scholarly journals Mechanical performance of marine sandwich composites subjected to flatwise compression and flexural loading: Effect of resin pins

2018 ◽  
Vol 22 (6) ◽  
pp. 2030-2048 ◽  
Author(s):  
F Balıkoğlu ◽  
TK Demircioğlu ◽  
M Yıldız ◽  
N Arslan ◽  
A Ataş
Keyword(s):  
Vinyl Ester ◽  
Failure Load ◽  
Mechanical Performance ◽  
Sandwich Panels ◽  
Foam Core ◽  
Compression Stress ◽  
Three Point Bending ◽  
Poly Vinyl Chloride ◽  
Circular Holes ◽  
Core Thickness

Mechanical performance of marine sandwich panels comprising E-glass/vinyl ester face sheets and perforated poly-vinyl chloride foam core was evaluated and compared with conventional foam core sandwich panels. Circular holes through the foam core thickness were drilled with 12 different arrangements in square patterns and the holes were filled with the resin during the infusion process which created the through-the-thickness solid resin pins. The effect of each pattern on the flatwise compression and core shear properties of the sandwich panels were experimentally investigated. The three-point bending maximum failure load of perforated foam core sandwich panels was increased over 133.8% by increasing the diameter of the resin pins at the expense of increased panel weight up to 67%. The flatwise compression stress to induce core crushing was significantly increased by reinforcing the resin pins.

STRUCTURAL RESPONSE OF ALUMINIUM FOAM HYBRID SANDWICH PANELS UNDER THREE-POINT BENDING LOADING

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1733-1738 ◽  
Author(s):  
KAVEH R. KABIR ◽  
TANIA VODENITCHAROVA ◽  
MARK HOFFMAN
Keyword(s):  
Failure Modes ◽  
Bending Strength ◽  
Sandwich Panels ◽  
Structural Response ◽  
Foam Core ◽  
Three Point Bending ◽  
Closed Cell ◽  
Core Thickness ◽  
Bending Loading ◽  
Foam Thickness

The present study focuses on the structural response of sandwich panels consisting of a commercial closed-cell foam core and thin aluminium sheet skins under static three-point bending loading. Panels of different thicknesses and span lengths were tested, and the influence of the foam density, core thickness and skin type on the response was revealed. The failure modes in bending were greatly dependent on the span length but independent on the foam thickness. For short spans, the deformed shape at failure was asymmetric, as opposed to a symmetric mode for long spans. The density and thickness of the foam core, the presence of reinforcing face sheets and the beam span determined the failure load and bending strength of the sandwich panels.

Static and dynamic response of sandwich beams with lattice and pantographic cores

2021 ◽  
pp. 109963622110338
Author(s):  
Yury Solyaev ◽  
Arseniy Babaytsev ◽  
Anastasia Ustenko ◽  
Andrey Ripetskiy ◽  
Alexander Volkov
Keyword(s):  
Mechanical Performance ◽  
Lattice Structure ◽  
Unit Length ◽  
Experimental Tests ◽  
Plane Geometry ◽  
Sandwich Beams ◽  
Static Tests ◽  
Three Point Bending ◽  
The Core ◽  
The Impact

Mechanical performance of 3d-printed polyamide sandwich beams with different type of the lattice cores is investigated. Four variants of the beams are considered, which differ in the type of connections between the elements in the lattice structure of the core. We consider the pantographic-type lattices formed by the two families of inclined beams placed with small offset and connected by stiff joints (variant 1), by hinges (variant 2) and made without joints (variant 3). The fourth type of the core has the standard plane geometry formed by the intersected beams lying in the same plane (variant 4). Experimental tests were performed for the localized indentation loading according to the three-point bending scheme with small span-to-thickness ratio. From the experiments we found that the plane geometry of variant 4 has the highest rigidity and the highest load bearing capacity in the static tests. However, other three variants of the pantographic-type cores (1–3) demonstrate the better performance under the impact loading. The impact strength of such structures are in 3.5–5 times higher than those one of variant 4 with almost the same mass per unit length. This result is validated by using numerical simulations and explained by the decrease of the stress concentration and the stress state triaxiality and also by the delocalization effects that arise in the pantographic-type cores.

