Effect of tensile properties mismatch on fracture driving force in sandwich plates using notched specimens

Abstract

This paper studies the effect of tensile properties mismatch on fracture driving force in sandwich plates using Double Edge Notched Tension (DENT) specimens. Notched specimens are used due to the difficulty in fatigue pre-cracking small sized specimens of sandwich plates. Two sandwich plates, SP1 and SP2, composed of different aluminum alloys layers are studied. AA6061 is used as cladding material in both cases while AA2017 and Al 1100 are used as core materials for SP1 and SP2, respectively. Homogenous specimens made of AA6061 are also studied for comparison. The critical fracture load is determined experimentally. Finite element elastic-plastic analysis is performed to evaluate the effect of tensile properties mismatch on fracture driving force ahead of notch tip, Jtip.The results showed that tensile properties mismatch between sandwich plate layers affects Jtip values. In case of SP1, the notch tip is shielded from the remote loading where Jtip is smaller than the remote one vice versa in case of SP2 where Jtip is amplified. It is demonstrated that the amount of shielding is normally less than amplification. In the meantime, notch depth plays an important role in the fracture process while effect of the studied notch radius is minor. Keywords: Sandwich, Mismatch, Shielding, Amplification, Notch, Fracture