Failure mechanism of geopolymer composite lightweight sandwich panel under flexural and edgewise compressive loads

Test and study of aluminum alloy helicopter deck under static load were carried out. The deck is made of aluminum alloy sandwich panel. In the experiment, the deflection and stress of deck are measured under different static load conditions. Load conditions are determined by the conditions that helicopter berths at the deck. When helicopter berths at the deck, the deck endures vertical compressive loads on the deck surface and diagonal tension loads on the tie-down rod which is used to fasten the helicopter. According to the test results under different load conditions, the characteristic behavior and ultimate load carrying capacity were analyzed. Based on experimental results, FEM simulation was made. The results of FEM analysis was agreed with the test results very well. It is shown that the helicopter deck which is composed of aluminum alloy sandwich panel has good mechanical performance.

Download Full-text

Analysis of the Failure Mechanism of the Sandwich Panel at the Supports

Procedia Engineering ◽

10.1016/j.proeng.2017.02.213 ◽

2017 ◽

Vol 177 ◽

pp. 168-174 ◽

Cited By ~ 5

Author(s):

Jolanta Pozorska ◽

Zbigniew Pozorski

Keyword(s):

Failure Mechanism ◽

Sandwich Panel

Download Full-text

Geometrical nonlinear thermal response of sandwich panels with temperature dependent mechanical properties—Extended high-order approach

Journal of Sandwich Structures & Materials ◽

10.1177/1099636218820703 ◽

2019 ◽

Vol 21 (5) ◽

pp. 1700-1725 ◽

Cited By ~ 1

Author(s):

Yeoshua Frostig ◽

George Kardomateas

Keyword(s):

Mechanical Properties ◽

Sandwich Panel ◽

Mechanical Response ◽

Numerical Study ◽

Thermal Response ◽

High Order ◽

Theory Approach ◽

Temperature Dependent ◽

The Core ◽

Compressive Loads

The thermal and the thermo-mechanical responses of a sandwich panel with a compliant core are investigated within the framework of the extended high-order approach where the core properties are temperature dependent or independent. Loads schemes include thermal field within temperature working range simultaneous with in-plane compressive loads applied to the core only and to the face sheets and core in the form of the uniform end—shortening of edge of panel. The mathematical formulations use the extended high-order sandwich panel theory approach that takes into account the in-plane rigidity of the core and uses the deformation patterns of the high-order sandwich panel theory. The linear and nonlinear field equations along with the appropriate boundary conditions are presented. A numerical study is conducted, and it investigates the thermal response with temperature independent and temperature dependent mechanical properties of the core as well as the thermo-mechanical response due to in-plane compressive loads. The results include displacements, stress resultants, and stress at critical locations along the panel as well as equilibria curves. They reveal that, in general, the panel with temperature independent properties response remains almost linear while with temperature dependent ones it takes a general nonlinear response. The addition of an external mechanical load changes the response from a linear/nonlinear one that may be allowable stress controlled to a case where loss of stability occurs.

Download Full-text

Experimental and numerical investigation on bending and compressive behavior of carbon-epoxy sandwich panel with novel M-shaped core

Journal of Thermoplastic Composite Materials ◽

10.1177/08927057211046653 ◽

2022 ◽

pp. 089270572110466

Author(s):

Himan Khaledi ◽

Yasser Rostamiyan

Keyword(s):

Polyurethane Foam ◽

Sandwich Panel ◽

Sandwich Panels ◽

Bending Tests ◽

Three Point Bending ◽

Composite Sandwich ◽

Compressive Loads ◽

Lattice Core ◽

Force Displacement ◽

Good Agreement

Present paper has experimentally and numerically investigated the mechanical behavior of composite sandwich panel with novel M-shaped lattice core subjected to three-point bending and compressive loads. For this purpose, a composite sandwich panel with M-shaped core made of carbon fiber has been fabricated in this experiment. In order to fabricate the sandwich panels, the vacuum assisted resin transfer molding (VARTM) has been used to achieve a laminate without any fault. Afterward, polyurethane foam with density of 80 kg/m3 has been injected into the core of the sandwich panel. Then, a unique design was presented to sandwich panel cores. The study of force-displacement curves obtained from sandwich panel compression and three-point bending tests, showed that an optimum mechanical strength with a considerable lightweight. It should be noted that the experimental data was compared to numerical simulation in ABAQUS software. According to the results, polyurethane foam has improved the flexural strength of sandwich panels by 14% while this improvement for compressive strength is equal to 23%. As well as, it turned out that numerical results are in good agreement with experimental ones and make it possible to use simulation instead of time-consuming experimental procedures for design and analysis.

