Burst Failure Analysis of Pvc-Uh Pipes with Axial Surface Crack Based on Multiple Criteria

Abstract

High-performance unplasticized polyvinyl chloride (PVC-UH) offers superior strength and performance compared to PVC, making it a common choice for municipal water supply pipelines. Cracks in PVC-UH pipes are challenging to prevent throughout the entire production and maintenance process. Precise and applicable failure assessment criteria and residual bearing capacity calculation methods are crucial for ensuring the safe operation and maintenance of PVC-UH municipal water supply pipes. To this end, this paper conducted material uniaxial tensile tests, fracture toughness tests, and pipe burst tests. The study determined the true stress-strain relationship, fracture toughness, burst pressure, and fracture morphology of PVC-UH pipes through testing. Failure pressures of cracked PVC-UH pipes were forecasted using different criteria and methods, and their accuracy was evaluated by comparing predicted values with the results of bursting tests. Two calculation methods for determining the failure pressure of pipelines with an axial outer surface crack are proposed based on plastic deformation, damage factor, and fracture mechanics theory. These proposed calculation methods are compared against current methods for determining the failure pressure of pipelines with crack defects, highlighting the higher accuracy of the methods introduced in this paper. The proposed calculation methods can accurately and rapidly predict the failure pressure of pipelines with identified axial surface crack sizes, providing the theoretical underpinning for engineering safety assessments.

Keywords: PVC-UH pipe, axial surface crack, burst test, failure pressure, failure criterion, calculation theory