Off-axis notched strength of fiber–metal laminates and a formula for predicting anisotropic size effect

Experimental and theoretical studies of the effects of notch size and fiber orientation on the off-axis notched strength of the fiber–metal laminate GLARE-3 have been conducted. The notched strength decreased with increasing notch size, regardless of the fiber orientation. The notch sensitivity in GLARE-3 was highest in the fiber direction, and it decreased with increasing fiber orientation angle to the lowest in the 45° direction. A new multiaxial criterion for the tensile failure of notched orthotropic fiber composites was developed from a phenomenological point of view. From the proposed multiaxial failure criterion, an anisotropic size effect law for predicting the off-axis notched strength of orthotropic composite laminates was derived. By comparison with the experimental results on GLARE-3, it was demonstrated that the anisotropic size effect law can accurately and efficiently predict the off-axis notched strength of GLARE-3, regardless of the notch size and fiber orientation.