Abstract
A metal-matrix specimen was investigated using high-sensitivity moire interferometry. The specimen was a 6-ply [0/±45]s boron-aluminum tensile coupon with a central slot. In-plane displacement fields were analyzed at various load levels from 15 to 95% of the failure load. Normal and shear strains were determined from displacement gradients. Highly localized plastic slip zones occurred in the ductile aluminum matrix tangent to the ends of the slot. Shear strains in the slip zone were an order of magnitude greater than the largest normal strains in the specimen. The shear-strain concentration factor γxy/ϵff rose dramatically with the onset of plastic slip and continued to rise gradually with load to 95% of the failure load. Upon unloading, shear strains in the slip zone remained precariously high. The maximum normal strain occurred at the end of the slot, where the normal-strain concentration factor ϵy/ϵff diminished as the load increased.
