Layered fairing method for complex curved surface

Abstract

Disclosed is a layered fairing method for a complex curved surface. The method particularly includes the following steps: step 1, adopting a cubic B-spline curve to respectively interpolate given design data points to acquire all section shape lines namely tolerance baselines; step 2, fairing each section shape line, and lofting to acquire a reference curved surface; step 3, extracting three iso-curvature lines on the curved surface according to a preset method to serve as keel lines, respectively projecting the keel lines on a ruled surface of average normal vector span of curved surface points where the keel lines are positioned, and acquiring three projection keel lines; step 4, integrally fairing the projection keel lines in a projection plane according to a constraint condition that scaling, rotating and translation transformation of the section shape lines in a projection plane meets profile degree, position degree and torsional angle tolerance of the section shape lines to acquire transformation amount of the section shape lines, and re-lofting to acquire a faired curved surface. By the layered fairing method, the problem of fairing of the curved surface is converted into the problem of fairing of the section shape lines and the keel lines of the curved surface, so that the problem is greatly simplified, and the curved surface after being faired is ensured to be capable of meeting requirements on designing and processing.

Description

technical field [0001] The invention relates to a smoothing method for complex curved surfaces, in particular to a layered smoothing method for complex curved surfaces, and belongs to the technical field of CAD / CAM. Background technique [0002] The design data of important complex surface structural parts such as aero-engine blades are usually given in the form of discrete data points on the section line. These points are usually designed according to the needs of aerodynamic performance, and most points only consider their 0-order characteristics. However, the characteristics above the first order are not considered, so the surface fitted only by these data points is not smooth, which will lead to serious tool path fluctuations during NC machining, and affect the processing quality of complex surfaces such as blades. Therefore, for the design data of complex curved surfaces, in order to ensure the processing requirements, it is usually necessary to smooth them, that is, to...

AI Technical Summary

Problems solved by technology

On the other hand, the surface smoothing problem is an optimization design problem, which is difficult to converge when there are too many design variables

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