ABSTRACT
There are many complex situations of structural geometry and loadings that make
analytical solutions of Mode I stress intensity factors impossible and numerical
simulations extremely difficult and expensive. Under these conditions the designer
resorts to experimental determinations of fracture parameters. Also, many times it
is advisable to conduct experiments to verify the results obtained through numeri-
cal analysis. Today, the experimentalist has many choices of using different
methods for the determination of K. These experimental techniques include: the
strain gage method, optical method of photoelasticity, shadow method of caustics,
optical fiber sensors, Moire´ interferometry, holographic interferometry, coherent
gradient sensing technique, and so on. The first four experimental techniques,
which are relatively simple to use, are discussed in this chapter.
