Quarter-Point Elements Are Unnecessary for the VCCT

The virtual crack closure technique (VCCT) is a well-established method for determining energy release rates and stress intensity factors in homogeneous, isotropic materials. It has been implemented with four-noded, eight-noded, quarter-point, and other higher order elements. It is most convenient and accurate when used with eight-noded, isoparametric elements. VCCT produces less accurate results when used with quarter-point elements. Yet, this method continues to be employed with quarter-point elements. It is strongly recommended to use VCCT with regular eight-noded elements. Three examples will be presented to illustrate the inaccuracy when using quarter-point elements with VCCT.