A Transparent ASME B31.8-Based Strain Assessment Method Using 3D Measurement of Dent Morphology

This paper presents a comprehensive methodology to evaluate the geometric strain of pipeline in a dented area caused by mechanical damage. This methodology was formulated based on the approach recommended by ASME B31.8 and built the transparency of the entire process of dent strain assessment using three-dimensional (3D) measurement of dent morphology reported by the Caliper tools from in-line inspection (i.e., Caliper data). The 2D Fourier Transform in conjunction with band rejection filtering method was used to filter the signal noise and smooth the 3D morphology of dent. The cubic spline was utilized to characterize the discrete 2D longitudinal and circumferential profiles for curvature and arch length calculations, which were used to evaluate the bending strain and membrane strain, respectively. The effective strain was then calculated using the method recommended by ASME B31.8. To demonstrate the application of the methodology, a tool with user-friendly interface and powerful visualization and reporting functions was developed using the methodologies reported in this paper. The reported methodology enables development of dent strain assessment tool and benefit pipeline operators to facilitate dent integrity management program.