Abstract
The Double Cantilever Beam (DCB) test method standardized in ANSI NACE TM0177 is increasingly applied as a quality assurance test to specify the performance of carbon and low alloy steels for sour service. The DCB test can contribute to the quantitative evaluation of fracture toughness in a specific environment via assessment of the crack arrest of a pre-cracked specimen. The test method has been modified and specified tightly from the view point of specimen geometry, test environment, and initial stress intensity factor controlled by arm displacement to obtain highly repeatable test results. In this paper, the influence of various side-groove root configurations on KISSC and Finite Element Analysis (FEA) results were focused upon, because different types of V notched side-groove roots are considered to change the stress concentration at the bottom of the side-groove and therefore affect the incidence of edge crack occurrence in the DCB test. On the other hand the KISSC value is not changed because the K value of different types of V notched side-groove configurations at the middle of of specimen thickness, is the same as a standard DCB test specimen. Decreasing the incidence of edge cracking with increasing V notched side-groove root is discussed from the viewpoint of fracture mechanics.