Q-stresses and constraint behavior of the notched cylindrical tensile specimen

A non-linear numerical analysis of sharp-notched cylindrical specimens under tensile loading was performed, and Q-stresses for various crack lengths were derived at a load level equal to the limit load, P 0. Single-material specimens, representing the base metal of a welded joint, and bi-material specimens, representing an overmatched weld at the site of the crack, were modeled. The results show that shallow-cracked specimens behave as in a plane-stress condition, whereas deeply cracked specimens tend to behave in a plane-strain fashion. The presence of a portion of material (weld metal volume fraction=1/3) with different deformation properties has the effect of raising the constraint on the specimen. The limiting ratio of the diameter of the notch, d, to the outer specimen diameter, D, for a change in the constraint behavior of the notched cylindrical specimens, appears to be of the order of d/ D≈0.50.