Thermosetting polymers are used in many applications where they might be susceptible to cracking deep inside the structure, making detection costly and difficult. In many cases, repair of the detected cracks is impossible or too expensive, rendering the structural component useless. For these reasons, recent research activities have focused on designing new materials which can exhibit in situ autonomic healing continuously over the lifetime of the structure (White et al. [1]). The focus of the current research project is to study the fatigue behavior of this material. Experiments conducted on this class of materials have shown substantial retardation and, in some cases, complete arrest of propagating fatigue cracks. We have studied this phenomenon numerically using the cohesive finite element based technique to simulate the fatigue crack growth and retardation. A new cohesive model for fatigue crack growth has been developed for polymeric materials. The effect of material deposition behind the crack tip has been accounted for in the model using a cohesive element based penalty formulation for contact enforcement. The healing cure kinetics has been coupled to the mechanical failure response through an adhesive model. The model has been used to study the effect of different parameters like rate of cure, geometry of deposited material and external loading conditions. Comparison with experimental observations will be presented.
REFERENCE
1. White, S.R, Sottos, N.R., Moore, J., Geubelle, P., Kessler, M., Brown, E., Suresh, S., and Viswanathan, S. (2001), "Autonomic Healing of Polymer Composites", Nature, 409, 794-797.
Back to Mechanics and Thermodynamics of Polymers
Back to SES Abstracts
Back to The 41st Annual SES Technical Meeting