AN EXPERIMENTAL AND PRELIMINARY ANALYTICAL STUDY ON THE IMPULSE RESPONSE OF METALLIC SANDWICH PANELS

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1337-1342
Author(s):  
FENG ZHU ◽  
LONGMAO ZHAO ◽  
GUOXING LU ◽  
ZHIHUA WANG
Keyword(s):  
Analytical Study ◽  
Empirical Equation ◽  
Sandwich Panels ◽  
Structural Response ◽  
Systematic Investigation ◽  
Front Face ◽  
Failure Patterns ◽  
Impulsive Loads ◽  
Back Face ◽  
Quantitative Results

To investigate the structural response of sandwich panels loaded by impulsive loads, a systematic investigation has been conducted, and some experimental results are reported and discussed in this paper. Quantitative results were obtained based on the measurement in the tests by a pendulum with corresponding sensors, and then the deformation/failure patterns of front face and core were classified and analyzed systematically. Finally, an empirical equation is proposed to predict the back face deflection of the panels.

Impact Analysis of Honeycomb Core Sandwich Panels

2020 ◽  
Author(s):  
Shah Alam ◽  
Damodar Khanal
Keyword(s):  
Sandwich Panels ◽  
Sheet Thickness ◽  
Composite Panel ◽  
Face Sheet ◽  
Impact Behavior ◽  
Front Face ◽  
Geometrical Parameters ◽  
Honeycomb Core ◽  
Back Face ◽  
The Impact

Abstract The goal of this paper is to analyze the impact behavior among geometrically different sandwich panels shown upon impact velocities. Initially, composite model with aluminum honeycomb core and Kevlar (K29) face sheets is developed in ABAQUS/Explicit and different impact velocities are applied. Keeping other parameters constant, model is simulated with T800S/epoxy face sheets. Residual velocities, energy absorption (%), and maximum deformation depth is calculated for sandwich panel for both models at five different velocities by executing finite element analysis. Once the better material is found for face sheets, process is extended by varying the ratio of front face sheet thickness to back face sheet thickness keeping other geometrical parameters constant to find the better geometry. Also, comparison of impact responses of sandwich composite panel on different ratio of front face sheet thickness to back face sheet thickness is done and validated with other results available in literature.

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.

Sandwich Beams With Corrugated and Y-frame Cores: Does the Back Face Contribute to the Bending Response?

2011 ◽  
Vol 79 (1) ◽  
Author(s):  
L. St-Pierre ◽  
N. A. Fleck ◽  
V. S. Deshpande
Keyword(s):  
Three Dimensional ◽  
Sandwich Panels ◽  
Equal Mass ◽  
Front Face ◽  
Sandwich Beams ◽  
Fe Method ◽  
Plastic Buckling ◽  
Three Point Bending ◽  
Simply Supported ◽  
Back Face

Stainless steel sandwich beams with a corrugated core or a Y-frame core have been tested in three-point bending and the role of the face-sheets has been assessed by considering beams with (i) front-and-back faces present, and (ii) front face present but back face absent. A fair comparison between competing beam designs is made on an equal mass basis by doubling the front face thickness when the back face is absent. The quasi-static, three-point bending responses were measured under simply supported and clamped boundary conditions. For both end conditions and for both types of core, the sandwich beams containing front-and-back faces underwent indentation beneath the mid-span roller whereas Brazier plastic buckling was responsible for the collapse of sandwich beams absent the back face. Three-dimensional finite element (FE) predictions were in good agreement with the measured responses and gave additional insight into the deformation modes. The FE method was also used to study the effect of (i) mass distribution between core and face-sheets and (ii) beam span upon the collapse response of a simply supported sandwich panel. Sandwich panels of short span are plastically indented by the mid-span roller and the panels absent a back face are stronger than those with front-and-back faces present. In contrast, sandwich panels of long span undergo Brazier plastic buckling, and the presence of a back face strengthens the panel.

