ABSTRACT
A good understanding of damage is essential to develop a rational methodology to address damage tolerance characteristics of advanced composite materials. This chapter discusses nondestructive evaluation (NDE) techniques, damage assessment using optical/SEM evaluation, and damage tolerance tests. The NDE examination is structured such that inspections involve progressively more detail of the damage condition, including initial plan view inspections, detailed plan view inspections, and through-thickness inspections. Typical ultrasonic inspection of homogeneous isotropic materials is a process that requires a trained operator using precision and care to avoid errors in the assessment of the damage conditions. In through-transmission ultrasonic, the sound attenuation results from three sources: viscoelastic effects, geometric dispersion due to material anisotropy, and dispersion due to geometric internal damage. In estimating the damage tolerance capability of polymer matrix composites, the tests provide critical information on the structural capability of the material.
