy has more advantages in energy-saving, environmental protection and safety control.

scholarly journals Field Test Research and Numerical Simulation on Aerodynamic Deloading Characteristics of V-Shaped Noise Barrier

2019 ◽  
Vol 24 (4) ◽  
pp. 764-773
Author(s):  
Ji Zhao ◽  
Ning Zhi ◽  
Lu Ming
Keyword(s):  
Numerical Simulation ◽  
Impact Strength ◽  
Field Test ◽  
High Speed ◽  
Rapid Development ◽  
Research Work ◽  
Load Shedding ◽  
Aerodynamic Load ◽  
Noise Barrier ◽  
The Impact

With the rapid development of the high-speed railway in China, the problems of the noise pollution induced by passing trains emerge. Theoretically, the V-shaped noise barrier is of pretty good performance of noise-reduction and load-shedding. To assess the practical aerodynamic deloading characteristics of the V-shaped noise barrier, a full-scale field test was carried out at three measuring-sections equipped with noise barriers of different heights. In order to quantify the research work, the impact strength and deloading rate were selected as indicators. The effects of train speeds, train types and barrier heights are studied. This study includes the variations of impact strength and deloading rate in vertical directions. Meanwhile, 2D numerical simulation research is conducted to analyze the experimental results from the angle of mechanism. It is observed that the aerodynamic load acting on the surface of the V-shaped noise barrier was weaker and more uniform compared with conventional barrier. The flow field distribution influenced the deloading characteristics of the V-shaped noise barrier significantly. Moreover, the load-shedding effect of V-shaped noise barrier, when CRH380AM passed by, was slightly better than CRH380A. The deloading rate improved with the increasing of the noise barrier height in general.

A note on the impact resistance of concrete target against rigid projectile

2018 ◽  
Vol 9 (3) ◽  
pp. 397-411 ◽  
Author(s):  
Yongchang Li ◽  
Hao Wu ◽  
Qin Fang ◽  
Yong Peng
Keyword(s):  
High Speed ◽  
Mass Density ◽  
Impact Resistance ◽  
Construction Materials ◽  
Cement Matrix ◽  
Depth Of Penetration ◽  
Coarse Aggregates ◽  
Rigid Projectile ◽  
The Impact ◽  
Concrete Target

Concrete is an inhomogeneous cementitious composite which mainly consists of the cement matrix and the random distributed coarse aggregates. As for the most widely used construction materials of the protective structures designed to withstand the intentional or accidental impact loadings caused by high-speed projectiles, the impact resistance of concrete target against the rigid projectile impact is mainly dependent on the mass, density, impact velocity, diameter, and nose shape of the projectile, as well as strength and density of the target, and hardness and size of the coarse aggregates. However, the above influential parameters are not sufficiently considered in the existing cavity expansion–based model and constant resistance model for predicting the depth of penetration of a projectile. In this article, the influences of the hardness and size of the coarse aggregates on the depth of penetration are examined through the existing experimental data, and an improved rigid projectile penetration model for concrete target is proposed and validated by 19 sets of ogive- and flat-nosed projectile penetration tests.

scholarly journals Optimizing the High-Performance Milling of Thin Aluminum Alloy Plates Using the Taguchi Method

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1526
Author(s):  
Cheng-Hsien Kuo ◽  
Zi-Yi Lin
Keyword(s):  
Surface Roughness ◽  
Aluminum Alloy ◽  
Cutting Force ◽  
High Speed ◽  
Cutting Parameters ◽  
Linear Velocity ◽  
Cutting Depth ◽  
Degree Of Deformation ◽  
High Speed Milling ◽  
The Impact

Most aerospace parts are thin walled and made of aluminum or titanium alloy that is machined to the required shape and dimensions. Deformation is a common issue. Although the reduced cutting forces used in high-speed milling generate low residual stress, the problem of deformation cannot be completely resolved. In this work, we emphasized that choosing the correct cutting parameters and machining techniques could increase the cutting performance and surface quality and reduce the deformation of thin plates. In this study, a part made of a thin 6061 aluminum alloy plate was machined by high-speed milling (HSM), and a Taguchi L16 orthogonal array was used to optimize the following parameters: linear velocity, feed per tooth, cutting depth, cutting width, and toolpath. The impact of cutting parameters on the degree of deformation, surface roughness, as well as the cutting force on the thin plate were all investigated. The results showed that the experimental parameters for the optimal degree of deformation were A1 (linear velocity 450 mm/min), B1 (feed per tooth 0.06 mm/tooth), C1 (cutting depth 0.3 mm), D4 (cutting width 70%), and E4 (rough zigzag). Feed per tooth was the most significant control factor, with a contribution as high as 63.5%. It should also be mentioned that, according to the factor response of deformation, there was a lower value of feed per tooth and less deformation. Furthermore, the feed per tooth and the cutting depth decreased and the surface roughness increased. The cutting force rose or fell with an increase or decrease of cutting depth.

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.

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