A temporal-averaging based approach to toughness homogenisation in heterogeneous material

Abstract

A new approach to defining the effective fracture toughness for heterogeneous materials is proposed. This temporal averaging approach is process-dependent, incorporating the crack velocity and material toughness. The effectiveness of the new technique is investigated in the context of hydraulic fracture through heterogeneous rock with a periodic material toughness. The plane strain model is considered without fluid leak-off, to more easily investigate different regimes (toughness/viscosity). Numerical simulations are used to examine the effectiveness of the new homogenisation strategy, with comparison against the recently-proposed maximum toughness strategy. Simulations are conducted using an extremely effective (in house-built) time-space adaptive solver. The regimes in which each strategy is effective are determined.