Experimental investigations and numerical simulations of the mechanical behaviour of polyamides

Abstract

The PhD Thesis entitled Experimental investigations and numerical simulations of the mechanical behaviour of polyamides deals with the analysis of the behaviour of a PA-12 based polymer that has applications in sports footwear components. The mechanical properties of this material were investigated for various loading scenarios, results being used in designing virtual material models for finite element analysis simulations. The thesis is structured in 5 chapters. The first chapter consists of the thesis introduction, presenting the research background, the state of the art and the objectives. The second chapter presents the experimental procedures and the obtained results for tensile loadings (monotone tests, cyclic tests, low-cycle fatigue tests), three-point bending tests, dynamic tests (dynamic tension, DMA tests, puncture impact tests) and for compression tests performed on footwear components. In the third chapter several analytical models for describing constitutive relations were presented: linear elasticity, hyperelasticity, plasticity and viscoelasticity. The fourth chapter presents the results for simulations performed on three constitutive formulations: an elasto-plastic model, a hyperelastic model and a viscoelastic model. The constitutive models were evaluated for several test scenarios (monotone tension, cyclic tension and three-point bending) and validated on component simulations. The fifth chapter presents the conclusions and the personal contributions.