Fig. 4.

(A) Fracture mechanics specimen geometry and testing schematic. DCB geometry illustrating relevant loading parameters (P, Δ), delamination extension as measured from loading axis points (a) and relevant specimen dimensions (b = 10 mm, h = 2.88 mm, length = 40 mm). (B) Illustration of graded properties measurement method in which initially tested DCB substrate (B) is adhered to new substrate (A′) to form new DCB specimen and subsequently tested. The original substrates are tested again in this manner using new substrates each time (A″), etc., until the desired number of delaminations is completed. (C) SC delamination energy as a function of UV treatment for abdomen or breast specimens from donors ranging in age from 22 to 81 y exposed to varying dosages of broadband and narrowband UVB radiation. Note the log scale used for UVB dosage. (D) Delamination energy values for DCB tests performed on untreated SC and SC exposed to a dosage of 20 J/cm² narrowband UVB radiation versus number of delaminations.