Effect of Treatment Conditions on the Mode I Delamination Fracture Toughness of Sandwich Structures

Abstract

The mode I interlaminar fracture behaviour of aluminum-composite sandwich structures has been investigated. Double cantilever beam (DCB) specimens have been used for the determination of G _Ic-values. Various different skin treatments were used. The data obtained from these tests have been analysed using several different analytical approaches found in literature and compared with respective G _Ic-values derived from a simple analytical method developed by the authors. The original contribution of the present method when compared to all the existing methods is that a variable correction factor for G _Ic as well as for G _I(prop) describing crack front propagation history is defined. Most important is the fact that the method applies to all types of mechanical behaviour such as linear elastic, nonlinear elastic and inelastic. The results obtained can be used for the optimum design of sandwich structures since suggestions for optimal skin treatment are presented.

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