Abstract
A distribution pattern of inherent strains in long bead-on-plate welds, which has 3 unknown parameters for each inherent strain component, is proposed. Based on the proposed distribution pattern of inherent strains, the measurements for three dimensional residual stresses can be done as followings.
(1) 3 pieces of specimens T, Ly and Lz (named TLyLz Method) are cut from bead-on-plate weld and three dimensional inherent strain components are separated.
(2) Measurements are performed on T, Ly and Lz specimens respectively to estimate the inherent strain zones and the unknown parameters for their distributions.
(3) Three dimensional residual stresses are computed by using the inherent strains measured in step 2).
When inherent strains distribute in all thickness of plate, the measurements are performed only on T specimen (named T Method), and the inherent strain zones and their distributions can be estimated.
To verify TLyLz method and T method, numerical experiment and actual measurement are carried out respectively for mild steel and stainless steel bead-on-plate welds. The measured residual stresses by the new methods show very good accuracy compared with the values computed by thermal elastic-plastic analysis and those directly measured on the surface.
