J-Integral for Deep and Shallow Notches Under Torsion

J-integral has been calculated along the free-of-stress border of deep and shallow rounded notches under torsion, under the hypothesis of a linear elastic behaviour of the material. Two exact closed-form solutions have been obtained which make it explicit the influence of the notch opening angle and the notch root radius. When the notch root radius tends to zero the proposed solution matches the expression for the corresponding pointed V-notch case.