Research On Deformation Analysis Method Of Tank Surface Based On Point Cloud

Large-scale storage tanks are affected by factors such as uneven settlement,corrosion,high temperature,high pressure and fatigue brittleness,which may easily cause changes in tank tilt and displacement.The traditional method often evaluates the tank's deformation by observing the volume at different ring plates of the tank and the change of the ellipticity of the monitoring points,so as to evaluate the safety and health of the tank.These methods are not only inefficient,but also limited monitoring points are difficult to accurately reflect the deformation information of the tank.The research on using the surface point cloud data of the tank to calculate the tank ellipticity,perpendicularity to reflect the tank deformation information has made initial progress.In order to carry out a more comprehensive safety assessment of the tank,this paper takes the point cloud data as the research object,and conducts an in-depth study on the local deformation of the tank surface.(1)Aiming at the problem of deformation of tank surface,a uniform grid division method is proposed.The coordinates and normal vector parameters of the space grid are analyzed to reflect the deformation information of the tank surface.Firstly,the horizontal section of the tank is fitted to obtain the coordinates of the center of the circle,and the center line of the tank is fitted by the overall least squares algorithm.Then,based on the center line of the tank,the uniform spatial grid is divided by the angle and distance constraints of the discrete point cloud in the horizontal direction and the vertical direction,respectively.Finally,the central coordinate of all grids and the plane normal vector are used to judge the adjacent spatial grid relationship,and the grid with deformation information is obtained.(2)Aiming at the problem of tank surface deformation,a calculation method of deformation based on pentahedron is studied.Firstly,the Delaunay triangulation algorithm is used to construct a triangulation mesh for the deformed grid region,then project the point cloud to the center of the tank to form a plurality of pentahedrons,calculate the sum of all the pentahedron volumes in the grid,and calculate the difference from the theoretical volume.Finally,the deformation of the body surface obtains the deformation region and the overall deformation by traversing all the grids.The experimental results show that the local deformation region of the tank surface can be quickly located based on the central coordinate and normal vector variation of the grid.The deformation calculation method based on the pentahedron can accurately obtain the deformation of the deformation region of the tank.