CREEP CRACK-GROWTH FROM A SEMICIRCULAR SURFACE CRACK IN A CREEP-DUCTILE MATERIAL

Creep crack growth results are presented for five lead alloy beams, of depth 40 mm and width 80 mm, subjected to pure bending. The beams each contained semi-circular, crack-like, surface defects, of radius 5 mm, centrally positioned, in mode I opening. The deformation and crack growth from this defect are presented along with the uniaxial properties of the material. The creep crack growth correlates with previous results for plane specimens on the basis of the C∗ parameter. The ‘cracks’ where found to bifurcate under creep conditions and they grew in a direction suggesting equivalent stress-controlled damage of the material. © 1990, Institution of Mechanical Engineers. All rights reserved.