Optimum Stacking Sequence Design of Composite Sandwich Panel Using Genetic Algorithms

In the present study, both critical buckling load maximization and face-sheet laminate thickness minimization problems for the composite sandwich panel, subjected to bi-axial compressive loading under various imposed constraints have been investigated using genetic algorithms. In the previously published work, the optimization of simple composite laminate panels with only even number of laminae has been considered [1, 3]. The present work allows the optimization of a composite sandwich panel with both even and odd number of laminae in the face-sheet laminates. Also, the effects of the bending-twisting coupling terms (D16and D26) in bending stiffness matrix which were neglected in the previous studies [1, 2, 3], are considered in the present work for exact solutions. In addition effect of both balanced and unbalanced face-sheet laminates on the optimum solutions have also been investigated, whereas only balanced laminates were considered in the previous studies [1, 2, 3].

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Numerical Modelling of Impact Behavior of Composite Sandwich Panel With Honeycomb Core

Volume 9: Mechanics of Solids, Structures, and Fluids ◽

10.1115/imece2019-11721 ◽

2019 ◽

Author(s):

Shah Alam ◽

Aakash Bungatavula

Keyword(s):

Sandwich Panel ◽

Sheet Thickness ◽

Face Sheet ◽

Honeycomb Core ◽

Impact Performance ◽

Composite Sandwich ◽

The Core ◽

The Face ◽

Core Height ◽

The Impact

Abstract The goal of this paper is to find the best impact response of the composite sandwich panels with honeycomb core. The focus of the study is to find the effects of changing the face sheet thickness and the core height of the sandwich panel subjected to variable velocities on impact performance. Initially, honeycomb core sandwich panel with 1mm thick face sheet is modelled in Abaqus/explicit to calculate the energy absorption, residual velocity, and deformation at four different velocities. Then, the process is repeated by changing the face sheets thickness to 2mm and 3mm to see the effects of changing the thickness on the impact performance of a composite sandwich panel. The honeycomb core height is also changed to see its effect on the performance. In all models, Al 7039 is used in the core and T1000G is used in the face sheets.

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Compression Test of Composite Sandwich Panel

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.348-349.605 ◽

2007 ◽

Vol 348-349 ◽

pp. 605-608

Author(s):

Jong Woong Lee ◽

Cheol Won Kong ◽

Se Won Eun ◽

Jae Sung Park ◽

Young Soon Jang ◽

...

Keyword(s):

Compression Test ◽

Sandwich Panel ◽

Weight Ratio ◽

Fem Analysis ◽

Face Sheet ◽

Bending Stress ◽

Composite Sandwich Panels ◽

Composite Sandwich ◽

Commercial Code ◽

The Face

Composite materials are used in aerospace structures due to their considerable bending stiffness and strength-to-weight ratio. A composite sandwich is composed of a face-sheet and an aluminum core. The face-sheet of the sandwich takes the bending stress and core of sandwich takes the shear stress. A compression test and FEM analysis accomplished about composite sandwich panels that have curvature. The FEM analysis was performed using a commercial code, ANSYS and the compression test was performed until failure occurred in the sandwich panel. A strain gauge and a displacement gauge were used to acquire the data. In this paper, the failure strength and failure mode was checked. Additionally, the results of the test and analysis were compared.

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Large deflection geometrically nonlinear bending of sandwich beams with flexible core and nanocomposite face sheets reinforced by nonuniformly distributed graphene platelets

Journal of Sandwich Structures & Materials ◽

10.1177/1099636219896070 ◽

2019 ◽

Vol 22 (3) ◽

pp. 866-895 ◽

Cited By ~ 2

Author(s):

S Jedari Salami

Keyword(s):

Sandwich Panel ◽

Sandwich Beam ◽

Weight Fraction ◽

Functionally Graded ◽

Face Sheet ◽

Sandwich Beams ◽

Nonlinear Bending ◽

Graphene Platelet ◽

The Face ◽

Graphene Platelets

This study investigates the nonlinear bending response of a novel class of sandwich beams with flexible core and face sheets reinforced with graphene platelets that are functionally graded distributed through the thickness. Nonlinear governing equations are established based on extended high-order sandwich panel theory and Von Kármán type of geometrical nonlinearity. In this theory, the face sheets follow the first-order shear deformation theory, and the two-dimensional elasticity is adopted for the core. These nonlinear differential equations are discretized into algebraic systems by means of the Ritz-based method from which the static bending solution can be achieved. The effective Young’s modulus of functionally graded graphene platelet-reinforced composite (GPLRC) face sheets is determined through the modified Halpin–Tsai micromechanics model, and associated Poisson’s ratio is evaluated by employing the rule of mixture. Comparison studies are provided for a sandwich beam with graphene-reinforced face sheets and conventional nanocomposite beam reinforced by graphene platelets due to lack of results for introduced sandwich beams. Besides, three-point bending test was carried out in order to assure the validity of nonlinear bending analysis of a sandwich beam based on extended high-order sandwich panel theory. Afterwards, parametric studies are given to examine the influences of graphene platelet distribution pattern, weight fraction, and core-to-face sheet thickness ratio together with the total number of layers on the linear and nonlinear bending performances of the sandwich beams. Numerical results demonstrate that distributing more graphene platelets near the upper and lower surface layers of the face sheets, named X-GPLRC, is capable to improve the bending strength and decrease the local deflection of the top face sheet, and this recovery effect becomes more significant as graphene platelet weight fraction increases. The results also reveal that the graphene platelet distribution pattern of the face sheets plays an important role to decrease the transverse shear stress of the core by dispersing more graphene platelets near surfaces of the face sheets (X-GPLRC). So, reducing the local deflection of the top face sheet tends to be much more safety of the soft core from any failure. Besides, sandwich beams with a lower weight fraction of graphene platelets in face sheets that are symmetrically distributed in such a way, called O-GPLRC, are also less sensitive to the nonlinear deformation.

