Size Effect in Compression Fracture: Splitting Crack Band Propagation

Abstract

A simplified fracture-mechanics-based model of compression failure of centrically or eccentrically loaded quasi-brittle columns is presented and the size effect on the nominal strength of a column is predicted. Failure is modeled as propagation of a band of axial splitting cracks in a direction orthogonal or inclined with respect to the column axis. The maximum load is calculated from the condition that the energy released from the column due to crack band advance be equal to the energy consumed by the splitting cracks. The axial stress transmitted across the crack band is determined as the critical stress for buckling of the microslabs of material between the axial splitting cracks, and the work on the microslabs during postbuckling deflections is taken into account. The critical postbuckling deflection of the microslabs is determined from a compatibility condition. Under the assumption of small enough material inhomogeneities, the spacing