فرسودگی پلی آمید تقویت شده با الیاف
Abstract
1-Introduction
2-Experimental
3-Conclusion
Acknowledgements
References
Abstract
The fatigue performance of laminated glass fiber reinforced polyamide composites was investigated in this study. Fatigue tests were conducted on both unidirectional and cross-ply specimens at room temperature. The S-N diagram of [0]8 followed a bilinear curve, however, the [90]8 laminates presented a linear S-N diagram. Compared to the same lamination of glass/epoxy, [0]8 and [90]8 glass/polyamide laminates presented a lower fatigue resistance, while [02/902]s laminates exhibited a superior fatigue resistance. In addition, stiffness degradation was investigated for the laminates and was compared with that of glass/epoxy with the same lamination. Glass/polyamide composites had lower stiffness reduction compared to glass/epoxy. During fatigue tests, an infrared (IR) camera was also used to monitor the temperature rise in [02/902]s and [04/904]s laminates resulting from mechanical cyclic loading, and to capture the temperature profile associated with the failure area in the specimens. The maximum temperature in [04/904]s laminates was comparable to that of [02/902]s laminates and the final temperature in some of the cross-ply specimens reached 50 °C, which was near the glass transition temperature of the polyamide matrix.
Introduction
Composite materials have gained much interest in different sections of industry due to a lot of advantages that they exhibit e.g. light weight, high stiffness and strength and damage tolerance. These materials are divided into two main groups namely thermoset and thermoplastic composites. In addition to recyclability, thermoplastic composites are tougher and more damage resistance than thermoset composites, so their application for structures under different static and cyclic fatigue loadings are preferred. In this regard, fatigue loading is more critical since it is expressed to be the reason of 80% of service failures [1]. There are some studies on fatigue behavior of thermoplastic composites but are limited to some high performance and engineering thermoplastic composites e.g. PEEK, PPS and PP-based composites. Some of the main research studies on the fatigue behaviour of these composites are as described here. Dickson et al. [2] studied the fatigue behavior of cross ply 0/90 and ±۴۵ carbon/PEEK and carbon/epoxy. They found that 0/90 lay-up for both materials had comparable fatigue resistance while ±۴۵ carbon/PEEK laminates had better fatigue resistance than carbon/epoxy laminates. Aymerich and Found [3] studied the fatigue behaviour of notched and unnotched quasi-isotropic carbon/PEEK and carbon/epoxy composites and evaluated fatigue damage mechanisms through X-radiography and C-scan.