RT Journal Article
SR Electronic
A1 Nedomová, Šárka
A1 Severa, Libor
T1 Constitutive equation of butter at static loading
JF Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis
YR 2014
VO 56
IS 5
SP 147
OP 152
DO 10.11118/actaun200856050147
UL https://acta.mendelu.cz/artkey/acu-200805-0020.php
AB This study focuses on the constitutive modelling of finite deformation in the commercially obtained butter (composition is 83 % of milk fat) at the temperature 17-20 °C. The specimens from the butter (height L<sub>0</sub>=14.6 mm and diameter 20 mm) have been compressed between two parallel metal plates at a fixed crosshead speed 20 mm/min using of the testing device TIRA TEST. The force F and the deformation ΔL are measured during compression and both quantities are recorded. The experimental records force F - displacement (deformation) were obtained. These records have been transformed into stress-strain dependences and into true stress-true strain. The basic data on the strain behaviour of a butter under low strain rates have been obtained. Experimental results show that the behaviour of butter can be described by a hyperelastic material model. In this model, the quasi-static response is defined by compressible hyperelasticity, whereby the strain energy potential is assumed to be representable by a newly proposed polynomial series with three independent parameters. The material parameters in the constitutive model are determined from compression test. A comparison of predictions based on the proposed constitutive equation with experiments shows that the model is able to describe the strain behaviour of the butter examined.