Thermoplastic Composites for Aerospace Applications

The effect of hot-wet storage aging on the mechanical response of a carbon fiber polyether ether ketone (PEEK)-matrix woven composite has been studied. A wide range of static loads and selected cyclic load tests on the interlaminar fatigue strength were performed. Static tests were conducted in batch mode, including on- and off-axis tension, compression, flexure, interlaminar shear strength (ILSS) and fracture tests in Modes I, II and I/II. Respective mechanical properties have been determined, indicating a degrading effect of aging on strength-related properties. The measured response in general, as well as the variance quantified by batch-mode test execution, indicated the appropriateness of the applied standards on the material under consideration, especially in the case of fracture tests. The material properties presented in the current work may provide a useful basis towards preliminary design with PEEK-based woven thermoplastic composites during service in aerospace applications.

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Simulation of laser heating distribution for a thermoplastic composite: effects of AFP head parameters

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-020-05876-9 ◽

2020 ◽

Vol 110 (7-8) ◽

pp. 2105-2117

Author(s):

Omar Baho ◽

Gilles Ausias ◽

Yves Grohens ◽

Julien Férec

Keyword(s):

Laser Beam ◽

Laser Heating ◽

Thermal Model ◽

Laser Energy ◽

Thermoplastic Composite ◽

Thermoplastic Composites ◽

Efficient Production ◽

Fiber Placement ◽

Aerospace Applications ◽

Automated Fiber Placement

Abstract Laser-assisted automated fiber placement (AFP) is highly suitable for an efficient production of thermoplastic-matrix composite parts, especially for aeronautic/aerospace applications. Heat input by laser heating provides many advantages such as better temperature controls and uniform heating projections. However, this laser beam distribution can be affected by the AFP head system, mainly at the roller level. In this paper, a new optico-thermal model is established to evaluate the laser energy quantity absorbed by a poly(ether ether ketone) reinforced with carbon fibers (APC-2). During the simulation process, the illuminated radiative material properties are characterized and evaluated in terms of the roller deformation, the tilt of the robot head, and the reflection phenomenon between the substrate and the incoming tape. After computing the radiative source term using a ray-tracing method, these data are used to predict the temperature distribution on both heated surfaces of the composite during the process. The results show that both the roller deformation and the tilt of head make it possible to focus the laser beam on a small area, which considerably affects the quality of the finished part. These findings demonstrate that this optico-thermal model can be used to predict numerically the insufficient heating area and thermoplastic composites heating law.

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A review of welding technologies for thermoplastic composites in aerospace applications

Journal of Aerospace Technology and Management ◽

10.5028/jatm.2012.040303912 ◽

2012 ◽

Vol 4 (3) ◽

pp. 255-266 ◽

Cited By ~ 48

Author(s):

Anahi Pereira da Costa ◽

Edson Cocchieri Botelho ◽

Michelle Leali Costa ◽

Nilson Eiji Narita ◽

José Ricardo Tarpani

Keyword(s):

Thermoplastic Composites ◽

Aerospace Applications

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Physical, Chemical, and Crystallographic Characterization of Anodic Coatings on High Strength Aluminum Base Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100093146 ◽

1976 ◽

Vol 34 ◽

pp. 636-637

Author(s):

R. E. Herfert ◽

N. T. McDevitt

Keyword(s):

Sulfuric Acid ◽

Salt Spray ◽

High Strength ◽

Environmental Stability ◽

Anodic Films ◽

Sodium Dichromate ◽

Corrosion Resistant ◽

Aerospace Applications ◽

Bond Strengths ◽

Adhesive Bonded Joints

Durability of adhesive bonded joints in moisture and salt spray environments is essential to USAF aircraft. Structural bonding technology for aerospace applications has depended for many years on the preparation of aluminum surfaces by a sulfuric acid/sodium dichromate (FPL etch) treatment. Recently, specific thin film anodizing techniques, phosphoric acid, and chromic acid anodizing have been developed which not only provide good initial bond strengths but vastly improved environmental durability. These thin anodic films are in contrast to the commonly used thick anodic films such as the sulfuric acid or "hard" sulfuric acid anodic films which are highly corrosion resistant in themselves, but which do not provide good initial bond strengths, particularly in low temperature peel.The objective of this study was to determine the characteristics of anodic films on aluminum alloys that make them corrosion resistant. The chemical composition, physical morphology and structure, and mechanical properties of the thin oxide films were to be defined and correlated with the environmental stability of these surfaces in humidity and salt spray. It is anticipated that anodic film characteristics and corrosion resistance will vary with the anodizing processing conditions.

