Dynamic Response of Sandwich Panels With Functionally Graded Aluminum Foam Cores Subjected to Underwater Explosion

2016 ◽  
Author(s):  
Changzai Zhang ◽  
Pan Zhang ◽  
Jun Liu ◽  
Jianqiang Pan ◽  
Yanjie Zhao ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Energy Absorption ◽  
High Efficiency ◽  
Sandwich Panels ◽  
Underwater Explosion ◽  
Functionally Graded ◽  
Face Sheet ◽  
Permanent Displacement ◽  
Bottom Face ◽  
Stretching Deformation

Numerical investigations were conducted using the MSC.Dytran software on the dynamic response of functionally graded sandwich panels when subjected to underwater explosion. The effects of the number of layers and density distribution of graded cores on the blast performance were analyzed in several aspects under the constraint of equivalent mass. The simulation results have demonstrated that sandwich panels experience both bending and large plastic stretching deformation. Compared to single layered sandwich panel, those panels with graded cores overall possess smaller central permanent displacement and better energy absorption capability. Central deflection of bottom face sheet decreases as the density of cores descends from top to bottom face. A large proportion of the energy dissipates in the plastic deformation of top face sheet by the end of response, followed by the bottom face sheet, and core compression absorbers the minimum. Utilizing the high efficiency of energy absorption by adjusting those cores with greater density near to the top face sheet can further mitigate the damage from explosion.

Numerical Investigation Into the Effect of Stand-Off Distance on the Blast Performance of Metallic Corrugated-Core Sandwich Panels

2018 ◽  
Author(s):  
Sipei Cai ◽  
Jun Liu ◽  
Yuansheng Cheng ◽  
Weiwei Hao ◽  
Pan Zhang
Keyword(s):  
Dynamic Response ◽  
Total Energy ◽  
Energy Absorption ◽  
Numerical Models ◽  
Sandwich Panels ◽  
Face Sheet ◽  
Front Face ◽  
Absorption Characteristic ◽  
Structural Dynamic ◽  
Blast Performance

The ANSYS/AUTODYN software was employed to investigate the dynamic response of the metallic sandwich panels subjected to air blast loading. The sandwich panels were composed of two face sheets and a trapezoidal corrugated-core. To validate the numerical models, the simulation results were compared with experimental data reported previously. In the simulation works, the process of shock wave propagation and the structural dynamic response were analyzed. Meanwhile, the influences of the stand-off distance between the explosive charge and the front face sheet on the fluid-structure interaction effect, dynamic response and the energy absorption of sandwich panels were investigated. Numerical results demonstrated that the impulse intensity decreased dramatically with the increase of stand-off distance. The slapping between the front face sheet and the back face sheet could be observed at the stand-off distances of 50 mm and 100 mm, while the sandwich panel exhibited the “strong core” response mode under the stand-off distance of 150 mm. Investigations into energy absorption characteristic revealed that the total energy absorption reduced with the increase of stand-off distance. The front face and corrugated-core provided the most contribution on total energy absorption. Moreover, the energy absorption proportion of corrugated-core had a positive correlation with the stand-off distance.

Ballistic impact behaviors of aluminum alloy sandwich panels with honeycomb cores: An experimental study

2016 ◽  
Vol 20 (7) ◽  
pp. 861-884 ◽  
Author(s):  
QN Zhang ◽  
XW Zhang ◽  
GX Lu ◽  
D Ruan
Keyword(s):  
Aluminum Alloy ◽  
Energy Absorption ◽  
Impact Velocity ◽  
Sandwich Panels ◽  
Sheet Thickness ◽  
Face Sheet ◽  
Ballistic Limit ◽  
Core Density ◽  
Impact Tests ◽  
Honeycomb Cores

To study the protection property of aluminum alloy sandwich panels with honeycomb cores under the attack of bullets or debris, quasi-static perforation, and ballistic impact tests were conducted, in which the thicknesses of the face sheet and core were 0.5–2.0 and 12.7 mm, respectively, while projectiles with diameter 7.5 mm and impact velocity 50–220 m/s were employed. Based on the experiments, the influences of impact velocity, face sheet thickness, core density as well as the nose shape of the projectiles were investigated. The results showed that in the impact tests, the sandwich panels dissipated much more energy than those in quasi-static perforation tests, and the energy absorption and ballistic limit of the sandwich panels increased with the increase of impact velocity. The influence of face sheet thickness was more remarkable than the core density, which was due to the relative density of honeycomb is too small. Although the increase of core density could induce the increase of energy absorption, this effect is more effective for thinner face sheet. Moreover, under the same impact velocity about 200 m/s and face sheet thickness 1.0 mm, the ballistic limit for conical-nosed projectile is highest, while it is lowest for flat-nosed projectile.

