A method of automatically obtaining master surfaces of resin matrix composites by time–temperature superposition

The time–temperature superposition (TTS) is a data processing method of viscoelastic mechanics, which is realized by translating and superposing the responses at different temperatures to get master curves beyond the test time or frequency. In this study, an automatic shift method is developed to obtain master surfaces of the carbon fiber reinforced plastics and epoxy resin. First step, an interpolation is used to process the dynamic mechanical analysis test data measured by frequency sweep/temperature step or continuous heating-up method. Second step, the Prony series of the generalized Maxwell model are used to fit the storage and loss modulus at each temperature, which makes the fitting curves have physical meaning and causality. Third step, the automatic shift is achieved by minimizing the sum of squares of the vertical distances between two fitting curves. Last step, master surfaces are created by Prony series fitting and interpolation, and the storage modulus, loss modulus, loss factors, and relaxation modulus at any temperature, frequency or time can be found on the master surfaces. Both storage modulus and loss modulus are considered at same time according to the weight. The effects of different weights are studied.