Innovative flitch sandwich beams with steel core under four-point bending

2021 ◽  
Vol 233 ◽  
pp. 111724
Author(s):  
Amin Nabati ◽  
Tohid Ghanbari-Ghazijahani ◽  
Hamid R. Valipour
Keyword(s):  
Sandwich Beams ◽  
Steel Core ◽  
Four Point Bending

scholarly journals Mechanical Properties Of Sandwich Composites Used For Aerofoil Shell Structures Of Wind Turbine Blade

2021 ◽  
Vol 5 (1) ◽  
pp. 26-37
Author(s):  
Fatih BALIKOĞLU ◽  
Tayfur Kerem Demircioğlu ◽  
Ali IŞIKTAŞ
Keyword(s):  
Mechanical Properties ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Maximum Load ◽  
Operating Conditions ◽  
Shear Behaviour ◽  
Sandwich Beams ◽  
Plane Shear ◽  
Compression Load ◽  
Four Point Bending

The grid-scored foams contribute significantly to the overall mechanical properties of the sandwich structures, such as aerofoil shell structure of wind turbine blades which are subjected to different loads under operating conditions. The goal of the present paper is to examine the four-point bending, flatwise and edgewise compression and in-plane shear behaviour of sandwich panels composed of composite face sheets of E-glass/ bisphenol-A epoxy resin and plain and grid-scored PVC foams. The four-point bending failure load of the grid-scored foamed sandwich beams increased by 28.1% compared to the plain foamed ones. The flatwise compression strength of samples with grid-scored foam increased by 546% compared to plain foamed samples. The resin grids contributed to an increase in the flat-wise compression stress inducing the core crushing. Under the edgewise compression load, using the grid-scored foam increased the maximum load values by only about 2.9% relative to the plain foam. The reason for this small difference can be addressed as the facings are more effective in carrying the edgewise loadings. With the use of the grid-scored foam, an increase of 38.2% was obtained in-plane shear strength compared to plain foamed sandwich beams. The resin grids improved bonding between the facings and PVC foam.

Experimental assessment of the Refined Zigzag Theory for the static bending analysis of sandwich beams

2016 ◽  
Vol 20 (1) ◽  
pp. 86-105 ◽  
Author(s):  
Luigi Iurlaro ◽  
Marco Gherlone ◽  
Massimiliano Mattone ◽  
Marco Di Sciuva
Keyword(s):  
Timoshenko Beam ◽  
Ad Hoc ◽  
Beam Theory ◽  
Timoshenko Beam Theory ◽  
Sandwich Beams ◽  
Equilibrium Equations ◽  
Four Point Bending ◽  
Core Thickness ◽  
Zigzag Theory ◽  
First Time

In the present work, for the first time, the accuracy of the Refined Zigzag Theory in reproducing the static bending response of sandwich beams is experimentally assessed. The theory is briefly reviewed and an analytical solution of the equilibrium equations is presented for the boundary and loading conditions under investigation (four-point bending). The experimental campaign is described, including the material characterization and the bending tests. The experimentally measured deflections and axial strains are compared with those provided by Refined Zigzag Theory and by the Timoshenko Beam Theory with an ad hoc shear correction factor. The Refined Zigzag Theory is shown to be more accurate than the Timoshenko Beam Theory, in particular for beams with higher face-to-core thickness and stiffness ratios and with a reduced slenderness.

The experimental static mechanical performance of ironed repaired GFRP–honeycomb sandwich beams

2012 ◽  
Vol 14 (6) ◽  
pp. 694-714 ◽  
Author(s):  
Benjamin William Mounir Kirollos ◽  
Richard Trede ◽  
Peter Lampen
Keyword(s):  
Glass Fibre ◽  
Mechanical Performance ◽  
Repair Process ◽  
Flexural Stiffness ◽  
Sandwich Beams ◽  
Four Point Bending ◽  
Reinforced Plastic ◽  
Glass Fibre Reinforced Plastic ◽  
Static Mechanical ◽  
Glass Fibre Reinforced

Damaged glass fibre reinforced plastic–honeycomb core sandwich beams are repaired using uncured glass fibre reinforced plastic fabrics and a handheld iron. The effect of iron temperature, application time and pressure on the effectiveness of repair is investigated by measuring the failure load and flexural stiffness of the repaired beams using third span four-point bending tests. Repairs are tested in compression and tension. A repair process is suggested which consistently recovers 95% of the compressive strength and 77% of the tensile strength of the damaged beam. The repair is shown to have little effect on beam flexural stiffness.

Viscoelastic behaviour investigation and new developed laboratory slamming test on foam core sandwich

2018 ◽  
Vol 22 (6) ◽  
pp. 2049-2074 ◽  
Author(s):  
Fahmi Alila ◽  
Jamal Fajoui ◽  
Raphael Gerard ◽  
Pascal Casari ◽  
Mohamed Kchaou ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Sandwich Structure ◽  
Viscoelastic Model ◽  
Fatigue Behaviour ◽  
Temperature Evolution ◽  
Physical Parameters ◽  
Foam Core ◽  
Sandwich Beams ◽  
Test Rig ◽  
Four Point Bending

In the first part of this paper, a viscoelastic model is used to numerically study the cellular foam core fatigue behaviour. Material’s temperature evolution is quantified with a numerical/experimental confrontation. In the second part, the slamming phenomenon is discussed by measuring the panel flexural strain on a racing sailboat during navigation. Making use of these results, a new slamming test rig was developed to evaluate the fatigue of sandwich structure under realistic loading. Four-point bending and slamming tests were performed on sandwich beams in order to compare their fatigue life and to discuss the physical parameters.

