Multi-Scale Modeling of Crystallization and Fracture in Rubbery Polymers

• Applicants: Professor Dr.-Ing. Marc-André Keip, since 2/2017; Dr.-Ing. Arun Raina
• Subject Area: Mechanics ; Applied Mechanics, Statics and Dynamics
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 273228006

Rubbery polymers are integral elements of various advanced engineering applications. Typical examples include tires, air ducts, turbocharger hoses, chassis suspension components in automobiles, heat and fuel-resistant seals in aircraft engines, flexible pipes for transport in oil and gas industry, elastomeric bridge bearings in civil engineering applications. These polymeric materials exhibit a very complex thermo-mechanical behavior. Besides their highly non-linear elasticity at large deformations, complicated inelastic features such as visco-elastic-plastic phenomena and damage-like response occur. Furthermore, the amorphous network of elastomers has a tendency to crystallize depending on the thermo-mechanical loading conditions. This temperature- and strain-induced crystallization can drastically alter the expected product response. The crystallization also has a critical influence on the fracture toughness. Goal of this reserach project is the modeling of these phenomena, which is of utmost importance with regard to a predictive analysis of failure mechanisms in rubbery polymers. In recent years, highly predictive multi-scale models have been developed for the visco-elastic response of rubbery polymers, which directly root the complex macroscopic material response in the micro-mechanical behavior of the polymer network. Advanced formulations are the so-called micro-sphere models of rubber elasticity, visco-elasticity and Mullins-type damage, which account for a non-affine link of a polymer chain orientation space to statistically-based micro-descriptions of single chain mechanisms. This research project will extend the micro-sphere models towards predictive simulations of strain-induced crystallization and fracture in rubbery polymers under non-isothermal conditions. It will combine and advance three aspects: (i) the multi-scale modeling of rate- and temperature-dependent strain-induced crystallization in rubbery polymers, (ii) its extension to time-dependent viscous effects within a thermo-visco-elastic constitutive framework and (iii) their combination with reliable and computationally efficient concepts for crack propagation during fracture. The project intends to deliver a major step towards a reliable simulation of crystallization and failure mechanisms in rubberlike materials.

• DFG Programme: Research Grants
• Ehemaliger Antragsteller: Professor Dr.-Ing. Christian Miehe, until 1/2017 (†)