FATIGUE FRACTURE-BEHAVIOR OF PEEK

Experimental results on fatigue crack propagation in PEEK under differ ent load levels, specimen thickness, and environmental temperatures re ported in References [1] and [2] are analyzed. When the kinetic data i s plotted against J1 = sigma(y)delta (where sigma(y) is the yield stre ss of the material and delta is the crack tip opening displacement), t he crack speed is practically independent of the load level, specimen thickness, and environmental temperatures up to 75-degrees-C. The expe rimental data is confronted with a power type kinetic equation and the kinetic equation of the crack layer model. The analysis indicates tha t both kinetic equations describe well the data under a wide spectrum of loading conditions.