In the process of production and service of pressure pipeline, local thinning defects may occur due to dielectric corrosion, manufacturing defects and other reasons. These defects reduce the carrying capacity of the pipeline and lead to leakage and rupture of the pipeline. Therefore, the integrity assessment of components and structures is required. Traditionally, the inelastic finite element method (FEM) is highly dependent on the specification of adequate mesh density and an assurance of numerically stable solutions. However, in engineering design, independent validation methods, such as Elastic Modulus Adjustment Procedures (EMAP), provide fast and stable solutions at relatively low cost. On the basis of elastic finite element analysis (FEA), the upper and lower bounds of limit load can be obtained by specifying the variations of elastic modulus in EMAP method. In this paper, an elastic modulus adjustment parameter $k$, which can improve the convergence of EMAP, is used to achieve stable convergence in the application of elbow with double defects. The EMAP method is also proved to be more efficient than the inelastic finite element analysis (FEA). Furthermore, the effect of defect size and distribution on the limit load of the elbow is studied.

在压力管道的生产和使用过程中，由于介质腐蚀、制造缺陷等原因，可能会出现局部变薄缺陷。这些缺陷降低了管道的承载能力，导致管道泄漏和破裂。因此，需要对构件和结构进行完整性评估。传统上，非弹性有限元方法 (FEM) 高度依赖于足够网格密度的规范和数值稳定解的保证。但是，在工程设计中，独立的验证方法，例如弹性模量调整程序 (EMAP)，可以以相对较低的成本提供快速稳定的解决方案。在弹性有限元分析（FEA）的基础上，极限载荷的上下限可以通过在 EMAP 方法中指定弹性模量的变化来获得。在本文中，弹性模量调整参数$克$可提高EMAP的收敛性，用于双缺陷弯头应用中实现稳定收敛。EMAP 方法也被证明比非弹性有限元分析 (FEA) 更有效。此外，研究了缺陷尺寸和分布对弯头极限载荷的影响。