1. Comparison of direct and indirect measurement of the elastocaloric effect in natural rubber
- Author
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Gael Sebald, Daniel Guyomar, Zhongjian Xie, Laboratoire de Génie Electrique et Ferroélectricité (LGEF), Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)
- Subjects
State variable ,Materials science ,Physics and Astronomy (miscellaneous) ,Direct and indirect measurements ,Thermodynamics ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Measure (mathematics) ,Shape memory effect ,Stress (mechanics) ,[SPI]Engineering Sciences [physics] ,Strain behaviors ,Natural rubber ,Static temperature ,Measured temperatures ,Quantitative agreement ,Strain (chemistry) ,Indirect methods ,State variables ,Shape-memory alloy ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Constant strains ,visual_art ,visual_art.visual_art_medium ,Rubber ,Deformation (engineering) ,0210 nano-technology ,Constant (mathematics) - Abstract
cited By 12; International audience; The directly measured temperature change Δ T upon deformation (elastocaloric effect) of natural rubber was compared with indirect method, which is deduced from the Clausius-Clapeyron factor (σ / T) ε, where σ is the stress and ε is the strain. The factor (σ / T) ε can be measured by two different methods. One is to measure the stress vs. strain behavior at different static temperatures. It is found that the Δ T deduction is underestimated or even of opposite sign compared with the directly measured one. These behaviors are different from elastocaloric effect of shape memory alloys. An interpretation based on strain-induced crystallite is proposed. The other characterization is to measure the stress vs. temperature at constant strain. It results in a prediction, which is in good quantitative agreement with the directly measured one. The stress appears then to be a non-state variable, thus questioning the ergodicity of the material. © 2016 AIP Publishing LLC.
- Published
- 2016