Structural Response and Energy Absorption of Sandwich Panels with an Aluminium Foam Core under Blast Loading

2008 ◽  
Vol 11 (5) ◽  
pp. 525-536 ◽  
Author(s):  
Feng Zhu ◽  
Longmao Zhao ◽  
Guoxing Lu ◽  
Zhihua Wang
Keyword(s):  
Energy Absorption ◽  
Sandwich Panels ◽  
Structural Response ◽  
Blast Loading ◽  
Aluminium Foam ◽  
Foam Core ◽  
Failure Patterns ◽  
Loading Process ◽  
Simulation And Experiment ◽  
Absorption Performance

This paper first presents an experimental investigation into the response of square sandwich panels with an aluminium foam core under blast loading, followed by a corresponding FE simulation using LS-DYNA. In the simulation, the loading process of explosive and response of the sandwich panels have been investigated. The blast loading process includes both the explosion procedure of the charge and interaction with the panel. The simulation result shows that the deformation/failure patterns observed in the tests are well captured by the numerical model, and quantitatively a reasonable agreement has been obtained between the simulation and experiment. Finally, a parametric study has been carried out to investigate the energy absorption performance of sandwich panels.

scholarly journals Buckling Behavior of FG-CNT Reinforced Composite Conical Shells Subjected to a Combined Loading

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 419 ◽  
Author(s):  
Abdullah H. Sofiyev ◽  
Francesco Tornabene ◽  
Rossana Dimitri ◽  
Nuri Kuruoglu
Keyword(s):  
Volume Fraction ◽  
Shear Deformation Theory ◽  
Structural Response ◽  
Systematic Investigation ◽  
Functionally Graded ◽  
Combined Loading ◽  
Proportional Loading ◽  
Conical Shells ◽  
Reinforced Composite ◽  
Buckling Behavior

The buckling behavior of functionally graded carbon nanotube reinforced composite conical shells (FG-CNTRC-CSs) is here investigated by means of the first order shear deformation theory (FSDT), under a combined axial/lateral or axial/hydrostatic loading condition. Two types of CNTRC-CSs are considered herein, namely, a uniform distribution or a functionally graded (FG) distribution of reinforcement, with a linear variation of the mechanical properties throughout the thickness. The basic equations of the problem are here derived and solved in a closed form, using the Galerkin procedure, to determine the critical combined loading for the selected structure. First, we check for the reliability of the proposed formulation and the accuracy of results with respect to the available literature. It follows a systematic investigation aimed at checking the sensitivity of the structural response to the geometry, the proportional loading parameter, the type of distribution, and volume fraction of CNTs.

scholarly journals Structural Response of Polyethylene Foam-Based Sandwich Panels Subjected to Edgewise Compression

Materials ◽  
2013 ◽  
Vol 6 (10) ◽  
pp. 4545-4564 ◽  
Author(s):  
Antonio Boccaccio ◽  
Caterina Casavola ◽  
Luciano Lamberti ◽  
Carmine Pappalettere
Keyword(s):  
Sandwich Panels ◽  
Structural Response

Numerical investigation on the dynamic response of foam-filled corrugated core sandwich panels subjected to air blast loading

2017 ◽  
Vol 21 (3) ◽  
pp. 838-864 ◽  
Author(s):  
Yuansheng Cheng ◽  
Tianyu Zhou ◽  
Hao Wang ◽  
Yong Li ◽  
Jun Liu ◽  
...  
Keyword(s):  
Total Energy ◽  
Energy Absorption ◽  
Sandwich Panels ◽  
Blast Loading ◽  
Front Face ◽  
Back Side ◽  
Air Blast ◽  
Foam Filled ◽  
Blast Performance ◽  
Air Blast Loading

The ANSYS/Autodyn software was employed to investigate the dynamic responses of foam-filled corrugated core sandwich panels under air blast loading. The panels were assembled from metallic face sheets and corrugated webs, and PVC foam inserts with different filling strategies. To calibrate the proposed numerical model, the simulation results were compared with experimental data reported previously. The response of the panels was also compared with that of the empty (unfilled) sandwich panels. Numerical results show that the fluid–structure interaction effect was dominated by front face regardless of the foam fillers. Foam filling would reduce the level of deformation/failure of front face, but did not always decrease the one of back face. It is found that the blast performance in terms of the plastic deflections of the face sheets can be sorted as the following sequence: fully filled hybrid panel, front side filled hybrid panel, back side filled hybrid panel, and the empty sandwich panel. Investigation into energy absorption characteristic revealed that the front face and core web provided the most contribution on total energy absorption. A reverse order of panels was obtained when the maximization of total energy dissipation was used as the criteria of blast performance.

