Evaluation of stress intensity factors by multiple reference state weight function approach

The advantages of expressing stress intensity factors in terms of weight functions are widely appreciated. However, the main obstacle in the determination of weight functions has been the definition of the crack opening displacement (COD) field. There are several approaches currently used, the most common is assuming an expression to define COD in terms of the crack dimensions and stress state. A recent development in weight function application simplifies the tranditional stress intensity factor calculation. This development uses more than one reference stress intensity factor and associated stress field to eliminate the need to assume a COD field. This paper describes current application of COD for weight functions and explains the full advantage of adopting a multiple reference state (MRS) weight function approach.