A COMPUTER PROGRAM TO EXTRACT THE CONTINUOUS AND DISCRETE RELAXATION SPECTRA FROM DYNAMIC VISCOELASTIC MEASUREMENTS

作者：Takeh Arsia; Shanbhag Sachin^*

来源：Applied Rheology, 2013, 23(2): 24628.

DOI：10.3933/ApplRheol-23-24628

• relaxation spectrum
• linear rheology
• continuous spectra
• discrete spectra

We describe and implement an efficient, open-source, multi-platform computer program ReSpect to infer the continuous and discrete relaxation spectra from dynamic moduli measurements obtained by small-angle oscillatory shear experiments. We employ nonlinear Tikhonov regularization and the Levenberg-Marquardt method to extract the continuous relaxation spectrum. To obtain the discrete relaxation spectrum, we introduce a novel algorithm that exploits the continuous spectrum to position the modes. It uses a simple criterion which balances accuracy and conditioning of the resulting least-squares problem to determine a parsimonious number of modes. The end result is an easy-to-use, and easy-to-extend program, which can be used from the command-line or from a graphical user interface to override some of the default algorithmic choices.

• 出版日期2013