Title: The TTS R library for predicting the mechanical behavior of viscoelastic materials
Authors: Mario Francisco-Fernandez - Universidade da Coruna (Spain) [presenting]
Antonio Meneses - Universidad de Chimborazo (Ecuador)
Salvador Naya - University of A Coruna (Spain)
Javier Tarrio-Saavedra - Universidade da Coruna (Spain)
Ricardo Cao - University of Coruna (Spain)
Abstract: The TTS library, implemented in R software, has been performed to estimate the mechanical properties of amorphous materials (mainly polymers) subjected to thermal and mechanical loads. It allows us to study the reliability of amorphous polymers in the framework of material science. It is the first free software tool available to perform this task, apart from commercial software. It provides predictions of mechanical properties of amorphous viscoelastic materials, e.g. modulus and strain, at short and long observation times using the time-temperature superposition (TTS) principle and statistical analysis. The TTS package provides tools to estimate master curves that characterize materials from a thermal-mechanical point of view. The master curve is the trend of some viscoelastic property depending on time/frequency at the required temperature. It is calculated by shifting vertically and horizontally the curves obtained at other temperatures. It provides mechanical property estimates at wider ranges of time/frequencies than the experimental ones. The TTS library proposes, implements and explains step by step a new method for obtaining the shift factors in a TTS analysis. This method is based on horizontal shifting of the first derivative function of viscoelastic property curves, and it is implemented by the application of B-spline regression and bootstrap.