Dynamic Response of Metallic Y-Frame Core Sandwich Panels Subjected to Air Blast Loading: Numerical Investigation

2019 ◽  
Author(s):  
Ting Liu ◽  
Yuansheng Cheng ◽  
Jun Liu ◽  
Ganchao Chen ◽  
Changhai Chen ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Face Sheet ◽  
Front Face ◽  
Sandwich Plates ◽  
Air Blast ◽  
Solid Plate ◽  
Blast Performance ◽  
Air Blast Loading

Abstract In this paper, the dynamic response of metallic Y-frame core sandwich plates subjected to air blast loading was investigated by employing the LS-DYNA software. The blast wave was generated by the directly detonation of TNT explosives. The deformation/failure modes and associated structural response were identified and analyzed in detail. Main attention was paid to explore the effects of face sheet thicknesses and core web thickness on the deformation response of Y-frame core sandwich plates. A comparison on the blast performance were drawn among the Y-frame core sandwich panel, corrugated core sandwich panel and solid plate in equal areal mass. Numerical results revealed that the Y-frame core sandwich panel experienced indent deformation in the front face, strut buckling in the core and large bending deformation in the back face under the stand-off distance of 100 mm. Increasing the face sheets and core web thicknesses could improve the blast performance of Y-frame core sandwich panels. The deflections of face sheets were sensitive to the variation of front face sheet and core thicknesses. Moreover, Y-frame sandwich panel has comparable anti-blast capacity with the corrugated counterparts and exhibits superior blast resistance than the solid plate.

Contact underwater explosion response of metallic sandwich panels with different face-sheet configurations and core materials

2020 ◽  
Vol 157 ◽  
pp. 107126 ◽  
Author(s):  
Ganchao Chen ◽  
Yuansheng Cheng ◽  
Pan Zhang ◽  
Jun Liu ◽  
Changhai Chen ◽  
...  
Keyword(s):  
Sandwich Panels ◽  
Underwater Explosion ◽  
Face Sheet ◽  
Core Materials

Numerical Simulation on Response of Foam Core Sandwich Panels Subjected to Underwater Explosion

2016 ◽  
Author(s):  
Dongjie Ai ◽  
Yuansheng Cheng ◽  
Jun Liu ◽  
Jianhu Liu ◽  
Haikun Wang ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures ◽  
Near Field ◽  
Sandwich Panels ◽  
Underwater Explosion ◽  
Core Material ◽  
Design Parameters ◽  
Equal Weight ◽  
Core Height ◽  
Panel Thickness

Sandwich panel structures, which consist of two thin faces and low relative density cores, can significantly mitigate the possibilities of panel fractures. In the present paper, numerical simulations are conducted to study the deformation and fracture modes of sandwich structures under near-field underwater blasts and contact underwater blasts. Two different core materials are employed, namely aluminum foam and PVC foam. Main focus of this paper was placed to (i) study the failure mechanisms and energy absorption characteristics of sandwich structures in typical conditions, (ii) to demonstrate the benefits of such structures compared with solid plates of equal weight, and (iii) to obtain the properties of withstanding underwater explosion for single core material sandwich panels. In addition, the effects of panel thickness configuration and core height on deformation and energy absorption of the plates were explored. Results indicated that sandwich structures showed an effective reduction in the maximum panel deflection compared with a monolithic plate of same mass. The design parameters have great impacts on the results.

Numerical Study on the Response of Functionally Graded PVC Foam Core Sandwich Panels Subjected to Non-Contact Underwater Explosion

2018 ◽  
Author(s):  
Tianyu Zhou ◽  
Pan Zhang ◽  
Yuansheng Cheng ◽  
Manxia Liu ◽  
Jun Liu
Keyword(s):  
Sandwich Panel ◽  
Blast Resistance ◽  
Sandwich Panels ◽  
Underwater Explosion ◽  
Functionally Graded ◽  
Front Face ◽  
Foam Core ◽  
Compression Phase ◽  
The Core ◽  
Back Face

In this paper, the numerical model was developed by using the commercial code LS/DYNA to investigate the dynamic response of sandwich panels with three PVC foam core layers subjected to non-contact underwater explosion. The simulation results showed that the structural response of the sandwich panel could be divided into four sequential regimes: (1) interaction between the shock wave and structure, (2) compression phase of sandwich core, (3) collapse of cavitation bubbles and (4) overall bending and stretching of sandwich panel under its own inertia. Main attention of present study was placed at the blast resistance improvement by tailoring the core layer gradation under the condition of same weight expense and same blast load. Using the minimization of back face deflection as the criteria for evaluating the blast resistant of panel, the panels with core gradation of high/middle/low or middle/low/high (relative densities) from the front face to back face demonstrated the optimal resistance. Moreover, the comparative studies on the blast resistance of the functionally graded sandwich panels and equivalent ungraded ones were carried out. The optimum functionally graded sandwich panel outperformed the equivalent ungraded one for relatively small charge masses. The energy absorption characteristics as well as the core compression were also discussed. It is found that the core gradation has a negligible effect on the whole energy dissipation of panel, but would significantly affect the energy distribution among sandwich panel components and the compression value of core.

