Influence of material properties of SIFs determined by frozen stress

In a prior study utilizing two materials for which thermal and mechanical p roperties of both materials in bimaterial specimens were matched except for modulus, it was found that modulus mismatch had a negligible effect on the stress intensity factor (SIF) level and distribution for cracks in bond li nes of stress frozen photoelastic bimaterial specimens. However, bond line residual stresses increased the SIF values. Since it is almost impossible t o obtain commercial stress freezing materials with matching critical temper atures (T-c) with different moduli, the present study of cracks parallel to and within bond lines utilized such materials with T-c mismatch and compar ed results with parallel studies with matched T-c values in order to evalua te T-c mismatch effects. Results show that T-c mismatch creates mixed mode conditions in cracks parallel to the bond line with significant increases i n the mode I SIF (K-1) for cracks very near the bond line but shows little effect for cracks within or away from the bond line. The absence of a modul us mismatch effect is again confirmed as well. (C) 1998 Elsevier Science Lt d. All rights reserved.