Acenter-cracked panel with an initial crack length of 0.010 mm is subjected to a tensile cyclic stress between 25 and 125 mpa for 35 cycles. the panel is then subjected to a tensile cycle stress between 0 and 250 mpa. how many of the larger stress amplitude cycles can be sustained before failure? the material has a fracture toughness of 25 mpa√m and material constants n = 3.1 and c = 1.8 x 10-10 for these units.