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Owing to their interesting mechanical behavior and their diversity, rubberlike materials are more and more used in the industry. Previous works (Poisson et al.) presented an important experimental investigation on the multiaxial fatigue of polychloroprene rubber, with both proportional and non-proportional combinations of tension and torsion loads (with a large range of loads and three different phase angles: 0°; 90°, 180°). A fatigue criterion, based on the dissipated energy density (DED) was introduced. Comparing this parameter to the most important criteria available on literature—which are the strain energy density (SED), the cracking energy density (CED), and the Eshelby tensor—in their accuracy allows one to predict fatigue life of rubberlike material. All the predictors are computed with an analytical viscoelastic model based on the kinematics of a combined tension and torsion loading applied on a cylinder. This cylinder represents the central part of the axisymetric dumbbell specimen, and the model was identified with a polychloroprene rubber. It is finally shown that the DED and CED reach more conclusive results, provided the structure, the material, and the loads investigated.

Some fundamental studies carried in a synthetic rubber - Chloroprene CR29 are presented in the first part of the paper. A critical analysis of test results, shows that an energy based approach permits the determination of fatigue lives in this material. This aspect is further enhanced by biaxial fatigue tests in the same material. These tests covering a life range from 10000 to 1000000 cycles show that the energy based model is very efficient to describe the fatigue behavior. Some evidence of strain induced crystallization (previously observed in natural rubber) with associated life enhancement at high load ratios is also presented. A comprehensive model based on the determination of the constitutive laws taking into account the viscoelastic behavior is developed showing excellent correlation with experimental data.

Due to their interesting mechanical behavior and their diversity, rubber materials are more and more used in industry. Indeed, formulating a multiaxial fatigue criterion to predict fatigue lives of rubber components constitutes an important objective to conceive rubber products. An experimental campaign is developed here to study the multiaxial fatigue behavior of polychloroprene rubber. To reproduce multiaxial solicitations, combined tension–torsion tests were carried out on a dumbbell-type specimen (an axisymmetric rubber part bonded to metal parts with a reduced section at mid-height), with several values of phase angles between tension and torsion. A constitutive model is needed to calculate multiaxial fatigue criteria, and then analyze fatigue results. A large strain viscoelastic model, based on the tension–torsion kinematics, is then used to determine the material's stress–strain law. Dissipated energy density is introduced as a multiaxial fatigue criterion, and compared with those usually used in the literature. A multiaxial Haigh diagram is then built to observe the influence of Rd-ratio (ratio of the axial displacement's minimum to the axial displacement's maximum) on the multiaxial fatigue lives of polychloroprene rubber.

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