scholarly journals Strength of Sandwich Panel ‘Cut and Fold’ Joints

2003 ◽  
Vol 12 (6) ◽  
pp. 096369350301200 ◽  
Author(s):  
N. Joulia ◽  
S.M. Grove
Keyword(s):  
Joint Strength ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
The Core ◽  
Honeycomb Sandwich ◽  
Strength And Stiffness ◽  
The Way

Right-angle ‘cut and fold’ joints in aluminium-honeycomb sandwich panels have been tested for strength and stiffness. The results indicate that joint strength increases with adhesive content, and that simple modifications to the way in which the core is cut can result in significantly higher strengths

scholarly journals Transverse fastening reinforcement of sandwich panels with upcycled bottle caps core

2020 ◽  
pp. 002199832096052
Author(s):  
PR Oliveira ◽  
LJ da Silva ◽  
TH Panzera ◽  
GG del Pino ◽  
F Scarpa
Keyword(s):  
Shear Modulus ◽  
Mechanical Strength ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Transverse Reinforcement ◽  
Moderate Increase ◽  
Remarkable Improvement ◽  
The Core ◽  
Panel Stiffness ◽  
Strength And Stiffness

This work describes the use of transverse reinforcement in eco-friendly sandwich panels made from aluminium skins and a core of upcycled bottle caps. The Design of Experiments technique identifies the effect of the position of the metal rivets on the panel. The results show a moderate increase in strength and a significant enhancement of the sandwich panel stiffness when the rivets are placed on the upper skin, with a remarkable improvement in terms of the core shear modulus. The use of metal rivets has also increased the specific mechanical strength and stiffness of the panels, which highlights the effectiveness of the transverse reinforcement in bottle caps panels.

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.

Shear-Lag Effect in Sandwich Panels With Stiffeners Under Three-Point Bending

1980 ◽  
Vol 47 (2) ◽  
pp. 383-388 ◽  
Author(s):  
K. Kemmochi ◽  
T. Akasaka ◽  
R. Hayashi ◽  
K. Ishiwata
Keyword(s):  
Strain Distribution ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Bending Rigidity ◽  
Shear Lag ◽  
Shear Lag Effect ◽  
Three Point Bending ◽  
The Core ◽  
Lag Effect ◽  
Modified Theory

In this paper, a modified theory based upon Reissner’s procedure for the shear-lag effect of the sandwich panel is presented, which includes the effects of the anisotropy of the faces and the shearing rigidity of the core. In order to verify this theory, bending experiments were performed with sandwich panels composed of a soft core, stiffeners, and orthotropic faces. It was found that the effective bending rigidity calculated from this theory was lower than that derived from the classical bending theory and that the theoretical strain distribution on the faces agreed well with the experimental results.

scholarly journals Impact perforation of sandwich panels with graded hollow sphere cores: Numerical and Analytical investigations

2021 ◽  
Vol 250 ◽  
pp. 02027
Author(s):  
Ibrahim Elnasri
Keyword(s):  
Boundary Conditions ◽  
Hollow Sphere ◽  
Sandwich Panel ◽  
Peak Load ◽  
Sandwich Panels ◽  
Core Density ◽  
Plateau Stress ◽  
The Core ◽  
The Impact ◽  
Force Displacement

In this study, we numerically and analytically 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 effect of boundary conditions on the perforation resistance of the studied graded core sandwich panels was 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 un-clumping boundary conditions in the graded core sandwich panel, which is rather too hard to achieve with clumping boundary conditions. Finally, an analytical model, taken account only gradient in the quasi-static plateau stress, is developed to predict the top skin pic peak load of the graded sandwich panel.

scholarly journals Comparative study of dynamically equivalent modeling methods for honeycomb sandwich structure: numerical simulations and experiments

2020 ◽  
Vol 11 (2) ◽  
pp. 317-328
Author(s):  
Ning Guo ◽  
Hao Chen ◽  
Zhong Zhang ◽  
Fei Du ◽  
Chao Xu
Keyword(s):  
Numerical Simulations ◽  
Sandwich Panel ◽  
Plate Theory ◽  
Sandwich Panels ◽  
Single Layer ◽  
Design Parameters ◽  
Modeling Methods ◽  
Honeycomb Sandwich ◽  
Equivalent Method ◽  
Honeycomb Sandwich Structure

Abstract. The structure of the lightweight honeycomb sandwich panel is complex. Thus, establishing an equivalent simplified model is indispensable to improve the efficiency of the dynamic analysis of honeycomb sandwich panels. In this paper, three commonly used dynamically equivalent modeling methods for honeycomb sandwich panel are studied: a dynamically equivalent method based on laminated plate theory, a single-layer plate equivalent method based on the theory of Hoff (1948), and an improved equivalent method based on Allen (1969). Using theoretical study, numerical simulations, and experiments, the applicability of these equivalent methods and the effect of design parameters on the dynamic characteristics are studied, and the optimal dynamically equivalent method for honeycomb sandwich panels is obtained.

scholarly journals High Temperature Mechanical Properties of a Vented Ti-6Al-4V Honeycomb Sandwich Panel

