DEFORMATION AND STRESS ANALYSIS OF VERTICAL STEEL SHELL OF TANKS BASED ON LASER SCANNING DATA

Abstract

The article considers a new technology of measurements of vertical steel tanks (ground-based laser scanning), which delivers a huge volume of unstructured information. There has been carried out a review of existing methods for solving tasks of tank walls' defomations determinations on laser reflec-tion point cloud. It is noted that the accuracy of laser scanning and scans' stitching is sufficient for tank walls' defomations determinations. The existing methods are implemented basically through building irregular triangular surfaces of tank shell on which then surface profiles are built manually or semi-automatically and the defomations are determined and compared to tolerance values. The au-thors suggest a method and algorithm for processing laser reflection point cloud, which by means of several infiltrations by height, radius tolerance and inclinations and interpolation by collocation meth-od is drawn to a rectangular topologically equivalent grid. These allow by several orders to decrease the information volume stored in the database, and regular grid model structure allows to apply numer-ical calculation method for calculating strains occurring in the tank walls. The strains are determined on semi-momentless theory for cylinder shell calculation. The method and algorithm are implemented in geodetic subsystem of automatic system of technical maintenance and repairs of equipment on the oil processing plant. The suggested method will allow in the future to move from normative assess-ment of technical tank state to the assessment on actual strains, which gives objective assessment of tank state for making substantiated decision on the prolongation of its exploitation, current mainte-nance and repair.