| The viscoelastic stress analysis of polymer and polymer composite products, remains an open field of research, due to the complex non-linear, time-dependent properties of polymers. Examples of polymer and polymer composite parts can be critical structural elements such as brackets, riveted plate-like aircraft structures, tubular bicycle composite elements, gears, bushings, to name a few. Finite Element Method (FEM) is the dominant technique in computational mechanics, but it presents limitations to accurately predict large deformations of materials due to severe mesh distortions. These mesh distortions can be diminished with optimization techniques using remeshing, however, it is impossible to completely overcome mesh-related difficulties. Meshless methods discretize the continuum body with nodal points with no need of interconnecting elements, thus avoiding mesh-related difficulties. This project utilizes the meshless Radial Basis Functions Method (RBF) to simulate the linear elastic, and the linear viscoelastic mechanical behavior of special two-dimensional polymer composite structures with isotropic and orthotropic properties and compares the results with analytical infinite-plate solutions, Finite Element Method (FEM) models and experimental data. Different plate sizes with various boundary conditions were simulated and are discussed. Furthermore, experimental creep data for a thermoplastic material is modeled using RBF and compared to FEM results. The technique successfully incorporates the time dependent behavior of plastics using the Prony-series model, a model widely accepted in industry. |
