Influence of damage and disorder on structural response of quasi-brittle materials

SUMMARY The tensile mechanical behaviour of quasi-brittle materials, such as concrete, has been the subject of numerous studies from which there has unequivocally emerged the centrality of the cracking phenomenon. The present study highlights this aspect by evaluating the tensile structural response of an in"nite plate with an in"nite set of collinear cracks that are spaced at a constant distance apart and are of variable length according to a distribution of self-similarity. The "rst part of this paper describes the general features of the method of the pseudo-tractions used to determine the stress-intensity factors, which is based on the application of the principle of superposition. Subsequently, by means of a numerical simulation, in which account is taken of crack propagation and coalescence (excluding overlapping), the link is obtained between critical tensile stress and the incremental displacement due to the damage present in the material, accounting for typical aspects of structural response, such as the strain-softening phenomenon. Copyright ( 2000 John Wiley & Sons, Ltd.