Hygrothermal Deformation of Composite Sandwich Panels

Coefficients of thermal and moisture expansion (CTE and CME) can be predicted for many composite laminates and sandwich panels. Core and adhesive properties, such as geometry and stiffness are important variables. Laminate theory is augmented with a modified model for anisotropic core properties to predict the CTE and CME of sandwich panels. Procedures to measure both CTE and CME are described. Since these are thermodynamic properties, methods to obtain equilibrium moisture strains are needed. Results are given for CFRP facesheets with Al and NOMEX honeycomb cores, and for woven Kevlar facesheets with Al cores. Agreement with predictions is good and depends highly on knowledge of properties of all constituents.

Download Full-text

DETERMINATION OF MECHANICAL PROPERTIES OF COMPOSITE SANDWICH PANEL WITH ALUMINIUM HONEYCOMB CORE

MM Science Journal ◽

10.17973/mmsj.2021_12_2021132 ◽

2021 ◽

Vol 2021 (6) ◽

pp. 5353-5359

Author(s):

MICHAL SKOVAJSA ◽

◽

FRANTISEK SEDLACEK ◽

MARTIN MRAZEK ◽

◽

...

Keyword(s):

Mechanical Properties ◽

Numerical Simulation ◽

Sandwich Panel ◽

Analytical Calculation ◽

Sandwich Panels ◽

Honeycomb Core ◽

Composite Sandwich Panels ◽

Composite Sandwich ◽

Three Point Bend Test ◽

Honeycomb Cores

This paper deal with comparison of mechanical properties of composite sandwich panel with aluminium honeycomb core which is determined by experimental measurement, analytic calculation and numerical simulation. The goal was to compared four composite sandwich panels. The composite sandwich panels were made of two different aluminium honeycomb cores with density 32 and 72 kg.m-3 and two different layup of skin with 4 and 5 layers. The comparison was performed on a three-point bend test with support span 400 mm. This paper confirms the possibility of a very precise design of a composite sandwich panel with an aluminium honeycomb core using analytical calculation and numerical simulation.

Download Full-text

Investigation of progressive failure in the composite sandwich panels with elastomeric foam core under concentrated loading

Journal of Sandwich Structures & Materials ◽

10.1177/1099636217719424 ◽

2017 ◽

Vol 21 (8) ◽

pp. 2585-2615

Author(s):

AR Nazari ◽

MZ Kabir ◽

H Hosseini-Toudeshky ◽

Y Alizadeh Vaghasloo ◽

S Najafian

Keyword(s):

Energy Absorption ◽

Composite Laminates ◽

Sandwich Panels ◽

Absorption Capacity ◽

Foam Core ◽

Energy Absorption Capacity ◽

Composite Sandwich Panels ◽

Composite Sandwich ◽

Load Carrying ◽

Composite Skins

Failure and damage of crushable materials employed as core for the sandwich structures reduces serviceability and energy absorption capacity of the components especially under bending load so that many beneficial properties seem to be achieved by application of noncrushable lightweight materials instead of crushable foams as core for the sandwich structures. In this paper, an elastomeric foam is employed as core for two aspect ratios of the composite sandwich panels and the enhancement of the load-carrying capacity in the elastomeric foam-cored sandwich panels is investigated in comparison to which is measured about the individual composite panels applied as skins. Both experimental and finite element simulation programs are included in the research. The load-carrying performance of the elastomeric foam-cored sandwich panels is considered dependent on two main features of the constituent materials as hyperelastic behavior of the foam core and progressive damage of the composite skins which are simulated in the finite element models in order to describe the failure mechanism in the panels. Collapse of the elastomeric foam-cored sandwich panels is considered due to connection of some failure lines in the composite skins; however, the foam core remains undamaged. The elastomeric foam core can transfer the load from the top composite skin to the bottom one so that a great energy absorption capacity is provided for these panels. The elastomeric foam after failure of the composite skins can mobilize the residual strength of the laminates to endure against large deformations prior to final collapse. By application of the composite laminates in sandwich form with elastomeric foam core, the maximum load carrying and energy absorption capacity of the composite laminates increased about 60 and 110%, respectively. The results show more favorite failure behavior for the elastomeric foam-cored sandwich panels in comparison to which is expected usually for the crushable foam-cored sandwich panels which may be concerned in many industrial applications.

Download Full-text

Effect of extreme cold temperatures on quasi-static indentation and impact behavior of woven carbon fiber epoxy composite sandwich panels with nomex honeycomb core

Journal of Sandwich Structures & Materials ◽

10.1177/1099636221993876 ◽

2021 ◽

pp. 109963622199387

Author(s):

Mathilde Jean-St-Laurent ◽

Marie-Laure Dano ◽

Marie-Josée Potvin

Keyword(s):

Epoxy Composite ◽

Impact Behavior ◽

Effect Of Temperature ◽

Cold Temperatures ◽

Composite Sandwich Panels ◽

Composite Sandwich ◽

Static Indentation ◽

Nomex Honeycomb ◽

Extreme Cold ◽

The Impact

The effect of extreme cold temperatures on the quasi-static indentation and the low velocity impact behavior of woven carbon/epoxy composite sandwich panels with Nomex honeycomb core was investigated. Impact tests were performed at room temperature, –70°C, and –150°C. Two sizes of hemispherical impactor were used combined to three different impactor masses. All the impact tests were performed at the same initial impact velocity. The effect of temperature on the impact behavior is investigated by studying the load history, load-displacement curves and transmitted energy as a function of time curves. Impact damage induced at various temperatures was studied using different non-destructive and destructive techniques. Globally, more damages are induced with impact temperature decreasing. The results also show that the effect of temperature on the impact behavior is function of the impactor size.

Download Full-text