scholarly journals Experimental and numerical study of auxetic sandwich panels on 160 grams of PE4 blast loading

2020 ◽  
pp. 109963622096175
Author(s):  
Faizal Arifurrahman ◽  
Richard Critchley ◽  
Ian Horsfall
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Laser System ◽  
Sandwich Panels ◽  
Local Deformation ◽  
Time Profile ◽  
Polymer Foam ◽  
Mass System ◽  
Energy Absorbing ◽  
The Impact

Mines, specifically as Anti-Tank (AT) mines are a significant threat for defence vehicles. While approaches such as v-shaped hulls are currently used to deflect the blast products from such threats, such a solution is not always usable when hull standoff is limited. As such the development of a low profile, energy absorbing solution is desirable. One approach that has potential to achieve these requirements are sandwich panels. While sandwich panel cores can be constructed from various materials, one material of particular interest are auxetics. Auxetic are materials that exhibit a negative Poisson’s ratio. This material has potential to be an efficient an impact energy absorber by increasing stiffness at local deformation by gathering mass at the impact location. This study investigates the effectiveness of novel auxetic core infills alongside three other panel types (monolithic, air gap, polymer foam sandwich) against buried charges. 160 grams of PE4 were buried in 100 mm depth and 500 mm stand off the target. Laser and High Speed Video (HSV) system were used to capture the deflection-time profile and load cell sensors were used to record the loading profile received by the panels. Experimental works were compared with numerical model. Explicit model were generated in LSDYNA software as ‘initial impulse mine’ keyword. The result found that the auxetic and foam core panels were effective in reducing peak structural loading and impulse by up to 33% and 34% respectively. Air-filled panels were the most effective to reduce the deflection of the rear of the plate, however variation between capture methods (HSV and Laser system) were reported, while numerical modelling provided comparable plate deflections responses. When normalised against panel weight, the air filled panels were experimentally the most efficient per unit mass system with the auxetics being the least effective.

scholarly journals A numerical study of the impact perforation of sandwich panels with graded hollow sphere cores

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110094
Author(s):  
Ibrahim Elnasri ◽  
Han Zhao
Keyword(s):  
Boundary Conditions ◽  
Hollow Sphere ◽  
Sandwich Panel ◽  
Numerical Study ◽  
Sandwich Panels ◽  
Hopkinson Bar ◽  
Core Density ◽  
The Core ◽  
The Impact ◽  
Force Displacement

In this study, we numerically investigate the impact perforation of sandwich panels made of 0.8 mm 2024-T3 aluminum alloy skin sheets and graded polymeric hollow sphere cores with four different gradient profiles. A suitable numerical model was conducted using the LS-DYNA code, calibrated with an inverse perforation test, instrumented with a Hopkinson bar, and validated using experimental data from the literature. Moreover, the effects of quasi-static loading, landing rates, and boundary conditions on the perforation resistance of the studied graded core sandwich panels were discussed. The simulation results showed that the piercing force–displacement response of the graded core sandwich panels is affected by the core density gradient profiles. Besides, the energy absorption capability can be effectively enhanced by modifying the arrangement of the core layers with unclumping boundary conditions in the graded core sandwich panel, which is rather too hard to achieve with clumping boundary conditions.

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.

Influence of Wave Shape on the Impact of Shallow-Water Waves on Vertical Walls

2006 ◽  
Author(s):  
Claudio Zanzi ◽  
Pablo Go´mez ◽  
Julia´n Palacios ◽  
Joaqui´n Lo´pez ◽  
Julio Herna´ndez
Keyword(s):  
Shallow Water ◽  
Level Set ◽  
Water Waves ◽  
High Speed ◽  
Numerical Study ◽  
Local Level ◽  
Wave Shape ◽  
Shallow Water Waves ◽  
Vertical Walls ◽  
The Impact

A numerical study of the impact of shallow-water waves on vertical walls is presented. The air-liquid flow was simulated using a code for incompressible viscous flow, based on a local level set algorithm and a second-order approximate projection method. The level set transport and reinitialization equations were solved in a narrow band around the interface using an adaptive refined grid. The wave is assumed to be generated by a plunger which is accelerated in an open channel containing water. An arbitrary Lagrangian-Eulerian method was used to take into account the relative movement between the plunger and the end wall of the channel. The evolution of the free surface was visualized using a laser light sheet and a high-speed camera, with a sampling frequency of 1000 Hz. Several simulations were carried out to investigate the influence of the shape of the wave approaching the wall on the relevant quantities associated with the impact. The wave shape just before the impact was changed varying the total length of the channel. The results are compared with experimental results and with results obtained by other authors.

