Bending analysis of honeycomb sandwich panels with metallic face sheets and GFRP core

In this paper, a novel multiscale and multi-stage structural design optimization procedure is developed for the weight minimization of hopper cars. The procedure is tested under various loading conditions according to guidelines established by regulatory bodies, as well as a novel load case that considers fluid-structure interaction by means of explicit finite elements employing Smoothed Particle Hydrodynamics. The first stage in the design procedure involves topology optimization whereby optimal beam locations are determined within the design space of the hopper car wall structure. This is followed by cross-sectional sizing of the frame to concentrate mass in critical regions of the hopper car. In the second stage, hexagonal honeycomb sandwich panels are considered in lower load regions, and are optimized by means of Multiscale Design Optimization (MSDO). The MSDO drew upon the Kreisselmeier–Steinhausser equations to calculate a penalized cost function for the mass and compliance of a hopper car Finite Element Model (FEM) at the mesoscale. For each iteration in the MSDO, the FEM was updated with homogenized sandwich composite properties according to four design variables of interest at the microscale. A cost penalty is summed with the base cost by comparing results of the FEM with the imposed constraints. Efficacy of the novel design methodology is compared according to a baseline design employing conventional materials. By invoking the proposed methodology in a case study, it is demonstrated that a mass savings as high as 16.36% can be yielded for a single hopper car, which translates into a reduction in greenhouse gas emissions of 13.09% per car based on available literature.

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The Bending Responses of Sandwich Panels with Aluminium Honeycomb Core and CFRP Skins Used in Electric Vehicle Body

Advances in Materials Science and Engineering ◽

10.1155/2018/5750607 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 5

Author(s):

Yong Xiao ◽

Yefa Hu ◽

Jinguang Zhang ◽

Chunsheng Song ◽

Xiangyang Huang ◽

...

Keyword(s):

Electric Vehicle ◽

Failure Modes ◽

Sandwich Panels ◽

Vehicle Body ◽

Stacking Sequence ◽

Honeycomb Core ◽

Fibre Direction ◽

Element Analysis ◽

Honeycomb Sandwich ◽

Carbon Fibre Reinforced Plastic

The aim of this paper was to investigate bending responses of sandwich panels with aluminium honeycomb core and carbon fibre-reinforced plastic (CFRP) skins used in electric vehicle body subjected to quasistatic bending. The typical load-displacement curves, failure modes, and energy absorption are studied. The effects of fibre direction, stacking sequence, layer thickness, and loading velocity on the crashworthiness characteristics are discussed. The finite element analysis (FEA) results are compared with experimental measurements. It is observed that there are good agreements between the FEA and experimental results. Numerical simulations and experiment predict that the honeycomb sandwich panels with ±30° and ±45° fibre direction, asymmetrical stacking sequence (45°/−45°/45°/−45°), thicker panels (0.2 mm∼0.4 mm), and smaller loading velocity (5 mm/min∼30 mm/min) have better crashworthiness performance. The FEA prediction is also helpful in understanding the initiation and propagation of cracks within the honeycomb sandwich panels.

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Single and double-layer honeycomb sandwich panels under impact loading

International Journal of Impact Engineering ◽

10.1016/j.ijimpeng.2018.07.013 ◽

2018 ◽

Vol 121 ◽

pp. 77-90 ◽

Cited By ~ 16

Author(s):

Giulia Palomba ◽

Gabriella Epasto ◽

Vincenzo Crupi ◽

Eugenio Guglielmino

Keyword(s):

Double Layer ◽

Impact Loading ◽

Sandwich Panels ◽

Honeycomb Sandwich

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Structural Performance of Fiber-Reinforced Polymer Honeycomb Sandwich Panels: Evaluation of Size Effect and Wrap Strengthening

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1845-21 ◽

2003 ◽

Vol 1845 (1) ◽

pp. 191-199 ◽

Cited By ~ 3

Author(s):

Ondrej Kalny ◽

Robert J. Peterman ◽

Guillermo Ramirez ◽

C. S. Cai ◽

Dave Meggers

Keyword(s):

Carrying Capacity ◽

Ultimate Load ◽

Sandwich Panels ◽

Fiber Reinforced Polymer ◽

Load Carrying Capacity ◽

Flexural Capacity ◽

Reinforced Polymer ◽

Load Carrying ◽

Honeycomb Sandwich ◽

Ultimate Load Carrying Capacity

Stiffness and ultimate load-carrying capacities of glass fiber-reinforced polymer honeycomb sandwich panels used in bridge applications were evaluated. Eleven full-scale panels with cross-section depths ranging from 6 to 31.5 in. (152 to 800 mm) have been tested to date. The effect of width-to-depth ratio on unit stiffness was found to be insignificant for panels with a width-to-depth ratio between 1 and 5. The effect of this ratio on the ultimate flexural capacity is uncertain because of the erratic nature of core-face bond failures. A simple analytical formula for bending and shear stiffness, based on material properties and geometry of transformed sections, was found to predict service-load deflections within 15% accuracy. Although some factors influencing the ultimate load-carrying capacity were clearly identified in this study, a reliable analytical prediction of the ultimate flexural capacity was not attained. This is because failures occur in the bond material between the outer faces and core, and there are significant variations in bond properties at this point due to the wet lay-up process, even for theoretically identical specimens. The use of external wrap layers may be used to shift the ultimate point of failure from the bond (resin) material to the glass fibers. Wrap serves to strengthen the relatively weak core–face interface and is believed to bring more consistency in determining the ultimate load-carrying capacity.

