Prior detailed microscopic observations have revealed the essential mechanisms of damage in through-thickness reinforcing tows when a delamination crack passes. As expected, the damage sequence depends quite strongly on whether the crack is loaded in Mode I or Mode II and, if loading is mixed mode, the order of loading. Here, micromechanical models are presented that show how geometry and const...

OBJECTIVES The primary aim of this research was to investigate the wear behavior and wear mechanism of five different veneering porcelains. METHODS Five kinds of veneering porcelains were selected in this research. The surface microhardness of all the samples was measured with a microhardness tester. Wear tests were performed on a ball-on-flat PLINT fretting wear machine, with lubrication of ...

Measured Amplitude Ratio (MAR) is a form of modal analysis for the classification of Acoustic Emission (AE) signals. MAR uses a comparison of the amplitudes of the first two primary lamb wave modes, symmetric (S0) and asymmetric (A0), to determine the orientation of the damage mechanisms in relation to the sensor. Previous researchers have demonstrated that some damage mechanisms, such as delam...

Delamination is an important concern in the context of structural behaviour of laminated composite materials. It is known that delamination can diminish the stiffness and the strength of the material and promote structural failure. Delamination onset and growth is governed by interlaminar fracture toughness of the material. Delamination propagation is frequently dominated by mode II fracture; c...

In the present work, the interaction of Rayleigh waves with a delamination in a fiber reinforced composite plate was analyzed. Rayleigh waves, upon interacting with delamination mode, convert into Lamb waves in the delamination zone. These guided Lamb modes have the capability to mode convert back into Rayleigh modes when they interact with the edge of the delamination. A unidirectional glass/e...

Advanced, waveform based acoustic emission (AE) techniques have been developed to evaluate damage mechanisms in the testing of composite materials. This approach, more recently referred to as Modal AE, provides an enhanced capability to discriminate and eliminate noise signals from those generated by damage mechanisms. Much more precise source location can also be obtained in comparison to conv...