Determination of residual stress intensity factor in the compact tension coupon

This paper provides an influence function required to compute the residual stress intensity factor in the compact tension coupon, as a function of crack length, from measurements of back-face strain as a function of crack length. The influence function is determined from a reference solution for the C(T) with uniform applied pressure on the crack face that provides stress intensity factor and strain over a broad range of crack length (measured from the front face) and strain gage length. A closed form surface fit provides values of the influence function as a function of crack length and strain gage length.

► A method is provided to find KRS in the C(T) from back-face strain and crack length.
► The influence function Z(a) is determined from a new reference solution for the C(T).
► A closed form expression provides Z(a) for a range of crack and strain gage sizes.