Closure to “Local Failure of Plastic-Foam Core Sandwich Panels”

1970 ◽  
Vol 96 (8) ◽  
pp. 1803-1805
Author(s):  
Billy J. Harris ◽  
Gene M. Nordby
Keyword(s):  
Sandwich Panels ◽  
Local Failure ◽  
Foam Core ◽  
Plastic Foam

Local Failure of Plastic-Foam Core Sandwich Panels

1969 ◽  
Vol 95 (4) ◽  
pp. 585-610
Author(s):  
Billy J. Harris ◽  
Gene M. Nordby
Keyword(s):  
Sandwich Panels ◽  
Local Failure ◽  
Foam Core ◽  
Plastic Foam

Design of composite lattice materials combined with fabrication approaches

2018 ◽  
Vol 53 (3) ◽  
pp. 393-404 ◽  
Author(s):  
Jun Xu ◽  
Yaobo Wu ◽  
Xiang Gao ◽  
Huaping Wu ◽  
Steven Nutt ◽  
...  
Keyword(s):  
Shear Strength ◽  
Mechanical Performance ◽  
Analytical Models ◽  
Core Material ◽  
Foam Core ◽  
Hierarchical Lattice ◽  
Bottom Up ◽  
Lattice Materials ◽  
Assembly Technique ◽  
Composite Lattice

Lattice materials can be designed through their microstructure while concurrently considering fabrication feasibility. Here, we propose two types of composite lattice materials with enhanced resistance to buckling: (a) hollow lattice materials fabricated by a newly developed bottom-up assembly technique and the previously developed thermal expansion molding technique and (b) hierarchical lattice materials with foam core sandwich trusses fabricated by interlocking assembly process. The mechanical performance of sandwich structures featuring the two types of lattice cores was tested and analyzed theoretically. For hollow lattice core material, samples from two different fabrication processes were compared and both failed by nodal rupture or debonding. In contrast, hierarchical lattice structures failed by shear buckling without interfacial failure in the sandwich struts. Calculations using established analytical models indicated that the shear strength of hollow lattice cores could be optimized by judicious selection of the thickness of patterned plates. Likewise, the shear strength of hierarchical foam core truss cores could be maximized (with minimal weight) through design of truss geometry. The bottom-up assembly technique could provide a feasible way for mass production of lattice cores, but the design about how to assembly is critical. Hierarchical lattice cores with foam sandwich trusses should be a suitable choice for future lightweight material application.

scholarly journals Flexural behavior of sandwich panels with cellular wood, plywood stiffener/foam and thermoplastic composite core

2017 ◽  
Vol 21 (2) ◽  
pp. 784-805 ◽  
Author(s):  
Edgars Labans ◽  
Kaspars Kalnins ◽  
Chiara Bisagni
Keyword(s):  
Mechanical Performance ◽  
Sandwich Panels ◽  
Experimental Tests ◽  
Design Tool ◽  
Thermoplastic Composite ◽  
Flexural Behavior ◽  
Four Point Bending ◽  
Reliable Design ◽  
Sufficient Strength ◽  
Core Part

A series of experimental tests have been carried out on three types of novel sandwich panels mainly designed for application in lightweight mobile housing. Two types of the panels are manufactured entirely from wood-based materials while the third one presents a combination of plywood for surfaces and corrugated thermoplastic composite as a core part. All sandwich panels are designed to allow rapid one-shot manufacturing. Mechanical performance has been evaluated in four-point bending comparing the data to the reference plywood board. Additionally, finite element simulations were performed to evaluate global behavior, stress distribution and provide the basis for a reliable design tool. Obtained results show sufficient mechanical characteristics suitable for floor and wall units. Compared to a solid plywood board, sandwich alternative can reach up to 42% higher specific stiffness, at the same time maintaining sufficient strength characteristics.

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