Constitutive modeling of amplitude dependent dynamic response of polymeric materials

Date

2024-1-08

Author

Usta Yayla, Ayşe

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Polymeric materials are an important class of materials extensively used in aerospace, automotive, and biomedical industries. Rubber-like materials with fillers stick out in this category due to their impacting characteristics like damping, strength, and impermeability. Optimizing their performance requires a thorough understanding of mechanical responses under distinct loading circumstances. In addition to material models developed for monotonic loadings, it is important to analyse the material reaction under dynamic loading since they are also used as dampening components in vehicle design. The filled rubbers exhibit distinct behaviours for dynamic loadings with varying amplitudes, temperature, and frequency as well as hardness of the material. Among these, the amplitude dependence is particularly relevant to Payne effect, which can be defined as a stress softening phenomenon due to increased dynamic amplitude. Constitutive models are created using a micro-mechanical or phenomenological approach. In addition to conventional internal variables, a new internal variable is introduced to describe the amplitude dependence by characterizing the micro-structural reaction of the material in terms of loading rate through dashpot elements. In this thesis, a new constitutive model is proposed for filled rubbers to describe the amplitude dependent dynamic response -Payne effect- accurately. The behaviour of hyperelastic and viscoelastic materials is investigated through quasi-static and dynamic loading experiments. The extended eight-chain method is used to capture the hyperelastic response. Viscoelastic response is described with the micro-sphere material model. The proposed method successfully characterizes the non-linear dependency of inelastic materials on the loading rate. The efficacy of the proposed method is illustrated through comparisons with the existing literature. In addition, several numerical studies are presented with finite element analyses.

Subject Keywords

Polymeric materials, Amplitude dependent behaviour, Payne effect, Dynamic loading, Constitutive modeling, Rubber-like materials, Filler particles

URI

https://hdl.handle.net/11511/108347

Collections

Graduate School of Natural and Applied Sciences, Thesis