“…Crack surfaces can be in contact and have significant roughness. Papers examining inspection models with real crack interface conditions include Thompson and Fiedler (1984), Punjani and Bond (1986), Thompson et al (1986), Rehbein et al (1986Rehbein et al ( , 1988Rehbein et al ( , 1990, Buck et al (1988), Hirose and Kitahara (1991), Ogilvy and Culverwell (1991), Bostrom (1993), Bostrom et al, (1994), Eriksson et al, (1995), Solodov (1998).…”