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TEM study of boron additions to cobalt aluminide

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104790 ◽

1988 ◽

Vol 46 ◽

pp. 546-547

Author(s):

Gerald B. Feldewerth

Keyword(s):

High Temperature ◽

Turbine Engines ◽

Major Drawback ◽

University Of Missouri ◽

Specific Strength ◽

Aerospace Applications ◽

Wide Range ◽

Ordered Alloys ◽

The University ◽

Very High

In recent years an increasing emphasis has been placed on the study of high temperature intermetallic compounds for possible aerospace applications. One group of interest is the B2 aiuminides. This group of intermetaliics has a very high melting temperature, good high temperature, and excellent specific strength. These qualities make it a candidate for applications such as turbine engines. The B2 aiuminides exist over a wide range of compositions and also have a large solubility for third element substitutional additions, which may allow alloying additions to overcome their major drawback, their brittle nature.One B2 aluminide currently being studied is cobalt aluminide. Optical microscopy of CoAl alloys produced at the University of Missouri-Rolla showed a dramatic decrease in the grain size which affects the yield strength and flow stress of long range ordered alloys, and a change in the grain shape with the addition of 0.5 % boron.

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Deformation at interfaces of Ti-6Al-4V/SiC fiber composites

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100121193 ◽

1992 ◽

Vol 50 (1) ◽

pp. 158-159

Author(s):

Warren J. Moberly ◽

Daniel B. Miracle ◽

S. Krishnamurthy

Keyword(s):

Thermal Stresses ◽

Load Transfer ◽

Coefficient Of Thermal Expansion ◽

Hot Isostatic Pressing ◽

Matrix Composites ◽

Ongoing Research ◽

Aerospace Applications ◽

Sic Fiber ◽

The Matrix ◽

Intermetallic Matrix Composites

Titanium-aluminum alloy metal matrix composites (MMC) and Ti-Al intermetallic matrix composites (IMC), reinforced with continuous SCS6 SiC fibers are leading candidates for high temperature aerospace applications such as the National Aerospace Plane (NASP). The nature of deformation at fiber / matrix interfaces is characterized in this ongoing research. One major concern is the mismatch in coefficient of thermal expansion (CTE) between the Ti-based matrix and the SiC fiber. This can lead to thermal stresses upon cooling down from the temperature incurred during hot isostatic pressing (HIP), which are sufficient to cause yielding in the matrix, and/or lead to fatigue from the thermal cycling that will be incurred during application, A second concern is the load transfer, from fiber to matrix, that is required if/when fiber fracture occurs. In both cases the stresses in the matrix are most severe at the interlace.

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TEM sample preparation of wear-tested room-temperature pulsed-laser-deposited thin films of MoS2 by ultramicrotomy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100151428 ◽

1993 ◽

Vol 51 ◽

pp. 1118-1119

Author(s):

Pamela F. Lloyd ◽

Scott D. Walck

Keyword(s):

Thin Films ◽

Sample Preparation ◽

Room Temperature ◽

High Vacuum ◽

Pulsed Laser ◽

Ultra High Vacuum ◽

Wear Testing ◽

Preparation Technique ◽

Cross Sectional ◽

Aerospace Applications

Pulsed laser deposition (PLD) is a novel technique for the deposition of tribological thin films. MoS2 is the archetypical solid lubricant material for aerospace applications. It provides a low coefficient of friction from cryogenic temperatures to about 350°C and can be used in ultra high vacuum environments. The TEM is ideally suited for studying the microstructural and tribo-chemical changes that occur during wear. The normal cross sectional TEM sample preparation method does not work well because the material’s lubricity causes the sandwich to separate. Walck et al. deposited MoS2 through a mesh mask which gave suitable results for as-deposited films, but the discontinuous nature of the film is unsuitable for wear-testing. To investigate wear-tested, room temperature (RT) PLD MoS2 films, the sample preparation technique of Heuer and Howitt was adapted.Two 300 run thick films were deposited on single crystal NaCl substrates. One was wear-tested on a ball-on-disk tribometer using a 30 gm load at 150 rpm for one minute, and subsequently coated with a heavy layer of evaporated gold.

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