Analytical and numerical investigations on the penetration of rigid projectiles into the foam core sandwich panels with aluminum face-sheets

2017 ◽  
Vol 233 (1) ◽  
pp. 285-298
Author(s):  
A Alavi Nia ◽  
M Kazemi
Keyword(s):  
Analytical Method ◽  
High Speed ◽  
Aluminum Foam ◽  
Metal Foam ◽  
Sandwich Panels ◽  
Foam Core ◽  
Polymer Foam ◽  
High Speed Impact ◽  
Mathematical Equations ◽  
Density Ratios

The aim of this study was to evaluate the penetration of ballistic projectiles into the sandwich panels both analytically and numerically. Due to the complexity of the mathematical equations governing this phenomenon, very few analytical studies have been conducted in this area. Given the widespread use of sandwich panels consisting of metal face-sheets and metal foam core in aerospace industries, revisions are carried out on analytical method provided by Hoo Fatt et al. on polymer foam core and composite face-sheets sandwich panels. Then using the improved relations, the high speed impact of a cylindrical projectile on the sandwich panels with aluminum face-sheets and aluminum foam core with different density ratios has been discussed. Also, the penetration process is simulated and finally to evaluate the accuracy of the improved analytical method and simulations, the results are compared to the experimental data obtained from tests have been done on the panels with aluminum foam core and aluminum face-sheets. Results of the research show that the improved procedure and numerical simulations are in good agreement with the experiments.

scholarly journals A numerical study of projectile impact on thin aluminium plates

2009 ◽  
Vol 223 (11) ◽  
pp. 2519-2530 ◽  
Author(s):  
M Raguraman ◽  
A Deb ◽  
G Jagadeesh
Keyword(s):  
High Speed ◽  
Failure Modes ◽  
Numerical Study ◽  
Impact Testing ◽  
Good Prediction ◽  
Residual Velocity ◽  
Shell Elements ◽  
Simulation Based ◽  
Mesh Density ◽  
The Impact

This article deals with a simulation-based study of the impact of projectiles on thin aluminium plates using LS-DYNA by modelling plates with shell elements and projectiles with solid elements. In order to establish the required modelling criterion in terms of element size for aluminium plates, a convergence study of residual velocity has been carried out by varying mesh density in the impact zone. Using the preferred material and meshing criteria arrived at here, extremely good prediction of test residual velocities and ballistic limits given by Gupta et al. (2001) for thin aluminium plates has been obtained. The simulation-based pattern of failure with localized bulging and jagged edge of perforation is similar to the perforation with petalling seen in tests. A number of simulation-based parametric studies have been carried out and results consistent with published test data have been obtained. Despite the robust correlation achieved against published experimental results, it would be prudent to conduct one's own experiments, for a final correlation via the present modelling procedure and analysis with the explicit LS-DYNA 970 solver. Hence, a sophisticated ballistic impact testing facility and a high-speed camera have been used to conduct additional tests on grade 1100 aluminium plates of 1 mm thickness with projectiles of four different nose shapes. Finally, using the developed numerical simulation procedure, an excellent correlation of residual velocity and failure modes with the corresponding test results has been obtained.

Numerical Study on High-Speed Impact Between a Water Droplet and a Deformable Solid Surface

2012 ◽  
Author(s):  
Yongqiang Han ◽  
Yonghui Xie ◽  
Di Zhang
Keyword(s):  
Solid Surface ◽  
Water Droplet ◽  
High Speed ◽  
Numerical Study ◽  
Contact Radius ◽  
Deformable Solid ◽  
Theoretical Predictions ◽  
Steam Turbine Blade ◽  
Set Up ◽  
The Impact

