From Bulk to Structural Failure: Fracture of Hyperelastic Materials

This thesis investigates the fracture of nearly incompressible hyperelastic media. It covers the different characteristics of bulk material failure under dilatational or distortional loads and develops a unified description of the corresponding failure surface. It proposes a coupled strain and energy failure criterion for the assessment of notch-induced crack nucleation and presents a weak-interface-model that allows for efficient stress, strain and failure analyses of hyperelastic adhesive lap joints. Theoretical concepts for the measurement of fracture properties of nonlinear elastic materials are provided. The methodology is developed using two exemplary hyperelastic silicones, DOWSIL 993 Structural Glazing Sealant and DOWSIL Transparent Structural Silicone Adhesive, and is validated using large sets of experiments of different loading conditions. Philipp Rosendahl studied mechanical engineering at the Technical University of Darmstadt, the University of Illinois at Urbana-Champaign and the Royal Institute of Technology in Stockholm. His doctoral thesis on the fracture mechanics of thin layers opened applications to problems of structural engineering such as adhesive bonding in the fields of mechanical and civil engineering and to geophysical problems such as skier-triggered snow slab avalanche release. The author is currently working as the Junior Research Group Head for Structural Mechanics and Additive Manufacturing of the Institute of Structural Mechanics and Design at the Technical University of Darmstadt and co-founded the startup company 2phi, which aims at improving skier safety in the backcountry by transferring scientific advances into practice.

Auteur

Philipp Rosendahl studied mechanical engineering at the Technical University of Darmstadt, the University of Illinois at Urbana-Champaign and the Royal Institute of Technology in Stockholm. He is currently working as the Junior Research Group Head for Structural Mechanics and Additive Manufacturing of the Institute of Structural Mechanics and Design at the Technical University of Darmstadt and co-founded the startup company 2phi, which aims at improving skier safety in the backcountry by transferring scientific advances into practice.

Contenu

Introduction.- Theoretical background.- Samples and finite element models.- Experimental material characterization.- Bulk material failure.- Nucleation of finite cracks in hyperelastic materials.-Hyperelastic weak interface model.- Conclusions and perspectives.