The turning couples on an elliptic particle settling in a vertical channel

1994 ◽  
Vol 271 ◽  
pp. 1-16 ◽  
Author(s):  
Peter Y. Huang ◽  
Jimmy Feng ◽  
Daniel D. Joseph
Keyword(s):  
Shear Stress ◽  
Vortex Shedding ◽  
Stokes Equations ◽  
Vertical Channel ◽  
Navier Stokes ◽  
Front Face ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Back Face ◽  
The One

We do a direct two-dimensional finite-elment simulation of the Navier–Stokes equations and compute the forces which turn an ellipse settling in a vertical channel of viscous fluid in a regime in which the ellipse oscillates under the action of vortex shedding. Turning this way and that is induced by large and unequal values of negative pressure at the rear separation points which are here identified with the two points on the back face where the shear stress vanishes. The main restoring mechanism which turns the broadside of the ellipse perpendicular to the fall is the high pressure at the ‘stagnation point’ on the front face, as in potential flow, which is here identified with the one point on the front face where the shear stress vanishes.

The Dynamic Strength of a Representative Double Layer Prismatic Core: A Combined Experimental, Numerical, and Analytical Assessment

2010 ◽  
Vol 77 (6) ◽  
Author(s):  
Enrico Ferri ◽  
V. S. Deshpande ◽  
A. G. Evans
Keyword(s):  
Finite Element ◽  
Double Layer ◽  
Dynamic Compression ◽  
Dynamic Strength ◽  
Element Model ◽  
Free Standing ◽  
The Core ◽  
Impulsive Loads ◽  
Back Face ◽  
Out Of Plane

Dynamic out-of-plane compressive testing was used to characterize the dynamic strength of stainless steel prismatic cores with representative double layer topology to be employed in sandwich panels for blast protection. Laboratory-scaled samples of the representative core unit cell were manufactured (relative density of 5.4%) and tested at constant axial impact velocities (ranging from quasi-static to 140 ms−1). The dynamic strength was evaluated by measuring the stresses transmitted to a direct impact Hopkinson bar. Two-dimensional, plane strain, finite element calculations (with a stationary back face) were used to replicate the experimental results upon incorporating imperfections calibrated using the observed dynamic buckling modes. To infer the response of cores when included in a sandwich plate subject to blast loading, the finite element model was modified to an unsupported (free-standing) back face boundary condition. The transmitted stress is found to be modulated by the momentum acquired by the back face mass and, as the mass becomes larger, the core strength approaches that measured and simulated for stationary conditions. This finding justifies the use of a simple dynamic compression test for calibration of the dynamic strength of the core. An analytical model that accounts for the shock effects in a homogenized core and embodies a simple dual-level dynamic strength is presented and shown to capture the experimental observations and simulated results with acceptable fidelity. This model provides the basis for a constitutive model that can be used to understand the response of sandwich plates subject to impulsive loads.

Four-Point Bending of Metallic I-Core Sandwich Beams With Longitudinal Girder

2019 ◽  
Author(s):  
Wenwei Hu ◽  
Jun Liu ◽  
Pan Zhang ◽  
Yuansheng Cheng
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Numerical Model ◽  
Sandwich Structure ◽  
Front Face ◽  
Beam Structure ◽  
Hull Structure ◽  
Bending Load ◽  
Back Face ◽  
Bending Loads

Abstract I-core sandwich structure has great potential in the application of hull structure construction due to its high specific strength and relatively simple manufacturing process. The topic on the study of mechanical properties of I-core sandwich structure under bending loads is of interest to structural designers since the structure is often subjected to bending loads in engineering applications. In this paper, a metallic I-core sandwich beam with longitudinal girder was designed and manufactured using laser welding technique, and finally tested under four-point bend loading. The elastic-plastic behaviors and the ultimate load carrying capacity of this novel beam structure were obtained. A numerical model was developed to investigate the mechanical properties of this novel beam structure by finite element method. The results of the numerical model were compared with experimental data. Stress components of the front face and back face in the failure process were analyzed and discussed to investigate the failure of them. Results showed that the huge local bending stresses of plate caused the failure of the front face and back face. Finally, an improved scheme for the test was proposed to provide a pure bending load, which was proved by finite element simulation. All the findings aim to guide the engineering application of this structure.

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