Temperature simulation of three-point bending geometry in a dynamic mechanical analyzer

Abstract

Dynamic mechanical analysis (DMA) is a thermo-analytical technique that is widely used as a part of polymer characterization. One of the most common tests consists of measuring viscoelastic properties as a function of temperature while subjecting the sample to controlled heating rates. In that tests, due to sample and instrument geometry and sample size, it is not possible to measure the temperature in all parts of the sample. As a result, the gradient of temperatures between different parts of the sample is unknown. Thus, an accurate estimation of the sample temperature in all its parts and of the temperature gradients between different parts are crucial for setting up experimental conditions and establishing confidence temperature ranges to better interpret the test results. In the present work, a simulation study is performed through the Comsol ™ software, to estimate the temperature distribution of samples of different density and heat capacity that are located inside a typical DMA furnace, which is subjected to different heating rates. The furnace has two gas inlets and three outlets and the sample is attached through standard 3-point bending fixtures. The results show that some of the temperature gradients produced in the sample high enough to significantly affect the viscoelastic response.