Mechanical performance of CF/PEEK–PEI foam core sandwich structures

2017 ◽  
Vol 21 (8) ◽  
pp. 2680-2699 ◽  
Author(s):  
Jonas Grünewald ◽  
Patricia P Parlevliet ◽  
Alexander Matschinski ◽  
Volker Altstädt
Keyword(s):  
Mechanical Performance ◽  
Sandwich Structures ◽  
Cell Structure ◽  
Processing Parameters ◽  
Thermoplastic Composite ◽  
Composite Sandwich ◽  
The Core ◽  
Composite Sandwich Structures ◽  
Cell Structures ◽  
Original Cell

Previous work showed that thermoplastic composite sandwich structures offer great potential to meet the demands of lightweight structures for aviation applications. In this study, the influence of several processing parameters on the mechanical properties of thermoplastic sandwich components, consisting of carbon fibre reinforced polyetheretherketone skins and polyetherimide foam cores, is characterised. Sandwich specimens are manufactured with varying skin temperatures, core compaction distances and different polyetherimide concentrations at the skin–core interface. Following, sandwich samples are mechanically tested to characterise the bond strength, the core performance as well as the performance of the whole sandwich. The results show that in most cases the processing parameters significantly affect the cell structure of the sandwich core, provided that a proper fusion bond between skins and core exists. Thereby, the core performance seems to be weakened and failure predominantly occurs in the transition between affected and original cell structures.

Modified foam cores for full thermoplastic composite sandwich structures

2017 ◽  
Vol 21 (3) ◽  
pp. 1150-1166
Author(s):  
Jonas Grünewald ◽  
Tilman Orth ◽  
Patricia Parlevliet ◽  
Volker Altstädt
Keyword(s):  
Mechanical Performance ◽  
State Of The Art ◽  
Sandwich Structures ◽  
Thermoplastic Composite ◽  
Foam Core ◽  
Cycle Times ◽  
Composite Sandwich ◽  
Current State ◽  
Composite Sandwich Structures ◽  
Honeycomb Cores

Full thermoplastic composite sandwich structures with a foam core offer the possibility to be manufactured by fusion bonding in significant shorter cycle times than thermoset-based sandwiches. However, the application of foam cores results in lower mechanical properties such as compression and shear strength compared to honeycomb cores, therefore foam-based sandwiches cannot compete with sandwich structures based on Aramid/phenolic honeycomb cores, the current state of the art. In order to improve the mechanical performance of foam core-based sandwiches while maintaining their advantages, concepts to reinforce the foams were developed in this study. By introducing rods either orthogonally or diagonally to the skin plane, which are fusion bonded to the skins during processing, the compression and shear properties can be improved by up to 1000% and 72%, respectively. Even when correcting for the weight increase, an improved specific compression strength could be achieved. And therefore, the pinning looks especially promising when only applied locally in highly loaded areas for example.

A parametric study of linear and nonlinear models for moisture diffusion in composite sandwich structures

2017 ◽  
Vol 52 (9) ◽  
pp. 1193-1201 ◽  
Author(s):  
Shane Paulson ◽  
John Peddieson ◽  
Jane Liu ◽  
Steve Mills
Keyword(s):  
Numerical Solutions ◽  
Model Problem ◽  
Sandwich Structures ◽  
Nonlinear Models ◽  
Relative Concentration ◽  
Moisture Diffusion ◽  
One Dimensional ◽  
Composite Sandwich ◽  
The Core ◽  
Composite Sandwich Structures

Disagreement has persisted in the modeling of Fickian moisture diffusion in sandwich structures as to the correct continuity conditions at the core/facesheet interface. The purpose of the present work is to compare moisture diffusion predictions based on two of the most widely used sets of these continuity conditions. The model problem of one-dimensional time-dependent moisture diffusion in a symmetric sandwich slab is selected for analysis. Finite difference numerical solutions reveal very little difference between the predictions of models assuming continuity of relative humidity and continuity of relative concentration over a wide variety of parametric conditions.

