Long-term durability of polymer matrix composites under simulated supersonic flight profile testing

2000 ◽  
Author(s):  
Thomas Gates ◽  
Karen Whitley
Keyword(s):  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Matrix Composites ◽  
Supersonic Flight ◽  
Flight Profile

Long-term durability of polymer matrix composites under hostile environments

2005 ◽  
Vol 412 (1-2) ◽  
pp. 159-164 ◽  
Author(s):  
H. Kawada ◽  
A. Kobiki ◽  
J. Koyanagi ◽  
A. Hosoi
Keyword(s):  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Matrix Composites ◽  
Hostile Environments

On the Transient Hygroscopic Stresses in Polymer Matrix Laminated Composites Plates with Cyclic and Unsymmetric Environmental Conditions

2005 ◽  
Vol 13 (5) ◽  
pp. 489-503 ◽  
Author(s):  
A. Tounsi ◽  
M. Bouazza ◽  
S. Meftah ◽  
E. Adda-Bedia
Keyword(s):  
Polymer Matrix ◽  
Composite Structures ◽  
Polymer Matrix Composites ◽  
Matrix Composites ◽  
Stress Distributions ◽  
Moist Environment ◽  
Cyclic Variations ◽  
Transient Hygroscopic Stresses ◽  
Structural Parts

The use of aircraft structural parts made of polymer matrix composites subjected to severe environment conditions calls for better knowledge of their long – term behaviour, with an emphasis on their ability to withstand important cyclic variations of moisture and temperature. The influence of temperature and moisture on such structures is receiving special attention, because it induces transient residual stresses within the plies. Such stresses must be taken into account in the design of composite materials, particularly aerospace structures, e.g. aircraft. In the present paper the transient hygroscopic stresses induced by cyclic and unsymmetric environmental loadings which simulate an aeronautical application are investigated. It is shown that the heterogeneity and anisotropy of such plates generally result in transient stress distributions which are very different from the equilibrium stress distribution. Some stacking sequences exhibit important stresses within the plies. These stresses have to be taken into account in the design of composite structures submitted to a moist environment.

Application of the Electronic Speckle Pattern Interferometry (ESPI) Technique for the Localisation Analysis of Damage Development in Composites

2002 ◽  
Author(s):  
Pascal J. P. Bouquet ◽  
Albert H. Cardon
Keyword(s):  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Electronic Speckle Pattern Interferometry ◽  
Strength Analysis ◽  
Creep Recovery ◽  
Matrix Composites ◽  
Damage Development ◽  
Damage Initiation ◽  
Delayed Failure

The analysis of the long-term behaviour of polymer matrix composites has to be performed for their stiffness evolution and for their strength changes. Long fiber reinforced polymer matrix composites exhibit an anisotropic viscoelastic-viscoplastic behaviour. The non-linear viscoelastic constitutive equations proposed by R. Schapery [1], with a viscoplastic correction are able to analyse the long-term stiffness evolution on the basis of some short-term creep and creep-recovery tests. For the strength analysis it is possible to consider some delayed failure approach as the end of a viscoelastic-viscoplastic behaviour. The experimental follow-up of the creep evolution till rupture needs a full field technique in order to have a complete view of the strain field and the evolution of this field where the damage initiation and development transforms the homogeneous strain distribution in an heterogeneous one. The ESPI technique shows clearly the location of the damage initiation and allows us to follow the damage development. Examples of the ESPI technique on graphite epoxy specimen will be presented and the results in relation to the delayed failure analysis will be discussed.

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