New Concepts on Caustics and Applications

A new formula of experimental evaluation of the stress intensity factor was proposed depending on the area of the caustic. From series of experiments, which were performed in single edge-cracked specimens made of Lexan (PCBA), it was found that the values of the stress intensity factor K I,, which were based on the diameters of the caustics, were varied with the load, the crack length and the caustic shape because the caustic become oval in higher loads or higher crack lengths. This means that the stress intensity values which are evaluated by the two diameters of the caustics (D t , D l), are significantly differed. The accurate stress intensity factor K I