Article: Yu, Y; Bouklas, N; Landis, CM; Huang, R; “A Linear Poroelastic Analysis of Time-Dependent Crack-Tip Fields in Polymer Gels”, Journal of Applied Mechanics-Transactions of the ASME, 85 (11)
Abstract: Based on a linear poroelastic formulation, we present an asymptotic analysis of the transient crack-tip fields for stationary cracks in polymer gels under plane-strain conditions. A center crack model is studied in detail, comparing numerical results by a finite element method to the asymptotic analysis. The time evolution of the crack-tip parameters is determined as a result of solvent diffusion coupled with elastic deformation of the gel. The short-time and long-time limits are obtained for the stress intensity factor and the crack-tip energy release rate under different chemo-mechanical boundary conditions (immersed versus not-immersed, displacement versus load controlled). It is found that, under displacement-controlled loading, the crack-tip energy release rate increases monotonically over time for the not-immersed case, but for the immersed case, it increases first and then decreases, with a long-time limit lower than the short-time limit.
Under load control, the energy release rate increases over time for both immersed and not-immersed cases, with different short-time limits but the same long-time limit. These results suggest that onset of crack growth may be delayed until the crack-tip energy release rate reaches a critical value if the applied displacement or traction is subcritical but greater than a threshold.
Funding Acknowledgement: National Science Foundation [CMMI-1538658]
Funding Text: The National Science Foundation (Grant No. CMMI-1538658).