RULES FOR THE ASSESSMENT OF INTERACTING SURFACE CRACKS UNDER MODE-I LOAD

A review of the current widely used methods for the assessment of adja cent and coplanar surface cracks under LEFM conditions shows them to b e neither realistic nor always safe, having little scientific basis. S ince such cracks can interact they cannot necessarily be assumed to be independent, so improved methods of accounting for the interaction ar e required and are provided by this work. In a companion paper a conti nuous method of estimating the interaction factors for two coplanar su rface cracks was developed and proven. This enables realistic predicti ons of crack interaction and growth and is used as a basis for compari son of simpler assessment methods, the crack interaction estimation be ing somewhat cumbersome for general use. The assessment methods develo ped are thus shown to be safe. Furthermore they are realistic and stra ightforward to use. Cracks under tension, bending, and combined tensio n and bending load are considered.