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Failure mode maps for honeycomb sandwich panels

Composite Structures ◽

10.1016/s0263-8223(98)00123-8 ◽

1999 ◽

Vol 44 (4) ◽

pp. 237-252 ◽

Cited By ~ 122

Author(s):

A. Petras ◽

M.P.F. Sutcliffe

Keyword(s):

Failure Mode ◽

Sandwich Panels ◽

Honeycomb Sandwich

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Ballistic Resistance of Honeycomb Sandwich Panels under In-Plane High-Velocity Impact

The Scientific World JOURNAL ◽

10.1155/2013/892781 ◽

2013 ◽

Vol 2013 ◽

pp. 1-20 ◽

Cited By ~ 23

Author(s):

Chang Qi ◽

Shu Yang ◽

Dong Wang ◽

Li-Jun Yang

Keyword(s):

Structural Parameters ◽

Sandwich Panels ◽

Unit Cell ◽

Dynamic Responses ◽

Honeycomb Core ◽

Ballistic Resistance ◽

Honeycomb Sandwich ◽

Aluminum Honeycomb ◽

Parametric Studies ◽

Nonmonotonic Effects

The dynamic responses of honeycomb sandwich panels (HSPs) subjected to in-plane projectile impact were studied by means of explicit nonlinear finite element simulations using LS-DYNA. The HSPs consisted of two identical aluminum alloy face-sheets and an aluminum honeycomb core featuring three types of unit cell configurations (regular, rectangular-shaped, and reentrant hexagons). The ballistic resistances of HSPs with the three core configurations were first analyzed. It was found that the HSP with the reentrant auxetic honeycomb core has the best ballistic resistance, due to the negative Poisson’s ratio effect of the core. Parametric studies were then carried out to clarify the influences of both macroscopic (face-sheet and core thicknesses, core relative density) and mesoscopic (unit cell angle and size) parameters on the ballistic responses of the auxetic HSPs. Numerical results show that the perforation resistant capabilities of the auxetic HSPs increase as the values of the macroscopic parameters increase. However, the mesoscopic parameters show nonmonotonic effects on the panels' ballistic capacities. The empirical equations for projectile residual velocities were formulated in terms of impact velocity and the structural parameters. It was also found that the blunter projectiles result in higher ballistic limits of the auxetic HSPs.

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Mechanical performance of polyester pin-reinforced foam filled honeycomb sandwich panels

Science and Engineering of Composite Materials ◽

10.1515/secm-2017-0039 ◽

2018 ◽

Vol 25 (4) ◽

pp. 797-805 ◽

Cited By ~ 4

Author(s):

R.S. Jayaram ◽

V.A. Nagarajan ◽

K.P. Vinod Kumar

Keyword(s):

Mechanical Properties ◽

Mechanical Performance ◽

Flexural Rigidity ◽

Sandwich Panels ◽

Interfacial Strength ◽

Structural Performance ◽

Experimental Investigations ◽

Honeycomb Sandwich ◽

Foam Filled ◽

Pin Reinforcement

Abstract Honeycomb sandwich panels entice continuously enhanced attention due to its excellent mechanical properties and multi-functional applications. However, the principal problem of sandwich panels is failure by face/core debond. Novel lightweight sandwich panels with hybrid core made of honeycomb, foam and through-thickness pin was developed. Reinforcing polyester pins between faces and core is an effectual way to strengthen the core and enhance the interfacial strength between the face/core to improve the structural performance of sandwich panels. To provide feasibility for pin reinforcement, honeycomb core was pre-filled with foam. Mechanical properties enhancement due to polyester pinning were investigated experimentally under flatwise compression, edgewise compression and flexural test. The experimental investigations were carried out for both “foam filled honeycomb sandwich panels” (FHS) and “polyester pin-reinforced foam filled honeycomb sandwich panels” (PFHS). The results show that polyester pin reinforcement in foam filled honeycomb sandwich panel enhanced the flatwise, edgewise compression and flexural properties considerably. Moreover, increasing the pin diameter has a larger effect on the flexural rigidity of PFHS panels. PFHS panels have inconsequential increase in weight but appreciably improved their structural performance.

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