11 - Interaction of matrix cracking and delamination

Abstract

Publisher Summary Laminated composite materials have high strength-to-weight and stiffness-to-weight ratios. They can be considered as laminar systems with weak interfaces. Consequently, they are very susceptible to interlaminar damage. In the presence of delamination, material stiffness, and consequently, the associated structure, can be drastically reduced, which can lead to its catastrophic failure. Moreover, delamination is a form of internal damage and is not easily detected, which increases the associated risks. In the majority of real applications delamination does not occur alone. It is known that matrix cracking inside layers and delamination are usually associated and constitute a typical damage mechanism of composites, especially when structures are subjected to bending loads. Although the phenomenon can occur under tensile loading, it acquires a marked importance under bending loads. It is commonly accepted that there is a strong interaction between matrix cracking inside layers and delamination between layers. This coupling phenomenon is initiated by matrix cracking, that is, shear and/or bending cracks in the early stages of the loading process. These cracks can cause delamination and significantly affect its propagation.