Effect of Strain Gage Length When Determining Residual Stress by Slitting

Full block geometry model. Variables are thickness of the part in the slitting direction t, the slit depth a, the slit width w, the length L, the gage length l, the depth B, and the distance between the center of the gage and the center of the slit s.

Finite element model used in analysis

Compliances for l∕t=0.005 and various input stress order

Compliances for a range of l∕t and input stress order, (a) j=2, (b) j=5, (c) j=9, and (d) j=12

Computed residual stress for σinp(x)=P5 and varying l∕t, computed using reference l∕t=0.005

Normalized RMS stress error for varying l∕t, over a range of reference l∕t and input stress order (a) j=2, (b) j=5, (c) j=9, and (d) j=12

Normalized RMS stress change due to mesh refinement

g(l∕t) for input stress order j=2, 5, 9, and 12, and g¯(l∕t)

Normalized rms difference in compliance matrix elements from geometry-specific FEM and from the compact representation using Eq. 10

Normalized rms difference in stress computed using compliance matrices from geometry-specific FEM and from the compact representation using Eq. 10

C(ai∕t,P12,l∕t=0.060) for geometry-specific FEM and for the compact representation using Eq. 10

Computed stress for input stress order=12 and l∕t=0.060 using compliance matrices from geometry-specific FEM and for the compact representation using Eq. 10

Residual stress in laser peened 316L stainless steel computed using a compact representation compliance matrix (left axis), and difference between stress computed using compact representation and geometry-specific FEM compliance matrices