Nous avons le plaisir de vous annoncer le séminaire de 

Gamze CAKIR KABAKCI, portant sur "Toughening Mechanism Analysis of Recycled Rubber Based Composites. Reinforced with Glass Bubbles and Alumina Fibers. (Experimental and Numerical Study)", thème Tribologie et Matériaux.

le 17/11 à 13h15 via Teams. 

Résumé  (EN) :

Low cost devulcanized recycled rubber composites designed with microscale volume fillers and reinforcements such as Glass Bubble Microspheres (GBM), Alumina (Al2O3) Fibers are investigated in detail by means of toughening mechanisms, mechanical and physical properties as well as microstructural and fracture surface analysis. Microwave devulcanization of rubbers and surface modification of rubbers and reinforcements are performed. Mechanical properties of the composites are extensively investigated to obtain the data for basic material parameters. After the general characterizations of the composites, certain additional tests and measurements

are carried out. The effect of rubber, glass bubbles and alumina fibers on material properties and fracture toughness for different volume ratios are identified through various laboratory tests. Very high strain tests (Split-Hopkinson Pressure Bar test) are performed, strain rate dependency and dynamic response of the composites are identified, and the outcomes are considered in the modeling attempt. Several representative volume elements (RVEs) with proper boundary conditions are created and a continuum-based approach is adopted to model the ingredients (such as glass bubbles and alumina fibers) of the RVEs of the candidate compositions. A state-of-the-art continuum-level material model is developed by following a proper homogenization technique which considers the complex microstructure of the candidate composites. Implementation of the multi-material model for Finite Element Analysis SoftwareABAQUS/Standard as a user subroutine UMAT for implicit nonlinear finite element calculations is carried out. The basic characterization tests are reproduced numerically. A comprehensive testing and manufacturing plan is proposed in order to identify the optimum compositions for fracture toughness, resistance to impact and cost effectiveness. A consistent methodology is proposed for the numerical modeling of the candidate composites considering their complex microstructure which constitute several reinforcements with different mechanical and geometrical properties. An extensive plan is also proposed to compare the experimental, analytical and numerical results for the validation of the homogenization model.