Parameter of local cyclic strain distribution

The local cyclic strain distribution near the crack tip was investigated by the Computer Aided Fine Grid Method. This method makes it possible to measure continuously every in-plane component of local cyclic strain distribution. It was found that the magnitude of the local cyclic strain distribution near the crack tip was varied by the applied cyclic load level and the material, but the shape of the local cyclic strain distribution near the crack tip was experimentally scarcely altered. The local cyclic strain field near the crack tip could be written as the following equation. Δε{lunate}_eq(r, θ) = ΔA · f(θ) · r^-1 A single parameter ΔA, which characterizes the local cyclic strain field near the crack tip, was newly proposed by authors.