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Damage Tolerance

2 tools in the Structures area.

Center Crack

Elastic stress field of a through crack of length 2a in an infinite plate under any uniform in-plane far-field state given as N_xx, N_yy, N_xy and the thickness t (Westergaard solution): the stress intensity factors K_I and K_II, the T-stress, the energy release rate, the full stress field at a user input point, the near-tip asymptotic field and the plastic-zone estimate, with fringe and line plots. The crack may be inclined to the plate axes.

3 worked examples reproduced, listed on the tool page.

Crack Growth

Fatigue crack growth from an initial to a critical crack size by the Paris, Walker, Forman or NASGRO equation: stress intensity from the geometry factor of a centre crack (infinite plate or Feddersen secant), a single or double edge crack (Tada polynomials), two cracks at a hole (Newman's collocation table), a semi-elliptical surface crack growing in depth and length by the Newman–Raju equations, or an entered Y(a/W); the critical crack size from the fracture toughness, the threshold check, the integration of da/dN by adaptive Runge–Kutta with the geometry factor re-evaluated (and the closed form written out when Y is constant), cycles to failure, the a–N curve, the da/dN–ΔK line, the crack size at 10 % steps of the life, the inspection interval from a detectable crack size, the residual strength against crack size and an optional block-loading sequence without retardation. Constants of 2024, 7050, 7075 and 7475 aluminum alloys from the FAA fatigue crack growth database (DOT/FAA/AR-05/15), the Forman constants of Hudson (NASA TN D-5390) and Barsom's upper-bound steel equations fill the fields from a material list; the default case is the 2024-T3 sheet of the FAA database with a centre crack in a 6 in wide plate under a 15 ksi stress range.

1 worked example reproduced, listed on the tool page.

Other Structures sections

Materials · Composites · Frames and Trusses · Beams · Loads and Dynamics · Joints · Stress and Strain · Stability · Plates and Shells · Thin-Walled Structures · Contact · Stress Concentrations · Fatigue