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Analysis of Mechanical Properties and Environmental Effect on Composite Sandwich Structure by Varying the Face Sheet Thickness

Advances in Engineering Materials - Lecture Notes in Mechanical Engineering ◽

10.1007/978-981-33-6029-7_19 ◽

2021 ◽

pp. 197-206

Author(s):

Arun Kumar Gaur ◽

Anil Kumar ◽

Aman Aggarwal

Keyword(s):

Mechanical Properties ◽

Environmental Effect ◽

Sandwich Structure ◽

Sheet Thickness ◽

Face Sheet ◽

Composite Sandwich ◽

The Face

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Reduction of strength of GFRP sandwich panels in naval ships by face sheet holes, cracks and impact damage

Journal of Sandwich Structures & Materials ◽

10.1177/1099636219836357 ◽

2019 ◽

Vol 21 (5) ◽

pp. 1621-1653 ◽

Cited By ~ 2

Author(s):

Brian Hayman ◽

Andreas T Echtermeyer

Keyword(s):

Impact Damage ◽

Compressive Loading ◽

Finite Size ◽

Sandwich Panels ◽

Average Stress ◽

Face Sheet ◽

Reinforced Plastics ◽

The Face ◽

Circular Holes ◽

Stress Models

Extensive studies have been previously carried out on the effects of various types of local damage on the performance of sandwich panels used in the hull structures of naval ships. More recently, the approach was adapted for application on board a specific ship series. Strength reduction data were obtained for a set of sandwich materials that were representative for the vessels in question. The face sheet materials were glass fibre-reinforced plastics with non-crimp fabrics and two different types of vinylester resin. The core materials were PVC foams. Tests were performed on laminate specimens with and without circular holes under tensile loading and on sandwich face sheets with holes, cracks and impact damage under compressive loading. The strength reductions caused by impacts with sharp and blunt objects were compared with those caused by machined cracks and circular holes, respectively, and with Whitney and Nuismer’s point stress and average stress models for infinitely large laminates with cracks and holes. It was found that strength reductions due to impact damage can be estimated using tests on specimens with machined cracks and holes, and also with the average stress models if appropriate values of characteristic length are assumed. Special attention is paid to the need to take account of the geometry and the finite size of tested specimens.

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Numerical Study on the Plastic Forming of Doubly Curved Surfaces of Aluminum Foam Sandwich Panel Using 3D Voronoi Model

Metals ◽

10.3390/met11050675 ◽

2021 ◽

Vol 11 (5) ◽

pp. 675

Author(s):

Xi Zhang ◽

Qingmin Chen ◽

Jiaxin Gao ◽

Mingwei Wang ◽

Ya Zhang ◽

...

Keyword(s):

Aluminum Foam ◽

Sandwich Panel ◽

Face Sheet ◽

Thickness Variation ◽

Shape Error ◽

Curved Surfaces ◽

The Face ◽

Plastic Forming ◽

Doubly Curved ◽

Forming Defects

This paper presents a numerical investigation on the plastic forming of doubly curved surfaces of aluminum foam sandwich panel (AFSP). A mesoscopic 3D Voronoi model that can describe the structure of closed-cell aluminum foam relatively realistically was established, and a series of numerical simulations using the model of the sandwich panel with a Voronoi foam core were conducted on the plastic forming of two typical doubly curved surfaces including spherical and saddle-shaped surfaces of AFSPs to analyze the deformation behaviors and the forming defects in detail. Multi-point forming experiments of spherical and saddle-shaped AFSPs with different target radii were implemented and the doubly curved panels with good forming quality were obtained. The simulated results of the surface illumination maps, the face sheet profiles, and the maximum strain differences in selected areas of the face sheet and the experimental results indicated that the Voronoi AFSP model can reflect the actual defects occurred in the plastic forming of doubly curved sandwich panels, and the high forming accuracy of the sandwich panel model was also demonstrated in terms of the shape error and the thickness variation.

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The effect of local bending stiffness on the wrinkling of sandwich panels

Proceedings of the Institution of Mechanical Engineers Part M Journal of Engineering for the Maritime Environment ◽

10.1243/147509003321921355 ◽

2003 ◽

Vol 217 (2) ◽

pp. 111-119

Author(s):

L Fagerberg

Keyword(s):

Elastic Modulus ◽

Sandwich Panel ◽

Volume Fraction ◽

Fibre Volume Fraction ◽

Fibre Volume ◽

Bending Stiffness ◽

Face Sheet ◽

Stacking Sequence ◽

The Core ◽

The Face

The use of the face sheet elastic modulus versus the face sheet local bending stiffness while designing against wrinkling is discussed in this paper. It shows that there are several ways to improve the critical wrinkling load of a sandwich panel without replacing the core. It is often possible to increase the wrinkling load by as much as 25 per cent without virtually any increase in weight or cost of the sandwich. This is achieved by improving the local bending stiffness of the sandwich face sheet by either optimizing the stacking sequence, lowering the fibre volume fraction or adding some extra layers of a cheap fibre material to the sandwich face, creating a minisandwich within the face sheet. Experiments are performed that clearly show the potential for increasing the critical wrinkling load by means of altering the face sheet.

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