ABSTRACT
Damage accumulations before ultimate failure in laminated composites containing an open hole were studied and compared under tensile and compressive loadings. For laminates where damage accumulations were found similar under different loading conditions, the same characteristic length can be used for the strength prediction under these loading conditions. On the other hand, if the damage mechanisms were different due to different type of loadings, then different characteristic lengths need to be used to predict the notched strength accurately. This chapter explains the use of the characteristic length as a parameter for the theoretical strength prediction. Some experimental techniques, such as the photoelasticity, moire methods, and holographic interferometry, can detect the surface cracks but not interior damage. The experimental results illustrated in the following subsections include effective laminate properties, radiographs to show the damage accumulation, and failure mechanisms of the specimens, as well as the fracture specimens.