Blast resistance and energy absorption of sandwich panels with layered gradient metallic foam cores

2017 ◽  
Vol 21 (2) ◽  
pp. 464-482 ◽  
Author(s):  
Lin Jing ◽  
Longmao Zhao
Keyword(s):  
Energy Absorption ◽  
Cross Sections ◽  
Blast Resistance ◽  
Sandwich Panels ◽  
Sheet Thickness ◽  
Core Layer ◽  
Metallic Foam ◽  
Foam Core ◽  
Stress Distributions ◽  
Bottom Face

The dynamic response, blast resistance and energy absorption capability of clamped square sandwich panels comparing two aluminum alloy face-sheets and a layered gradient metallic foam core, subjected to air-blast loading, were studied numerically in this paper. Graded sandwich specimens with six different core-layer arrangements and three different face-sheet thickness arrangements were examined, respectively, compared to those ungraded sandwich panels with an equivalent nominally mass. Simulation results show that the blast resistance and energy absorption capability of sandwich panels with layered gradient metallic foam cores could be improved by optimizing the arrangements of different density metallic foam core-layers, and the graded sandwich panel with low-middle-high density core configuration has the best blast resistance capability. The blast resistance of graded sandwich panels with different thickness arrangements for top and bottom face-sheets has no obvious change tendency, since the normal stress distributions of their sandwich cross sections are controlled simultaneously by face-sheets and gradient foam core.

Experimental and numerical study of buckling behavior of foam-filled honeycomb core sandwich panels considering viscoelastic effects

2020 ◽  
pp. 109963622097516
Author(s):  
M Safarabadi ◽  
M Haghighi-Yazdi ◽  
MA Sorkhi ◽  
A Yousefi
Keyword(s):  
Energy Absorption ◽  
Viscoelastic Properties ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Face Sheet ◽  
Honeycomb Core ◽  
Buckling Behavior ◽  
Foam Filling ◽  
Foam Filled ◽  
Composite Face

Honeycomb sandwich panels are widely used in marine, aerospace, automotive and shipbuilding industries. High strength to weight and excellent energy absorption are features that make these structures unique. Foam filling the honeycomb core enhances the mechanical properties of sandwich panels considerably. In the present study, the buckling behavior of Nomex honeycomb core/glass-epoxy face sheet sandwich panel for both bare and foam-filled honeycomb core is investigated numerically and experimentally, considering the viscoelastic properties of the sandwich panel. Indeed, the viscoelastic properties of the composite face sheet and foam are determined by relaxation test and are implemented in ABAQUS using VUmat code. The finite element method is also performed using ABAQUS to model the buckling behavior of the sandwich panel incorporating both elastic and viscoelastic material behaviour. The effects of composite face sheet lay-up, core thickness, core cell size, and foam filling are also evaluated. The experimental and numerical results show that the foam increases the critical buckling load and energy absorption.

Numerical investigations on blast resistance of sandwich panels with multilayered graded hourglass lattice cores

2018 ◽  
Vol 22 (7) ◽  
pp. 2139-2156 ◽  
Author(s):  
Lihong Yang ◽  
Xiao Han ◽  
Lijia Feng ◽  
Zongbing Chen ◽  
Guocai Yu ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Energy Absorption ◽  
Blast Resistance ◽  
Three Dimensional ◽  
Sandwich Panels ◽  
Core Layer ◽  
Load Intensity ◽  
Lattice Core ◽  
Blast Loadings ◽  
Impulsive Pressure

This research focuses on the dynamic response of sandwich panels with multilayered graded hourglass lattice core subjected to blast loading. A three-layer lattice core configuration is proposed to improve the absorption efficient of kinetic energy resulted from blast shock wave. The relative density of each core layer is changed with sectional dimension of core truss members to regulate the energy absorption of each core layer. Three-dimensional numerical simulation analyses of dynamic response are carried out, and the applied impulsive pressure distribution on the surface of the panels is calculated using the CONWEP code. The panels are made of stainless steel AL6XN, which is assumed to follow bilinear strain hardening and strain rate-dependence. Peak back sheet deflection and energy absorption of core layers for four types of hourglass lattice panels are comparatively analyzed and the effects of load intensity on the peak deflection are discussed. Furthermore, the near-optimal configuration under blast loadings is proposed.

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