Taiqu LIU : "Multi-scale damping characterization of plant fiber composite materials"

Phd works of Taiqu LIU : "Multi-scale damping characterization of plant fiber composite materials"

Abstract: Vibration and noise are unavoidable problems in engineering products and daily life. Thus, the knowledge of the damping performances of engineering materials and the factors that affect these properties are highly required. Plant fiber composites (PFCs) have become a new option when considering the compromise between damping and stiffness. Current researches on damping are mainly work at the macroscale and the damping sources and mechanisms in plant fiber composites are complex and not fully revealed. Thus, the main objective of this thesis is to provide a better characterization and understanding of damping in PFCs using various experimental techniques at different scales and on a wide range of frequency. This thesis starts with the review of literature on the damping behavior of PFCs. Then, the influences of many parameters including matrix types, fiber architecture, woven pattern, temperature, frequency and moisture content on the damping properties of PFCs are investigated based on dynamic mechanical analysis (DMA) and modal analysis. Furthermore, a constant amplitude method as well as constant stiffness method are used to map the in situ damping properties at the microscale based on grid dynamic Nanoindentation (DNI). These results are then compared to those obtained from dynamic mechanical analysis and modal test methods. The results from DNI show the contribution of each component (fiber, matrix and interface) on energy dissipation. Finally, the damping properties measured using these three experimental techniques at the three different scales are plotted on a wide frequency and temperature range.

Jury Composition :

Morvan OUISSE, PR1, Université Bourgogne Franche-Comté, PhD Director

Jean-François DEU, Professeur des Universités, Conservatoire National des Arts et Métiers (Cnam), Reporter

Alain BOURMAUD, Ingénieur de recherche, Institut de Recherche Dupuy de Lôme, Reporter

Stéphane FONTAINE, Professeur des Universités, ARTS ET MÉTIERS CAMPUS DE METZ, Reviewer

Vincent PLACET, Ingénieur de recherche, Université Bourgogne Franche-Comté, PhD CoDirector

Pauline BUTAUD, Maître de conférences, Université Bourgogne Franche-Comté, PhD CoDirector

Localization : Amphithéâtre Emilie du Chatelet - 26, Rue de l'Epitaphe, 25000 Besançon