Download Full-text

Improvement of Poisson’s Ratio using Carbon Nanotubes Reinforcement for Laminated Sandwich Plate

International Journal of Vehicle Structures and Systems ◽

10.4273/ijvss.11.1.14 ◽

2019 ◽

Vol 11 (1) ◽

Author(s):

M. Senbagan ◽

R. Sarathkumar ◽

D. Dominic Xavier ◽

S. Seralathan ◽

V. Hariram

Keyword(s):

Carbon Nanotubes ◽

Poisson’S Ratio ◽

Longitudinal Strain ◽

Sandwich Panel ◽

Sandwich Plate ◽

Relative Difference ◽

Poisson's Ratio ◽

Face Sheet ◽

Lateral Strain ◽

Compressive Loads

The focus of this study is to improve the material properties like Poisson's ratio and flexural strength of a sandwich plate by adding carbon nanotubes. A comparative analysis is carried out between sandwich plate with and without addition of carbon nanotubes. Nastran / Patran are the main tools used for this analysis. The experimental work focuses on the behaviour of the sandwich plate while applying tensile and compressive loads. The reduction of displacement in orthogonal sides under compressive stress and tensile stress are observed for carbon nanotubes enriched sandwich plate. This is due to increased face sheet relative difference of lateral strain with longitudinal strain. It is also observed that the mechanical properties of carbon nanotubes enriched sandwich plate are enhanced in comparison to sandwich plate without carbon nanotubes. It is found that, for feasible applications, the sandwich plate enhanced with carbon nanotubes, possess greater face sheet relative difference of lateral strain with longitudinal strain. It is concluded that the Poisson’s ratio for the sandwich panel enriched with carbon nanotubes is advantageous than sandwich panel without carbon nanotubes.

Download Full-text

Experimental study on the low-velocity impact failure mechanism of foam core sandwich panels with shape memory alloy hybrid face-sheets

Science and Engineering of Composite Materials ◽

10.1515/secm-2021-0059 ◽

2021 ◽

Vol 28 (1) ◽

pp. 592-604

Author(s):

Hao Li ◽

Cong Jiang ◽

Ye Wu ◽

Yonghu Huang ◽

Yun Wan ◽

...

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Failure Mechanism ◽

Sandwich Panel ◽

Sandwich Panels ◽

Foam Core ◽

Rear Face ◽

Impact Failure ◽

Impact Performance ◽

The Impact

Abstract Superelastic shape memory alloy (SMA) as an advanced smart material has been used to improve the impact performance of fiber-reinforced composites in recent decades. Due to the low impact toughness of the thin composite face-sheet and the poor strength of the foam core, sandwich panels are sensitive to the transverse loading. SMA fibers were embedded into the composite laminated to improve the impact resistance of the traditional foam core sandwich panel in this work. Five new types of SMA hybrid panels were prepared, and the testing panels with penetration failure were observed at the impact energy of 50 J. The impact mechanical responses and the damage morphology were analyzed, and the impact failure mechanism was also revealed. Results show that all sandwich panels were failed, the fiber breakage occurred at the impact region in the traditional panels, while part plies of the rear face-sheets split-off in the SMA hybrid panels. The impact performance of the SMA hybrid panels is improved when compared with the traditional panel, the reduction of the delamination area by 48.15% and the increase of the load-bearing threshold by 32.75% are acquired for the hybrid sandwich panel with two layers of SMA fibers in the rear face-sheet.

Download Full-text

On the role of tin underlays for the prevention of thermal grooving in thin gold films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100145030 ◽

1986 ◽

Vol 44 ◽

pp. 732-733

Author(s):

Jin Young Kim ◽

R. E. Hummel ◽

R. T. DeHoff

Keyword(s):

Thin Film ◽

Free Surface ◽

Grain Boundary ◽

Beneficial Effect ◽

Failure Mechanism ◽

Failure Mechanisms ◽

Distinct Advantage ◽

Gold Films ◽

Gold Thin Film

Gold thin film metallizations in microelectronic circuits have a distinct advantage over those consisting of aluminum because they are less susceptible to electromigration. When electromigration is no longer the principal failure mechanism, other failure mechanisms caused by d.c. stressing might become important. In gold thin-film metallizations, grain boundary grooving is the principal failure mechanism.Previous studies have shown that grain boundary grooving in gold films can be prevented by an indium underlay between the substrate and gold. The beneficial effect of the In/Au composite film is mainly due to roughening of the surface of the gold films, redistribution of indium on the gold films and formation of In2O3 on the free surface and along the grain boundaries of the gold films during air annealing.

Download Full-text