TTS package: Computational tools for the application of the Time Temperature Superposition principle

Area of Science:

• Material Science
• Computational Physics
• Rheology

Background:

• The Time Temperature Superposition (TTS) principle is crucial for estimating material properties beyond experimental limits.
• Existing methods for TTS analysis often rely on specific parametric models or manual data manipulation.
• There is a need for accessible, open-source computational tools to apply TTS principles effectively.

Purpose of the Study:

• To introduce an R package designed for predicting mechanical properties of viscoelastic materials using the TTS principle.
• To provide an open-source computational tool for generating material master curves.
• To present a novel, automatic method for estimating TTS shift factors and master curves.

Main Methods:

• Development of an R package implementing the Time Temperature Superposition (TTS) principle.
• Application of a novel method based on horizontal shifting of the first derivative of viscoelastic properties to obtain shift factors.
• Utilizing B-spline fitting for automatic, non-parametric estimation of smooth master curves.
• Implementation of Williams-Landel-Ferry (WLF) and Arrhenius TTS parametric models for fitting shift factors.

Main Results:

• The TTS R package provides a user-friendly interface for applying the TTS principle.
• The proposed derivative-based method enables automatic and accurate estimation of shift factors and master curves.
• The package facilitates material characterization through a thermal-mechanical approach, extending experimental data ranges.
• Successful implementation of both novel and established TTS models within the R environment.

Conclusions:

• The TTS R package offers a valuable, open-source resource for material scientists and engineers.
• The automated, derivative-based method simplifies and enhances the accuracy of TTS analyses.
• This tool aids in understanding material behavior over extended time/frequency ranges, relevant for reliability and accelerated testing.