Unified correlation of in-plane and out-of-plane constraint with fracture resistance of a dissimilar metal welded joint

• Fracture resistance of two cracks in a dissimilar metal welded joint was measured.
• Area surrounded by equivalent plastic strain isoline ahead of crack tip was analyzed.
• A correlation of in-plane and out-of-plane constraint with toughness was obtained.
• A unified constraint parameter for geometry and material constraint was identified.

In this study, the fracture resistance of a dissimilar metal welded joint was measured by single edge-notched bend specimens with different in-plane and out-of-plane constraints. Based on the area surrounded by the equivalent plastic strain isoline ahead of a crack tip (a unified constraint parameter), a unified correlation of in-plane and out-of-plane constraint with fracture resistance of the dissimilar metal welded joint with local strength mismatch was established. The results show that the unified constraint parameter can characterize combining constraint composed of in-plane, out-of-plane and material constraint (local strength mismatch).