Fatigue behavior enhancement of short fiber glass reinforced polyamide by adding phase change materials

High responsibility thermoplastic components subjected to dynamic forces show serious in-service thermal limitations. This paper shows that adding the adequate material with a phase-change, PCM, to a thermoplastic matrix component significantly increases its fatigue life. To do this, the fatigue resistance of short fibre-glass reinforced polyamide is analysed by means of monotonous fatigue tests on tensile specimens. Next, the design of the pieces of this material, used in high-speed rail fastenings, is optimised for fatigue efforts by means of accelerated single-piece tests. Finally, it is verified that the fatigue resistance of these pieces endowed with hydrated salt, Na2S2O3·5H2O, which acts as a PCM, increases by a surprising 400% with respect to the reference pieces without PCM.