Theoretical and Experimental Investigation of Elastomer (Rubber) Straight Rod under the Tension

Theoretical and experimental studies of tension of a rod with rectangular cross-section made of elastomeric material were carried out. The stress-strain state in the rod was homogeneous. Under the assumption, that true axial strains in transverse directions are proportional to true axial strain in longitudinal direction, based on geometric pattern of deformation by introducing two Poisson’s ratios for transversely isotropic material, exact analytical dependencies were obtained. They relate linking engineering (nominal) normal stress recorded in experiments with calculated true normal stress in rod cross-section, true axial strain, measured in experiments with calculated volumetric strain and true measures of shear strains with axes rotated by $$45^{\circ}$$ . Experimental studies of tension of specimens made of sheet technical rubber were carried out and experimental results were processed based on obtained analytical dependencies, valid for finite strains. It has been established that even with considerable extension ratios, the true normal stress in the cross section of the specimen with the true axial strain can be permissibly related by the elasticity relation obeying the linear Hooke’s law. In it, the incoming Poisson’s ratios depend nonlinearly on the true axial deformation. With the same degree of accuracy, similar linear dependencies exist between the true tangential stresses in the rotated axes with the corresponding measures of the true shear strain. The possibility of realizing the phenomenon of instability of the tension process of specimens made of the technical rubber under consideration has been studied.