Abstract: For improving smooth transition of the elbow and keeping geometric modeling characteristics of the elbow, the equation of blending surfaces was established by the means of implicit geometric modeling. Adjustable function of controlling parameter increases freedom of blending surfaces modeling. Sudden changes of stresses at three conjunctions, which are the conjunction of anchor ring and small circular cylinder, the conjunction of small circular cylinder and blending surfaces, the conjunction of blending surfaces and big circular cylinder, are all very small by analyzing stresses of the elbow. This illustrates that bending effect of the elbow is good. It is feasible to use the blending surfaces for the elbow.

Key words: computer application, elbow surface modeling, blending surface, geometry modeling