In this study an axisymmetric model is set up to study the impact of a spherical water droplet with a planar deformable solid surface using the Lagrange-Euler coupling method which is based on a penalty formulation. The diameter and velocity of the droplet are 0.4 mm and 500 m/s respectively, while the solid is a kind of steam turbine blade material. The generated pressure distribution in the droplet and its variation with time, the formation of lateral jet, the deformation and stress distribution in the solid are obtained and investigated. It is shown that the compressibility of the droplet and the solid plays a significant role during the impact. The water-hammer pressure and the maximum contact edge pressure are calculated and in good agreement with the existing theoretical predictions. The calculated contact radius for shock departure is larger than that of the conventional theoretical prediction, which is analyzed and attributable to the radial motion of the liquid in the compressed region. The formation of the high-speed lateral jet is calculated and the time for the observable jetting is much later than that of the shock departure. This delay is discussed and the reason needs more research. The pressure of the contact edge region remains highest even after a considerable time of shock departure and lateral jetting. In the mean time, a saucer-shaped depression is generated in the center of the impact. The stress waves in solid move faster even before shock departure in the liquid. This causes disturbance of the solid surface before the high-speed lateral jetting and provides site for the scouring action of it, and subsequently may cause material damage and erosion.

An Experimental and Numerical Study of the Behavior of the Thin Glass Edge Under Ball Drop Impact

2013 ◽  
Author(s):  
Liang Xue ◽  
Dapeng Liu ◽  
Hohyung Lee ◽  
Da Yu ◽  
Satish Chaparala ◽  
...  
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Image Correlation ◽  
Cover Glass ◽  
Thin Glass ◽  
Impact Process ◽  
Fea Model ◽  
Plane Displacement ◽  
The Impact ◽  
Glass Edge

Glass is widely used as cover glass to protect the smartphones, tablets, PCs, and TVs from everyday wear and tear nowadays. There has been an increasing effort to understand the global behavior of glass substrate under impact, but the behavior of the edge for the thin glass has rarely been touched. In this study, the dynamic response of the glass edge when impacted with 1.75-inch steel ball from different heights (different potential energy) and different angles is studied. High-speed camera is applied for the direct visualization of the whole impact process. The Digital Image Correlation (DIC) method enables to obtain displacements (in-plane displacement and out-of-plane displacement) of the glass during the impact process. The failure mode for the edge impact is found to be predominantly buckling. The tape used in this study decreases wave propagation from the impact location. In addition, the FEA model of edge impact test is developed in ANSYS/LS-DYNA™.

Study on Vehicle Hook Buffer Mechanism Based on Sequential Image Analysis

2013 ◽  
Vol 365-366 ◽  
pp. 482-485
Author(s):  
Rui Li ◽  
Ping Xu ◽  
Yuan Mu Zhong ◽  
Long Xi Liu
Keyword(s):  
Image Analysis ◽  
Template Matching ◽  
High Speed ◽  
Feature Recognition ◽  
Energy Change ◽  
Sequential Image ◽  
Energy Absorbing ◽  
Sequential Images ◽  
Short Time ◽  
The Impact

As the impact process of train energy absorbing components occurs in a short time, high-speed cameras are used to record it and the amount of deformation and energy change of the energy absorbing components can be obtained by analyzing sequential images. The method of sequential images analysis presented is based on feature recognition of mark points by template matching method. In addition to this, error introduced by the camera positions is corrected to obtain more exact results. During the process of collision, the amount of its deformation is 52mm and its energy change is 2.69KJ when using the sequential image analysis.

Parametric Study of the Effect of Hinged Connectors on the Behavior of Origami-Inspired Structures Comprised of Sandwich Panels

2015 ◽  
Author(s):  
Zach C. Ballard ◽  
Ashley P. Thrall ◽  
Brian J. Smith
Keyword(s):  
Parametric Study ◽  
Numerical Study ◽  
Sandwich Panels ◽  
Rigid Wall ◽  
Fiber Reinforced Polymer ◽  
Structural Performance ◽  
Uniform Load ◽  
Reinforced Polymer ◽  
Relative Placement ◽  
The Impact

Origami can be a source of inspiration for rapidly deployable, rigid wall shelters. Folding panels comprised of sandwich panels will result in a lightweight, transportable design. The design of connections between panels is critical to the overall structural performance, but can pose a major design challenge. This paper investigates the implementation of hinges for connections between panels. A single panel, comprised of fiber-reinforced polymer faces and a foam core, is restrained by aluminum hinged connectors and subjected to a uniform load. An exhaustive parametric study is performed using a numerical model previously validated by experimental data. The numerical study will facilitate better understanding of the impact of the 1) number, 2) size, and 3) relative placement of connectors on panel behavior, with data comparisons focusing on the longitudinal surface strains and displacements of the panel. This investigation culminates in a set of guidelines for hinged connectors in origami-inspired structures.

Sign in / Sign up

Export Citation Format

Share Document