Asymmetric, fully plastic crack growth mechanics and tests for structures and piping

Many structures damaged in recent earthquakes had cracks from welds that broke the flanges of beams, broke flanges from columns, or veered off, sometimes through columns. At least some structures were fully plastic during crack growth. A complete asymmetric, plane strain, non-hardening, isotropic, rigid-plastic fracture mechanics is developed to predict such asymmetric crack growth from small specimen tests. For short cantilever specimens with an EDM slot across from an offset shoulder, slip line fields give the three crack up driving parameters: a slip direction 58* to 77* from the transverse (loading) direct ion, a moderate mean normal stress, and a slip of about half the applied displacement. Tests on A710 steel, TS = 630 MPa, gave the crack up growth responses at that mean normal stress: cracking within 4* of the observed slip direction and growth per unit slip of 3 to 5, somewhat low compared to other configurations and materials.