Manufacturing of thermoplastic composite sandwich structures

2016 ◽  
Vol 30 (4) ◽  
pp. 437-464 ◽  
Author(s):  
Jonas Grünewald ◽  
Patricia Parlevliet ◽  
Volker Altstädt
Keyword(s):  
Adhesive Bonding ◽  
Sandwich Structures ◽  
Thermoplastic Composite ◽  
Aviation Industry ◽  
Compression Moulding ◽  
Fusion Bonding ◽  
Composite Sandwich ◽  
Composite Sandwich Structures ◽  
Vacuum Moulding

Composite sandwich structures show promising lightweight properties for the aviation industry. Nowadays time-consuming manufacturing methods still prevent an extensive application of composite sandwiches, which can be overcome by the use of thermoplastic polymers in skins and core. During manufacturing of thermoplastic composite (TPC) sandwich structures, the joining of skins and core is a critical step. Therefore, several skin–core joining methods have been under investigation and development in the published literature, which can be categorized into adhesive bonding or fusion bonding. Fusion bonding by means of vacuum moulding, compression moulding or in situ foaming shows great potential for joining sandwich skins and core. Although various phenomena such as core collapsing or skin deconsolidation challenge the processes. This article aims to present an overview of research that has been done in the area of manufacturing TPC sandwich structures and will serve as a baseline and aid for further research and development efforts.

Research on Deformation Properties and Boundary Effect of Composite Sandwich Structure under Deep Hydrostatic Pressure

2012 ◽  
Vol 490-495 ◽  
pp. 3907-3911
Author(s):  
Jia Bo Qiu ◽  
Zhi Yuan Mei
Keyword(s):  
Hydrostatic Pressure ◽  
Theoretical Analysis ◽  
Deep Water ◽  
Surface Deformation ◽  
Sandwich Structures ◽  
Boundary Effect ◽  
Composite Sandwich ◽  
The Core ◽  
Composite Sandwich Structures ◽  
Deformation Properties

Composite sandwich structures have been used more and more widely in the underwater structures, therefore deformation problems under deep-water hydrostatic pressure can not be ignored. For the deformation properties of composite sandwich structures under deep-water hydrostatic pressure, the paper carried out theoretical and test research. First, the paper analyzed the surface deformation features as well as the law of the element’s cross-sectional dimension, the core thickness and elastic modulus to the surface deformation by establishing theoretical analysis model; The results show that the deformation area can be divided into central area and boundary area, and the boundary effect is an important factor affecting the deformation, the core parameters can affect the reach of boundary effect. Second, the paper carried out hydrostatic test of composite sandwich structural element model, and then verified the theoretical analysis model’s rationality and accuracy by comparing the test results and theoretical results.

scholarly journals Influence of the Thermal Field on Static Behaviour of Sandwich Structures

2019 ◽  
Vol 56 (1) ◽  
pp. 110-114
Author(s):  
Elena-Felicia Beznea ◽  
Gelu Coman ◽  
Nicusor Baroiu ◽  
Ionel Chirica
Keyword(s):  
Thermal Conductivity ◽  
Numerical Simulation ◽  
Thermal Field ◽  
Sandwich Structures ◽  
Experimental Studies ◽  
Sandwich Plates ◽  
Composite Sandwich ◽  
The Core ◽  
Composite Sandwich Structures ◽  
Static Behaviour

In this paper, numerical and experimental studies on the influence of the thermal field on behavior of the structure of sandwich plates in three points bending is analysed. Various materials are used so for skins. For the core only extruded polystyrene, with various thicknesses is used. The thermal conductivity n was determined by using the Hilton B480 unit, based on the heat flowmeter method described in ISO 8301:1991. We have been analyzed 12 cases of composite sandwich structures. The results obtained by experimental determination and numerical simulation of all cases of modeling are compared and certain differences occurred on the analyzing of influence of the thermal field on the bending characteristics of sandwich structures.

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