Development of an analytical reference stress equation for inner-diameter defected curved plates in tension

The tensile failure behaviour of defected structures is determined by plastic collapse and fracture. Reference stress equations can be used to predict these failure modes. Up to now, some solutions have been developed for flat plates and pipes. For curved plates, which are applied for pipe girth weld testing, however, no solutions can be found in the literature. Therefore, the authors have developed a reference stress equation that applies for curved plates with a part-through defect, located centrally along the inner diameter. The solution is global, and similar to the Goodall and Webster equation for flat plates. This article elaborates the analytical development and studies the influence of all geometrical parameters, plate curvature in particular. It is found that the solution converges to the Goodall and Webster equation for increasingly flat plates, and allows larger tensile stresses for increasingly curved plates. Hence, the proposed equation is less conservative for inner-diameter defected curved plates than Goodall and Webster’s equivalent for flat plates. Nevertheless, the difference between Goodall and Webster’s solution and the proposed solution is fairly restricted (less than 5% for all considered geometries). An extensive validation of the proposed equation is part of current and future work. ► An analytical reference stress equation for inner-diameter defected curved plates in tension has been developed. ► The equation converges to the Goodall and Webster solution for flat plates. ► The equation calculates slightly lower reference stresses than the Goodall and Webster solution.