FATIGUE ASSESSMENT AND MONITORING OF A DENTED PIPELINE SPECIMEN

摘要

The present paper reports initial results from an investigation program launched with the objective of presenting combinations of analytical, experimental and numerical methods to predict and monitor fatigue initiation and fatigue damage progression in equipment such as pressure vessels, tanks, piping and pipelines with dents or complex shaped anomalies. The monitoring of fatigue initiation and propagation in the actual specimens used nondestructive infrared inspection techniques. Thermoelasticity stress analysis (TSA), three-dimensional digital image correlation (3D-DIC) and fiber optic Bragg strain gages (FBSG) were used to determine strains at fatigue hot spots locations. Strain fields determined from the experimental measurements and from finite element analysis (FEA) were combined with the fatigue Coffin-Manson strain-life equation and the Miner's fatigue damage rule to predict fatigue life (Nc). Results from one tested 3 m long tubular specimen containing a complex shaped dent are reported and fully analyzed.