Ilan Raphael, a doctoral student at the I2M laboratory ( Arts et Métiers campus Arts et Métiers Bordeaux-Talence), will defend his thesis entitled "Fatigue-creep of reinforced polyamide 6,6" on Thursday, December 5 at 1:30 p.m.
Summary
This work aims to supplement the current description and understanding of the fatigue behavior and damage mechanisms of thermoplastic polymers reinforced with short glass fibers. After reviewing the state of the art, the work focuses on evaluating the fatigue damage mechanisms in the composite as observed by micro-tomography and microscopy. In order to better understand the damage mechanisms in the composite matrix, additional observations are made on the polymer, revealing a complete scenario of intraspherulitic damage under fatigue loading. Microstructure calculation is used to complement this approach and improve understanding of damage mechanisms through the calculation of local mechanical fields. Based on the similarities between fatigue damage mechanisms and those observed in creep, a fatigue life assessment model based on cyclic strain rate is proposed. It proves to be very effective in unifying the fatigue life of the composite under a wide range of loading conditions, including the effect of the load ratio R, the effect of frequency, the effect of fiber orientation, and humidity. The proposed criterion is also suitable for application to notched specimens and gives promising results.
COMPOSITION OF THE JURY
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Mr. AndreaBERNASCONI, Politecnico di Milano, Rapporteur
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Mr. ChristopherPLUMMER, EPFL, Rapporteur
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Ms. CaroleNADOT-MARTIN, Pprime Institute, Examiner
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Mr. LucienLAIARINANDRASANA, Materials Center - MinesParisTech, Examiner
PRACTICAL INFORMATION
- Thursday, December 5, 2019, at 1:30 p.m.
- Arts et Métiers Campus Arts et Métiers Bordeaux-Talence
- LRL Lecture Hall
- Public defense
