The influence of aspect ratio on the determination of tearing energy in mode I fracture tests

•A refined analysis of Rivlin and Thomas’ approach (1953) to determine the energy for tearing in the pure shear fracture test is proposed.•Combined computational analysis and experimental results reveal the dependence of the determined apparent tearing energy on sample aspect ratio, and suggest that corresponding guidelines in literature are mainly overconservative.•The admissible aspect ratio depends on the fracture toughness of the material.•Surprisingly, for many typical elastomers even an aspect ratio of 1/1 may still yield very good estimates.