Plastics Sandwich Beams under Bending Loads of Short Duration

1967 ◽  
Vol 9 (5) ◽  
pp. 355-361 ◽  
Author(s):  
R. M. Ogorkiewicz ◽  
A. A. M. Sayigh
Keyword(s):  
Polyvinyl Chloride ◽  
Short Duration ◽  
Stress Function ◽  
Local Stress ◽  
Sandwich Beams ◽  
Stress Concentrations ◽  
Four Point Bending ◽  
Bending Loads ◽  
Uniformly Distributed Loads ◽  
Good Agreement

Design of plastics sandwich structures calls for methods of predicting their deformation under load, which were studied with particular reference to beams under three- and four-point bending and under uniformly distributed loads. A preliminary series of tests established the stress-strain characteristics of p.v.c. (polyvinyl chloride) and polyurethane core and rigid p.v.c. skin materials. Using stress function solutions deflections and skin strains of different beams of these materials were then calculated and compared with experimental results obtained with beams made of the same combinations of materials. Good agreement was found for loads of short duration within the limits imposed by local stress concentrations.

scholarly journals Failure of Composite Sandwich Beams

2002 ◽  
Vol 11 (3) ◽  
pp. 096369350201100 ◽  
Author(s):  
I. M. Daniel ◽  
E. E. Gdoutos ◽  
K.-A. Wang
Keyword(s):  
Failure Modes ◽  
Foam Core ◽  
Sandwich Beams ◽  
Composite Sandwich ◽  
Four Point Bending ◽  
Constituent Material ◽  
Closed Cell ◽  
Failure Envelopes ◽  
Geometrical Dimensions ◽  
Cell Foam

A thorough investigation of failure behaviour of composite sandwich beams under three- and four-point bending was undertaken. The beams were made of unidirectional carbon/epoxy facings and a PVC closed-cell foam core. The constituent materials were fully characterised and in the case of the foam core, failure envelopes were developed for general two-dimensional states of stress. Various failure modes including facing wrinkling, indentation failure and core failure were observed and compared with analytical predictions. The initiation, propagation and interaction of failure modes depend on the type of loading, constituent material properties and geometrical dimensions.

Improving four-point bending performance of marine composite sandwich beams by core modification

2020 ◽  
Vol 54 (8) ◽  
pp. 1049-1066
Author(s):  
F Balıkoğlu ◽  
N Arslan ◽  
TK Demircioğlu ◽  
O İnal ◽  
M İren ◽  
...  
Keyword(s):  
Bending Strength ◽  
Mechanical Performance ◽  
Composite Beams ◽  
Bending Stiffness ◽  
Bending Test ◽  
Sandwich Composite ◽  
Foam Core ◽  
Sandwich Beams ◽  
Bending Performance ◽  
Four Point Bending

The aim of this study was to improve four-point bending performance of foam core sandwich composite beams by applying various core machining configurations. Sandwich composites have been manufactured using perforated and grooved foam cores by vacuum-assisted resin transfer moulding method with vinyl-ester resin system. The influence of grooves and perforations on the mechanical performance of marine sandwich composite beams was investigated under four-point bending test considering the weight gain. Bending strength and effective bending stiffness increased up to 34% and 61%, respectively, in comparison to a control beam without core modification. Analytical equations were utilised for calculating the mid-span deflection, equivalent bending stiffness and ultimate bending strength of the sandwich beams. Finite element analysis was also performed to analyse the flexural response of the specimens taking into account the combined effect of orthotropic linear elasticity of the face sheet and the non-linear behaviour of the foam core.

Finite Element Analysis of Centrally-Debonded Composite Sandwich Beam under Four Point Bending

2011 ◽  
Vol 335-336 ◽  
pp. 351-354 ◽  
Author(s):  
Meng Kao Yeh ◽  
Yu Wen Chiu
Keyword(s):  
Finite Element ◽  
Composite Structures ◽  
Sandwich Structure ◽  
Sandwich Beam ◽  
Core Material ◽  
Sandwich Beams ◽  
Element Analysis ◽  
Specific Strength ◽  
Composite Sandwich ◽  
Four Point Bending

Sandwich structure, with high specific strength, high specific stiffness facesheet and light-weighted core material bonded together, is one of commonly used composite structures. During the manufacturing process, it is possible to have debonding between facesheet and core. This facesheet/core debonding affects the mechanical property and strength of sandwich structure. In this study, sandwich beams are made of graphite/epoxy laminate as facesheet and MWNTs/epoxy nanocomposites as core material. The composite sandwich beam, with a central facesheet/core debond and under four point bending, was analyzed by the finite element method. The length of the debonding layer, the fiber orientation of the facesheet laminate and MWNTs content in core were varied to assess their effects on the bending behavior and the strengths of the centrally-debonded sandwich beams.

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