Some Geometric Considerations for Rubber—Metal Bond Test Specimens

Most methods for predicting fatigue lives of rubber components rely heavily on experimental studies that involve specimens subjected to essentially uniform states of deformation. But, in service, rubber components often fail at or near rubber-metal bonds where the state of deformation is far from uniform. Before experimental studies of fatigue failure in the vicinity of rubber-metal bonds, it is prudent to perform an analysis of the specimen geometry to make sure it has been optimized. This paper reports on finite element analyses of cylindrical rubber-metal bond test specimens recommended in ASTM D 429. The results suggest that taller specimens (height/radius ratio >= 2) have some advantages. Interpretation in terms of the strain energy release rate is recommended. A new asymmetric test specimen is proposed.