School of Engineering and Materials Science Publication:

"Transitions in tear and fatigue crack growth in elastomers"

Author(s): J.J.C. Busfield, I.C. Papadopoulos and A.G. Thomas

Journal: Constitutive Models for Rubber IV. edited by L. Kari and P-E. Austrell, A.A. Balkema (Leiden), p. 145-151

It has been observed previously that cracks grow more rapidly from sharp cuts in elastomer materials under stress than is expected from a consideration of the strain energy release rate alone. After the crack has grown, the behaviour returns to the ‘steady state’ crack growth rate per cycle anticipated for the applied strain energy release rate. This work examines these transitions from an artificial sharp crack tip, introduced for example by a razor in a pure shear tear test piece for a range of elastomer materials. The changes in the rate of crack growth are also reflected by changes in the fracture surface appearance which roughens as the crack develops. This work is of practical significance in real engineering applications, where an initially fast crack growth rate from a sharp cut in a rubber product can result in significantly reduced fatigue life. A second phenomenon that has been examined concerns both tearing and fatigue crack growth, where the crack growth can follow complex paths that are not always simply normal to the applied stress. This work examines the ability of a finite element analysis package to predict the crack growth path for simple test piece geometries.

Related site: http://www.materials.qmul.ac.uk/rubber