Experimental studies on uniaxial and echibiaxial tensile tests applied to plastic materials sheets

Abstract The main objective of this paper is to determine the behavior of few plastic materials using two different type of tests. We use classical uniaxial tensile test to determine the most important mechanical and elastic characteristics, such as: yield stress, Young modulus, tangent modulus, maximum stress and maximum strain and to plot engineering stress vs. engineering strain curve for these materials. The second test, that was used in this study, was echibiaxial tensile test on the spherical punch. This test was used to determine maximum breaking force and, of course maximum displacement of specimen on punch direction and others few important characteristics, such as: major and minor strain, equivalent von Mises strain, shear angle and thickness reduction. If we look on the results, we can see a very good repeatability of these. From the analysis of the results, we can observe that polyamide (PA) and polyethylene (PE) have the best deformation capacity for both type of tensile test (uniaxial and echibiaxial). The weakest behavior is polyoxymethylene (POM-C) which has a low elongation and requires large forces for deformation. All data collected after these tests can be used to characterize elastic and plastic behavior of these materials which are more and more used in various applications and engineering processes. Selection and peer-review under responsibility of 35th Danubia Adria Symposium on Advances in Experimental Mechanics.