Fatigue crack growth of filled rubber under constant and variable amplitude loading conditions
Service conditions experienced by rubber components often involve cyclic loads which are more complex than a constant amplitude loading history. Consequently, a model is needed for relating the results of constant amplitude characterization of fatigue behaviour to the effects of variable amplitude loading signals. The issue is explored here via fatigue crack growth experiments on pure shear specimens conducted in order to evaluate the applicability of a linear crack growth model equivalent to Miner's linear damage rule. This model equates the crack growth rate for a variable amplitude signal to the sum of the constant amplitude crack growth rates associated with each individual cycle. The variable amplitude signals were selected to show the effects of R-ratio (ratio of minimum to maximum energy release rate), load level, load sequence, and dwell periods on crack growth rates. In order to distinguish the effects of strain crystallization on crack growth behaviour, two filled rubber compounds were included: one that strain crystallizes, natural rubber, and one that does not, styrene-butadiene rubber. The linear crack growth model was found to be applicable in most cases, but a dwell effect was observed that is not accounted for by the model.
Document Type: Research Article
Affiliations: 1: Formerly Graduate Research Assistant at The University of Toledo, Currently at Goodyear Tire and Rubber Company 2: Professor, Mechanical, Industrial and Manufacturing Engineering Department, The University of Toledo, 2801 West Bancroft Street Toledo, Ohio 43606, USA 3: Lead Engineer, Research Department, Cooper Tire and Rubber Company, 701 Lima Avenue, Findlay, Ohio 45840, USA
Publication date: July 1, 2007