Predicting Crack Growth Elastomeric Materials

Abstract

Elastomers constitute an essential group of materials that are widely used in the automotive, aerospace, biomedical, microfluidic industries and in signal processing applications. Elastomeric materials undergo large deformations without fracture and exhibit time dependency under a prescribed displacement or load. Characterization of elastomeric materials can be challenging, due to the nonlinear behavior of elastomeric materials. Hence the use of a proper constitutive and fracture model that captures the behavior of elastomeric materials is essential. An experimental-numerical study was performed to predict long-term crack growth behavior using existing crack characterization parameters on both natural and synthetic rubbers. Experimental data obtained from uniaxial tension and creep tests were used to approximate a hyper-viscoelastic constitutive model. Good agreement between numerical simulations performed using ABAQUS and experimental results validated the hyper-constitutive model developed. Quasi-static crack growth, creep crack growth and fatigue tests were conducted to characterize crack propagation and fatigue life of elastomers. The displacement and strain fields surrounding the crack tip captured by digital image correlation was evaluated for the computation of fracture energy models. In this study, a modified contour integral was proposed to characterize crack opening behavior in elastomers. A comparison between the J-integral, T* integral and the Modified Contour Integral proposed was evaluated using data from quasi-static and creep crack growth experimental results. The Modified Contour Integral is a promising fracture model and was able to characterize crack growth behavior observed in elastomers.The results in this study indicate that the critical energy release of 12 MPa.mm led to the formation of new crack surfaces, in which beyond this value, the onset of critical crack growth occurred.