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3008
Author(s):  
Lei Shang ◽  
Ye Wu ◽  
Yuchao Fang ◽  
Yao Li
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Cell Walls ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Honeycomb Core ◽  
Compression Performance ◽  
High Temperature Mechanical Properties ◽  
Honeycomb Sandwich ◽  
The Face

For aerospace applications, honeycomb sandwich panels may have small perforations on the cell walls of the honeycomb core to equilibrate the internal core pressure with external gas pressure, which prevent face-sheet/core debonding due to pressure build-up at high temperature. We propose a new form of perforation on the cell walls of honeycomb sandwich panels to reduce the influence of the perforations on the cell walls on the mechanical properties. In this paper, the high temperature mechanical properties of a new vented Ti-6Al-4V honeycomb sandwich panel were investigated. A vented Ti-6AL-4V honeycomb sandwich panel with 35Ti-35Zr-15Cu-15Ni as the filler alloy was manufactured by high-temperature brazing. The element distribution of the brazed joints was examined by means of SEM (scanning electron microscopy) and EDS (energy-dispersive spectroscopy) analyses. Compared to the interaction between the face-sheets and the brazing filler, the diffusion and reaction between the honeycomb core and the brazing filler were stronger. The flatwise compression and flexural mechanical properties of the vented honeycomb sandwich panels were investigated at 20, 160, 300, and 440 °C, respectively. The flatwise compression strength, elastic modulus, and the flexural strength of the vented honeycomb sandwich panels decreased with the increase of temperature. Moreover, the flexural strength of the L-direction sandwich panels was larger than that of the W-direction sandwich panels at the same temperature. More importantly, the vented honeycomb sandwich panels exhibited good compression performance similar to the unvented honeycomb sandwich panels, and the open holes on the cell walls have no negative effect on the compression performance of the honeycomb sandwich panels in these conditions. The damage morphology observed by SEM revealed that the face-sheets and the brazing zone show ductile and brittle fracture behaviors, respectively.

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.

Selection of Fitting Models of the Moisture Content for Paper Honeycomb Sandwich Panel

2012 ◽  
Vol 200 ◽  
pp. 58-61
Author(s):  
Dong Mei Wang
Keyword(s):  
Experimental Data ◽  
Moisture Content ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Influence Of Temperature ◽  
Honeycomb Sandwich ◽  
Best Fitting ◽  
Paper Honeycomb ◽  
Fitting Model ◽  
Selection Of

The influence of temperature and relative humidity on the moisture content of paper honeycomb sandwich panels was studied. The moisture content of paper honeycomb sandwich panels was fitted by three mathematical models. The fitting results were evaluated by experimental data, and the best fitting model and its parameters were determined. The results indicate that in three models, the GAB (Guggenheim, Anderson and De Boer) model is the best suited to predict the moisture content of paper honeycomb sandwich panels in different temperature and humidity conditions.

Bending Vibration Analysis of Thick Honeycomb Sandwich Panel

2012 ◽  
Vol 229-231 ◽  
pp. 369-372 ◽  
Author(s):  
Wei Dong Shen ◽  
Sheng Chun Wang ◽  
Jian Li Wang ◽  
Jia Feng Xu ◽  
Si Hong Song
Keyword(s):  
Sandwich Panel ◽  
Differential Operators ◽  
Natural Frequencies ◽  
Equations Of Motion ◽  
Sandwich Panels ◽  
Sheet Thickness ◽  
Single Equation ◽  
Displacement Function ◽  
Bending Vibration ◽  
Honeycomb Sandwich

A simple approach to reduce the governing equations for thick honeycomb sandwich panels to a single equation containing only one displacement function is proposed in this article. The variational equations of motion are derived using Hamilton’s principle and by introducing differential operators. The exact solution of the natural frequencies for rectangular honeycomb sandwich panels with all edges simply-supported is obtained and leading to a satisfied agreement with theoretical results. The influence of the ratio of core thickness to face sheet thickness and aspect ratio on the natural frequencies is studied. The analysis results demonstrate that the presence of inertia of rotation will decrease natural frequencies, and the aspect ration changes not only the value of natural frequencies of the sandwich panel but also the mode order.

scholarly journals Numerical modelling of sandwich panels with a non-continuous soft core

2018 ◽  
Vol 157 ◽  
pp. 06007
Author(s):  
Jolanta Pozorska
Keyword(s):  
Numerical Modelling ◽  
Static Analysis ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Soft Core ◽  
Structural Behavior ◽  
Progressive Damage ◽  
Local Instability ◽  
Unilateral Constraints ◽  
The Core

The paper presents the problem of static analysis of sandwich structures with a non-continuous soft core. In the numerical 3D FE models, the core is divided into separated parts. The contact between these parts has the form of unilateral constraints. The model also allows for local debonding of the facing and local imperfections of sandwich panel geometry. Particular attention is paid to the problem of local instability of the facing that is compressed during bending. The phenomenon of progressive damage and the influence of non-continuity of the core on the structural behavior of the sandwich panel is also discussed.

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