Creep behaviour of butt-welded joints

A theoretical investigation has been made of the strains accumulating in the steady state creep of butt-welded joints. This was done by using a refined plate theory-Cosserat plate theory. Appropriate constitutive equations were developed for the theory which correspond to standard uniaxial and three-dimensional equations. In particular, a choice of Norton's Law, $\text{? = Aσ}{}^{\mathrm{n}}$ was made. Then, the plane strain problem of a plate containing a weld of different mechanical and creep properties was solved for the case of tensile loading. Results were obtained both numerically and analytically for a wide range of parameter values: for different ratios of the creep strengths, $\text{A}$, of the parent and weld metals, for values of the index, $\text{n}$, (including the limit $\text{n}$ → ∞) and for values of the length, $\text{l}$, of the weld (including the limit $\text{l}$ → 0).