Approximation of mode I crack-tip displacement fields by a gradient enhanced elasticity theory.

Highlights: [•] Mode I deformation fields in gradient enhanced materials are derived in closed form. [•] The theory resembles experimental results in fracture experiments on a fiber material. [•] A structural effect results in crack tip blunting in heterogeneous materials such as fiber networks. [•] The average segment length gives the internal length scale parameter, hence allow for bridging between scales. [Copyright &y& Elsevier]