# Study on the Ultimate Load Capacity of Cu-Ni Alloy Pipelines with Double Pitting Defects

## TL;DR

This study evaluates how double pitting corrosion affects the strength of Cu-Ni alloy pipelines using simulations and tests.

## Contribution

A new model is proposed to predict the load capacity of Cu-Ni pipelines with double pitting defects, validated by experiments.

## Key findings

- The ultimate load capacity increases with greater distance between defects.
- The proposed model has a maximum error of 3%.
- Failure involves axial cracks and bulging deformation in double-defect pipelines.

## Abstract

To accurately evaluate the load-bearing capacity of Cu-Ni alloy pipelines with double pitting corrosion defects, in this study, the influence of dual-defect morphological parameters on the ultimate load capacity was investigated through finite element simulation. On the basis of the ultimate load capacity model for single pit defects and simulation results, an assessment model was developed for Cu-Ni alloy pipelines containing double pitting defects, and its accuracy was validated through hydrostatic burst tests. The results indicate that the ultimate load capacity increases gradually with increasing interdefect center distance, asymptotically approaching the load-bearing capacity of a single-defect pipeline with an equivalent depth and diameter. The proposed model demonstrates excellent predictive performance, with a maximum error margin within 3%. During failure, Cu-Ni alloy pipelines with double pitting defects develop fine axial cracks at the defect sites while exhibiting significant overall bulging deformation. These findings can be effectively applied to predict the ultimate load capacity of Cu-Ni alloy pipelines with double pitting defects, providing substantial engineering value for an accurate assessment of the load-bearing capacity of pipelines with actual corrosion defects.